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[net-next-2.6.git] / drivers / md / raid5.c
CommitLineData
1da177e4
LT		 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
72626685
N		 27#include <linux/raid/bitmap.h>
28
1da177e4
LT		 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
fccddba0 38#define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
1da177e4
LT		 39#define HASH_MASK (NR_HASH - 1)
40
fccddba0 41#define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
1da177e4
LT		 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
70static void print_raid5_conf (raid5_conf_t *conf);
71
72static inline 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);
72626685
N		 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);
1da177e4 87 list_add_tail(&sh->lru, &conf->handle_list);
72626685 88 }
1da177e4
LT		 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 ||
5036805b 99 atomic_read(&conf->active_stripes) < (conf->max_nr_stripes*3/4))
1da177e4
LT		 100 wake_up(&conf->wait_for_stripe);
101 }
102 }
103}
104static 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
fccddba0 114static inline void remove_hash(struct stripe_head *sh)
1da177e4
LT		 115{
116 PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector);
117
fccddba0 118 hlist_del_init(&sh->hash);
1da177e4
LT		 119}
120
fccddba0 121static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
1da177e4 122{
fccddba0 123 struct hlist_head *hp = stripe_hash(conf, sh->sector);
1da177e4
LT		 124
125 PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector);
126
127 CHECK_DEVLOCK();
fccddba0 128 hlist_add_head(&sh->hash, hp);
1da177e4
LT		 129}
130
131
132/* find an idle stripe, make sure it is unhashed, and return it. */
133static 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);
146out:
147 return sh;
148}
149
150static 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;
2d1f3b5d 160 put_page(p);
1da177e4
LT		 161 }
162}
163
164static 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
179static void raid5_build_block (struct stripe_head *sh, int i);
180
181static inline 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
218static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector)
219{
220 struct stripe_head *sh;
fccddba0 221 struct hlist_node *hn;
1da177e4
LT		 222
223 CHECK_DEVLOCK();
224 PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector);
fccddba0 225 hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
1da177e4
LT		 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
232static void unplug_slaves(mddev_t *mddev);
233static void raid5_unplug_device(request_queue_t *q);
234
235static 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 {
72626685
N		 245 wait_event_lock_irq(conf->wait_for_stripe,
246 conf->quiesce == 0,
247 conf->device_lock, /* nothing */);
1da177e4
LT		 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) &&
5036805b
N		 258 (atomic_read(&conf->active_stripes)
259 < (conf->max_nr_stripes *3/4)
1da177e4
LT		 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
3f294f4f 288static int grow_one_stripe(raid5_conf_t *conf)
1da177e4
LT		 289{
290 struct stripe_head *sh;
3f294f4f
N		 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
311static int grow_stripes(raid5_conf_t *conf, int num)
312{
1da177e4
LT		 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--) {
3f294f4f 325 if (!grow_one_stripe(conf))
1da177e4 326 return 1;
1da177e4
LT		 327 }
328 return 0;
329}
330
3f294f4f 331static int drop_one_stripe(raid5_conf_t *conf)
1da177e4
LT		 332{
333 struct stripe_head *sh;
334
3f294f4f
N		 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
348static void shrink_stripes(raid5_conf_t *conf)
349{
350 while (drop_one_stripe(conf))
351 ;
352
1da177e4
LT		 353 kmem_cache_destroy(conf->slab_cache);
354 conf->slab_cache = NULL;
355}
356
4e5314b5 357static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done,
1da177e4
LT		 358 int error)
359{
360 struct stripe_head *sh = bi->bi_private;
361 raid5_conf_t *conf = sh->raid_conf;
362 int disks = conf->raid_disks, i;
363 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
364
365 if (bi->bi_size)
366 return 1;
367
368 for (i=0 ; i<disks; i++)
369 if (bi == &sh->dev[i].req)
370 break;
371
372 PRINTK("end_read_request %llu/%d, count: %d, uptodate %d.\n",
373 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
374 uptodate);
375 if (i == disks) {
376 BUG();
377 return 0;
378 }
379
380 if (uptodate) {
381#if 0
382 struct bio *bio;
383 unsigned long flags;
384 spin_lock_irqsave(&conf->device_lock, flags);
385 /* we can return a buffer if we bypassed the cache or
386 * if the top buffer is not in highmem. If there are
387 * multiple buffers, leave the extra work to
388 * handle_stripe
389 */
390 buffer = sh->bh_read[i];
