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BUG_ON() Conversion in md/dm-hw-handler.c
[linux-2.6/linux-loongson.git] / drivers / md / raid5.c
blob2dba305daf3c887799453caefae8d5a36535de4b
1 /*
2 * raid5.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 *
6 * RAID-5 management functions.
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2, or (at your option)
11 * any later version.
12 *
13 * You should have received a copy of the GNU General Public License
14 * (for example /usr/src/linux/COPYING); if not, write to the Free
15 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
16 */
17
18
19 #include <linux/config.h>
20 #include <linux/module.h>
21 #include <linux/slab.h>
22 #include <linux/raid/raid5.h>
23 #include <linux/highmem.h>
24 #include <linux/bitops.h>
25 #include <asm/atomic.h>
26
27 #include <linux/raid/bitmap.h>
28
29 /*
30 * Stripe cache
31 */
32
33 #define NR_STRIPES 256
34 #define STRIPE_SIZE PAGE_SIZE
35 #define STRIPE_SHIFT (PAGE_SHIFT - 9)
36 #define STRIPE_SECTORS (STRIPE_SIZE>>9)
37 #define IO_THRESHOLD 1
38 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
39 #define HASH_MASK (NR_HASH - 1)
40
41 #define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
42
43 /* bio's attached to a stripe+device for I/O are linked together in bi_sector
44 * order without overlap. There may be several bio's per stripe+device, and
45 * a bio could span several devices.
46 * When walking this list for a particular stripe+device, we must never proceed
47 * beyond a bio that extends past this device, as the next bio might no longer
48 * be valid.
49 * This macro is used to determine the 'next' bio in the list, given the sector
50 * of the current stripe+device
51 */
52 #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL)
53 /*
54 * The following can be used to debug the driver
55 */
56 #define RAID5_DEBUG 0
57 #define RAID5_PARANOIA 1
58 #if RAID5_PARANOIA && defined(CONFIG_SMP)
59 # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
60 #else
61 # define CHECK_DEVLOCK()
62 #endif
63
64 #define PRINTK(x...) ((void)(RAID5_DEBUG && printk(x)))
65 #if RAID5_DEBUG
66 #define inline
67 #define __inline__
68 #endif
69
70 static void print_raid5_conf (raid5_conf_t *conf);
71
72 static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
73 {
74 if (atomic_dec_and_test(&sh->count)) {
75 if (!list_empty(&sh->lru))
76 BUG();
77 if (atomic_read(&conf->active_stripes)==0)
78 BUG();
79 if (test_bit(STRIPE_HANDLE, &sh->state)) {
80 if (test_bit(STRIPE_DELAYED, &sh->state))
81 list_add_tail(&sh->lru, &conf->delayed_list);
82 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
83 conf->seq_write == sh->bm_seq)
84 list_add_tail(&sh->lru, &conf->bitmap_list);
85 else {
86 clear_bit(STRIPE_BIT_DELAY, &sh->state);
87 list_add_tail(&sh->lru, &conf->handle_list);
88 }
89 md_wakeup_thread(conf->mddev->thread);
90 } else {
91 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
92 atomic_dec(&conf->preread_active_stripes);
93 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
94 md_wakeup_thread(conf->mddev->thread);
95 }
96 list_add_tail(&sh->lru, &conf->inactive_list);
97 atomic_dec(&conf->active_stripes);
98 if (!conf->inactive_blocked ||
99 atomic_read(&conf->active_stripes) < (conf->max_nr_stripes*3/4))
100 wake_up(&conf->wait_for_stripe);
101 }
102 }
103 }
104 static void release_stripe(struct stripe_head *sh)
105 {
106 raid5_conf_t *conf = sh->raid_conf;
107 unsigned long flags;
108
109 spin_lock_irqsave(&conf->device_lock, flags);
110 __release_stripe(conf, sh);
111 spin_unlock_irqrestore(&conf->device_lock, flags);
112 }
113
114 static inline void remove_hash(struct stripe_head *sh)
115 {
116 PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector);
117
118 hlist_del_init(&sh->hash);
119 }
120
121 static void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
122 {
123 struct hlist_head *hp = stripe_hash(conf, sh->sector);
124
125 PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector);
126
127 CHECK_DEVLOCK();
128 hlist_add_head(&sh->hash, hp);
129 }
130
131
132 /* find an idle stripe, make sure it is unhashed, and return it. */
133 static struct stripe_head *get_free_stripe(raid5_conf_t *conf)
134 {
135 struct stripe_head *sh = NULL;
136 struct list_head *first;
137
138 CHECK_DEVLOCK();
139 if (list_empty(&conf->inactive_list))
140 goto out;
141 first = conf->inactive_list.next;
142 sh = list_entry(first, struct stripe_head, lru);
143 list_del_init(first);
144 remove_hash(sh);
145 atomic_inc(&conf->active_stripes);
146 out:
147 return sh;
148 }
149
150 static void shrink_buffers(struct stripe_head *sh, int num)
151 {
152 struct page *p;
153 int i;
154
155 for (i=0; i<num ; i++) {
156 p = sh->dev[i].page;
157 if (!p)
158 continue;
159 sh->dev[i].page = NULL;
160 put_page(p);
161 }
162 }
163
164 static int grow_buffers(struct stripe_head *sh, int num)
165 {
166 int i;
167
168 for (i=0; i<num; i++) {
169 struct page *page;
170
171 if (!(page = alloc_page(GFP_KERNEL))) {
172 return 1;
173 }
174 sh->dev[i].page = page;
175 }
176 return 0;
177 }
178
179 static void raid5_build_block (struct stripe_head *sh, int i);
180
181 static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx)
182 {
183 raid5_conf_t *conf = sh->raid_conf;
184 int disks = conf->raid_disks, i;
185
186 if (atomic_read(&sh->count) != 0)
187 BUG();
188 if (test_bit(STRIPE_HANDLE, &sh->state))
189 BUG();
190
191 CHECK_DEVLOCK();
192 PRINTK("init_stripe called, stripe %llu\n",
193 (unsigned long long)sh->sector);
194
195 remove_hash(sh);
196
197 sh->sector = sector;
198 sh->pd_idx = pd_idx;
199 sh->state = 0;
200
201 for (i=disks; i--; ) {
202 struct r5dev *dev = &sh->dev[i];
203
204 if (dev->toread || dev->towrite || dev->written ||
205 test_bit(R5_LOCKED, &dev->flags)) {
206 printk("sector=%llx i=%d %p %p %p %d\n",
207 (unsigned long long)sh->sector, i, dev->toread,
208 dev->towrite, dev->written,
209 test_bit(R5_LOCKED, &dev->flags));
210 BUG();
211 }
212 dev->flags = 0;
213 raid5_build_block(sh, i);
214 }
215 insert_hash(conf, sh);
216 }
217
218 static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector)
219 {
220 struct stripe_head *sh;
221 struct hlist_node *hn;
222
223 CHECK_DEVLOCK();
224 PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector);
225 hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
226 if (sh->sector == sector)
227 return sh;
228 PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector);
229 return NULL;
230 }
231
232 static void unplug_slaves(mddev_t *mddev);
233 static void raid5_unplug_device(request_queue_t *q);
234
235 static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector,
236 int pd_idx, int noblock)
237 {
238 struct stripe_head *sh;
239
240 PRINTK("get_stripe, sector %llu\n", (unsigned long long)sector);
241
242 spin_lock_irq(&conf->device_lock);
243
244 do {
245 wait_event_lock_irq(conf->wait_for_stripe,
246 conf->quiesce == 0,
247 conf->device_lock, /* nothing */);
248 sh = __find_stripe(conf, sector);
249 if (!sh) {
250 if (!conf->inactive_blocked)
251 sh = get_free_stripe(conf);
252 if (noblock && sh == NULL)
253 break;
254 if (!sh) {
255 conf->inactive_blocked = 1;
256 wait_event_lock_irq(conf->wait_for_stripe,
257 !list_empty(&conf->inactive_list) &&
258 (atomic_read(&conf->active_stripes)
259 < (conf->max_nr_stripes *3/4)
260 || !conf->inactive_blocked),
261 conf->device_lock,
262 unplug_slaves(conf->mddev);
263 );
264 conf->inactive_blocked = 0;
265 } else
266 init_stripe(sh, sector, pd_idx);
267 } else {
268 if (atomic_read(&sh->count)) {
269 if (!list_empty(&sh->lru))
270 BUG();
271 } else {
272 if (!test_bit(STRIPE_HANDLE, &sh->state))
273 atomic_inc(&conf->active_stripes);
274 if (list_empty(&sh->lru))
275 BUG();
276 list_del_init(&sh->lru);
277 }
278 }
279 } while (sh == NULL);
280
281 if (sh)
282 atomic_inc(&sh->count);
283
284 spin_unlock_irq(&conf->device_lock);
285 return sh;
286 }
287
288 static int grow_one_stripe(raid5_conf_t *conf)
289 {
290 struct stripe_head *sh;
