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[PATCH] W1: w1_netlink: New init/fini netlink callbacks.
[linux-2.6/verdex.git] / drivers / md / raid6main.c
blob495dee1d1e8335bcef634be427e0132bb596413e
1 /*
2 * raid6main.c : Multiple Devices driver for Linux
3 * Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
4 * Copyright (C) 1999, 2000 Ingo Molnar
5 * Copyright (C) 2002, 2003 H. Peter Anvin
6 *
7 * RAID-6 management functions. This code is derived from raid5.c.
8 * Last merge from raid5.c bkcvs version 1.79 (kernel 2.6.1).
9 *
10 * Thanks to Penguin Computing for making the RAID-6 development possible
11 * by donating a test server!
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
16 * any later version.
17 *
18 * You should have received a copy of the GNU General Public License
19 * (for example /usr/src/linux/COPYING); if not, write to the Free
20 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23
24 #include <linux/config.h>
25 #include <linux/module.h>
26 #include <linux/slab.h>
27 #include <linux/highmem.h>
28 #include <linux/bitops.h>
29 #include <asm/atomic.h>
30 #include "raid6.h"
31
32 /*
33 * Stripe cache
34 */
35
36 #define NR_STRIPES 256
37 #define STRIPE_SIZE PAGE_SIZE
38 #define STRIPE_SHIFT (PAGE_SHIFT - 9)
39 #define STRIPE_SECTORS (STRIPE_SIZE>>9)
40 #define IO_THRESHOLD 1
41 #define HASH_PAGES 1
42 #define HASH_PAGES_ORDER 0
43 #define NR_HASH (HASH_PAGES * PAGE_SIZE / sizeof(struct stripe_head *))
44 #define HASH_MASK (NR_HASH - 1)
45
46 #define stripe_hash(conf, sect) ((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK])
47
48 /* bio's attached to a stripe+device for I/O are linked together in bi_sector
49 * order without overlap. There may be several bio's per stripe+device, and
50 * a bio could span several devices.
51 * When walking this list for a particular stripe+device, we must never proceed
52 * beyond a bio that extends past this device, as the next bio might no longer
53 * be valid.
54 * This macro is used to determine the 'next' bio in the list, given the sector
55 * of the current stripe+device
56 */
57 #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL)
58 /*
59 * The following can be used to debug the driver
60 */
61 #define RAID6_DEBUG 0 /* Extremely verbose printk */
62 #define RAID6_PARANOIA 1 /* Check spinlocks */
63 #define RAID6_DUMPSTATE 0 /* Include stripe cache state in /proc/mdstat */
64 #if RAID6_PARANOIA && defined(CONFIG_SMP)
65 # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
66 #else
67 # define CHECK_DEVLOCK()
68 #endif
69
70 #define PRINTK(x...) ((void)(RAID6_DEBUG && printk(KERN_DEBUG x)))
71 #if RAID6_DEBUG
72 #undef inline
73 #undef __inline__
74 #define inline
75 #define __inline__
76 #endif
77
78 #if !RAID6_USE_EMPTY_ZERO_PAGE
79 /* In .bss so it's zeroed */
80 const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
81 #endif
82
83 static inline int raid6_next_disk(int disk, int raid_disks)
84 {
85 disk++;
86 return (disk < raid_disks) ? disk : 0;
87 }
88
89 static void print_raid6_conf (raid6_conf_t *conf);
90
91 static inline void __release_stripe(raid6_conf_t *conf, struct stripe_head *sh)
92 {
93 if (atomic_dec_and_test(&sh->count)) {
94 if (!list_empty(&sh->lru))
95 BUG();
96 if (atomic_read(&conf->active_stripes)==0)
97 BUG();
98 if (test_bit(STRIPE_HANDLE, &sh->state)) {
99 if (test_bit(STRIPE_DELAYED, &sh->state))
100 list_add_tail(&sh->lru, &conf->delayed_list);
101 else
102 list_add_tail(&sh->lru, &conf->handle_list);
103 md_wakeup_thread(conf->mddev->thread);
104 } else {
105 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
106 atomic_dec(&conf->preread_active_stripes);
107 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
108 md_wakeup_thread(conf->mddev->thread);
109 }
110 list_add_tail(&sh->lru, &conf->inactive_list);
111 atomic_dec(&conf->active_stripes);
112 if (!conf->inactive_blocked ||
113 atomic_read(&conf->active_stripes) < (NR_STRIPES*3/4))
114 wake_up(&conf->wait_for_stripe);
115 }
116 }
117 }
118 static void release_stripe(struct stripe_head *sh)
119 {
120 raid6_conf_t *conf = sh->raid_conf;
121 unsigned long flags;
122
123 spin_lock_irqsave(&conf->device_lock, flags);
124 __release_stripe(conf, sh);
125 spin_unlock_irqrestore(&conf->device_lock, flags);
126 }
127
128 static void remove_hash(struct stripe_head *sh)
129 {
130 PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector);
131
132 if (sh->hash_pprev) {
133 if (sh->hash_next)
134 sh->hash_next->hash_pprev = sh->hash_pprev;
135 *sh->hash_pprev = sh->hash_next;
136 sh->hash_pprev = NULL;
137 }
138 }
139
140 static __inline__ void insert_hash(raid6_conf_t *conf, struct stripe_head *sh)
141 {
142 struct stripe_head **shp = &stripe_hash(conf, sh->sector);
143
144 PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector);
145
146 CHECK_DEVLOCK();
147 if ((sh->hash_next = *shp) != NULL)
148 (*shp)->hash_pprev = &sh->hash_next;
149 *shp = sh;
150 sh->hash_pprev = shp;
151 }
152
153
154 /* find an idle stripe, make sure it is unhashed, and return it. */
155 static struct stripe_head *get_free_stripe(raid6_conf_t *conf)
156 {
157 struct stripe_head *sh = NULL;
158 struct list_head *first;
159
160 CHECK_DEVLOCK();
161 if (list_empty(&conf->inactive_list))
162 goto out;
163 first = conf->inactive_list.next;
164 sh = list_entry(first, struct stripe_head, lru);
165 list_del_init(first);
166 remove_hash(sh);
167 atomic_inc(&conf->active_stripes);
168 out:
169 return sh;
170 }
171
172 static void shrink_buffers(struct stripe_head *sh, int num)
173 {
174 struct page *p;
175 int i;
176
177 for (i=0; i<num ; i++) {
178 p = sh->dev[i].page;
179 if (!p)
180 continue;
181 sh->dev[i].page = NULL;
182 page_cache_release(p);
183 }
184 }
185
186 static int grow_buffers(struct stripe_head *sh, int num)
187 {
188 int i;
189
190 for (i=0; i<num; i++) {
191 struct page *page;
192
193 if (!(page = alloc_page(GFP_KERNEL))) {
194 return 1;
195 }
196 sh->dev[i].page = page;
197 }
198 return 0;
199 }
200
201 static void raid6_build_block (struct stripe_head *sh, int i);
202
203 static inline void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx)
204 {
205 raid6_conf_t *conf = sh->raid_conf;
206 int disks = conf->raid_disks, i;
207
208 if (atomic_read(&sh->count) != 0)
209 BUG();
210 if (test_bit(STRIPE_HANDLE, &sh->state))
211 BUG();
212
213 CHECK_DEVLOCK();
214 PRINTK("init_stripe called, stripe %llu\n",
215 (unsigned long long)sh->sector);
216
217 remove_hash(sh);
218
219 sh->sector = sector;
220 sh->pd_idx = pd_idx;
221 sh->state = 0;
222
223 for (i=disks; i--; ) {
224 struct r5dev *dev = &sh->dev[i];
225
226 if (dev->toread || dev->towrite || dev->written ||
227 test_bit(R5_LOCKED, &dev->flags)) {
228 PRINTK("sector=%llx i=%d %p %p %p %d\n",
229 (unsigned long long)sh->sector, i, dev->toread,
230 dev->towrite, dev->written,
231 test_bit(R5_LOCKED, &dev->flags));
232 BUG();
233 }
234 dev->flags = 0;
235 raid6_build_block(sh, i);
236 }
237 insert_hash(conf, sh);
238 }
239
240 static struct stripe_head *__find_stripe(raid6_conf_t *conf, sector_t sector)
241 {
242 struct stripe_head *sh;
243
244 CHECK_DEVLOCK();
245 PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector);
246 for (sh = stripe_hash(conf, sector); sh; sh = sh->hash_next)
247 if (sh->sector == sector)
248 return sh;
249 PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector);
250 return NULL;
251 }
252
253 static void unplug_slaves(mddev_t *mddev);
254
255 static struct stripe_head *get_active_stripe(raid6_conf_t *conf, sector_t sector,
256 int pd_idx, int noblock)
257 {
258 struct stripe_head *sh;
259
260 PRINTK("get_stripe, sector %llu\n", (unsigned long long)sector);
261
262 spin_lock_irq(&conf->device_lock);
263
264 do {
265 sh = __find_stripe(conf, sector);
266 if (!sh) {
267 if (!conf->inactive_blocked)
268 sh = get_free_stripe(conf);
269 if (noblock && sh == NULL)