391 if (buffer &&
392 (!PageHighMem(buffer->b_page)
393 || buffer->b_page == bh->b_page )
394 ) {
395 sh->bh_read[i] = buffer->b_reqnext;
396 buffer->b_reqnext = NULL;
397 } else
398 buffer = NULL;
399 spin_unlock_irqrestore(&conf->device_lock, flags);
400 if (sh->bh_page[i]==bh->b_page)
401 set_buffer_uptodate(bh);
402 if (buffer) {
403 if (buffer->b_page != bh->b_page)
404 memcpy(buffer->b_data, bh->b_data, bh->b_size);
405 buffer->b_end_io(buffer, 1);
406 }
407#else
408 set_bit(R5_UPTODATE, &sh->dev[i].flags);
4e5314b5
N		 409#endif
410 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
14f8d26b 411 printk(KERN_INFO "raid5: read error corrected!!\n");
4e5314b5
N		 412 clear_bit(R5_ReadError, &sh->dev[i].flags);
413 clear_bit(R5_ReWrite, &sh->dev[i].flags);
414 }
ba22dcbf
N		 415 if (atomic_read(&conf->disks[i].rdev->read_errors))
416 atomic_set(&conf->disks[i].rdev->read_errors, 0);
1da177e4 417 } else {
ba22dcbf 418 int retry = 0;
1da177e4 419 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
ba22dcbf
N		 420 atomic_inc(&conf->disks[i].rdev->read_errors);
421 if (conf->mddev->degraded)
14f8d26b 422 printk(KERN_WARNING "raid5: read error not correctable.\n");
ba22dcbf 423 else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
4e5314b5 424 /* Oh, no!!! */
14f8d26b 425 printk(KERN_WARNING "raid5: read error NOT corrected!!\n");
ba22dcbf
N		 426 else if (atomic_read(&conf->disks[i].rdev->read_errors)
427 > conf->max_nr_stripes)
14f8d26b
N		 428 printk(KERN_WARNING
429 "raid5: Too many read errors, failing device.\n");
ba22dcbf
N		 430 else
431 retry = 1;
432 if (retry)
433 set_bit(R5_ReadError, &sh->dev[i].flags);
434 else {
4e5314b5
N		 435 clear_bit(R5_ReadError, &sh->dev[i].flags);
436 clear_bit(R5_ReWrite, &sh->dev[i].flags);
437 md_error(conf->mddev, conf->disks[i].rdev);
ba22dcbf 438 }
1da177e4
LT		 439 }
440 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
441#if 0
442 /* must restore b_page before unlocking buffer... */
443 if (sh->bh_page[i] != bh->b_page) {
444 bh->b_page = sh->bh_page[i];
445 bh->b_data = page_address(bh->b_page);
446 clear_buffer_uptodate(bh);
447 }
448#endif
449 clear_bit(R5_LOCKED, &sh->dev[i].flags);
450 set_bit(STRIPE_HANDLE, &sh->state);
451 release_stripe(sh);
452 return 0;
453}
454
455static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done,
456 int error)
457{
458 struct stripe_head *sh = bi->bi_private;
459 raid5_conf_t *conf = sh->raid_conf;
460 int disks = conf->raid_disks, i;
461 unsigned long flags;
462 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
463
464 if (bi->bi_size)
465 return 1;
466
467 for (i=0 ; i<disks; i++)
468 if (bi == &sh->dev[i].req)
469 break;
470
471 PRINTK("end_write_request %llu/%d, count %d, uptodate: %d.\n",
472 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
473 uptodate);
474 if (i == disks) {
475 BUG();
476 return 0;
477 }
478
479 spin_lock_irqsave(&conf->device_lock, flags);
480 if (!uptodate)
481 md_error(conf->mddev, conf->disks[i].rdev);
482
483 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
484
485 clear_bit(R5_LOCKED, &sh->dev[i].flags);
486 set_bit(STRIPE_HANDLE, &sh->state);
487 __release_stripe(conf, sh);
488 spin_unlock_irqrestore(&conf->device_lock, flags);
489 return 0;
490}
491
492
493static sector_t compute_blocknr(struct stripe_head *sh, int i);
494
495static void raid5_build_block (struct stripe_head *sh, int i)
496{
497 struct r5dev *dev = &sh->dev[i];
498
499 bio_init(&dev->req);
500 dev->req.bi_io_vec = &dev->vec;
501 dev->req.bi_vcnt++;
502 dev->req.bi_max_vecs++;
503 dev->vec.bv_page = dev->page;
504 dev->vec.bv_len = STRIPE_SIZE;
505 dev->vec.bv_offset = 0;
506
507 dev->req.bi_sector = sh->sector;
508 dev->req.bi_private = sh;
509
510 dev->flags = 0;
511 if (i != sh->pd_idx)
512 dev->sector = compute_blocknr(sh, i);
513}
514
515static void error(mddev_t *mddev, mdk_rdev_t *rdev)
516{
517 char b[BDEVNAME_SIZE];
518 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
519 PRINTK("raid5: error called\n");
520
b2d444d7 521 if (!test_bit(Faulty, &rdev->flags)) {
1da177e4 522 mddev->sb_dirty = 1;
b2d444d7 523 if (test_bit(In_sync, &rdev->flags)) {
1da177e4
LT		 524 conf->working_disks--;
525 mddev->degraded++;
526 conf->failed_disks++;
b2d444d7 527 clear_bit(In_sync, &rdev->flags);
1da177e4
LT		 528 /*
529 * if recovery was running, make sure it aborts.
530 */
531 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
532 }
b2d444d7 533 set_bit(Faulty, &rdev->flags);
1da177e4
LT		 534 printk (KERN_ALERT
535 "raid5: Disk failure on %s, disabling device."
536 " Operation continuing on %d devices\n",
537 bdevname(rdev->bdev,b), conf->working_disks);
538 }
539}
540
541/*
542 * Input: a 'big' sector number,
543 * Output: index of the data and parity disk, and the sector # in them.