291 sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL);
292 if (!sh)
293 return 0;
294 memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev));
295 sh->raid_conf = conf;
296 spin_lock_init(&sh->lock);
297
298 if (grow_buffers(sh, conf->raid_disks)) {
299 shrink_buffers(sh, conf->raid_disks);
300 kmem_cache_free(conf->slab_cache, sh);
301 return 0;
302 }
303 /* we just created an active stripe so... */
304 atomic_set(&sh->count, 1);
305 atomic_inc(&conf->active_stripes);
306 INIT_LIST_HEAD(&sh->lru);
307 release_stripe(sh);
308 return 1;
309 }
310
311 static int grow_stripes(raid5_conf_t *conf, int num)
312 {
313 kmem_cache_t *sc;
314 int devs = conf->raid_disks;
315
316 sprintf(conf->cache_name, "raid5/%s", mdname(conf->mddev));
317
318 sc = kmem_cache_create(conf->cache_name,
319 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
320 0, 0, NULL, NULL);
321 if (!sc)
322 return 1;
323 conf->slab_cache = sc;
324 while (num--) {
325 if (!grow_one_stripe(conf))
326 return 1;
327 }
328 return 0;
329 }
330
331 static int drop_one_stripe(raid5_conf_t *conf)
332 {
333 struct stripe_head *sh;
334
335 spin_lock_irq(&conf->device_lock);
336 sh = get_free_stripe(conf);
337 spin_unlock_irq(&conf->device_lock);
338 if (!sh)
339 return 0;
340 if (atomic_read(&sh->count))
341 BUG();
342 shrink_buffers(sh, conf->raid_disks);
343 kmem_cache_free(conf->slab_cache, sh);
344 atomic_dec(&conf->active_stripes);
345 return 1;
346 }
347
348 static void shrink_stripes(raid5_conf_t *conf)
349 {
350 while (drop_one_stripe(conf))
351 ;
352
353 if (conf->slab_cache)
354 kmem_cache_destroy(conf->slab_cache);
355 conf->slab_cache = NULL;
356 }
357
358 static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done,
359 int error)
360 {
361 struct stripe_head *sh = bi->bi_private;
362 raid5_conf_t *conf = sh->raid_conf;
363 int disks = conf->raid_disks, i;
364 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
365
366 if (bi->bi_size)
367 return 1;
368
369 for (i=0 ; i<disks; i++)
370 if (bi == &sh->dev[i].req)
371 break;
372
373 PRINTK("end_read_request %llu/%d, count: %d, uptodate %d.\n",
374 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
375 uptodate);
376 if (i == disks) {
377 BUG();
378 return 0;
379 }
380
381 if (uptodate) {
382 #if 0
383 struct bio *bio;
384 unsigned long flags;
385 spin_lock_irqsave(&conf->device_lock, flags);
386 /* we can return a buffer if we bypassed the cache or
387 * if the top buffer is not in highmem. If there are
388 * multiple buffers, leave the extra work to
389 * handle_stripe
390 */
391 buffer = sh->bh_read[i];
392 if (buffer &&
393 (!PageHighMem(buffer->b_page)
394 || buffer->b_page == bh->b_page )
395 ) {
396 sh->bh_read[i] = buffer->b_reqnext;
397 buffer->b_reqnext = NULL;
398 } else
399 buffer = NULL;
400 spin_unlock_irqrestore(&conf->device_lock, flags);
401 if (sh->bh_page[i]==bh->b_page)
402 set_buffer_uptodate(bh);
403 if (buffer) {
404 if (buffer->b_page != bh->b_page)
405 memcpy(buffer->b_data, bh->b_data, bh->b_size);
406 buffer->b_end_io(buffer, 1);
407 }
408 #else
409 set_bit(R5_UPTODATE, &sh->dev[i].flags);
410 #endif
411 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
412 printk(KERN_INFO "raid5: read error corrected!!\n");
413 clear_bit(R5_ReadError, &sh->dev[i].flags);
414 clear_bit(R5_ReWrite, &sh->dev[i].flags);
415 }
416 if (atomic_read(&conf->disks[i].rdev->read_errors))
417 atomic_set(&conf->disks[i].rdev->read_errors, 0);
418 } else {
419 int retry = 0;
420 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
421 atomic_inc(&conf->disks[i].rdev->read_errors);
422 if (conf->mddev->degraded)
423 printk(KERN_WARNING "raid5: read error not correctable.\n");
424 else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
425 /* Oh, no!!! */
426 printk(KERN_WARNING "raid5: read error NOT corrected!!\n");
427 else if (atomic_read(&conf->disks[i].rdev->read_errors)
428 > conf->max_nr_stripes)
429 printk(KERN_WARNING
430 "raid5: Too many read errors, failing device.\n");
431 else
432 retry = 1;
433 if (retry)
434 set_bit(R5_ReadError, &sh->dev[i].flags);
435 else {
436 clear_bit(R5_ReadError, &sh->dev[i].flags);
437 clear_bit(R5_ReWrite, &sh->dev[i].flags);
438 md_error(conf->mddev, conf->disks[i].rdev);
439 }
440 }
441 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
442 #if 0
443 /* must restore b_page before unlocking buffer... */
444 if (sh->bh_page[i] != bh->b_page) {
445 bh->b_page = sh->bh_page[i];
446 bh->b_data = page_address(bh->b_page);
447 clear_buffer_uptodate(bh);
448 }
449 #endif
450 clear_bit(R5_LOCKED, &sh->dev[i].flags);
451 set_bit(STRIPE_HANDLE, &sh->state);
452 release_stripe(sh);
453 return 0;
454 }
455
456 static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done,
457 int error)
458 {
459 struct stripe_head *sh = bi->bi_private;
460 raid5_conf_t *conf = sh->raid_conf;
461 int disks = conf->raid_disks, i;
462 unsigned long flags;
463 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
464
465 if (bi->bi_size)
466 return 1;
467
468 for (i=0 ; i<disks; i++)
469 if (bi == &sh->dev[i].req)
470 break;
471
472 PRINTK("end_write_request %llu/%d, count %d, uptodate: %d.\n",
473 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
474 uptodate);
475 if (i == disks) {
476 BUG();
477 return 0;
478 }
479
480 spin_lock_irqsave(&conf->device_lock, flags);
481 if (!uptodate)
482 md_error(conf->mddev, conf->disks[i].rdev);
483
484 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
485
486 clear_bit(R5_LOCKED, &sh->dev[i].flags);
487 set_bit(STRIPE_HANDLE, &sh->state);
488 __release_stripe(conf, sh);
489 spin_unlock_irqrestore(&conf->device_lock, flags);
490 return 0;
491 }
492
493
494 static sector_t compute_blocknr(struct stripe_head *sh, int i);
495
496 static void raid5_build_block (struct stripe_head *sh, int i)
497 {
498 struct r5dev *dev = &sh->dev[i];
499
500 bio_init(&dev->req);
501 dev->req.bi_io_vec = &dev->vec;
502 dev->req.bi_vcnt++;
503 dev->req.bi_max_vecs++;
504 dev->vec.bv_page = dev->page;
505 dev->vec.bv_len = STRIPE_SIZE;
506 dev->vec.bv_offset = 0;
507
508 dev->req.bi_sector = sh->sector;
509 dev->req.bi_private = sh;
510
511 dev->flags = 0;
512 if (i != sh->pd_idx)
513 dev->sector = compute_blocknr(sh, i);
514 }
515
516 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
517 {
518 char b[BDEVNAME_SIZE];
519 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
520 PRINTK("raid5: error called\n");
521
522 if (!test_bit(Faulty, &rdev->flags)) {
523 mddev->sb_dirty = 1;
524 if (test_bit(In_sync, &rdev->flags)) {
525 conf->working_disks--;
526 mddev->degraded++;
527 conf->failed_disks++;
528 clear_bit(In_sync, &rdev->flags);
529 /*
530 * if recovery was running, make sure it aborts.
531 */
532 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
533 }
534 set_bit(Faulty, &rdev->flags);
535 printk (KERN_ALERT
536 "raid5: Disk failure on %s, disabling device."
537 " Operation continuing on %d devices\n",
538 bdevname(rdev->bdev,b), conf->working_disks);
539 }
540 }
541
542 /*
543 * Input: a 'big' sector number,
544 * Output: index of the data and parity disk, and the sector # in them.
545 */
546 static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks,
547 unsigned int data_disks, unsigned int * dd_idx,
548 unsigned int * pd_idx, raid5_conf_t *conf)
549 {
550 long stripe;
551 unsigned long chunk_number;
552 unsigned int chunk_offset;
553 sector_t new_sector;
554 int sectors_per_chunk = conf->chunk_size >> 9;
555
556 /* First compute the information on this sector */
557
558 /*
559 * Compute the chunk number and the sector offset inside the chunk
560 */
561 chunk_offset = sector_div(r_sector, sectors_per_chunk);
562 chunk_number = r_sector;
563 BUG_ON(r_sector != chunk_number);
564
565 /*
566 * Compute the stripe number
567 */
568 stripe = chunk_number / data_disks;
569
570 /*
571 * Compute the data disk and parity disk indexes inside the stripe
572 */
573 *dd_idx = chunk_number % data_disks;
574
575 /*
576 * Select the parity disk based on the user selected algorithm.