270 break;
271 if (!sh) {
272 conf->inactive_blocked = 1;
273 wait_event_lock_irq(conf->wait_for_stripe,
274 !list_empty(&conf->inactive_list) &&
275 (atomic_read(&conf->active_stripes) < (NR_STRIPES *3/4)
276 || !conf->inactive_blocked),
277 conf->device_lock,
278 unplug_slaves(conf->mddev);
279 );
280 conf->inactive_blocked = 0;
281 } else
282 init_stripe(sh, sector, pd_idx);
283 } else {
284 if (atomic_read(&sh->count)) {
285 if (!list_empty(&sh->lru))
286 BUG();
287 } else {
288 if (!test_bit(STRIPE_HANDLE, &sh->state))
289 atomic_inc(&conf->active_stripes);
290 if (list_empty(&sh->lru))
291 BUG();
292 list_del_init(&sh->lru);
293 }
294 }
295 } while (sh == NULL);
296
297 if (sh)
298 atomic_inc(&sh->count);
299
300 spin_unlock_irq(&conf->device_lock);
301 return sh;
302 }
303
304 static int grow_stripes(raid6_conf_t *conf, int num)
305 {
306 struct stripe_head *sh;
307 kmem_cache_t *sc;
308 int devs = conf->raid_disks;
309
310 sprintf(conf->cache_name, "raid6/%s", mdname(conf->mddev));
311
312 sc = kmem_cache_create(conf->cache_name,
313 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
314 0, 0, NULL, NULL);
315 if (!sc)
316 return 1;
317 conf->slab_cache = sc;
318 while (num--) {
319 sh = kmem_cache_alloc(sc, GFP_KERNEL);
320 if (!sh)
321 return 1;
322 memset(sh, 0, sizeof(*sh) + (devs-1)*sizeof(struct r5dev));
323 sh->raid_conf = conf;
324 spin_lock_init(&sh->lock);
325
326 if (grow_buffers(sh, conf->raid_disks)) {
327 shrink_buffers(sh, conf->raid_disks);
328 kmem_cache_free(sc, sh);
329 return 1;
330 }
331 /* we just created an active stripe so... */
332 atomic_set(&sh->count, 1);
333 atomic_inc(&conf->active_stripes);
334 INIT_LIST_HEAD(&sh->lru);
335 release_stripe(sh);
336 }
337 return 0;
338 }
339
340 static void shrink_stripes(raid6_conf_t *conf)
341 {
342 struct stripe_head *sh;
343
344 while (1) {
345 spin_lock_irq(&conf->device_lock);
346 sh = get_free_stripe(conf);
347 spin_unlock_irq(&conf->device_lock);
348 if (!sh)
349 break;
350 if (atomic_read(&sh->count))
351 BUG();
352 shrink_buffers(sh, conf->raid_disks);
353 kmem_cache_free(conf->slab_cache, sh);
354 atomic_dec(&conf->active_stripes);
355 }
356 kmem_cache_destroy(conf->slab_cache);
357 conf->slab_cache = NULL;
358 }
359
360 static int raid6_end_read_request (struct bio * bi, unsigned int bytes_done,
361 int error)
362 {
363 struct stripe_head *sh = bi->bi_private;
364 raid6_conf_t *conf = sh->raid_conf;
365 int disks = conf->raid_disks, i;
366 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
367
368 if (bi->bi_size)
369 return 1;
370
371 for (i=0 ; i<disks; i++)
372 if (bi == &sh->dev[i].req)
373 break;
374
375 PRINTK("end_read_request %llu/%d, count: %d, uptodate %d.\n",
376 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
377 uptodate);
378 if (i == disks) {
379 BUG();
380 return 0;
381 }
382
383 if (uptodate) {
384 #if 0
385 struct bio *bio;
386 unsigned long flags;
387 spin_lock_irqsave(&conf->device_lock, flags);
388 /* we can return a buffer if we bypassed the cache or
389 * if the top buffer is not in highmem. If there are
390 * multiple buffers, leave the extra work to
391 * handle_stripe
392 */
393 buffer = sh->bh_read[i];
394 if (buffer &&
395 (!PageHighMem(buffer->b_page)
396 || buffer->b_page == bh->b_page )
397 ) {
398 sh->bh_read[i] = buffer->b_reqnext;
399 buffer->b_reqnext = NULL;
400 } else
401 buffer = NULL;
402 spin_unlock_irqrestore(&conf->device_lock, flags);
403 if (sh->bh_page[i]==bh->b_page)
404 set_buffer_uptodate(bh);
405 if (buffer) {
406 if (buffer->b_page != bh->b_page)
407 memcpy(buffer->b_data, bh->b_data, bh->b_size);
408 buffer->b_end_io(buffer, 1);
409 }
410 #else
411 set_bit(R5_UPTODATE, &sh->dev[i].flags);
412 #endif
413 } else {
414 md_error(conf->mddev, conf->disks[i].rdev);
415 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
416 }
417 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
418 #if 0
419 /* must restore b_page before unlocking buffer... */
420 if (sh->bh_page[i] != bh->b_page) {
421 bh->b_page = sh->bh_page[i];
422 bh->b_data = page_address(bh->b_page);
423 clear_buffer_uptodate(bh);
424 }
425 #endif
426 clear_bit(R5_LOCKED, &sh->dev[i].flags);
427 set_bit(STRIPE_HANDLE, &sh->state);
428 release_stripe(sh);
429 return 0;
430 }
431
432 static int raid6_end_write_request (struct bio *bi, unsigned int bytes_done,
433 int error)
434 {
435 struct stripe_head *sh = bi->bi_private;
436 raid6_conf_t *conf = sh->raid_conf;
437 int disks = conf->raid_disks, i;
438 unsigned long flags;
439 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
440
441 if (bi->bi_size)
442 return 1;
443
444 for (i=0 ; i<disks; i++)
445 if (bi == &sh->dev[i].req)
446 break;
447
448 PRINTK("end_write_request %llu/%d, count %d, uptodate: %d.\n",
449 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
450 uptodate);
451 if (i == disks) {
452 BUG();
453 return 0;
454 }
455
456 spin_lock_irqsave(&conf->device_lock, flags);
457 if (!uptodate)
458 md_error(conf->mddev, conf->disks[i].rdev);
459
460 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
461
462 clear_bit(R5_LOCKED, &sh->dev[i].flags);
463 set_bit(STRIPE_HANDLE, &sh->state);
464 __release_stripe(conf, sh);
465 spin_unlock_irqrestore(&conf->device_lock, flags);
466 return 0;
467 }
468
469
470 static sector_t compute_blocknr(struct stripe_head *sh, int i);
471
472 static void raid6_build_block (struct stripe_head *sh, int i)
473 {
474 struct r5dev *dev = &sh->dev[i];
475 int pd_idx = sh->pd_idx;
476 int qd_idx = raid6_next_disk(pd_idx, sh->raid_conf->raid_disks);
477
478 bio_init(&dev->req);
479 dev->req.bi_io_vec = &dev->vec;
480 dev->req.bi_vcnt++;
481 dev->req.bi_max_vecs++;
482 dev->vec.bv_page = dev->page;
483 dev->vec.bv_len = STRIPE_SIZE;
484 dev->vec.bv_offset = 0;
485
486 dev->req.bi_sector = sh->sector;
487 dev->req.bi_private = sh;
488
489 dev->flags = 0;
490 if (i != pd_idx && i != qd_idx)
491 dev->sector = compute_blocknr(sh, i);
492 }
493
494 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
495 {
496 char b[BDEVNAME_SIZE];
497 raid6_conf_t *conf = (raid6_conf_t *) mddev->private;
498 PRINTK("raid6: error called\n");
499
500 if (!rdev->faulty) {
501 mddev->sb_dirty = 1;
502 if (rdev->in_sync) {
503 conf->working_disks--;
504 mddev->degraded++;
505 conf->failed_disks++;
506 rdev->in_sync = 0;
507 /*
508 * if recovery was running, make sure it aborts.
509 */
510 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
511 }
512 rdev->faulty = 1;
513 printk (KERN_ALERT
514 "raid6: Disk failure on %s, disabling device."
515 " Operation continuing on %d devices\n",
516 bdevname(rdev->bdev,b), conf->working_disks);
517 }
518 }
519
520 /*
521 * Input: a 'big' sector number,
522 * Output: index of the data and parity disk, and the sector # in them.
523 */
524 static sector_t raid6_compute_sector(sector_t r_sector, unsigned int raid_disks,
525 unsigned int data_disks, unsigned int * dd_idx,
526 unsigned int * pd_idx, raid6_conf_t *conf)
527 {
528 long stripe;
529 unsigned long chunk_number;
530 unsigned int chunk_offset;
531 sector_t new_sector;
532 int sectors_per_chunk = conf->chunk_size >> 9;
533
534 /* First compute the information on this sector */
535
536 /*
537 * Compute the chunk number and the sector offset inside the chunk
538 */
539 chunk_offset = sector_div(r_sector, sectors_per_chunk);
540 chunk_number = r_sector;
541 if ( r_sector != chunk_number ) {
542 printk(KERN_CRIT "raid6: ERROR: r_sector = %llu, chunk_number = %lu\n",
543 (unsigned long long)r_sector, (unsigned long)chunk_number);
544 BUG();
545 }
546
547 /*
548 * Compute the stripe number
549 */
550 stripe = chunk_number / data_disks;
551
552 /*
553 * Compute the data disk and parity disk indexes inside the stripe
554 */
555 *dd_idx = chunk_number % data_disks;
556
557 /*
558 * Select the parity disk based on the user selected algorithm.