544 */
545static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks,
546 unsigned int data_disks, unsigned int * dd_idx,
547 unsigned int * pd_idx, raid5_conf_t *conf)
548{
549 long stripe;
550 unsigned long chunk_number;
551 unsigned int chunk_offset;
552 sector_t new_sector;
553 int sectors_per_chunk = conf->chunk_size >> 9;
554
555 /* First compute the information on this sector */
556
557 /*
558 * Compute the chunk number and the sector offset inside the chunk
559 */
560 chunk_offset = sector_div(r_sector, sectors_per_chunk);
561 chunk_number = r_sector;
562 BUG_ON(r_sector != chunk_number);
563
564 /*
565 * Compute the stripe number
566 */
567 stripe = chunk_number / data_disks;
568
569 /*
570 * Compute the data disk and parity disk indexes inside the stripe
571 */
572 *dd_idx = chunk_number % data_disks;
573
574 /*
575 * Select the parity disk based on the user selected algorithm.
576 */
577 if (conf->level == 4)
578 *pd_idx = data_disks;
579 else switch (conf->algorithm) {
580 case ALGORITHM_LEFT_ASYMMETRIC:
581 *pd_idx = data_disks - stripe % raid_disks;
582 if (*dd_idx >= *pd_idx)
583 (*dd_idx)++;
584 break;
585 case ALGORITHM_RIGHT_ASYMMETRIC:
586 *pd_idx = stripe % raid_disks;
587 if (*dd_idx >= *pd_idx)
588 (*dd_idx)++;
589 break;
590 case ALGORITHM_LEFT_SYMMETRIC:
591 *pd_idx = data_disks - stripe % raid_disks;
592 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
593 break;
594 case ALGORITHM_RIGHT_SYMMETRIC:
595 *pd_idx = stripe % raid_disks;
596 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
597 break;
598 default:
14f8d26b 599 printk(KERN_ERR "raid5: unsupported algorithm %d\n",
1da177e4
LT		 600 conf->algorithm);
601 }
602
603 /*
604 * Finally, compute the new sector number
605 */
606 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
607 return new_sector;
608}
609
610
611static sector_t compute_blocknr(struct stripe_head *sh, int i)
612{
613 raid5_conf_t *conf = sh->raid_conf;
614 int raid_disks = conf->raid_disks, data_disks = raid_disks - 1;
615 sector_t new_sector = sh->sector, check;
616 int sectors_per_chunk = conf->chunk_size >> 9;
617 sector_t stripe;
618 int chunk_offset;
619 int chunk_number, dummy1, dummy2, dd_idx = i;
620 sector_t r_sector;
621
622 chunk_offset = sector_div(new_sector, sectors_per_chunk);
623 stripe = new_sector;
624 BUG_ON(new_sector != stripe);
625
626
627 switch (conf->algorithm) {
628 case ALGORITHM_LEFT_ASYMMETRIC:
629 case ALGORITHM_RIGHT_ASYMMETRIC:
630 if (i > sh->pd_idx)
631 i--;
632 break;
633 case ALGORITHM_LEFT_SYMMETRIC:
634 case ALGORITHM_RIGHT_SYMMETRIC:
635 if (i < sh->pd_idx)
636 i += raid_disks;
637 i -= (sh->pd_idx + 1);
638 break;
639 default:
14f8d26b 640 printk(KERN_ERR "raid5: unsupported algorithm %d\n",
1da177e4
LT		 641 conf->algorithm);
642 }
643
644 chunk_number = stripe * data_disks + i;
645 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
646
647 check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
648 if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
14f8d26b 649 printk(KERN_ERR "compute_blocknr: map not correct\n");
1da177e4
LT		 650 return 0;
651 }
652 return r_sector;
653}
654
655
656
657/*
658 * Copy data between a page in the stripe cache, and a bio.
659 * There are no alignment or size guarantees between the page or the
660 * bio except that there is some overlap.
661 * All iovecs in the bio must be considered.