577 */
578 if (conf->level == 4)
579 *pd_idx = data_disks;
580 else switch (conf->algorithm) {
581 case ALGORITHM_LEFT_ASYMMETRIC:
582 *pd_idx = data_disks - stripe % raid_disks;
583 if (*dd_idx >= *pd_idx)
584 (*dd_idx)++;
585 break;
586 case ALGORITHM_RIGHT_ASYMMETRIC:
587 *pd_idx = stripe % raid_disks;
588 if (*dd_idx >= *pd_idx)
589 (*dd_idx)++;
590 break;
591 case ALGORITHM_LEFT_SYMMETRIC:
592 *pd_idx = data_disks - stripe % raid_disks;
593 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
594 break;
595 case ALGORITHM_RIGHT_SYMMETRIC:
596 *pd_idx = stripe % raid_disks;
597 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
598 break;
599 default:
600 printk(KERN_ERR "raid5: unsupported algorithm %d\n",
601 conf->algorithm);
602 }
603
604 /*
605 * Finally, compute the new sector number
606 */
607 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
608 return new_sector;
609 }
610
611
612 static sector_t compute_blocknr(struct stripe_head *sh, int i)
613 {
614 raid5_conf_t *conf = sh->raid_conf;
615 int raid_disks = conf->raid_disks, data_disks = raid_disks - 1;
616 sector_t new_sector = sh->sector, check;
617 int sectors_per_chunk = conf->chunk_size >> 9;
618 sector_t stripe;
619 int chunk_offset;
620 int chunk_number, dummy1, dummy2, dd_idx = i;
621 sector_t r_sector;
622
623 chunk_offset = sector_div(new_sector, sectors_per_chunk);
624 stripe = new_sector;
625 BUG_ON(new_sector != stripe);
626
627
628 switch (conf->algorithm) {
629 case ALGORITHM_LEFT_ASYMMETRIC:
630 case ALGORITHM_RIGHT_ASYMMETRIC:
631 if (i > sh->pd_idx)
632 i--;
633 break;
634 case ALGORITHM_LEFT_SYMMETRIC:
635 case ALGORITHM_RIGHT_SYMMETRIC:
636 if (i < sh->pd_idx)
637 i += raid_disks;
638 i -= (sh->pd_idx + 1);
639 break;
640 default:
641 printk(KERN_ERR "raid5: unsupported algorithm %d\n",
642 conf->algorithm);
643 }
644
645 chunk_number = stripe * data_disks + i;
646 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
647
648 check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
649 if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
650 printk(KERN_ERR "compute_blocknr: map not correct\n");
651 return 0;
652 }
653 return r_sector;
654 }
655
656
657
658 /*
659 * Copy data between a page in the stripe cache, and a bio.
660 * There are no alignment or size guarantees between the page or the
661 * bio except that there is some overlap.
662 * All iovecs in the bio must be considered.
663 */
664 static void copy_data(int frombio, struct bio *bio,
665 struct page *page,
666 sector_t sector)
667 {
668 char *pa = page_address(page);
669 struct bio_vec *bvl;
670 int i;
671 int page_offset;
672
673 if (bio->bi_sector >= sector)
674 page_offset = (signed)(bio->bi_sector - sector) * 512;
675 else
676 page_offset = (signed)(sector - bio->bi_sector) * -512;
677 bio_for_each_segment(bvl, bio, i) {
678 int len = bio_iovec_idx(bio,i)->bv_len;
679 int clen;
680 int b_offset = 0;
681
682 if (page_offset < 0) {
683 b_offset = -page_offset;
684 page_offset += b_offset;
685 len -= b_offset;
686 }
687
688 if (len > 0 && page_offset + len > STRIPE_SIZE)
689 clen = STRIPE_SIZE - page_offset;
690 else clen = len;
691
692 if (clen > 0) {
693 char *ba = __bio_kmap_atomic(bio, i, KM_USER0);
694 if (frombio)
695 memcpy(pa+page_offset, ba+b_offset, clen);
696 else
697 memcpy(ba+b_offset, pa+page_offset, clen);
698 __bio_kunmap_atomic(ba, KM_USER0);
699 }
700 if (clen < len) /* hit end of page */
701 break;
702 page_offset += len;
703 }
704 }
705
706 #define check_xor() do { \
707 if (count == MAX_XOR_BLOCKS) { \
708 xor_block(count, STRIPE_SIZE, ptr); \
709 count = 1; \
710 } \
711 } while(0)
712
713
714 static void compute_block(struct stripe_head *sh, int dd_idx)
715 {
716 raid5_conf_t *conf = sh->raid_conf;
717 int i, count, disks = conf->raid_disks;
718 void *ptr[MAX_XOR_BLOCKS], *p;
719
720 PRINTK("compute_block, stripe %llu, idx %d\n",
721 (unsigned long long)sh->sector, dd_idx);
722
723 ptr[0] = page_address(sh->dev[dd_idx].page);
724 memset(ptr[0], 0, STRIPE_SIZE);
725 count = 1;
726 for (i = disks ; i--; ) {
727 if (i == dd_idx)
728 continue;
729 p = page_address(sh->dev[i].page);
730 if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
731 ptr[count++] = p;
732 else
733 printk(KERN_ERR "compute_block() %d, stripe %llu, %d"
734 " not present\n", dd_idx,
735 (unsigned long long)sh->sector, i);
736
737 check_xor();
738 }
739 if (count != 1)
740 xor_block(count, STRIPE_SIZE, ptr);
741 set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
742 }
743
744 static void compute_parity(struct stripe_head *sh, int method)
745 {
746 raid5_conf_t *conf = sh->raid_conf;
747 int i, pd_idx = sh->pd_idx, disks = conf->raid_disks, count;
748 void *ptr[MAX_XOR_BLOCKS];
749 struct bio *chosen;
750
751 PRINTK("compute_parity, stripe %llu, method %d\n",
752 (unsigned long long)sh->sector, method);
753
754 count = 1;
755 ptr[0] = page_address(sh->dev[pd_idx].page);
756 switch(method) {
757 case READ_MODIFY_WRITE:
758 if (!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags))
759 BUG();
760 for (i=disks ; i-- ;) {
761 if (i==pd_idx)
762 continue;
763 if (sh->dev[i].towrite &&
764 test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
765 ptr[count++] = page_address(sh->dev[i].page);
766 chosen = sh->dev[i].towrite;
767 sh->dev[i].towrite = NULL;
768
769 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
770 wake_up(&conf->wait_for_overlap);
771
772 if (sh->dev[i].written) BUG();
773 sh->dev[i].written = chosen;
774 check_xor();
775 }
776 }
777 break;
778 case RECONSTRUCT_WRITE:
779 memset(ptr[0], 0, STRIPE_SIZE);
780 for (i= disks; i-- ;)
781 if (i!=pd_idx && sh->dev[i].towrite) {
782 chosen = sh->dev[i].towrite;
783 sh->dev[i].towrite = NULL;
784
785 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
786 wake_up(&conf->wait_for_overlap);
787
788 if (sh->dev[i].written) BUG();
789 sh->dev[i].written = chosen;
790 }
791 break;
792 case CHECK_PARITY:
793 break;
794 }
795 if (count>1) {
796 xor_block(count, STRIPE_SIZE, ptr);
797 count = 1;
798 }
799
800 for (i = disks; i--;)
801 if (sh->dev[i].written) {
802 sector_t sector = sh->dev[i].sector;
803 struct bio *wbi = sh->dev[i].written;
804 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
805 copy_data(1, wbi, sh->dev[i].page, sector);
806 wbi = r5_next_bio(wbi, sector);
807 }
808
809 set_bit(R5_LOCKED, &sh->dev[i].flags);
810 set_bit(R5_UPTODATE, &sh->dev[i].flags);
811 }
812
813 switch(method) {
814 case RECONSTRUCT_WRITE:
815 case CHECK_PARITY:
816 for (i=disks; i--;)
817 if (i != pd_idx) {
818 ptr[count++] = page_address(sh->dev[i].page);
819 check_xor();
820 }
821 break;
822 case READ_MODIFY_WRITE:
823 for (i = disks; i--;)
824 if (sh->dev[i].written) {
825 ptr[count++] = page_address(sh->dev[i].page);
826 check_xor();
827 }
828 }
829 if (count != 1)
830 xor_block(count, STRIPE_SIZE, ptr);
831
832 if (method != CHECK_PARITY) {
833 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
834 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
835 } else
836 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
837 }
838
839 /*
840 * Each stripe/dev can have one or more bion attached.
841 * toread/towrite point to the first in a chain.
842 * The bi_next chain must be in order.
843 */
844 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
845 {
846 struct bio **bip;
847 raid5_conf_t *conf = sh->raid_conf;
848 int firstwrite=0;
849
850 PRINTK("adding bh b#%llu to stripe s#%llu\n",
851 (unsigned long long)bi->bi_sector,
852 (unsigned long long)sh->sector);
853
854
855 spin_lock(&sh->lock);
856 spin_lock_irq(&conf->device_lock);
857 if (forwrite) {
858 bip = &sh->dev[dd_idx].towrite;
859 if (*bip == NULL && sh->dev[dd_idx].written == NULL)
860 firstwrite = 1;
861 } else
862 bip = &sh->dev[dd_idx].toread;
863 while (*bip && (*bip)->bi_sector < bi->bi_sector) {
864 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
865 goto overlap;
866 bip = & (*bip)->bi_next;
867 }
868 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
869 goto overlap;
870
871 if (*bip && bi->bi_next && (*bip) != bi->bi_next)
872 BUG();
873 if (*bip)
874 bi->bi_next = *bip;
875 *bip = bi;
876 bi->bi_phys_segments ++;
877 spin_unlock_irq(&conf->device_lock);
878 spin_unlock(&sh->lock);
879
880 PRINTK("added bi b#%llu to stripe s#%llu, disk %d.\n",
881 (unsigned long long)bi->bi_sector,
882 (unsigned long long)sh->sector, dd_idx);
883
884 if (conf->mddev->bitmap && firstwrite) {
885 sh->bm_seq = conf->seq_write;
886 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
887 STRIPE_SECTORS, 0);
888 set_bit(STRIPE_BIT_DELAY, &sh->state);
889 }
890
891 if (forwrite) {
892 /* check if page is covered */
893 sector_t sector = sh->dev[dd_idx].sector;
894 for (bi=sh->dev[dd_idx].towrite;
895 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
896 bi && bi->bi_sector <= sector;
897 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
898 if (bi->bi_sector + (bi->bi_size>>9) >= sector)
899 sector = bi->bi_sector + (bi->bi_size>>9);
900 }
901 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
902 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
903 }
904 return 1;
905
906 overlap:
907 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
908 spin_unlock_irq(&conf->device_lock);
909 spin_unlock(&sh->lock);
910 return 0;
911 }
912
913
914 /*
915 * handle_stripe - do things to a stripe.