559 */
560
561 /**** FIX THIS ****/
562 switch (conf->algorithm) {
563 case ALGORITHM_LEFT_ASYMMETRIC:
564 *pd_idx = raid_disks - 1 - (stripe % raid_disks);
565 if (*pd_idx == raid_disks-1)
566 (*dd_idx)++; /* Q D D D P */
567 else if (*dd_idx >= *pd_idx)
568 (*dd_idx) += 2; /* D D P Q D */
569 break;
570 case ALGORITHM_RIGHT_ASYMMETRIC:
571 *pd_idx = stripe % raid_disks;
572 if (*pd_idx == raid_disks-1)
573 (*dd_idx)++; /* Q D D D P */
574 else if (*dd_idx >= *pd_idx)
575 (*dd_idx) += 2; /* D D P Q D */
576 break;
577 case ALGORITHM_LEFT_SYMMETRIC:
578 *pd_idx = raid_disks - 1 - (stripe % raid_disks);
579 *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
580 break;
581 case ALGORITHM_RIGHT_SYMMETRIC:
582 *pd_idx = stripe % raid_disks;
583 *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
584 break;
585 default:
586 printk (KERN_CRIT "raid6: unsupported algorithm %d\n",
587 conf->algorithm);
588 }
589
590 PRINTK("raid6: chunk_number = %lu, pd_idx = %u, dd_idx = %u\n",
591 chunk_number, *pd_idx, *dd_idx);
592
593 /*
594 * Finally, compute the new sector number
595 */
596 new_sector = (sector_t) stripe * sectors_per_chunk + chunk_offset;
597 return new_sector;
598 }
599
600
601 static sector_t compute_blocknr(struct stripe_head *sh, int i)
602 {
603 raid6_conf_t *conf = sh->raid_conf;
604 int raid_disks = conf->raid_disks, data_disks = raid_disks - 2;
605 sector_t new_sector = sh->sector, check;
606 int sectors_per_chunk = conf->chunk_size >> 9;
607 sector_t stripe;
608 int chunk_offset;
609 int chunk_number, dummy1, dummy2, dd_idx = i;
610 sector_t r_sector;
611 int i0 = i;
612
613 chunk_offset = sector_div(new_sector, sectors_per_chunk);
614 stripe = new_sector;
615 if ( new_sector != stripe ) {
616 printk(KERN_CRIT "raid6: ERROR: new_sector = %llu, stripe = %lu\n",
617 (unsigned long long)new_sector, (unsigned long)stripe);
618 BUG();
619 }
620
621 switch (conf->algorithm) {
622 case ALGORITHM_LEFT_ASYMMETRIC:
623 case ALGORITHM_RIGHT_ASYMMETRIC:
624 if (sh->pd_idx == raid_disks-1)
625 i--; /* Q D D D P */
626 else if (i > sh->pd_idx)
627 i -= 2; /* D D P Q D */
628 break;
629 case ALGORITHM_LEFT_SYMMETRIC:
630 case ALGORITHM_RIGHT_SYMMETRIC:
631 if (sh->pd_idx == raid_disks-1)
632 i--; /* Q D D D P */
633 else {
634 /* D D P Q D */
635 if (i < sh->pd_idx)
636 i += raid_disks;
637 i -= (sh->pd_idx + 2);
638 }
639 break;
640 default:
641 printk (KERN_CRIT "raid6: unsupported algorithm %d\n",
642 conf->algorithm);
643 }
644
645 PRINTK("raid6: compute_blocknr: pd_idx = %u, i0 = %u, i = %u\n", sh->pd_idx, i0, i);
646
647 chunk_number = stripe * data_disks + i;
648 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
649
650 check = raid6_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
651 if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
652 printk(KERN_CRIT "raid6: compute_blocknr: map not correct\n");
653 return 0;
654 }
655 return r_sector;
656 }
657
658
659
660 /*
661 * Copy data between a page in the stripe cache, and one or more bion
662 * The page could align with the middle of the bio, or there could be
663 * several bion, each with several bio_vecs, which cover part of the page
664 * Multiple bion are linked together on bi_next. There may be extras
665 * at the end of this list. We ignore them.
666 */
667 static void copy_data(int frombio, struct bio *bio,
668 struct page *page,
669 sector_t sector)
670 {
671 char *pa = page_address(page);
672 struct bio_vec *bvl;
673 int i;
674 int page_offset;
675
676 if (bio->bi_sector >= sector)
677 page_offset = (signed)(bio->bi_sector - sector) * 512;
678 else
679 page_offset = (signed)(sector - bio->bi_sector) * -512;
680 bio_for_each_segment(bvl, bio, i) {
681 int len = bio_iovec_idx(bio,i)->bv_len;
682 int clen;
683 int b_offset = 0;
684
685 if (page_offset < 0) {
686 b_offset = -page_offset;
687 page_offset += b_offset;
688 len -= b_offset;
689 }
690
691 if (len > 0 && page_offset + len > STRIPE_SIZE)
692 clen = STRIPE_SIZE - page_offset;
693 else clen = len;
694
695 if (clen > 0) {
696 char *ba = __bio_kmap_atomic(bio, i, KM_USER0);
697 if (frombio)
698 memcpy(pa+page_offset, ba+b_offset, clen);
699 else
700 memcpy(ba+b_offset, pa+page_offset, clen);
701 __bio_kunmap_atomic(ba, KM_USER0);
702 }
703 if (clen < len) /* hit end of page */
704 break;
705 page_offset += len;
706 }
707 }
708
709 #define check_xor() do { \
710 if (count == MAX_XOR_BLOCKS) { \
711 xor_block(count, STRIPE_SIZE, ptr); \
712 count = 1; \
713 } \
714 } while(0)
715
716 /* Compute P and Q syndromes */
717 static void compute_parity(struct stripe_head *sh, int method)
718 {
719 raid6_conf_t *conf = sh->raid_conf;
720 int i, pd_idx = sh->pd_idx, qd_idx, d0_idx, disks = conf->raid_disks, count;
721 struct bio *chosen;
722 /**** FIX THIS: This could be very bad if disks is close to 256 ****/
723 void *ptrs[disks];
724
725 qd_idx = raid6_next_disk(pd_idx, disks);
726 d0_idx = raid6_next_disk(qd_idx, disks);
727
728 PRINTK("compute_parity, stripe %llu, method %d\n",
729 (unsigned long long)sh->sector, method);
730
731 switch(method) {
732 case READ_MODIFY_WRITE:
733 BUG(); /* READ_MODIFY_WRITE N/A for RAID-6 */
734 case RECONSTRUCT_WRITE:
735 for (i= disks; i-- ;)
736 if ( i != pd_idx && i != qd_idx && sh->dev[i].towrite ) {
737 chosen = sh->dev[i].towrite;
738 sh->dev[i].towrite = NULL;
739
740 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
741 wake_up(&conf->wait_for_overlap);
742
743 if (sh->dev[i].written) BUG();
744 sh->dev[i].written = chosen;
745 }
746 break;
747 case CHECK_PARITY:
748 BUG(); /* Not implemented yet */
749 }
750
751 for (i = disks; i--;)
752 if (sh->dev[i].written) {
753 sector_t sector = sh->dev[i].sector;
754 struct bio *wbi = sh->dev[i].written;
755 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
756 copy_data(1, wbi, sh->dev[i].page, sector);
757 wbi = r5_next_bio(wbi, sector);
758 }
759
760 set_bit(R5_LOCKED, &sh->dev[i].flags);
761 set_bit(R5_UPTODATE, &sh->dev[i].flags);
762 }
763
764 // switch(method) {
765 // case RECONSTRUCT_WRITE:
766 // case CHECK_PARITY:
767 // case UPDATE_PARITY:
768 /* Note that unlike RAID-5, the ordering of the disks matters greatly. */
769 /* FIX: Is this ordering of drives even remotely optimal? */
770 count = 0;
771 i = d0_idx;
772 do {
773 ptrs[count++] = page_address(sh->dev[i].page);
774 if (count <= disks-2 && !test_bit(R5_UPTODATE, &sh->dev[i].flags))
775 printk("block %d/%d not uptodate on parity calc\n", i,count);
776 i = raid6_next_disk(i, disks);
777 } while ( i != d0_idx );
778 // break;
779 // }
780
781 raid6_call.gen_syndrome(disks, STRIPE_SIZE, ptrs);
782
783 switch(method) {
784 case RECONSTRUCT_WRITE:
785 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
786 set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
787 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
788 set_bit(R5_LOCKED, &sh->dev[qd_idx].flags);
789 break;
790 case UPDATE_PARITY:
791 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
792 set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
793 break;
794 }
795 }
796
797 /* Compute one missing block */
798 static void compute_block_1(struct stripe_head *sh, int dd_idx)
799 {
800 raid6_conf_t *conf = sh->raid_conf;
801 int i, count, disks = conf->raid_disks;
802 void *ptr[MAX_XOR_BLOCKS], *p;
803 int pd_idx = sh->pd_idx;
804 int qd_idx = raid6_next_disk(pd_idx, disks);
805
806 PRINTK("compute_block_1, stripe %llu, idx %d\n",
807 (unsigned long long)sh->sector, dd_idx);
808
809 if ( dd_idx == qd_idx ) {
810 /* We're actually computing the Q drive */
811 compute_parity(sh, UPDATE_PARITY);
812 } else {
813 ptr[0] = page_address(sh->dev[dd_idx].page);
814 memset(ptr[0], 0, STRIPE_SIZE);
815 count = 1;
816 for (i = disks ; i--; ) {
817 if (i == dd_idx || i == qd_idx)
818 continue;
819 p = page_address(sh->dev[i].page);
820 if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
821 ptr[count++] = p;
822 else
823 printk("compute_block() %d, stripe %llu, %d"
824 " not present\n", dd_idx,
825 (unsigned long long)sh->sector, i);
826
827 check_xor();
828 }
829 if (count != 1)
830 xor_block(count, STRIPE_SIZE, ptr);
831 set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
832 }
833 }
834
835 /* Compute two missing blocks */
836 static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
837 {
838 raid6_conf_t *conf = sh->raid_conf;
839 int i, count, disks = conf->raid_disks;
840 int pd_idx = sh->pd_idx;
841 int qd_idx = raid6_next_disk(pd_idx, disks);
842 int d0_idx = raid6_next_disk(qd_idx, disks);
843 int faila, failb;
844
845 /* faila and failb are disk numbers relative to d0_idx */
846 /* pd_idx become disks-2 and qd_idx become disks-1 */
847 faila = (dd_idx1 < d0_idx) ? dd_idx1+(disks-d0_idx) : dd_idx1-d0_idx;
848 failb = (dd_idx2 < d0_idx) ? dd_idx2+(disks-d0_idx) : dd_idx2-d0_idx;
849
850 BUG_ON(faila == failb);
851 if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; }
852
853 PRINTK("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n",
854 (unsigned long long)sh->sector, dd_idx1, dd_idx2, faila, failb);
855
856 if ( failb == disks-1 ) {
857 /* Q disk is one of the missing disks */
858 if ( faila == disks-2 ) {
859 /* Missing P+Q, just recompute */
860 compute_parity(sh, UPDATE_PARITY);
861 return;
862 } else {
863 /* We're missing D+Q; recompute D from P */
864 compute_block_1(sh, (dd_idx1 == qd_idx) ? dd_idx2 : dd_idx1);
865 compute_parity(sh, UPDATE_PARITY); /* Is this necessary? */
866 return;
867 }
868 }
869
870 /* We're missing D+P or D+D; build pointer table */
871 {
872 /**** FIX THIS: This could be very bad if disks is close to 256 ****/
873 void *ptrs[disks];
874
875 count = 0;
876 i = d0_idx;
877 do {
878 ptrs[count++] = page_address(sh->dev[i].page);
879 i = raid6_next_disk(i, disks);
880 if (i != dd_idx1 && i != dd_idx2 &&
881 !test_bit(R5_UPTODATE, &sh->dev[i].flags))
882 printk("compute_2 with missing block %d/%d\n", count, i);
883 } while ( i != d0_idx );
884
885 if ( failb == disks-2 ) {
886 /* We're missing D+P. */
887 raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs);
888 } else {
889 /* We're missing D+D. */
890 raid6_2data_recov(disks, STRIPE_SIZE, faila, failb, ptrs);
891 }
892
893 /* Both the above update both missing blocks */
894 set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags);
895 set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags);
896 }
897 }
898
899
900 /*
901 * Each stripe/dev can have one or more bion attached.