662 */
663static void copy_data(int frombio, struct bio *bio,
664 struct page *page,
665 sector_t sector)
666{
667 char *pa = page_address(page);
668 struct bio_vec *bvl;
669 int i;
670 int page_offset;
671
672 if (bio->bi_sector >= sector)
673 page_offset = (signed)(bio->bi_sector - sector) * 512;
674 else
675 page_offset = (signed)(sector - bio->bi_sector) * -512;
676 bio_for_each_segment(bvl, bio, i) {
677 int len = bio_iovec_idx(bio,i)->bv_len;
678 int clen;
679 int b_offset = 0;
680
681 if (page_offset < 0) {
682 b_offset = -page_offset;
683 page_offset += b_offset;
684 len -= b_offset;
685 }
686
687 if (len > 0 && page_offset + len > STRIPE_SIZE)
688 clen = STRIPE_SIZE - page_offset;
689 else clen = len;
690
691 if (clen > 0) {
692 char *ba = __bio_kmap_atomic(bio, i, KM_USER0);
693 if (frombio)
694 memcpy(pa+page_offset, ba+b_offset, clen);
695 else
696 memcpy(ba+b_offset, pa+page_offset, clen);
697 __bio_kunmap_atomic(ba, KM_USER0);
698 }
699 if (clen < len) /* hit end of page */
700 break;
701 page_offset += len;
702 }
703}
704
705#define check_xor() do { \
706 if (count == MAX_XOR_BLOCKS) { \
707 xor_block(count, STRIPE_SIZE, ptr); \
708 count = 1; \
709 } \
710 } while(0)
711
712
713static void compute_block(struct stripe_head *sh, int dd_idx)
714{
715 raid5_conf_t *conf = sh->raid_conf;
716 int i, count, disks = conf->raid_disks;
717 void *ptr[MAX_XOR_BLOCKS], *p;
718
719 PRINTK("compute_block, stripe %llu, idx %d\n",
720 (unsigned long long)sh->sector, dd_idx);
721
722 ptr[0] = page_address(sh->dev[dd_idx].page);
723 memset(ptr[0], 0, STRIPE_SIZE);
724 count = 1;
725 for (i = disks ; i--; ) {
726 if (i == dd_idx)
727 continue;
728 p = page_address(sh->dev[i].page);
729 if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
730 ptr[count++] = p;
731 else
14f8d26b 732 printk(KERN_ERR "compute_block() %d, stripe %llu, %d"
1da177e4
LT		 733 " not present\n", dd_idx,
734 (unsigned long long)sh->sector, i);
735
736 check_xor();
737 }
738 if (count != 1)
739 xor_block(count, STRIPE_SIZE, ptr);
740 set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
741}
742
743static void compute_parity(struct stripe_head *sh, int method)
744{
745 raid5_conf_t *conf = sh->raid_conf;
746 int i, pd_idx = sh->pd_idx, disks = conf->raid_disks, count;
747 void *ptr[MAX_XOR_BLOCKS];
748 struct bio *chosen;
749
750 PRINTK("compute_parity, stripe %llu, method %d\n",
751 (unsigned long long)sh->sector, method);
752
753 count = 1;
754 ptr[0] = page_address(sh->dev[pd_idx].page);
755 switch(method) {
756 case READ_MODIFY_WRITE:
757 if (!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags))
758 BUG();
759 for (i=disks ; i-- ;) {
760 if (i==pd_idx)
761 continue;
762 if (sh->dev[i].towrite &&
763 test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
764 ptr[count++] = page_address(sh->dev[i].page);
765 chosen = sh->dev[i].towrite;
766 sh->dev[i].towrite = NULL;
767
768 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
769 wake_up(&conf->wait_for_overlap);
770
771 if (sh->dev[i].written) BUG();
772 sh->dev[i].written = chosen;
773 check_xor();
774 }
775 }
776 break;
777 case RECONSTRUCT_WRITE:
778 memset(ptr[0], 0, STRIPE_SIZE);
779 for (i= disks; i-- ;)
780 if (i!=pd_idx && sh->dev[i].towrite) {
781 chosen = sh->dev[i].towrite;
782 sh->dev[i].towrite = NULL;
783
784 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
785 wake_up(&conf->wait_for_overlap);
786
787 if (sh->dev[i].written) BUG();
788 sh->dev[i].written = chosen;
789 }
790 break;
791 case CHECK_PARITY:
792 break;
793 }
794 if (count>1) {
795 xor_block(count, STRIPE_SIZE, ptr);
796 count = 1;
797 }
798
799 for (i = disks; i--;)
800 if (sh->dev[i].written) {
801 sector_t sector = sh->dev[i].sector;
802 struct bio *wbi = sh->dev[i].written;
803 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
804 copy_data(1, wbi, sh->dev[i].page, sector);
805 wbi = r5_next_bio(wbi, sector);
806 }
807
808 set_bit(R5_LOCKED, &sh->dev[i].flags);
809 set_bit(R5_UPTODATE, &sh->dev[i].flags);
810 }
811
812 switch(method) {
813 case RECONSTRUCT_WRITE:
814 case CHECK_PARITY:
815 for (i=disks; i--;)
816 if (i != pd_idx) {
817 ptr[count++] = page_address(sh->dev[i].page);
818 check_xor();
819 }
820 break;
821 case READ_MODIFY_WRITE:
822 for (i = disks; i--;)
823 if (sh->dev[i].written) {
824 ptr[count++] = page_address(sh->dev[i].page);
825 check_xor();
826 }
827 }
828 if (count != 1)
829 xor_block(count, STRIPE_SIZE, ptr);
830
831 if (method != CHECK_PARITY) {
832 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
833 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
834 } else
835 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
836}
837
838/*
839 * Each stripe/dev can have one or more bion attached.
840 * toread/towrite point to the first in a chain.
841 * The bi_next chain must be in order.