916 *
917 * We lock the stripe and then examine the state of various bits
918 * to see what needs to be done.
919 * Possible results:
920 * return some read request which now have data
921 * return some write requests which are safely on disc
922 * schedule a read on some buffers
923 * schedule a write of some buffers
924 * return confirmation of parity correctness
925 *
926 * Parity calculations are done inside the stripe lock
927 * buffers are taken off read_list or write_list, and bh_cache buffers
928 * get BH_Lock set before the stripe lock is released.
929 *
930 */
931
932 static void handle_stripe(struct stripe_head *sh)
933 {
934 raid5_conf_t *conf = sh->raid_conf;
935 int disks = conf->raid_disks;
936 struct bio *return_bi= NULL;
937 struct bio *bi;
938 int i;
939 int syncing;
940 int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
941 int non_overwrite = 0;
942 int failed_num=0;
943 struct r5dev *dev;
944
945 PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n",
946 (unsigned long long)sh->sector, atomic_read(&sh->count),
947 sh->pd_idx);
948
949 spin_lock(&sh->lock);
950 clear_bit(STRIPE_HANDLE, &sh->state);
951 clear_bit(STRIPE_DELAYED, &sh->state);
952
953 syncing = test_bit(STRIPE_SYNCING, &sh->state);
954 /* Now to look around and see what can be done */
955
956 rcu_read_lock();
957 for (i=disks; i--; ) {
958 mdk_rdev_t *rdev;
959 dev = &sh->dev[i];
960 clear_bit(R5_Insync, &dev->flags);
961
962 PRINTK("check %d: state 0x%lx read %p write %p written %p\n",
963 i, dev->flags, dev->toread, dev->towrite, dev->written);
964 /* maybe we can reply to a read */
965 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
966 struct bio *rbi, *rbi2;
967 PRINTK("Return read for disc %d\n", i);
968 spin_lock_irq(&conf->device_lock);
969 rbi = dev->toread;
970 dev->toread = NULL;
971 if (test_and_clear_bit(R5_Overlap, &dev->flags))
972 wake_up(&conf->wait_for_overlap);
973 spin_unlock_irq(&conf->device_lock);
974 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) {
975 copy_data(0, rbi, dev->page, dev->sector);
976 rbi2 = r5_next_bio(rbi, dev->sector);
977 spin_lock_irq(&conf->device_lock);
978 if (--rbi->bi_phys_segments == 0) {
979 rbi->bi_next = return_bi;
980 return_bi = rbi;
981 }
982 spin_unlock_irq(&conf->device_lock);
983 rbi = rbi2;
984 }
985 }
986
987 /* now count some things */
988 if (test_bit(R5_LOCKED, &dev->flags)) locked++;
989 if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
990
991
992 if (dev->toread) to_read++;
993 if (dev->towrite) {
994 to_write++;
995 if (!test_bit(R5_OVERWRITE, &dev->flags))
996 non_overwrite++;
997 }
998 if (dev->written) written++;
999 rdev = rcu_dereference(conf->disks[i].rdev);
1000 if (!rdev || !test_bit(In_sync, &rdev->flags)) {
1001 /* The ReadError flag will just be confusing now */
1002 clear_bit(R5_ReadError, &dev->flags);
1003 clear_bit(R5_ReWrite, &dev->flags);
1004 }
1005 if (!rdev || !test_bit(In_sync, &rdev->flags)
1006 || test_bit(R5_ReadError, &dev->flags)) {
1007 failed++;
1008 failed_num = i;
1009 } else
1010 set_bit(R5_Insync, &dev->flags);
1011 }
1012 rcu_read_unlock();
1013 PRINTK("locked=%d uptodate=%d to_read=%d"
1014 " to_write=%d failed=%d failed_num=%d\n",
1015 locked, uptodate, to_read, to_write, failed, failed_num);
1016 /* check if the array has lost two devices and, if so, some requests might
1017 * need to be failed
1018 */
1019 if (failed > 1 && to_read+to_write+written) {
1020 for (i=disks; i--; ) {
1021 int bitmap_end = 0;
1022
1023 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1024 mdk_rdev_t *rdev;
1025 rcu_read_lock();
1026 rdev = rcu_dereference(conf->disks[i].rdev);
1027 if (rdev && test_bit(In_sync, &rdev->flags))
1028 /* multiple read failures in one stripe */
1029 md_error(conf->mddev, rdev);
1030 rcu_read_unlock();
1031 }
1032
1033 spin_lock_irq(&conf->device_lock);
1034 /* fail all writes first */
1035 bi = sh->dev[i].towrite;
1036 sh->dev[i].towrite = NULL;
1037 if (bi) { to_write--; bitmap_end = 1; }
1038
1039 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1040 wake_up(&conf->wait_for_overlap);
1041
1042 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
1043 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1044 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1045 if (--bi->bi_phys_segments == 0) {
1046 md_write_end(conf->mddev);
1047 bi->bi_next = return_bi;
1048 return_bi = bi;
1049 }
1050 bi = nextbi;
1051 }
1052 /* and fail all 'written' */
1053 bi = sh->dev[i].written;
1054 sh->dev[i].written = NULL;
1055 if (bi) bitmap_end = 1;
1056 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) {
1057 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
1058 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1059 if (--bi->bi_phys_segments == 0) {
1060 md_write_end(conf->mddev);
1061 bi->bi_next = return_bi;
1062 return_bi = bi;
1063 }
1064 bi = bi2;
1065 }
1066
1067 /* fail any reads if this device is non-operational */
1068 if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
1069 test_bit(R5_ReadError, &sh->dev[i].flags)) {
1070 bi = sh->dev[i].toread;
1071 sh->dev[i].toread = NULL;
1072 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1073 wake_up(&conf->wait_for_overlap);
1074 if (bi) to_read--;
1075 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
1076 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1077 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1078 if (--bi->bi_phys_segments == 0) {
1079 bi->bi_next = return_bi;
1080 return_bi = bi;
1081 }
1082 bi = nextbi;
1083 }
1084 }
1085 spin_unlock_irq(&conf->device_lock);
1086 if (bitmap_end)
1087 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
1088 STRIPE_SECTORS, 0, 0);
1089 }
1090 }
1091 if (failed > 1 && syncing) {
1092 md_done_sync(conf->mddev, STRIPE_SECTORS,0);
1093 clear_bit(STRIPE_SYNCING, &sh->state);
1094 syncing = 0;
1095 }
1096
1097 /* might be able to return some write requests if the parity block
1098 * is safe, or on a failed drive
1099 */
1100 dev = &sh->dev[sh->pd_idx];
1101 if ( written &&
1102 ( (test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) &&
1103 test_bit(R5_UPTODATE, &dev->flags))
1104 || (failed == 1 && failed_num == sh->pd_idx))
1105 ) {
1106 /* any written block on an uptodate or failed drive can be returned.
1107 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
1108 * never LOCKED, so we don't need to test 'failed' directly.
1109 */
1110 for (i=disks; i--; )
1111 if (sh->dev[i].written) {
1112 dev = &sh->dev[i];
1113 if (!test_bit(R5_LOCKED, &dev->flags) &&
1114 test_bit(R5_UPTODATE, &dev->flags) ) {
1115 /* We can return any write requests */
1116 struct bio *wbi, *wbi2;
1117 int bitmap_end = 0;
1118 PRINTK("Return write for disc %d\n", i);
1119 spin_lock_irq(&conf->device_lock);
1120 wbi = dev->written;
1121 dev->written = NULL;
1122 while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) {
1123 wbi2 = r5_next_bio(wbi, dev->sector);
1124 if (--wbi->bi_phys_segments == 0) {
1125 md_write_end(conf->mddev);
1126 wbi->bi_next = return_bi;
1127 return_bi = wbi;
1128 }
1129 wbi = wbi2;
1130 }
1131 if (dev->towrite == NULL)
1132 bitmap_end = 1;
1133 spin_unlock_irq(&conf->device_lock);
1134 if (bitmap_end)
1135 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
1136 STRIPE_SECTORS,
1137 !test_bit(STRIPE_DEGRADED, &sh->state), 0);
1138 }
1139 }
1140 }
1141
1142 /* Now we might consider reading some blocks, either to check/generate
1143 * parity, or to satisfy requests
1144 * or to load a block that is being partially written.