902 * toread/towrite point to the first in a chain.
903 * The bi_next chain must be in order.
904 */
905 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
906 {
907 struct bio **bip;
908 raid6_conf_t *conf = sh->raid_conf;
909
910 PRINTK("adding bh b#%llu to stripe s#%llu\n",
911 (unsigned long long)bi->bi_sector,
912 (unsigned long long)sh->sector);
913
914
915 spin_lock(&sh->lock);
916 spin_lock_irq(&conf->device_lock);
917 if (forwrite)
918 bip = &sh->dev[dd_idx].towrite;
919 else
920 bip = &sh->dev[dd_idx].toread;
921 while (*bip && (*bip)->bi_sector < bi->bi_sector) {
922 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
923 goto overlap;
924 bip = &(*bip)->bi_next;
925 }
926 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
927 goto overlap;
928
929 if (*bip && bi->bi_next && (*bip) != bi->bi_next)
930 BUG();
931 if (*bip)
932 bi->bi_next = *bip;
933 *bip = bi;
934 bi->bi_phys_segments ++;
935 spin_unlock_irq(&conf->device_lock);
936 spin_unlock(&sh->lock);
937
938 PRINTK("added bi b#%llu to stripe s#%llu, disk %d.\n",
939 (unsigned long long)bi->bi_sector,
940 (unsigned long long)sh->sector, dd_idx);
941
942 if (forwrite) {
943 /* check if page is covered */
944 sector_t sector = sh->dev[dd_idx].sector;
945 for (bi=sh->dev[dd_idx].towrite;
946 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
947 bi && bi->bi_sector <= sector;
948 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
949 if (bi->bi_sector + (bi->bi_size>>9) >= sector)
950 sector = bi->bi_sector + (bi->bi_size>>9);
951 }
952 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
953 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
954 }
955 return 1;
956
957 overlap:
958 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
959 spin_unlock_irq(&conf->device_lock);
960 spin_unlock(&sh->lock);
961 return 0;
962 }
963
964
965 /*
966 * handle_stripe - do things to a stripe.
967 *
968 * We lock the stripe and then examine the state of various bits
969 * to see what needs to be done.
970 * Possible results:
971 * return some read request which now have data
972 * return some write requests which are safely on disc
973 * schedule a read on some buffers
974 * schedule a write of some buffers
975 * return confirmation of parity correctness
976 *
977 * Parity calculations are done inside the stripe lock
978 * buffers are taken off read_list or write_list, and bh_cache buffers
979 * get BH_Lock set before the stripe lock is released.
980 *
981 */
982
983 static void handle_stripe(struct stripe_head *sh)
984 {
985 raid6_conf_t *conf = sh->raid_conf;
986 int disks = conf->raid_disks;
987 struct bio *return_bi= NULL;
988 struct bio *bi;
989 int i;
990 int syncing;
991 int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
992 int non_overwrite = 0;
993 int failed_num[2] = {0, 0};
994 struct r5dev *dev, *pdev, *qdev;
995 int pd_idx = sh->pd_idx;
996 int qd_idx = raid6_next_disk(pd_idx, disks);
997 int p_failed, q_failed;
998
999 PRINTK("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d, qd_idx=%d\n",
1000 (unsigned long long)sh->sector, sh->state, atomic_read(&sh->count),
1001 pd_idx, qd_idx);
1002
1003 spin_lock(&sh->lock);
1004 clear_bit(STRIPE_HANDLE, &sh->state);
1005 clear_bit(STRIPE_DELAYED, &sh->state);
1006
1007 syncing = test_bit(STRIPE_SYNCING, &sh->state);
1008 /* Now to look around and see what can be done */
1009
1010 for (i=disks; i--; ) {
1011 mdk_rdev_t *rdev;
1012 dev = &sh->dev[i];
1013 clear_bit(R5_Insync, &dev->flags);
1014 clear_bit(R5_Syncio, &dev->flags);
1015
1016 PRINTK("check %d: state 0x%lx read %p write %p written %p\n",
1017 i, dev->flags, dev->toread, dev->towrite, dev->written);
1018 /* maybe we can reply to a read */
1019 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
1020 struct bio *rbi, *rbi2;
1021 PRINTK("Return read for disc %d\n", i);
1022 spin_lock_irq(&conf->device_lock);
1023 rbi = dev->toread;
1024 dev->toread = NULL;
1025 if (test_and_clear_bit(R5_Overlap, &dev->flags))
1026 wake_up(&conf->wait_for_overlap);
1027 spin_unlock_irq(&conf->device_lock);
1028 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) {
1029 copy_data(0, rbi, dev->page, dev->sector);
1030 rbi2 = r5_next_bio(rbi, dev->sector);
1031 spin_lock_irq(&conf->device_lock);
1032 if (--rbi->bi_phys_segments == 0) {
1033 rbi->bi_next = return_bi;
1034 return_bi = rbi;
1035 }
1036 spin_unlock_irq(&conf->device_lock);
1037 rbi = rbi2;
1038 }
1039 }
1040
1041 /* now count some things */
1042 if (test_bit(R5_LOCKED, &dev->flags)) locked++;
1043 if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
1044
1045
1046 if (dev->toread) to_read++;
1047 if (dev->towrite) {
1048 to_write++;
1049 if (!test_bit(R5_OVERWRITE, &dev->flags))
1050 non_overwrite++;
1051 }
1052 if (dev->written) written++;
1053 rdev = conf->disks[i].rdev; /* FIXME, should I be looking rdev */
1054 if (!rdev || !rdev->in_sync) {
1055 if ( failed < 2 )
1056 failed_num[failed] = i;
1057 failed++;
1058 } else
1059 set_bit(R5_Insync, &dev->flags);
1060 }
1061 PRINTK("locked=%d uptodate=%d to_read=%d"
1062 " to_write=%d failed=%d failed_num=%d,%d\n",
1063 locked, uptodate, to_read, to_write, failed,
1064 failed_num[0], failed_num[1]);
1065 /* check if the array has lost >2 devices and, if so, some requests might
1066 * need to be failed
1067 */
1068 if (failed > 2 && to_read+to_write+written) {
1069 spin_lock_irq(&conf->device_lock);
1070 for (i=disks; i--; ) {
1071 /* fail all writes first */
1072 bi = sh->dev[i].towrite;
1073 sh->dev[i].towrite = NULL;
1074 if (bi) to_write--;
1075
1076 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1077 wake_up(&conf->wait_for_overlap);
1078
1079 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
1080 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1081 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1082 if (--bi->bi_phys_segments == 0) {
1083 md_write_end(conf->mddev);
1084 bi->bi_next = return_bi;
1085 return_bi = bi;
1086 }
1087 bi = nextbi;
1088 }
1089 /* and fail all 'written' */
1090 bi = sh->dev[i].written;
1091 sh->dev[i].written = NULL;
1092 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) {
1093 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
1094 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1095 if (--bi->bi_phys_segments == 0) {
1096 md_write_end(conf->mddev);
1097 bi->bi_next = return_bi;
1098 return_bi = bi;
1099 }
1100 bi = bi2;
1101 }
1102
1103 /* fail any reads if this device is non-operational */
1104 if (!test_bit(R5_Insync, &sh->dev[i].flags)) {
1105 bi = sh->dev[i].toread;
1106 sh->dev[i].toread = NULL;
1107 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1108 wake_up(&conf->wait_for_overlap);
1109 if (bi) to_read--;
1110 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
1111 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1112 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1113 if (--bi->bi_phys_segments == 0) {
1114 bi->bi_next = return_bi;
1115 return_bi = bi;
1116 }
1117 bi = nextbi;
1118 }
1119 }
1120 }
1121 spin_unlock_irq(&conf->device_lock);
1122 }
1123 if (failed > 2 && syncing) {
1124 md_done_sync(conf->mddev, STRIPE_SECTORS,0);
1125 clear_bit(STRIPE_SYNCING, &sh->state);
1126 syncing = 0;
1127 }
1128
1129 /*
1130 * might be able to return some write requests if the parity blocks
1131 * are safe, or on a failed drive
1132 */
1133 pdev = &sh->dev[pd_idx];
1134 p_failed = (failed >= 1 && failed_num[0] == pd_idx)
1135 || (failed >= 2 && failed_num[1] == pd_idx);
1136 qdev = &sh->dev[qd_idx];
1137 q_failed = (failed >= 1 && failed_num[0] == qd_idx)
1138 || (failed >= 2 && failed_num[1] == qd_idx);
1139
1140 if ( written &&
1141 ( p_failed || ((test_bit(R5_Insync, &pdev->flags)
1142 && !test_bit(R5_LOCKED, &pdev->flags)
1143 && test_bit(R5_UPTODATE, &pdev->flags))) ) &&
1144 ( q_failed || ((test_bit(R5_Insync, &qdev->flags)
1145 && !test_bit(R5_LOCKED, &qdev->flags)
1146 && test_bit(R5_UPTODATE, &qdev->flags))) ) ) {
1147 /* any written block on an uptodate or failed drive can be
1148 * returned. Note that if we 'wrote' to a failed drive,
1149 * it will be UPTODATE, but never LOCKED, so we don't need
1150 * to test 'failed' directly.