842 */
843static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
844{
845 struct bio **bip;
846 raid5_conf_t *conf = sh->raid_conf;
72626685 847 int firstwrite=0;
1da177e4
LT		 848
849 PRINTK("adding bh b#%llu to stripe s#%llu\n",
850 (unsigned long long)bi->bi_sector,
851 (unsigned long long)sh->sector);
852
853
854 spin_lock(&sh->lock);
855 spin_lock_irq(&conf->device_lock);
72626685 856 if (forwrite) {
1da177e4 857 bip = &sh->dev[dd_idx].towrite;
72626685
N		 858 if (*bip == NULL && sh->dev[dd_idx].written == NULL)
859 firstwrite = 1;
860 } else
1da177e4
LT		 861 bip = &sh->dev[dd_idx].toread;
862 while (*bip && (*bip)->bi_sector < bi->bi_sector) {
863 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
864 goto overlap;
865 bip = & (*bip)->bi_next;
866 }
867 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
868 goto overlap;
869
870 if (*bip && bi->bi_next && (*bip) != bi->bi_next)
871 BUG();
872 if (*bip)
873 bi->bi_next = *bip;
874 *bip = bi;
875 bi->bi_phys_segments ++;
876 spin_unlock_irq(&conf->device_lock);
877 spin_unlock(&sh->lock);
878
879 PRINTK("added bi b#%llu to stripe s#%llu, disk %d.\n",
880 (unsigned long long)bi->bi_sector,
881 (unsigned long long)sh->sector, dd_idx);
882
72626685
N		 883 if (conf->mddev->bitmap && firstwrite) {
884 sh->bm_seq = conf->seq_write;
885 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
886 STRIPE_SECTORS, 0);
887 set_bit(STRIPE_BIT_DELAY, &sh->state);
888 }
889
1da177e4
LT		 890 if (forwrite) {
891 /* check if page is covered */
892 sector_t sector = sh->dev[dd_idx].sector;
893 for (bi=sh->dev[dd_idx].towrite;
894 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
895 bi && bi->bi_sector <= sector;
896 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
897 if (bi->bi_sector + (bi->bi_size>>9) >= sector)
898 sector = bi->bi_sector + (bi->bi_size>>9);
899 }
900 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
901 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
902 }
903 return 1;
904
905 overlap:
906 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
907 spin_unlock_irq(&conf->device_lock);
908 spin_unlock(&sh->lock);
909 return 0;
910}
911
912
913/*
914 * handle_stripe - do things to a stripe.
915 *
916 * We lock the stripe and then examine the state of various bits
917 * to see what needs to be done.
918 * Possible results:
919 * return some read request which now have data
920 * return some write requests which are safely on disc
921 * schedule a read on some buffers
922 * schedule a write of some buffers
923 * return confirmation of parity correctness
924 *
925 * Parity calculations are done inside the stripe lock
926 * buffers are taken off read_list or write_list, and bh_cache buffers
927 * get BH_Lock set before the stripe lock is released.
928 *
929 */
930
931static void handle_stripe(struct stripe_head *sh)
932{
933 raid5_conf_t *conf = sh->raid_conf;
934 int disks = conf->raid_disks;
935 struct bio *return_bi= NULL;
936 struct bio *bi;
937 int i;
938 int syncing;
939 int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
940 int non_overwrite = 0;
941 int failed_num=0;
942 struct r5dev *dev;
943
944 PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n",
945 (unsigned long long)sh->sector, atomic_read(&sh->count),
946 sh->pd_idx);
947
948 spin_lock(&sh->lock);
949 clear_bit(STRIPE_HANDLE, &sh->state);
950 clear_bit(STRIPE_DELAYED, &sh->state);
951
952 syncing = test_bit(STRIPE_SYNCING, &sh->state);
953 /* Now to look around and see what can be done */
954
9910f16a 955 rcu_read_lock();
1da177e4
LT		 956 for (i=disks; i--; ) {
957 mdk_rdev_t *rdev;
958 dev = &sh->dev[i];
959 clear_bit(R5_Insync, &dev->flags);
1da177e4
LT		 960
961 PRINTK("check %d: state 0x%lx read %p write %p written %p\n",
962 i, dev->flags, dev->toread, dev->towrite, dev->written);
963 /* maybe we can reply to a read */
964 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
965 struct bio *rbi, *rbi2;
966 PRINTK("Return read for disc %d\n", i);
967 spin_lock_irq(&conf->device_lock);
968 rbi = dev->toread;
969 dev->toread = NULL;
970 if (test_and_clear_bit(R5_Overlap, &dev->flags))
971 wake_up(&conf->wait_for_overlap);
972 spin_unlock_irq(&conf->device_lock);
973 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) {
974 copy_data(0, rbi, dev->page, dev->sector);
975 rbi2 = r5_next_bio(rbi, dev->sector);
976 spin_lock_irq(&conf->device_lock);
977 if (--rbi->bi_phys_segments == 0) {
978 rbi->bi_next = return_bi;
979 return_bi = rbi;
980 }
981 spin_unlock_irq(&conf->device_lock);
982 rbi = rbi2;
983 }
984 }
985
986 /* now count some things */
987 if (test_bit(R5_LOCKED, &dev->flags)) locked++;
988 if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
989
990
991 if (dev->toread) to_read++;
992 if (dev->towrite) {
993 to_write++;
994 if (!test_bit(R5_OVERWRITE, &dev->flags))
995 non_overwrite++;
996 }
997 if (dev->written) written++;
9910f16a 998 rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 999 if (!rdev || !test_bit(In_sync, &rdev->flags)) {
14f8d26b 1000 /* The ReadError flag will just be confusing now */
4e5314b5