1145 */
1146 if (to_read || non_overwrite || (syncing && (uptodate < disks))) {
1147 for (i=disks; i--;) {
1148 dev = &sh->dev[i];
1149 if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1150 (dev->toread ||
1151 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
1152 syncing ||
1153 (failed && (sh->dev[failed_num].toread ||
1154 (sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags))))
1155 )
1156 ) {
1157 /* we would like to get this block, possibly
1158 * by computing it, but we might not be able to
1159 */
1160 if (uptodate == disks-1) {
1161 PRINTK("Computing block %d\n", i);
1162 compute_block(sh, i);
1163 uptodate++;
1164 } else if (test_bit(R5_Insync, &dev->flags)) {
1165 set_bit(R5_LOCKED, &dev->flags);
1166 set_bit(R5_Wantread, &dev->flags);
1167 #if 0
1168 /* if I am just reading this block and we don't have
1169 a failed drive, or any pending writes then sidestep the cache */
1170 if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext &&
1171 ! syncing && !failed && !to_write) {
1172 sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page;
1173 sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data;
1174 }
1175 #endif
1176 locked++;
1177 PRINTK("Reading block %d (sync=%d)\n",
1178 i, syncing);
1179 }
1180 }
1181 }
1182 set_bit(STRIPE_HANDLE, &sh->state);
1183 }
1184
1185 /* now to consider writing and what else, if anything should be read */
1186 if (to_write) {
1187 int rmw=0, rcw=0;
1188 for (i=disks ; i--;) {
1189 /* would I have to read this buffer for read_modify_write */
1190 dev = &sh->dev[i];
1191 if ((dev->towrite || i == sh->pd_idx) &&
1192 (!test_bit(R5_LOCKED, &dev->flags)
1193 #if 0
1194 || sh->bh_page[i]!=bh->b_page
1195 #endif
1196 ) &&
1197 !test_bit(R5_UPTODATE, &dev->flags)) {
1198 if (test_bit(R5_Insync, &dev->flags)
1199 /* && !(!mddev->insync && i == sh->pd_idx) */
1200 )
1201 rmw++;
1202 else rmw += 2*disks; /* cannot read it */
1203 }
1204 /* Would I have to read this buffer for reconstruct_write */
1205 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
1206 (!test_bit(R5_LOCKED, &dev->flags)
1207 #if 0
1208 || sh->bh_page[i] != bh->b_page
1209 #endif
1210 ) &&
1211 !test_bit(R5_UPTODATE, &dev->flags)) {
1212 if (test_bit(R5_Insync, &dev->flags)) rcw++;
1213 else rcw += 2*disks;
1214 }
1215 }
1216 PRINTK("for sector %llu, rmw=%d rcw=%d\n",
1217 (unsigned long long)sh->sector, rmw, rcw);
1218 set_bit(STRIPE_HANDLE, &sh->state);
1219 if (rmw < rcw && rmw > 0)
1220 /* prefer read-modify-write, but need to get some data */
1221 for (i=disks; i--;) {
1222 dev = &sh->dev[i];
1223 if ((dev->towrite || i == sh->pd_idx) &&
1224 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1225 test_bit(R5_Insync, &dev->flags)) {
1226 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1227 {
1228 PRINTK("Read_old block %d for r-m-w\n", i);
1229 set_bit(R5_LOCKED, &dev->flags);
1230 set_bit(R5_Wantread, &dev->flags);
1231 locked++;
1232 } else {
1233 set_bit(STRIPE_DELAYED, &sh->state);
1234 set_bit(STRIPE_HANDLE, &sh->state);
1235 }
1236 }
1237 }
1238 if (rcw <= rmw && rcw > 0)
1239 /* want reconstruct write, but need to get some data */
1240 for (i=disks; i--;) {
1241 dev = &sh->dev[i];
1242 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
1243 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1244 test_bit(R5_Insync, &dev->flags)) {
1245 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1246 {
1247 PRINTK("Read_old block %d for Reconstruct\n", i);
1248 set_bit(R5_LOCKED, &dev->flags);
1249 set_bit(R5_Wantread, &dev->flags);
1250 locked++;
1251 } else {
1252 set_bit(STRIPE_DELAYED, &sh->state);
1253 set_bit(STRIPE_HANDLE, &sh->state);
1254 }
1255 }
1256 }
1257 /* now if nothing is locked, and if we have enough data, we can start a write request */
1258 if (locked == 0 && (rcw == 0 ||rmw == 0) &&
1259 !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
1260 PRINTK("Computing parity...\n");
1261 compute_parity(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
1262 /* now every locked buffer is ready to be written */
1263 for (i=disks; i--;)
1264 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
1265 PRINTK("Writing block %d\n", i);
1266 locked++;
1267 set_bit(R5_Wantwrite, &sh->dev[i].flags);
1268 if (!test_bit(R5_Insync, &sh->dev[i].flags)
1269 || (i==sh->pd_idx && failed == 0))
1270 set_bit(STRIPE_INSYNC, &sh->state);
1271 }
1272 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
1273 atomic_dec(&conf->preread_active_stripes);
1274 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
1275 md_wakeup_thread(conf->mddev->thread);
1276 }
1277 }
1278 }
1279
1280 /* maybe we need to check and possibly fix the parity for this stripe
1281 * Any reads will already have been scheduled, so we just see if enough data
1282 * is available
1283 */
1284 if (syncing && locked == 0 &&
1285 !test_bit(STRIPE_INSYNC, &sh->state)) {
1286 set_bit(STRIPE_HANDLE, &sh->state);
1287 if (failed == 0) {
1288 char *pagea;
1289 if (uptodate != disks)
1290 BUG();
1291 compute_parity(sh, CHECK_PARITY);
1292 uptodate--;
1293 pagea = page_address(sh->dev[sh->pd_idx].page);
1294 if ((*(u32*)pagea) == 0 &&
1295 !memcmp(pagea, pagea+4, STRIPE_SIZE-4)) {
1296 /* parity is correct (on disc, not in buffer any more) */
1297 set_bit(STRIPE_INSYNC, &sh->state);
1298 } else {
1299 conf->mddev->resync_mismatches += STRIPE_SECTORS;
1300 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
1301 /* don't try to repair!! */
1302 set_bit(STRIPE_INSYNC, &sh->state);
1303 else {
1304 compute_block(sh, sh->pd_idx);
1305 uptodate++;
1306 }
1307 }
1308 }
1309 if (!test_bit(STRIPE_INSYNC, &sh->state)) {
1310 /* either failed parity check, or recovery is happening */
1311 if (failed==0)
1312 failed_num = sh->pd_idx;
1313 dev = &sh->dev[failed_num];
1314 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
1315 BUG_ON(uptodate != disks);
1316
1317 set_bit(R5_LOCKED, &dev->flags);
1318 set_bit(R5_Wantwrite, &dev->flags);
1319 clear_bit(STRIPE_DEGRADED, &sh->state);
1320 locked++;
1321 set_bit(STRIPE_INSYNC, &sh->state);
1322 }
1323 }
1324 if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
1325 md_done_sync(conf->mddev, STRIPE_SECTORS,1);
1326 clear_bit(STRIPE_SYNCING, &sh->state);
1327 }
1328
1329 /* If the failed drive is just a ReadError, then we might need to progress
1330 * the repair/check process
1331 */
1332 if (failed == 1 && ! conf->mddev->ro &&
1333 test_bit(R5_ReadError, &sh->dev[failed_num].flags)
1334 && !test_bit(R5_LOCKED, &sh->dev[failed_num].flags)
1335 && test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)
1336 ) {
1337 dev = &sh->dev[failed_num];
1338 if (!test_bit(R5_ReWrite, &dev->flags)) {
1339 set_bit(R5_Wantwrite, &dev->flags);
1340 set_bit(R5_ReWrite, &dev->flags);
1341 set_bit(R5_LOCKED, &dev->flags);
1342 } else {
1343 /* let's read it back */
1344 set_bit(R5_Wantread, &dev->flags);
1345 set_bit(R5_LOCKED, &dev->flags);
1346 }
1347 }
1348
1349 spin_unlock(&sh->lock);
1350
1351 while ((bi=return_bi)) {
1352 int bytes = bi->bi_size;
1353
1354 return_bi = bi->bi_next;
1355 bi->bi_next = NULL;
1356 bi->bi_size = 0;
1357 bi->bi_end_io(bi, bytes, 0);
1358 }
1359 for (i=disks; i-- ;) {
1360 int rw;
1361 struct bio *bi;
1362 mdk_rdev_t *rdev;
1363 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
1364 rw = 1;
1365 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1366 rw = 0;
1367 else
1368 continue;
1369
1370 bi = &sh->dev[i].req;
1371
1372 bi->bi_rw = rw;
1373 if (rw)
1374 bi->bi_end_io = raid5_end_write_request;
1375 else
1376 bi->bi_end_io = raid5_end_read_request;
1377
1378 rcu_read_lock();
1379 rdev = rcu_dereference(conf->disks[i].rdev);
1380 if (rdev && test_bit(Faulty, &rdev->flags))
1381 rdev = NULL;
1382 if (rdev)
1383 atomic_inc(&rdev->nr_pending);
1384 rcu_read_unlock();
1385
1386 if (rdev) {
1387 if (syncing)
1388 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1389
1390 bi->bi_bdev = rdev->bdev;
1391 PRINTK("for %llu schedule op %ld on disc %d\n",
1392 (unsigned long long)sh->sector, bi->bi_rw, i);
1393 atomic_inc(&sh->count);
1394 bi->bi_sector = sh->sector + rdev->data_offset;
1395 bi->bi_flags = 1 << BIO_UPTODATE;
1396 bi->bi_vcnt = 1;
1397 bi->bi_max_vecs = 1;
1398 bi->bi_idx = 0;
1399 bi->bi_io_vec = &sh->dev[i].vec;
1400 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1401 bi->bi_io_vec[0].bv_offset = 0;
1402 bi->bi_size = STRIPE_SIZE;
1403 bi->bi_next = NULL;
1404 if (rw == WRITE &&
1405 test_bit(R5_ReWrite, &sh->dev[i].flags))