1151 */
1152 for (i=disks; i--; )
1153 if (sh->dev[i].written) {
1154 dev = &sh->dev[i];
1155 if (!test_bit(R5_LOCKED, &dev->flags) &&
1156 test_bit(R5_UPTODATE, &dev->flags) ) {
1157 /* We can return any write requests */
1158 struct bio *wbi, *wbi2;
1159 PRINTK("Return write for stripe %llu disc %d\n",
1160 (unsigned long long)sh->sector, i);
1161 spin_lock_irq(&conf->device_lock);
1162 wbi = dev->written;
1163 dev->written = NULL;
1164 while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) {
1165 wbi2 = r5_next_bio(wbi, dev->sector);
1166 if (--wbi->bi_phys_segments == 0) {
1167 md_write_end(conf->mddev);
1168 wbi->bi_next = return_bi;
1169 return_bi = wbi;
1170 }
1171 wbi = wbi2;
1172 }
1173 spin_unlock_irq(&conf->device_lock);
1174 }
1175 }
1176 }
1177
1178 /* Now we might consider reading some blocks, either to check/generate
1179 * parity, or to satisfy requests
1180 * or to load a block that is being partially written.
1181 */
1182 if (to_read || non_overwrite || (to_write && failed) || (syncing && (uptodate < disks))) {
1183 for (i=disks; i--;) {
1184 dev = &sh->dev[i];
1185 if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1186 (dev->toread ||
1187 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
1188 syncing ||
1189 (failed >= 1 && (sh->dev[failed_num[0]].toread || to_write)) ||
1190 (failed >= 2 && (sh->dev[failed_num[1]].toread || to_write))
1191 )
1192 ) {
1193 /* we would like to get this block, possibly
1194 * by computing it, but we might not be able to
1195 */
1196 if (uptodate == disks-1) {
1197 PRINTK("Computing stripe %llu block %d\n",
1198 (unsigned long long)sh->sector, i);
1199 compute_block_1(sh, i);
1200 uptodate++;
1201 } else if ( uptodate == disks-2 && failed >= 2 ) {
1202 /* Computing 2-failure is *very* expensive; only do it if failed >= 2 */
1203 int other;
1204 for (other=disks; other--;) {
1205 if ( other == i )
1206 continue;
1207 if ( !test_bit(R5_UPTODATE, &sh->dev[other].flags) )
1208 break;
1209 }
1210 BUG_ON(other < 0);
1211 PRINTK("Computing stripe %llu blocks %d,%d\n",
1212 (unsigned long long)sh->sector, i, other);
1213 compute_block_2(sh, i, other);
1214 uptodate += 2;
1215 } else if (test_bit(R5_Insync, &dev->flags)) {
1216 set_bit(R5_LOCKED, &dev->flags);
1217 set_bit(R5_Wantread, &dev->flags);
1218 #if 0
1219 /* if I am just reading this block and we don't have
1220 a failed drive, or any pending writes then sidestep the cache */
1221 if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext &&
1222 ! syncing && !failed && !to_write) {
1223 sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page;
1224 sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data;
1225 }
1226 #endif
1227 locked++;
1228 PRINTK("Reading block %d (sync=%d)\n",
1229 i, syncing);
1230 if (syncing)
1231 md_sync_acct(conf->disks[i].rdev->bdev,
1232 STRIPE_SECTORS);
1233 }
1234 }
1235 }
1236 set_bit(STRIPE_HANDLE, &sh->state);
1237 }
1238
1239 /* now to consider writing and what else, if anything should be read */
1240 if (to_write) {
1241 int rcw=0, must_compute=0;
1242 for (i=disks ; i--;) {
1243 dev = &sh->dev[i];
1244 /* Would I have to read this buffer for reconstruct_write */
1245 if (!test_bit(R5_OVERWRITE, &dev->flags)
1246 && i != pd_idx && i != qd_idx
1247 && (!test_bit(R5_LOCKED, &dev->flags)
1248 #if 0
1249 || sh->bh_page[i] != bh->b_page
1250 #endif
1251 ) &&
1252 !test_bit(R5_UPTODATE, &dev->flags)) {
1253 if (test_bit(R5_Insync, &dev->flags)) rcw++;
1254 else {
1255 PRINTK("raid6: must_compute: disk %d flags=%#lx\n", i, dev->flags);
1256 must_compute++;
1257 }
1258 }
1259 }
1260 PRINTK("for sector %llu, rcw=%d, must_compute=%d\n",
1261 (unsigned long long)sh->sector, rcw, must_compute);
1262 set_bit(STRIPE_HANDLE, &sh->state);
1263
1264 if (rcw > 0)
1265 /* want reconstruct write, but need to get some data */
1266 for (i=disks; i--;) {
1267 dev = &sh->dev[i];
1268 if (!test_bit(R5_OVERWRITE, &dev->flags)
1269 && !(failed == 0 && (i == pd_idx || i == qd_idx))
1270 && !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1271 test_bit(R5_Insync, &dev->flags)) {
1272 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1273 {
1274 PRINTK("Read_old stripe %llu block %d for Reconstruct\n",
1275 (unsigned long long)sh->sector, i);
1276 set_bit(R5_LOCKED, &dev->flags);
1277 set_bit(R5_Wantread, &dev->flags);
1278 locked++;
1279 } else {
1280 PRINTK("Request delayed stripe %llu block %d for Reconstruct\n",
1281 (unsigned long long)sh->sector, i);
1282 set_bit(STRIPE_DELAYED, &sh->state);
1283 set_bit(STRIPE_HANDLE, &sh->state);
1284 }
1285 }
1286 }
1287 /* now if nothing is locked, and if we have enough data, we can start a write request */
1288 if (locked == 0 && rcw == 0) {
1289 if ( must_compute > 0 ) {
1290 /* We have failed blocks and need to compute them */
1291 switch ( failed ) {
1292 case 0: BUG();
1293 case 1: compute_block_1(sh, failed_num[0]); break;
1294 case 2: compute_block_2(sh, failed_num[0], failed_num[1]); break;
1295 default: BUG(); /* This request should have been failed? */
1296 }
1297 }
1298
1299 PRINTK("Computing parity for stripe %llu\n", (unsigned long long)sh->sector);
1300 compute_parity(sh, RECONSTRUCT_WRITE);
1301 /* now every locked buffer is ready to be written */
1302 for (i=disks; i--;)
1303 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
1304 PRINTK("Writing stripe %llu block %d\n",
1305 (unsigned long long)sh->sector, i);
1306 locked++;
1307 set_bit(R5_Wantwrite, &sh->dev[i].flags);
1308 #if 0 /**** FIX: I don't understand the logic here... ****/
1309 if (!test_bit(R5_Insync, &sh->dev[i].flags)
1310 || ((i==pd_idx || i==qd_idx) && failed == 0)) /* FIX? */
1311 set_bit(STRIPE_INSYNC, &sh->state);
1312 #endif
1313 }
1314 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
1315 atomic_dec(&conf->preread_active_stripes);
1316 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
1317 md_wakeup_thread(conf->mddev->thread);
1318 }
1319 }
1320 }
1321
1322 /* maybe we need to check and possibly fix the parity for this stripe
1323 * Any reads will already have been scheduled, so we just see if enough data
1324 * is available
1325 */
1326 if (syncing && locked == 0 &&
1327 !test_bit(STRIPE_INSYNC, &sh->state) && failed <= 2) {
1328 set_bit(STRIPE_HANDLE, &sh->state);
1329 #if 0 /* RAID-6: Don't support CHECK PARITY yet */
1330 if (failed == 0) {
1331 char *pagea;
1332 if (uptodate != disks)
1333 BUG();
1334 compute_parity(sh, CHECK_PARITY);
1335 uptodate--;
1336 pagea = page_address(sh->dev[pd_idx].page);
1337 if ((*(u32*)pagea) == 0 &&
1338 !memcmp(pagea, pagea+4, STRIPE_SIZE-4)) {
1339 /* parity is correct (on disc, not in buffer any more) */
1340 set_bit(STRIPE_INSYNC, &sh->state);
1341 }
1342 }
1343 #endif
1344 if (!test_bit(STRIPE_INSYNC, &sh->state)) {
1345 int failed_needupdate[2];
1346 struct r5dev *adev, *bdev;
1347
1348 if ( failed < 1 )
1349 failed_num[0] = pd_idx;
1350 if ( failed < 2 )
1351 failed_num[1] = (failed_num[0] == qd_idx) ? pd_idx : qd_idx;
1352
1353 failed_needupdate[0] = !test_bit(R5_UPTODATE, &sh->dev[failed_num[0]].flags);
1354 failed_needupdate[1] = !test_bit(R5_UPTODATE, &sh->dev[failed_num[1]].flags);
1355
1356 PRINTK("sync: failed=%d num=%d,%d fnu=%u%u\n",
1357 failed, failed_num[0], failed_num[1], failed_needupdate[0], failed_needupdate[1]);
1358
1359 #if 0 /* RAID-6: This code seems to require that CHECK_PARITY destroys the uptodateness of the parity */
1360 /* should be able to compute the missing block(s) and write to spare */
1361 if ( failed_needupdate[0] ^ failed_needupdate[1] ) {
1362 if (uptodate+1 != disks)
1363 BUG();
1364 compute_block_1(sh, failed_needupdate[0] ? failed_num[0] : failed_num[1]);
1365 uptodate++;
1366 } else if ( failed_needupdate[0] & failed_needupdate[1] ) {
1367 if (uptodate+2 != disks)
1368 BUG();
1369 compute_block_2(sh, failed_num[0], failed_num[1]);
1370 uptodate += 2;
1371 }
1372 #else
1373 compute_block_2(sh, failed_num[0], failed_num[1]);
1374 uptodate += failed_needupdate[0] + failed_needupdate[1];
1375 #endif
1376
1377 if (uptodate != disks)
1378 BUG();
1379
1380 PRINTK("Marking for sync stripe %llu blocks %d,%d\n",
1381 (unsigned long long)sh->sector, failed_num[0], failed_num[1]);