N		 1001 clear_bit(R5_ReadError, &dev->flags);
1002 clear_bit(R5_ReWrite, &dev->flags);
1003 }
b2d444d7 1004 if (!rdev || !test_bit(In_sync, &rdev->flags)
4e5314b5 1005 || test_bit(R5_ReadError, &dev->flags)) {
1da177e4
LT		 1006 failed++;
1007 failed_num = i;
1008 } else
1009 set_bit(R5_Insync, &dev->flags);
1010 }
9910f16a 1011 rcu_read_unlock();
1da177e4
LT		 1012 PRINTK("locked=%d uptodate=%d to_read=%d"
1013 " to_write=%d failed=%d failed_num=%d\n",
1014 locked, uptodate, to_read, to_write, failed, failed_num);
1015 /* check if the array has lost two devices and, if so, some requests might
1016 * need to be failed
1017 */
1018 if (failed > 1 && to_read+to_write+written) {
1da177e4 1019 for (i=disks; i--; ) {
72626685 1020 int bitmap_end = 0;
4e5314b5
N		 1021
1022 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
9910f16a
N		 1023 mdk_rdev_t *rdev;
1024 rcu_read_lock();
1025 rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 1026 if (rdev && test_bit(In_sync, &rdev->flags))
4e5314b5
N		 1027 /* multiple read failures in one stripe */
1028 md_error(conf->mddev, rdev);
9910f16a 1029 rcu_read_unlock();
4e5314b5
N		 1030 }
1031
72626685 1032 spin_lock_irq(&conf->device_lock);
1da177e4
LT		 1033 /* fail all writes first */
1034 bi = sh->dev[i].towrite;
1035 sh->dev[i].towrite = NULL;
72626685 1036 if (bi) { to_write--; bitmap_end = 1; }
1da177e4
LT		 1037
1038 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1039 wake_up(&conf->wait_for_overlap);
1040
1041 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
1042 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1043 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1044 if (--bi->bi_phys_segments == 0) {
1045 md_write_end(conf->mddev);
1046 bi->bi_next = return_bi;
1047 return_bi = bi;
1048 }
1049 bi = nextbi;
1050 }
1051 /* and fail all 'written' */
1052 bi = sh->dev[i].written;
1053 sh->dev[i].written = NULL;
72626685 1054 if (bi) bitmap_end = 1;
1da177e4
LT		 1055 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) {
1056 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
1057 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1058 if (--bi->bi_phys_segments == 0) {
1059 md_write_end(conf->mddev);
1060 bi->bi_next = return_bi;
1061 return_bi = bi;
1062 }
1063 bi = bi2;
1064 }
1065
1066 /* fail any reads if this device is non-operational */
4e5314b5
N		 1067 if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
1068 test_bit(R5_ReadError, &sh->dev[i].flags)) {
1da177e4
LT		 1069 bi = sh->dev[i].toread;
1070 sh->dev[i].toread = NULL;
1071 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1072 wake_up(&conf->wait_for_overlap);
1073 if (bi) to_read--;
1074 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
1075 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1076 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1077 if (--bi->bi_phys_segments == 0) {
1078 bi->bi_next = return_bi;
1079 return_bi = bi;
1080 }
1081 bi = nextbi;
1082 }
1083 }
72626685
N		 1084 spin_unlock_irq(&conf->device_lock);
1085 if (bitmap_end)
1086 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
1087 STRIPE_SECTORS, 0, 0);
1da177e4 1088 }
1da177e4
LT		 1089 }
1090 if (failed > 1 && syncing) {
1091 md_done_sync(conf->mddev, STRIPE_SECTORS,0);
1092 clear_bit(STRIPE_SYNCING, &sh->state);
1093 syncing = 0;
1094 }
1095
1096 /* might be able to return some write requests if the parity block
1097 * is safe, or on a failed drive
1098 */
1099 dev = &sh->dev[sh->pd_idx];
1100 if ( written &&
1101 ( (test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) &&
1102 test_bit(R5_UPTODATE, &dev->flags))
1103 || (failed == 1 && failed_num == sh->pd_idx))
1104 ) {
1105 /* any written block on an uptodate or failed drive can be returned.
1106 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
1107 * never LOCKED, so we don't need to test 'failed' directly.
1108 */
1109 for (i=disks; i--; )
1110 if (sh->dev[i].written) {
1111 dev = &sh->dev[i];
1112 if (!test_bit(R5_LOCKED, &dev->flags) &&
1113 test_bit(R5_UPTODATE, &dev->flags) ) {
1114 /* We can return any write requests */
1115 struct bio *wbi, *wbi2;
72626685 1116 int bitmap_end = 0;
1da177e4
LT		 1117 PRINTK("Return write for disc %d\n", i);
1118 spin_lock_irq(&conf->device_lock);
1119 wbi = dev->written;
1120 dev->written = NULL;
1121 while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) {
1122 wbi2 = r5_next_bio(wbi, dev->sector);
1123 if (--wbi->bi_phys_segments == 0) {
1124 md_write_end(conf->mddev);
1125 wbi->bi_next = return_bi;
1126 return_bi = wbi;
1127 }
1128 wbi = wbi2;
1129 }
72626685
N		 1130 if (dev->towrite == NULL)
1131 bitmap_end = 1;
1da177e4 1132 spin_unlock_irq(&conf->device_lock);
72626685
N		 1133 if (bitmap_end)
1134 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
1135 STRIPE_SECTORS,
1136 !test_bit(STRIPE_DEGRADED, &sh->state), 0);
1da177e4
LT		 1137 }
1138 }
1139 }
1140
1141 /* Now we might consider reading some blocks, either to check/generate
1142 * parity, or to satisfy requests
1143 * or to load a block that is being partially written.