1406 atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1407 generic_make_request(bi);
1408 } else {
1409 if (rw == 1)
1410 set_bit(STRIPE_DEGRADED, &sh->state);
1411 PRINTK("skip op %ld on disc %d for sector %llu\n",
1412 bi->bi_rw, i, (unsigned long long)sh->sector);
1413 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1414 set_bit(STRIPE_HANDLE, &sh->state);
1415 }
1416 }
1417 }
1418
1419 static void raid5_activate_delayed(raid5_conf_t *conf)
1420 {
1421 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
1422 while (!list_empty(&conf->delayed_list)) {
1423 struct list_head *l = conf->delayed_list.next;
1424 struct stripe_head *sh;
1425 sh = list_entry(l, struct stripe_head, lru);
1426 list_del_init(l);
1427 clear_bit(STRIPE_DELAYED, &sh->state);
1428 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1429 atomic_inc(&conf->preread_active_stripes);
1430 list_add_tail(&sh->lru, &conf->handle_list);
1431 }
1432 }
1433 }
1434
1435 static void activate_bit_delay(raid5_conf_t *conf)
1436 {
1437 /* device_lock is held */
1438 struct list_head head;
1439 list_add(&head, &conf->bitmap_list);
1440 list_del_init(&conf->bitmap_list);
1441 while (!list_empty(&head)) {
1442 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
1443 list_del_init(&sh->lru);
1444 atomic_inc(&sh->count);
1445 __release_stripe(conf, sh);
1446 }
1447 }
1448
1449 static void unplug_slaves(mddev_t *mddev)
1450 {
1451 raid5_conf_t *conf = mddev_to_conf(mddev);
1452 int i;
1453
1454 rcu_read_lock();
1455 for (i=0; i<mddev->raid_disks; i++) {
1456 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
1457 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
1458 request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
1459
1460 atomic_inc(&rdev->nr_pending);
1461 rcu_read_unlock();
1462
1463 if (r_queue->unplug_fn)
1464 r_queue->unplug_fn(r_queue);
1465
1466 rdev_dec_pending(rdev, mddev);
1467 rcu_read_lock();
1468 }
1469 }
1470 rcu_read_unlock();
1471 }
1472
1473 static void raid5_unplug_device(request_queue_t *q)
1474 {
1475 mddev_t *mddev = q->queuedata;
1476 raid5_conf_t *conf = mddev_to_conf(mddev);
1477 unsigned long flags;
1478
1479 spin_lock_irqsave(&conf->device_lock, flags);
1480
1481 if (blk_remove_plug(q)) {
1482 conf->seq_flush++;
1483 raid5_activate_delayed(conf);
1484 }
1485 md_wakeup_thread(mddev->thread);
1486
1487 spin_unlock_irqrestore(&conf->device_lock, flags);
1488
1489 unplug_slaves(mddev);
1490 }
1491
1492 static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk,
1493 sector_t *error_sector)
1494 {
1495 mddev_t *mddev = q->queuedata;
1496 raid5_conf_t *conf = mddev_to_conf(mddev);
1497 int i, ret = 0;
1498
1499 rcu_read_lock();
1500 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
1501 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
1502 if (rdev && !test_bit(Faulty, &rdev->flags)) {
1503 struct block_device *bdev = rdev->bdev;
1504 request_queue_t *r_queue = bdev_get_queue(bdev);
1505
1506 if (!r_queue->issue_flush_fn)
1507 ret = -EOPNOTSUPP;
1508 else {
1509 atomic_inc(&rdev->nr_pending);
1510 rcu_read_unlock();
1511 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
1512 error_sector);
1513 rdev_dec_pending(rdev, mddev);
1514 rcu_read_lock();
1515 }
1516 }
1517 }
1518 rcu_read_unlock();
1519 return ret;
1520 }
1521
1522 static inline void raid5_plug_device(raid5_conf_t *conf)
1523 {
1524 spin_lock_irq(&conf->device_lock);
1525 blk_plug_device(conf->mddev->queue);
1526 spin_unlock_irq(&conf->device_lock);
1527 }
1528
1529 static int make_request (request_queue_t *q, struct bio * bi)
1530 {
1531 mddev_t *mddev = q->queuedata;
1532 raid5_conf_t *conf = mddev_to_conf(mddev);
1533 const unsigned int raid_disks = conf->raid_disks;
1534 const unsigned int data_disks = raid_disks - 1;
1535 unsigned int dd_idx, pd_idx;
1536 sector_t new_sector;
1537 sector_t logical_sector, last_sector;
1538 struct stripe_head *sh;
1539 const int rw = bio_data_dir(bi);
1540
1541 if (unlikely(bio_barrier(bi))) {
1542 bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
1543 return 0;
1544 }
1545
1546 md_write_start(mddev, bi);
1547
1548 disk_stat_inc(mddev->gendisk, ios[rw]);
1549 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
1550
1551 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
1552 last_sector = bi->bi_sector + (bi->bi_size>>9);
1553 bi->bi_next = NULL;
1554 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
1555
1556 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
1557 DEFINE_WAIT(w);
1558
1559 new_sector = raid5_compute_sector(logical_sector,
1560 raid_disks, data_disks, &dd_idx, &pd_idx, conf);
1561
1562 PRINTK("raid5: make_request, sector %llu logical %llu\n",
1563 (unsigned long long)new_sector,
1564 (unsigned long long)logical_sector);
1565
1566 retry:
1567 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
1568 sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK));
1569 if (sh) {
1570 if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
1571 /* Add failed due to overlap. Flush everything
1572 * and wait a while
1573 */
1574 raid5_unplug_device(mddev->queue);
1575 release_stripe(sh);
1576 schedule();
1577 goto retry;
1578 }
1579 finish_wait(&conf->wait_for_overlap, &w);
1580 raid5_plug_device(conf);
1581 handle_stripe(sh);
1582 release_stripe(sh);
1583
1584 } else {
1585 /* cannot get stripe for read-ahead, just give-up */
1586 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1587 finish_wait(&conf->wait_for_overlap, &w);
1588 break;
1589 }
1590
1591 }
1592 spin_lock_irq(&conf->device_lock);
1593 if (--bi->bi_phys_segments == 0) {
1594 int bytes = bi->bi_size;
1595
1596 if ( bio_data_dir(bi) == WRITE )
1597 md_write_end(mddev);
1598 bi->bi_size = 0;
1599 bi->bi_end_io(bi, bytes, 0);
1600 }
1601 spin_unlock_irq(&conf->device_lock);
1602 return 0;
1603 }
1604
1605 /* FIXME go_faster isn't used */
1606 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1607 {
1608 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
1609 struct stripe_head *sh;
1610 int sectors_per_chunk = conf->chunk_size >> 9;
1611 sector_t x;
1612 unsigned long stripe;
1613 int chunk_offset;
1614 int dd_idx, pd_idx;
1615 sector_t first_sector;
1616 int raid_disks = conf->raid_disks;
1617 int data_disks = raid_disks-1;
1618 sector_t max_sector = mddev->size << 1;
1619 int sync_blocks;
1620
1621 if (sector_nr >= max_sector) {
1622 /* just being told to finish up .. nothing much to do */
1623 unplug_slaves(mddev);
1624
1625 if (mddev->curr_resync < max_sector) /* aborted */
1626 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1627 &sync_blocks, 1);
1628 else /* compelted sync */
1629 conf->fullsync = 0;
1630 bitmap_close_sync(mddev->bitmap);
1631
1632 return 0;
1633 }
1634 /* if there is 1 or more failed drives and we are trying
1635 * to resync, then assert that we are finished, because there is
1636 * nothing we can do.
1637 */
1638 if (mddev->degraded >= 1 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
1639 sector_t rv = (mddev->size << 1) - sector_nr;
1640 *skipped = 1;
1641 return rv;
1642 }
1643 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1644 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1645 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
1646 /* we can skip this block, and probably more */
1647 sync_blocks /= STRIPE_SECTORS;
1648 *skipped = 1;
1649 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
1650 }
1651
1652 x = sector_nr;
1653 chunk_offset = sector_div(x, sectors_per_chunk);
1654 stripe = x;
1655 BUG_ON(x != stripe);
1656
1657 first_sector = raid5_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk
1658 + chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf);
1659 sh = get_active_stripe(conf, sector_nr, pd_idx, 1);
1660 if (sh == NULL) {
1661 sh = get_active_stripe(conf, sector_nr, pd_idx, 0);
1662 /* make sure we don't swamp the stripe cache if someone else
1663 * is trying to get access
1664 */
1665 schedule_timeout_uninterruptible(1);
1666 }
1667 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 0);
1668 spin_lock(&sh->lock);
1669 set_bit(STRIPE_SYNCING, &sh->state);
1670 clear_bit(STRIPE_INSYNC, &sh->state);
1671 spin_unlock(&sh->lock);
1672
1673 handle_stripe(sh);
1674 release_stripe(sh);
1675
1676 return STRIPE_SECTORS;
1677 }
1678
1679 /*
1680 * This is our raid5 kernel thread.
1681 *
1682 * We scan the hash table for stripes which can be handled now.
1683 * During the scan, completed stripes are saved for us by the interrupt
1684 * handler, so that they will not have to wait for our next wakeup.