1382
1383 /**** FIX: Should we really do both of these unconditionally? ****/
1384 adev = &sh->dev[failed_num[0]];
1385 locked += !test_bit(R5_LOCKED, &adev->flags);
1386 set_bit(R5_LOCKED, &adev->flags);
1387 set_bit(R5_Wantwrite, &adev->flags);
1388 bdev = &sh->dev[failed_num[1]];
1389 locked += !test_bit(R5_LOCKED, &bdev->flags);
1390 set_bit(R5_LOCKED, &bdev->flags);
1391 set_bit(R5_Wantwrite, &bdev->flags);
1392
1393 set_bit(STRIPE_INSYNC, &sh->state);
1394 set_bit(R5_Syncio, &adev->flags);
1395 set_bit(R5_Syncio, &bdev->flags);
1396 }
1397 }
1398 if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
1399 md_done_sync(conf->mddev, STRIPE_SECTORS,1);
1400 clear_bit(STRIPE_SYNCING, &sh->state);
1401 }
1402
1403 spin_unlock(&sh->lock);
1404
1405 while ((bi=return_bi)) {
1406 int bytes = bi->bi_size;
1407
1408 return_bi = bi->bi_next;
1409 bi->bi_next = NULL;
1410 bi->bi_size = 0;
1411 bi->bi_end_io(bi, bytes, 0);
1412 }
1413 for (i=disks; i-- ;) {
1414 int rw;
1415 struct bio *bi;
1416 mdk_rdev_t *rdev;
1417 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
1418 rw = 1;
1419 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1420 rw = 0;
1421 else
1422 continue;
1423
1424 bi = &sh->dev[i].req;
1425
1426 bi->bi_rw = rw;
1427 if (rw)
1428 bi->bi_end_io = raid6_end_write_request;
1429 else
1430 bi->bi_end_io = raid6_end_read_request;
1431
1432 rcu_read_lock();
1433 rdev = conf->disks[i].rdev;
1434 if (rdev && rdev->faulty)
1435 rdev = NULL;
1436 if (rdev)
1437 atomic_inc(&rdev->nr_pending);
1438 rcu_read_unlock();
1439
1440 if (rdev) {
1441 if (test_bit(R5_Syncio, &sh->dev[i].flags))
1442 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1443
1444 bi->bi_bdev = rdev->bdev;
1445 PRINTK("for %llu schedule op %ld on disc %d\n",
1446 (unsigned long long)sh->sector, bi->bi_rw, i);
1447 atomic_inc(&sh->count);
1448 bi->bi_sector = sh->sector + rdev->data_offset;
1449 bi->bi_flags = 1 << BIO_UPTODATE;
1450 bi->bi_vcnt = 1;
1451 bi->bi_max_vecs = 1;
1452 bi->bi_idx = 0;
1453 bi->bi_io_vec = &sh->dev[i].vec;
1454 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1455 bi->bi_io_vec[0].bv_offset = 0;
1456 bi->bi_size = STRIPE_SIZE;
1457 bi->bi_next = NULL;
1458 generic_make_request(bi);
1459 } else {
1460 PRINTK("skip op %ld on disc %d for sector %llu\n",
1461 bi->bi_rw, i, (unsigned long long)sh->sector);
1462 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1463 set_bit(STRIPE_HANDLE, &sh->state);
1464 }
1465 }
1466 }
1467
1468 static inline void raid6_activate_delayed(raid6_conf_t *conf)
1469 {
1470 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
1471 while (!list_empty(&conf->delayed_list)) {
1472 struct list_head *l = conf->delayed_list.next;
1473 struct stripe_head *sh;
1474 sh = list_entry(l, struct stripe_head, lru);
1475 list_del_init(l);
1476 clear_bit(STRIPE_DELAYED, &sh->state);
1477 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1478 atomic_inc(&conf->preread_active_stripes);
1479 list_add_tail(&sh->lru, &conf->handle_list);
1480 }
1481 }
1482 }
1483
1484 static void unplug_slaves(mddev_t *mddev)
1485 {
1486 raid6_conf_t *conf = mddev_to_conf(mddev);
1487 int i;
1488
1489 rcu_read_lock();
1490 for (i=0; i<mddev->raid_disks; i++) {
1491 mdk_rdev_t *rdev = conf->disks[i].rdev;
1492 if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
1493 request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
1494
1495 atomic_inc(&rdev->nr_pending);
1496 rcu_read_unlock();
1497
1498 if (r_queue->unplug_fn)
1499 r_queue->unplug_fn(r_queue);
1500
1501 rdev_dec_pending(rdev, mddev);
1502 rcu_read_lock();
1503 }
1504 }
1505 rcu_read_unlock();
1506 }
1507
1508 static void raid6_unplug_device(request_queue_t *q)
1509 {
1510 mddev_t *mddev = q->queuedata;
1511 raid6_conf_t *conf = mddev_to_conf(mddev);
1512 unsigned long flags;
1513
1514 spin_lock_irqsave(&conf->device_lock, flags);
1515
1516 if (blk_remove_plug(q))
1517 raid6_activate_delayed(conf);
1518 md_wakeup_thread(mddev->thread);
1519
1520 spin_unlock_irqrestore(&conf->device_lock, flags);
1521
1522 unplug_slaves(mddev);
1523 }
1524
1525 static int raid6_issue_flush(request_queue_t *q, struct gendisk *disk,
1526 sector_t *error_sector)
1527 {
1528 mddev_t *mddev = q->queuedata;
1529 raid6_conf_t *conf = mddev_to_conf(mddev);
1530 int i, ret = 0;
1531
1532 rcu_read_lock();
1533 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
1534 mdk_rdev_t *rdev = conf->disks[i].rdev;
1535 if (rdev && !rdev->faulty) {
1536 struct block_device *bdev = rdev->bdev;
1537 request_queue_t *r_queue = bdev_get_queue(bdev);
1538
1539 if (!r_queue->issue_flush_fn)
1540 ret = -EOPNOTSUPP;
1541 else {
1542 atomic_inc(&rdev->nr_pending);
1543 rcu_read_unlock();
1544 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
1545 error_sector);
1546 rdev_dec_pending(rdev, mddev);
1547 rcu_read_lock();
1548 }
1549 }
1550 }
1551 rcu_read_unlock();
1552 return ret;
1553 }
1554
1555 static inline void raid6_plug_device(raid6_conf_t *conf)
1556 {
1557 spin_lock_irq(&conf->device_lock);
1558 blk_plug_device(conf->mddev->queue);
1559 spin_unlock_irq(&conf->device_lock);
1560 }
1561
1562 static int make_request (request_queue_t *q, struct bio * bi)
1563 {
1564 mddev_t *mddev = q->queuedata;
1565 raid6_conf_t *conf = mddev_to_conf(mddev);
1566 const unsigned int raid_disks = conf->raid_disks;
1567 const unsigned int data_disks = raid_disks - 2;
1568 unsigned int dd_idx, pd_idx;
1569 sector_t new_sector;
1570 sector_t logical_sector, last_sector;
1571 struct stripe_head *sh;
1572
1573 md_write_start(mddev, bi);
1574
1575 if (bio_data_dir(bi)==WRITE) {
1576 disk_stat_inc(mddev->gendisk, writes);
1577 disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bi));
1578 } else {
1579 disk_stat_inc(mddev->gendisk, reads);
1580 disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bi));
1581 }
1582
1583 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
1584 last_sector = bi->bi_sector + (bi->bi_size>>9);
1585
1586 bi->bi_next = NULL;
1587 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
1588
1589 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
1590 DEFINE_WAIT(w);
1591
1592 new_sector = raid6_compute_sector(logical_sector,
1593 raid_disks, data_disks, &dd_idx, &pd_idx, conf);
1594
1595 PRINTK("raid6: make_request, sector %llu logical %llu\n",
1596 (unsigned long long)new_sector,
1597 (unsigned long long)logical_sector);
1598
1599 retry:
1600 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
1601 sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK));
1602 if (sh) {
1603 if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
1604 /* Add failed due to overlap. Flush everything
1605 * and wait a while
1606 */
1607 raid6_unplug_device(mddev->queue);
1608 release_stripe(sh);
1609 schedule();
1610 goto retry;
1611 }
1612 finish_wait(&conf->wait_for_overlap, &w);
1613 raid6_plug_device(conf);
1614 handle_stripe(sh);
1615 release_stripe(sh);
1616 } else {
1617 /* cannot get stripe for read-ahead, just give-up */
1618 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1619 finish_wait(&conf->wait_for_overlap, &w);
1620 break;
1621 }
1622
1623 }
1624 spin_lock_irq(&conf->device_lock);
1625 if (--bi->bi_phys_segments == 0) {
1626 int bytes = bi->bi_size;
1627
1628 if ( bio_data_dir(bi) == WRITE )
1629 md_write_end(mddev);
1630 bi->bi_size = 0;
1631 bi->bi_end_io(bi, bytes, 0);
1632 }
1633 spin_unlock_irq(&conf->device_lock);
1634 return 0;
1635 }
1636
1637 /* FIXME go_faster isn't used */
1638 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1639 {
1640 raid6_conf_t *conf = (raid6_conf_t *) mddev->private;
1641 struct stripe_head *sh;
1642 int sectors_per_chunk = conf->chunk_size >> 9;
1643 sector_t x;
1644 unsigned long stripe;
1645 int chunk_offset;
1646 int dd_idx, pd_idx;
1647 sector_t first_sector;
1648 int raid_disks = conf->raid_disks;
1649 int data_disks = raid_disks - 2;
1650
1651 if (sector_nr >= mddev->size <<1) {
1652 /* just being told to finish up .. nothing much to do */
1653 unplug_slaves(mddev);
1654 return 0;
1655 }
1656 /* if there are 2 or more failed drives and we are trying
1657 * to resync, then assert that we are finished, because there is
1658 * nothing we can do.