1144 */
1145 if (to_read || non_overwrite || (syncing && (uptodate < disks))) {
1146 for (i=disks; i--;) {
1147 dev = &sh->dev[i];
1148 if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1149 (dev->toread ||
1150 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
1151 syncing ||
1152 (failed && (sh->dev[failed_num].toread ||
1153 (sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags))))
1154 )
1155 ) {
1156 /* we would like to get this block, possibly
1157 * by computing it, but we might not be able to
1158 */
1159 if (uptodate == disks-1) {
1160 PRINTK("Computing block %d\n", i);
1161 compute_block(sh, i);
1162 uptodate++;
1163 } else if (test_bit(R5_Insync, &dev->flags)) {
1164 set_bit(R5_LOCKED, &dev->flags);
1165 set_bit(R5_Wantread, &dev->flags);
1166#if 0
1167 /* if I am just reading this block and we don't have
1168 a failed drive, or any pending writes then sidestep the cache */
1169 if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext &&
1170 ! syncing && !failed && !to_write) {
1171 sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page;
1172 sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data;
1173 }
1174#endif
1175 locked++;
1176 PRINTK("Reading block %d (sync=%d)\n",
1177 i, syncing);
1da177e4
LT		 1178 }
1179 }
1180 }
1181 set_bit(STRIPE_HANDLE, &sh->state);
1182 }
1183
1184 /* now to consider writing and what else, if anything should be read */
1185 if (to_write) {
1186 int rmw=0, rcw=0;
1187 for (i=disks ; i--;) {
1188 /* would I have to read this buffer for read_modify_write */
1189 dev = &sh->dev[i];
1190 if ((dev->towrite || i == sh->pd_idx) &&
1191 (!test_bit(R5_LOCKED, &dev->flags)
1192#if 0
1193|| sh->bh_page[i]!=bh->b_page
1194#endif
1195 ) &&
1196 !test_bit(R5_UPTODATE, &dev->flags)) {
1197 if (test_bit(R5_Insync, &dev->flags)
1198/* && !(!mddev->insync && i == sh->pd_idx) */
1199 )
1200 rmw++;
1201 else rmw += 2*disks; /* cannot read it */
1202 }
1203 /* Would I have to read this buffer for reconstruct_write */
1204 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
1205 (!test_bit(R5_LOCKED, &dev->flags)
1206#if 0
1207|| sh->bh_page[i] != bh->b_page
1208#endif
1209 ) &&
1210 !test_bit(R5_UPTODATE, &dev->flags)) {
1211 if (test_bit(R5_Insync, &dev->flags)) rcw++;
1212 else rcw += 2*disks;
1213 }
1214 }
1215 PRINTK("for sector %llu, rmw=%d rcw=%d\n",
1216 (unsigned long long)sh->sector, rmw, rcw);
1217 set_bit(STRIPE_HANDLE, &sh->state);
1218 if (rmw < rcw && rmw > 0)
1219 /* prefer read-modify-write, but need to get some data */
1220 for (i=disks; i--;) {
1221 dev = &sh->dev[i];
1222 if ((dev->towrite || i == sh->pd_idx) &&
1223 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1224 test_bit(R5_Insync, &dev->flags)) {
1225 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1226 {
1227 PRINTK("Read_old block %d for r-m-w\n", i);
1228 set_bit(R5_LOCKED, &dev->flags);
1229 set_bit(R5_Wantread, &dev->flags);
1230 locked++;
1231 } else {
1232 set_bit(STRIPE_DELAYED, &sh->state);
1233 set_bit(STRIPE_HANDLE, &sh->state);
1234 }
1235 }
1236 }
1237 if (rcw <= rmw && rcw > 0)
1238 /* want reconstruct write, but need to get some data */
1239 for (i=disks; i--;) {
1240 dev = &sh->dev[i];
1241 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
1242 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1243 test_bit(R5_Insync, &dev->flags)) {
1244 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1245 {
1246 PRINTK("Read_old block %d for Reconstruct\n", i);
1247 set_bit(R5_LOCKED, &dev->flags);
1248 set_bit(R5_Wantread, &dev->flags);
1249 locked++;
1250 } else {
1251 set_bit(STRIPE_DELAYED, &sh->state);
1252 set_bit(STRIPE_HANDLE, &sh->state);
1253 }
1254 }
1255 }
1256 /* now if nothing is locked, and if we have enough data, we can start a write request */
72626685
N		 1257 if (locked == 0 && (rcw == 0 ||rmw == 0) &&
1258 !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
1da177e4
LT		 1259 PRINTK("Computing parity...\n");
1260 compute_parity(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
1261 /* now every locked buffer is ready to be written */
1262 for (i=disks; i--;)
1263 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