1685 */
1686 static void raid5d (mddev_t *mddev)
1687 {
1688 struct stripe_head *sh;
1689 raid5_conf_t *conf = mddev_to_conf(mddev);
1690 int handled;
1691
1692 PRINTK("+++ raid5d active\n");
1693
1694 md_check_recovery(mddev);
1695
1696 handled = 0;
1697 spin_lock_irq(&conf->device_lock);
1698 while (1) {
1699 struct list_head *first;
1700
1701 if (conf->seq_flush - conf->seq_write > 0) {
1702 int seq = conf->seq_flush;
1703 spin_unlock_irq(&conf->device_lock);
1704 bitmap_unplug(mddev->bitmap);
1705 spin_lock_irq(&conf->device_lock);
1706 conf->seq_write = seq;
1707 activate_bit_delay(conf);
1708 }
1709
1710 if (list_empty(&conf->handle_list) &&
1711 atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
1712 !blk_queue_plugged(mddev->queue) &&
1713 !list_empty(&conf->delayed_list))
1714 raid5_activate_delayed(conf);
1715
1716 if (list_empty(&conf->handle_list))
1717 break;
1718
1719 first = conf->handle_list.next;
1720 sh = list_entry(first, struct stripe_head, lru);
1721
1722 list_del_init(first);
1723 atomic_inc(&sh->count);
1724 if (atomic_read(&sh->count)!= 1)
1725 BUG();
1726 spin_unlock_irq(&conf->device_lock);
1727
1728 handled++;
1729 handle_stripe(sh);
1730 release_stripe(sh);
1731
1732 spin_lock_irq(&conf->device_lock);
1733 }
1734 PRINTK("%d stripes handled\n", handled);
1735
1736 spin_unlock_irq(&conf->device_lock);
1737
1738 unplug_slaves(mddev);
1739
1740 PRINTK("--- raid5d inactive\n");
1741 }
1742
1743 static ssize_t
1744 raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
1745 {
1746 raid5_conf_t *conf = mddev_to_conf(mddev);
1747 if (conf)
1748 return sprintf(page, "%d\n", conf->max_nr_stripes);
1749 else
1750 return 0;
1751 }
1752
1753 static ssize_t
1754 raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
1755 {
1756 raid5_conf_t *conf = mddev_to_conf(mddev);
1757 char *end;
1758 int new;
1759 if (len >= PAGE_SIZE)
1760 return -EINVAL;
1761 if (!conf)
1762 return -ENODEV;
1763
1764 new = simple_strtoul(page, &end, 10);
1765 if (!*page || (*end && *end != '\n') )
1766 return -EINVAL;
1767 if (new <= 16 || new > 32768)
1768 return -EINVAL;
1769 while (new < conf->max_nr_stripes) {
1770 if (drop_one_stripe(conf))
1771 conf->max_nr_stripes--;
1772 else
1773 break;
1774 }
1775 while (new > conf->max_nr_stripes) {
1776 if (grow_one_stripe(conf))
1777 conf->max_nr_stripes++;
1778 else break;
1779 }
1780 return len;
1781 }
1782
1783 static struct md_sysfs_entry
1784 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
1785 raid5_show_stripe_cache_size,
1786 raid5_store_stripe_cache_size);
1787
1788 static ssize_t
1789 stripe_cache_active_show(mddev_t *mddev, char *page)
1790 {
1791 raid5_conf_t *conf = mddev_to_conf(mddev);
1792 if (conf)
1793 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
1794 else
1795 return 0;
1796 }
1797
1798 static struct md_sysfs_entry
1799 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
1800
1801 static struct attribute *raid5_attrs[] = {
1802 &raid5_stripecache_size.attr,
1803 &raid5_stripecache_active.attr,
1804 NULL,
1805 };
1806 static struct attribute_group raid5_attrs_group = {
1807 .name = NULL,
1808 .attrs = raid5_attrs,
1809 };
1810
1811 static int run(mddev_t *mddev)
1812 {
1813 raid5_conf_t *conf;
1814 int raid_disk, memory;
1815 mdk_rdev_t *rdev;
1816 struct disk_info *disk;
1817 struct list_head *tmp;
1818
1819 if (mddev->level != 5 && mddev->level != 4) {
1820 printk(KERN_ERR "raid5: %s: raid level not set to 4/5 (%d)\n",
1821 mdname(mddev), mddev->level);
1822 return -EIO;
1823 }
1824
1825 mddev->private = kzalloc(sizeof (raid5_conf_t)
1826 + mddev->raid_disks * sizeof(struct disk_info),
1827 GFP_KERNEL);
1828 if ((conf = mddev->private) == NULL)
1829 goto abort;
1830
1831 conf->mddev = mddev;
1832
1833 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
1834 goto abort;
1835
1836 spin_lock_init(&conf->device_lock);
1837 init_waitqueue_head(&conf->wait_for_stripe);
1838 init_waitqueue_head(&conf->wait_for_overlap);
1839 INIT_LIST_HEAD(&conf->handle_list);
1840 INIT_LIST_HEAD(&conf->delayed_list);
1841 INIT_LIST_HEAD(&conf->bitmap_list);
1842 INIT_LIST_HEAD(&conf->inactive_list);
1843 atomic_set(&conf->active_stripes, 0);
1844 atomic_set(&conf->preread_active_stripes, 0);
1845
1846 PRINTK("raid5: run(%s) called.\n", mdname(mddev));
1847
1848 ITERATE_RDEV(mddev,rdev,tmp) {
1849 raid_disk = rdev->raid_disk;
1850 if (raid_disk >= mddev->raid_disks
1851 || raid_disk < 0)
1852 continue;
1853 disk = conf->disks + raid_disk;
1854
1855 disk->rdev = rdev;
1856
1857 if (test_bit(In_sync, &rdev->flags)) {
1858 char b[BDEVNAME_SIZE];
1859 printk(KERN_INFO "raid5: device %s operational as raid"
1860 " disk %d\n", bdevname(rdev->bdev,b),
1861 raid_disk);
1862 conf->working_disks++;
1863 }
1864 }
1865
1866 conf->raid_disks = mddev->raid_disks;
1867 /*
1868 * 0 for a fully functional array, 1 for a degraded array.
1869 */
1870 mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks;
1871 conf->mddev = mddev;
1872 conf->chunk_size = mddev->chunk_size;
1873 conf->level = mddev->level;
1874 conf->algorithm = mddev->layout;
1875 conf->max_nr_stripes = NR_STRIPES;
1876
1877 /* device size must be a multiple of chunk size */
1878 mddev->size &= ~(mddev->chunk_size/1024 -1);
1879 mddev->resync_max_sectors = mddev->size << 1;
1880
1881 if (!conf->chunk_size || conf->chunk_size % 4) {
1882 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
1883 conf->chunk_size, mdname(mddev));
1884 goto abort;
1885 }
1886 if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) {
1887 printk(KERN_ERR
1888 "raid5: unsupported parity algorithm %d for %s\n",
1889 conf->algorithm, mdname(mddev));
1890 goto abort;
1891 }
1892 if (mddev->degraded > 1) {
1893 printk(KERN_ERR "raid5: not enough operational devices for %s"
1894 " (%d/%d failed)\n",
1895 mdname(mddev), conf->failed_disks, conf->raid_disks);
1896 goto abort;
1897 }
1898
1899 if (mddev->degraded == 1 &&
1900 mddev->recovery_cp != MaxSector) {
1901 if (mddev->ok_start_degraded)
1902 printk(KERN_WARNING
1903 "raid5: starting dirty degraded array: %s"
1904 "- data corruption possible.\n",
1905 mdname(mddev));
1906 else {
1907 printk(KERN_ERR
1908 "raid5: cannot start dirty degraded array for %s\n",
1909 mdname(mddev));
1910 goto abort;
1911 }
1912 }
1913
1914 {
1915 mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5");
1916 if (!mddev->thread) {
1917 printk(KERN_ERR
1918 "raid5: couldn't allocate thread for %s\n",
1919 mdname(mddev));
1920 goto abort;
1921 }
1922 }
1923 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
1924 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
1925 if (grow_stripes(conf, conf->max_nr_stripes)) {
1926 printk(KERN_ERR
1927 "raid5: couldn't allocate %dkB for buffers\n", memory);
1928 shrink_stripes(conf);
1929 md_unregister_thread(mddev->thread);
1930 goto abort;
1931 } else
1932 printk(KERN_INFO "raid5: allocated %dkB for %s\n",
1933 memory, mdname(mddev));
1934
1935 if (mddev->degraded == 0)
1936 printk("raid5: raid level %d set %s active with %d out of %d"
1937 " devices, algorithm %d\n", conf->level, mdname(mddev),
1938 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
1939 conf->algorithm);
1940 else
1941 printk(KERN_ALERT "raid5: raid level %d set %s active with %d"
1942 " out of %d devices, algorithm %d\n", conf->level,
1943 mdname(mddev), mddev->raid_disks - mddev->degraded,
1944 mddev->raid_disks, conf->algorithm);
1945
1946 print_raid5_conf(conf);
1947
1948 /* read-ahead size must cover two whole stripes, which is
1949 * 2 * (n-1) * chunksize where 'n' is the number of raid devices
1950 */
1951 {
1952 int stripe = (mddev->raid_disks-1) * mddev->chunk_size
1953 / PAGE_SIZE;
1954 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
1955 mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
1956 }
1957
1958 /* Ok, everything is just fine now */
1959 sysfs_create_group(&mddev->kobj, &raid5_attrs_group);
1960