1659 */
1660 if (mddev->degraded >= 2 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
1661 sector_t rv = (mddev->size << 1) - sector_nr;
1662 *skipped = 1;
1663 return rv;
1664 }
1665
1666 x = sector_nr;
1667 chunk_offset = sector_div(x, sectors_per_chunk);
1668 stripe = x;
1669 BUG_ON(x != stripe);
1670
1671 first_sector = raid6_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk
1672 + chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf);
1673 sh = get_active_stripe(conf, sector_nr, pd_idx, 1);
1674 if (sh == NULL) {
1675 sh = get_active_stripe(conf, sector_nr, pd_idx, 0);
1676 /* make sure we don't swamp the stripe cache if someone else
1677 * is trying to get access
1678 */
1679 set_current_state(TASK_UNINTERRUPTIBLE);
1680 schedule_timeout(1);
1681 }
1682 spin_lock(&sh->lock);
1683 set_bit(STRIPE_SYNCING, &sh->state);
1684 clear_bit(STRIPE_INSYNC, &sh->state);
1685 spin_unlock(&sh->lock);
1686
1687 handle_stripe(sh);
1688 release_stripe(sh);
1689
1690 return STRIPE_SECTORS;
1691 }
1692
1693 /*
1694 * This is our raid6 kernel thread.
1695 *
1696 * We scan the hash table for stripes which can be handled now.
1697 * During the scan, completed stripes are saved for us by the interrupt
1698 * handler, so that they will not have to wait for our next wakeup.
1699 */
1700 static void raid6d (mddev_t *mddev)
1701 {
1702 struct stripe_head *sh;
1703 raid6_conf_t *conf = mddev_to_conf(mddev);
1704 int handled;
1705
1706 PRINTK("+++ raid6d active\n");
1707
1708 md_check_recovery(mddev);
1709
1710 handled = 0;
1711 spin_lock_irq(&conf->device_lock);
1712 while (1) {
1713 struct list_head *first;
1714
1715 if (list_empty(&conf->handle_list) &&
1716 atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
1717 !blk_queue_plugged(mddev->queue) &&
1718 !list_empty(&conf->delayed_list))
1719 raid6_activate_delayed(conf);
1720
1721 if (list_empty(&conf->handle_list))
1722 break;
1723
1724 first = conf->handle_list.next;
1725 sh = list_entry(first, struct stripe_head, lru);
1726
1727 list_del_init(first);
1728 atomic_inc(&sh->count);
1729 if (atomic_read(&sh->count)!= 1)
1730 BUG();
1731 spin_unlock_irq(&conf->device_lock);
1732
1733 handled++;
1734 handle_stripe(sh);
1735 release_stripe(sh);
1736
1737 spin_lock_irq(&conf->device_lock);
1738 }
1739 PRINTK("%d stripes handled\n", handled);
1740
1741 spin_unlock_irq(&conf->device_lock);
1742
1743 unplug_slaves(mddev);
1744
1745 PRINTK("--- raid6d inactive\n");
1746 }
1747
1748 static int run (mddev_t *mddev)
1749 {
1750 raid6_conf_t *conf;
1751 int raid_disk, memory;
1752 mdk_rdev_t *rdev;
1753 struct disk_info *disk;
1754 struct list_head *tmp;
1755
1756 if (mddev->level != 6) {
1757 PRINTK("raid6: %s: raid level not set to 6 (%d)\n", mdname(mddev), mddev->level);
1758 return -EIO;
1759 }
1760
1761 mddev->private = kmalloc (sizeof (raid6_conf_t)
1762 + mddev->raid_disks * sizeof(struct disk_info),
1763 GFP_KERNEL);
1764 if ((conf = mddev->private) == NULL)
1765 goto abort;
1766 memset (conf, 0, sizeof (*conf) + mddev->raid_disks * sizeof(struct disk_info) );
1767 conf->mddev = mddev;
1768
1769 if ((conf->stripe_hashtbl = (struct stripe_head **) __get_free_pages(GFP_ATOMIC, HASH_PAGES_ORDER)) == NULL)
1770 goto abort;
1771 memset(conf->stripe_hashtbl, 0, HASH_PAGES * PAGE_SIZE);
1772
1773 spin_lock_init(&conf->device_lock);
1774 init_waitqueue_head(&conf->wait_for_stripe);
1775 init_waitqueue_head(&conf->wait_for_overlap);
1776 INIT_LIST_HEAD(&conf->handle_list);
1777 INIT_LIST_HEAD(&conf->delayed_list);
1778 INIT_LIST_HEAD(&conf->inactive_list);
1779 atomic_set(&conf->active_stripes, 0);
1780 atomic_set(&conf->preread_active_stripes, 0);
1781
1782 PRINTK("raid6: run(%s) called.\n", mdname(mddev));
1783
1784 ITERATE_RDEV(mddev,rdev,tmp) {
1785 raid_disk = rdev->raid_disk;
1786 if (raid_disk >= mddev->raid_disks
1787 || raid_disk < 0)
1788 continue;
1789 disk = conf->disks + raid_disk;
1790
1791 disk->rdev = rdev;
1792
1793 if (rdev->in_sync) {
1794 char b[BDEVNAME_SIZE];
1795 printk(KERN_INFO "raid6: device %s operational as raid"
1796 " disk %d\n", bdevname(rdev->bdev,b),
1797 raid_disk);
1798 conf->working_disks++;
1799 }
1800 }
1801
1802 conf->raid_disks = mddev->raid_disks;
1803
1804 /*
1805 * 0 for a fully functional array, 1 or 2 for a degraded array.