1961 mddev->queue->unplug_fn = raid5_unplug_device;
1962 mddev->queue->issue_flush_fn = raid5_issue_flush;
1963
1964 mddev->array_size = mddev->size * (mddev->raid_disks - 1);
1965 return 0;
1966 abort:
1967 if (conf) {
1968 print_raid5_conf(conf);
1969 kfree(conf->stripe_hashtbl);
1970 kfree(conf);
1971 }
1972 mddev->private = NULL;
1973 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev));
1974 return -EIO;
1975 }
1976
1977
1978
1979 static int stop(mddev_t *mddev)
1980 {
1981 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
1982
1983 md_unregister_thread(mddev->thread);
1984 mddev->thread = NULL;
1985 shrink_stripes(conf);
1986 kfree(conf->stripe_hashtbl);
1987 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
1988 sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
1989 kfree(conf);
1990 mddev->private = NULL;
1991 return 0;
1992 }
1993
1994 #if RAID5_DEBUG
1995 static void print_sh (struct stripe_head *sh)
1996 {
1997 int i;
1998
1999 printk("sh %llu, pd_idx %d, state %ld.\n",
2000 (unsigned long long)sh->sector, sh->pd_idx, sh->state);
2001 printk("sh %llu, count %d.\n",
2002 (unsigned long long)sh->sector, atomic_read(&sh->count));
2003 printk("sh %llu, ", (unsigned long long)sh->sector);
2004 for (i = 0; i < sh->raid_conf->raid_disks; i++) {
2005 printk("(cache%d: %p %ld) ",
2006 i, sh->dev[i].page, sh->dev[i].flags);
2007 }
2008 printk("\n");
2009 }
2010
2011 static void printall (raid5_conf_t *conf)
2012 {
2013 struct stripe_head *sh;
2014 struct hlist_node *hn;
2015 int i;
2016
2017 spin_lock_irq(&conf->device_lock);
2018 for (i = 0; i < NR_HASH; i++) {
2019 hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
2020 if (sh->raid_conf != conf)
2021 continue;
2022 print_sh(sh);
2023 }
2024 }
2025 spin_unlock_irq(&conf->device_lock);
2026 }
2027 #endif
2028
2029 static void status (struct seq_file *seq, mddev_t *mddev)
2030 {
2031 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
2032 int i;
2033
2034 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout);
2035 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks);
2036 for (i = 0; i < conf->raid_disks; i++)
2037 seq_printf (seq, "%s",
2038 conf->disks[i].rdev &&
2039 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
2040 seq_printf (seq, "]");
2041 #if RAID5_DEBUG
2042 #define D(x) \
2043 seq_printf (seq, "<"#x":%d>", atomic_read(&conf->x))
2044 printall(conf);
2045 #endif
2046 }
2047
2048 static void print_raid5_conf (raid5_conf_t *conf)
2049 {
2050 int i;
2051 struct disk_info *tmp;
2052
2053 printk("RAID5 conf printout:\n");
2054 if (!conf) {
2055 printk("(conf==NULL)\n");
2056 return;
2057 }
2058 printk(" --- rd:%d wd:%d fd:%d\n", conf->raid_disks,
2059 conf->working_disks, conf->failed_disks);
2060
2061 for (i = 0; i < conf->raid_disks; i++) {
2062 char b[BDEVNAME_SIZE];
2063 tmp = conf->disks + i;
2064 if (tmp->rdev)
2065 printk(" disk %d, o:%d, dev:%s\n",
2066 i, !test_bit(Faulty, &tmp->rdev->flags),
2067 bdevname(tmp->rdev->bdev,b));
2068 }
2069 }
2070
2071 static int raid5_spare_active(mddev_t *mddev)
2072 {
2073 int i;
2074 raid5_conf_t *conf = mddev->private;
2075 struct disk_info *tmp;
2076
2077 for (i = 0; i < conf->raid_disks; i++) {
2078 tmp = conf->disks + i;
2079 if (tmp->rdev
2080 && !test_bit(Faulty, &tmp->rdev->flags)
2081 && !test_bit(In_sync, &tmp->rdev->flags)) {
2082 mddev->degraded--;
2083 conf->failed_disks--;
2084 conf->working_disks++;
2085 set_bit(In_sync, &tmp->rdev->flags);
2086 }
2087 }
2088 print_raid5_conf(conf);
2089 return 0;
2090 }
2091
2092 static int raid5_remove_disk(mddev_t *mddev, int number)
2093 {
2094 raid5_conf_t *conf = mddev->private;
2095 int err = 0;
2096 mdk_rdev_t *rdev;
2097 struct disk_info *p = conf->disks + number;
2098
2099 print_raid5_conf(conf);
2100 rdev = p->rdev;
2101 if (rdev) {
2102 if (test_bit(In_sync, &rdev->flags) ||
2103 atomic_read(&rdev->nr_pending)) {
2104 err = -EBUSY;
2105 goto abort;
2106 }
2107 p->rdev = NULL;
2108 synchronize_rcu();
2109 if (atomic_read(&rdev->nr_pending)) {
2110 /* lost the race, try later */
2111 err = -EBUSY;
2112 p->rdev = rdev;
2113 }
2114 }
2115 abort:
2116
2117 print_raid5_conf(conf);
2118 return err;
2119 }
2120
2121 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
2122 {
2123 raid5_conf_t *conf = mddev->private;
2124 int found = 0;
2125 int disk;
2126 struct disk_info *p;
2127
2128 if (mddev->degraded > 1)
2129 /* no point adding a device */
2130 return 0;
2131
2132 /*
2133 * find the disk ...
2134 */
2135 for (disk=0; disk < mddev->raid_disks; disk++)
2136 if ((p=conf->disks + disk)->rdev == NULL) {
2137 clear_bit(In_sync, &rdev->flags);
2138 rdev->raid_disk = disk;
2139 found = 1;
2140 if (rdev->saved_raid_disk != disk)
2141 conf->fullsync = 1;
2142 rcu_assign_pointer(p->rdev, rdev);
2143 break;
2144 }
2145 print_raid5_conf(conf);
2146 return found;
2147 }
2148
2149 static int raid5_resize(mddev_t *mddev, sector_t sectors)
2150 {
2151 /* no resync is happening, and there is enough space
2152 * on all devices, so we can resize.
2153 * We need to make sure resync covers any new space.
2154 * If the array is shrinking we should possibly wait until
2155 * any io in the removed space completes, but it hardly seems
2156 * worth it.
2157 */
2158 sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
2159 mddev->array_size = (sectors * (mddev->raid_disks-1))>>1;
2160 set_capacity(mddev->gendisk, mddev->array_size << 1);
2161 mddev->changed = 1;
2162 if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) {
2163 mddev->recovery_cp = mddev->size << 1;
2164 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2165 }
2166 mddev->size = sectors /2;
2167 mddev->resync_max_sectors = sectors;
2168 return 0;
2169 }
2170
2171 static void raid5_quiesce(mddev_t *mddev, int state)
2172 {
2173 raid5_conf_t *conf = mddev_to_conf(mddev);
2174
2175 switch(state) {
2176 case 1: /* stop all writes */
2177 spin_lock_irq(&conf->device_lock);
2178 conf->quiesce = 1;
2179 wait_event_lock_irq(conf->wait_for_stripe,
2180 atomic_read(&conf->active_stripes) == 0,
2181 conf->device_lock, /* nothing */);
2182 spin_unlock_irq(&conf->device_lock);
2183 break;
2184
2185 case 0: /* re-enable writes */
2186 spin_lock_irq(&conf->device_lock);
2187 conf->quiesce = 0;
2188 wake_up(&conf->wait_for_stripe);
2189 spin_unlock_irq(&conf->device_lock);
2190 break;
2191 }
2192 }
2193
2194 static struct mdk_personality raid5_personality =
2195 {
2196 .name = "raid5",
2197 .level = 5,
2198 .owner = THIS_MODULE,
2199 .make_request = make_request,
2200 .run = run,
2201 .stop = stop,
2202 .status = status,
2203 .error_handler = error,
2204 .hot_add_disk = raid5_add_disk,
2205 .hot_remove_disk= raid5_remove_disk,
2206 .spare_active = raid5_spare_active,
2207 .sync_request = sync_request,
2208 .resize = raid5_resize,
2209 .quiesce = raid5_quiesce,
2210 };
2211
2212 static struct mdk_personality raid4_personality =
2213 {
2214 .name = "raid4",
2215 .level = 4,
2216 .owner = THIS_MODULE,
2217 .make_request = make_request,
2218 .run = run,
2219 .stop = stop,
2220 .status = status,
2221 .error_handler = error,
2222 .hot_add_disk = raid5_add_disk,
2223 .hot_remove_disk= raid5_remove_disk,
2224 .spare_active = raid5_spare_active,
2225 .sync_request = sync_request,
2226 .resize = raid5_resize,
2227 .quiesce = raid5_quiesce,
2228 };
2229
2230 static int __init raid5_init(void)
2231 {
2232 register_md_personality(&raid5_personality);
2233 register_md_personality(&raid4_personality);
2234 return 0;
2235 }
2236
2237 static void raid5_exit(void)
2238 {
2239 unregister_md_personality(&raid5_personality);
2240 unregister_md_personality(&raid4_personality);
2241 }
2242
2243 module_init(raid5_init);
2244 module_exit(raid5_exit);
2245 MODULE_LICENSE("GPL");
2246 MODULE_ALIAS("md-personality-4"); /* RAID5 */
2247 MODULE_ALIAS("md-raid5");
2248 MODULE_ALIAS("md-raid4");
2249 MODULE_ALIAS("md-level-5");
2250 MODULE_ALIAS("md-level-4");
linux kernel for loongson