1806 */
1807 mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks;
1808 conf->mddev = mddev;
1809 conf->chunk_size = mddev->chunk_size;
1810 conf->level = mddev->level;
1811 conf->algorithm = mddev->layout;
1812 conf->max_nr_stripes = NR_STRIPES;
1813
1814 /* device size must be a multiple of chunk size */
1815 mddev->size &= ~(mddev->chunk_size/1024 -1);
1816 mddev->resync_max_sectors = mddev->size << 1;
1817
1818 if (conf->raid_disks < 4) {
1819 printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
1820 mdname(mddev), conf->raid_disks);
1821 goto abort;
1822 }
1823 if (!conf->chunk_size || conf->chunk_size % 4) {
1824 printk(KERN_ERR "raid6: invalid chunk size %d for %s\n",
1825 conf->chunk_size, mdname(mddev));
1826 goto abort;
1827 }
1828 if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) {
1829 printk(KERN_ERR
1830 "raid6: unsupported parity algorithm %d for %s\n",
1831 conf->algorithm, mdname(mddev));
1832 goto abort;
1833 }
1834 if (mddev->degraded > 2) {
1835 printk(KERN_ERR "raid6: not enough operational devices for %s"
1836 " (%d/%d failed)\n",
1837 mdname(mddev), conf->failed_disks, conf->raid_disks);
1838 goto abort;
1839 }
1840
1841 #if 0 /* FIX: For now */
1842 if (mddev->degraded > 0 &&
1843 mddev->recovery_cp != MaxSector) {
1844 printk(KERN_ERR "raid6: cannot start dirty degraded array for %s\n", mdname(mddev));
1845 goto abort;
1846 }
1847 #endif
1848
1849 {
1850 mddev->thread = md_register_thread(raid6d, mddev, "%s_raid6");
1851 if (!mddev->thread) {
1852 printk(KERN_ERR
1853 "raid6: couldn't allocate thread for %s\n",
1854 mdname(mddev));
1855 goto abort;
1856 }
1857 }
1858
1859 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
1860 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
1861 if (grow_stripes(conf, conf->max_nr_stripes)) {
1862 printk(KERN_ERR
1863 "raid6: couldn't allocate %dkB for buffers\n", memory);
1864 shrink_stripes(conf);
1865 md_unregister_thread(mddev->thread);
1866 goto abort;
1867 } else
1868 printk(KERN_INFO "raid6: allocated %dkB for %s\n",
1869 memory, mdname(mddev));
1870
1871 if (mddev->degraded == 0)
1872 printk(KERN_INFO "raid6: raid level %d set %s active with %d out of %d"
1873 " devices, algorithm %d\n", conf->level, mdname(mddev),
1874 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
1875 conf->algorithm);
1876 else
1877 printk(KERN_ALERT "raid6: raid level %d set %s active with %d"
1878 " out of %d devices, algorithm %d\n", conf->level,
1879 mdname(mddev), mddev->raid_disks - mddev->degraded,
1880 mddev->raid_disks, conf->algorithm);
1881
1882 print_raid6_conf(conf);
1883
1884 /* read-ahead size must cover two whole stripes, which is
1885 * 2 * (n-2) * chunksize where 'n' is the number of raid devices
1886 */
1887 {
1888 int stripe = (mddev->raid_disks-2) * mddev->chunk_size
1889 / PAGE_CACHE_SIZE;
1890 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
1891 mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
1892 }
1893
1894 /* Ok, everything is just fine now */
1895 mddev->array_size = mddev->size * (mddev->raid_disks - 2);
1896
1897 mddev->queue->unplug_fn = raid6_unplug_device;
1898 mddev->queue->issue_flush_fn = raid6_issue_flush;
1899 return 0;
1900 abort:
1901 if (conf) {
1902 print_raid6_conf(conf);
1903 if (conf->stripe_hashtbl)
1904 free_pages((unsigned long) conf->stripe_hashtbl,
1905 HASH_PAGES_ORDER);
1906 kfree(conf);
1907 }
1908 mddev->private = NULL;
1909 printk(KERN_ALERT "raid6: failed to run raid set %s\n", mdname(mddev));
1910 return -EIO;
1911 }
1912
1913
1914
1915 static int stop (mddev_t *mddev)
1916 {
1917 raid6_conf_t *conf = (raid6_conf_t *) mddev->private;
1918
1919 md_unregister_thread(mddev->thread);
1920 mddev->thread = NULL;
1921 shrink_stripes(conf);
1922 free_pages((unsigned long) conf->stripe_hashtbl, HASH_PAGES_ORDER);
1923 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
1924 kfree(conf);
1925 mddev->private = NULL;
1926 return 0;
1927 }
1928
1929 #if RAID6_DUMPSTATE
1930 static void print_sh (struct seq_file *seq, struct stripe_head *sh)
1931 {
1932 int i;
1933
1934 seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n",
1935 (unsigned long long)sh->sector, sh->pd_idx, sh->state);
1936 seq_printf(seq, "sh %llu, count %d.\n",
1937 (unsigned long long)sh->sector, atomic_read(&sh->count));
1938 seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector);
1939 for (i = 0; i < sh->raid_conf->raid_disks; i++) {
1940 seq_printf(seq, "(cache%d: %p %ld) ",
1941 i, sh->dev[i].page, sh->dev[i].flags);
1942 }
1943 seq_printf(seq, "\n");
1944 }
1945
1946 static void printall (struct seq_file *seq, raid6_conf_t *conf)
1947 {
1948 struct stripe_head *sh;
1949 int i;
1950
1951 spin_lock_irq(&conf->device_lock);
1952 for (i = 0; i < NR_HASH; i++) {
1953 sh = conf->stripe_hashtbl[i];
1954 for (; sh; sh = sh->hash_next) {
1955 if (sh->raid_conf != conf)
1956 continue;
1957 print_sh(seq, sh);
1958 }
1959 }
1960 spin_unlock_irq(&conf->device_lock);
1961 }
1962 #endif
1963
1964 static void status (struct seq_file *seq, mddev_t *mddev)
1965 {
1966 raid6_conf_t *conf = (raid6_conf_t *) mddev->private;
1967 int i;
1968
1969 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout);
1970 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks);
1971 for (i = 0; i < conf->raid_disks; i++)
1972 seq_printf (seq, "%s",
1973 conf->disks[i].rdev &&
1974 conf->disks[i].rdev->in_sync ? "U" : "_");
1975 seq_printf (seq, "]");
1976 #if RAID6_DUMPSTATE
1977 seq_printf (seq, "\n");
1978 printall(seq, conf);
1979 #endif
1980 }
1981
1982 static void print_raid6_conf (raid6_conf_t *conf)
1983 {
1984 int i;
1985 struct disk_info *tmp;
1986
1987 printk("RAID6 conf printout:\n");
1988 if (!conf) {
1989 printk("(conf==NULL)\n");
1990 return;
1991 }
1992 printk(" --- rd:%d wd:%d fd:%d\n", conf->raid_disks,
1993 conf->working_disks, conf->failed_disks);
1994
1995 for (i = 0; i < conf->raid_disks; i++) {
1996 char b[BDEVNAME_SIZE];
1997 tmp = conf->disks + i;
1998 if (tmp->rdev)
1999 printk(" disk %d, o:%d, dev:%s\n",
2000 i, !tmp->rdev->faulty,
2001 bdevname(tmp->rdev->bdev,b));
2002 }
2003 }
2004
2005 static int raid6_spare_active(mddev_t *mddev)
2006 {
2007 int i;
2008 raid6_conf_t *conf = mddev->private;
2009 struct disk_info *tmp;
2010
2011 for (i = 0; i < conf->raid_disks; i++) {
2012 tmp = conf->disks + i;
2013 if (tmp->rdev
2014 && !tmp->rdev->faulty
2015 && !tmp->rdev->in_sync) {
2016 mddev->degraded--;
2017 conf->failed_disks--;
2018 conf->working_disks++;
2019 tmp->rdev->in_sync = 1;
2020 }
2021 }
2022 print_raid6_conf(conf);
2023 return 0;
2024 }
2025
2026 static int raid6_remove_disk(mddev_t *mddev, int number)
2027 {
2028 raid6_conf_t *conf = mddev->private;
2029 int err = 0;
2030 mdk_rdev_t *rdev;
2031 struct disk_info *p = conf->disks + number;
2032
2033 print_raid6_conf(conf);
2034 rdev = p->rdev;
2035 if (rdev) {
2036 if (rdev->in_sync ||
2037 atomic_read(&rdev->nr_pending)) {
2038 err = -EBUSY;
2039 goto abort;
2040 }
2041 p->rdev = NULL;
2042 synchronize_rcu();
2043 if (atomic_read(&rdev->nr_pending)) {
2044 /* lost the race, try later */
2045 err = -EBUSY;
2046 p->rdev = rdev;
2047 }
2048 }
2049
2050 abort:
2051
2052 print_raid6_conf(conf);
2053 return err;
2054 }
2055
2056 static int raid6_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
2057 {
2058 raid6_conf_t *conf = mddev->private;
2059 int found = 0;
2060 int disk;
2061 struct disk_info *p;
2062
2063 if (mddev->degraded > 2)
2064 /* no point adding a device */
2065 return 0;
2066 /*
2067 * find the disk ...
2068 */
2069 for (disk=0; disk < mddev->raid_disks; disk++)
2070 if ((p=conf->disks + disk)->rdev == NULL) {
2071 rdev->in_sync = 0;
2072 rdev->raid_disk = disk;
2073 found = 1;
2074 p->rdev = rdev;
2075 break;
2076 }
2077 print_raid6_conf(conf);
2078 return found;
2079 }
2080
2081 static int raid6_resize(mddev_t *mddev, sector_t sectors)
2082 {
2083 /* no resync is happening, and there is enough space
2084 * on all devices, so we can resize.
2085 * We need to make sure resync covers any new space.
2086 * If the array is shrinking we should possibly wait until
2087 * any io in the removed space completes, but it hardly seems
2088 * worth it.
2089 */
2090 sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
2091 mddev->array_size = (sectors * (mddev->raid_disks-2))>>1;
2092 set_capacity(mddev->gendisk, mddev->array_size << 1);
2093 mddev->changed = 1;
2094 if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) {
2095 mddev->recovery_cp = mddev->size << 1;
2096 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2097 }
2098 mddev->size = sectors /2;
2099 mddev->resync_max_sectors = sectors;
2100 return 0;
2101 }
2102
2103 static mdk_personality_t raid6_personality=
2104 {
2105 .name = "raid6",
2106 .owner = THIS_MODULE,
2107 .make_request = make_request,
2108 .run = run,
2109 .stop = stop,
2110 .status = status,
2111 .error_handler = error,
2112 .hot_add_disk = raid6_add_disk,
2113 .hot_remove_disk= raid6_remove_disk,
2114 .spare_active = raid6_spare_active,
2115 .sync_request = sync_request,
2116 .resize = raid6_resize,
2117 };
2118
2119 static int __init raid6_init (void)
2120 {
2121 int e;
2122
2123 e = raid6_select_algo();
2124 if ( e )
2125 return e;
2126
2127 return register_md_personality (RAID6, &raid6_personality);
2128 }
2129
2130 static void raid6_exit (void)
2131 {
2132 unregister_md_personality (RAID6);
2133 }
2134
2135 module_init(raid6_init);
2136 module_exit(raid6_exit);
2137 MODULE_LICENSE("GPL");
2138 MODULE_ALIAS("md-personality-8"); /* RAID6 */
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