1264 PRINTK("Writing block %d\n", i);
1265 locked++;
1266 set_bit(R5_Wantwrite, &sh->dev[i].flags);
1267 if (!test_bit(R5_Insync, &sh->dev[i].flags)
1268 || (i==sh->pd_idx && failed == 0))
1269 set_bit(STRIPE_INSYNC, &sh->state);
1270 }
1271 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
1272 atomic_dec(&conf->preread_active_stripes);
1273 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
1274 md_wakeup_thread(conf->mddev->thread);
1275 }
1276 }
1277 }
1278
1279 /* maybe we need to check and possibly fix the parity for this stripe
1280 * Any reads will already have been scheduled, so we just see if enough data
1281 * is available
1282 */
1283 if (syncing && locked == 0 &&
14f8d26b 1284 !test_bit(STRIPE_INSYNC, &sh->state)) {
1da177e4
LT		 1285 set_bit(STRIPE_HANDLE, &sh->state);
1286 if (failed == 0) {
1287 char *pagea;
1288 if (uptodate != disks)
1289 BUG();
1290 compute_parity(sh, CHECK_PARITY);
1291 uptodate--;
1292 pagea = page_address(sh->dev[sh->pd_idx].page);
1293 if ((*(u32*)pagea) == 0 &&
1294 !memcmp(pagea, pagea+4, STRIPE_SIZE-4)) {
1295 /* parity is correct (on disc, not in buffer any more) */
1296 set_bit(STRIPE_INSYNC, &sh->state);
9d88883e
N		 1297 } else {
1298 conf->mddev->resync_mismatches += STRIPE_SECTORS;
1299 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
1300 /* don't try to repair!! */
1301 set_bit(STRIPE_INSYNC, &sh->state);
14f8d26b
N		 1302 else {
1303 compute_block(sh, sh->pd_idx);
1304 uptodate++;
1305 }
1da177e4
LT		 1306 }
1307 }
1308 if (!test_bit(STRIPE_INSYNC, &sh->state)) {
14f8d26b 1309 /* either failed parity check, or recovery is happening */
1da177e4
LT		 1310 if (failed==0)
1311 failed_num = sh->pd_idx;
1da177e4 1312 dev = &sh->dev[failed_num];
14f8d26b
N		 1313 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
1314 BUG_ON(uptodate != disks);
1315
1da177e4
LT		 1316 set_bit(R5_LOCKED, &dev->flags);
1317 set_bit(R5_Wantwrite, &dev->flags);
72626685 1318 clear_bit(STRIPE_DEGRADED, &sh->state);
1da177e4
LT		 1319 locked++;
1320 set_bit(STRIPE_INSYNC, &sh->state);
1da177e4
LT		 1321 }
1322 }
1323 if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
1324 md_done_sync(conf->mddev, STRIPE_SECTORS,1);
1325 clear_bit(STRIPE_SYNCING, &sh->state);
1326 }
4e5314b5
N		 1327
1328 /* If the failed drive is just a ReadError, then we might need to progress
1329 * the repair/check process
1330 */
ba22dcbf
N		 1331 if (failed == 1 && ! conf->mddev->ro &&
1332 test_bit(R5_ReadError, &sh->dev[failed_num].flags)
4e5314b5
N		 1333 && !test_bit(R5_LOCKED, &sh->dev[failed_num].flags)
1334 && test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)
1335 ) {
1336 dev = &sh->dev[failed_num];
1337 if (!test_bit(R5_ReWrite, &dev->flags)) {
1338 set_bit(R5_Wantwrite, &dev->flags);
1339 set_bit(R5_ReWrite, &dev->flags);
1340 set_bit(R5_LOCKED, &dev->flags);
1341 } else {
1342 /* let's read it back */
1343 set_bit(R5_Wantread, &dev->flags);
1344 set_bit(R5_LOCKED, &dev->flags);
1345 }
1346 }
1347
1da177e4
LT		 1348 spin_unlock(&sh->lock);
1349
1350 while ((bi=return_bi)) {
1351 int bytes = bi->bi_size;
1352
1353 return_bi = bi->bi_next;
1354 bi->bi_next = NULL;
1355 bi->bi_size = 0;
1356 bi->bi_end_io(bi, bytes, 0);
1357 }
1358 for (i=disks; i-- ;) {
1359 int rw;
1360 struct bio *bi;
1361 mdk_rdev_t *rdev;
1362 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
1363 rw = 1;
1364 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1365 rw = 0;
1366 else
1367 continue;
1368
1369 bi = &sh->dev[i].req;
1370
1371 bi->bi_rw = rw;
1372 if (rw)
1373 bi->bi_end_io = raid5_end_write_request;
1374 else
1375 bi->bi_end_io = raid5_end_read_request;
1376
1377 rcu_read_lock();
d6065f7b 1378 rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 1379 if (rdev && test_bit(Faulty, &rdev->flags))
1da177e4
LT		 1380 rdev = NULL;
1381 if (rdev)
1382 atomic_inc(&rdev->nr_pending);
1383 rcu_read_unlock();
1384
1385 if (rdev) {
9910f16a 1386 if (syncing)
1da177e4
LT		 1387 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1388
1389 bi->bi_bdev = rdev->bdev;
1390 PRINTK("for %llu schedule op %ld on disc %d\n",
1391 (unsigned long long)sh->sector, bi->bi_rw, i);
1392 atomic_inc(&sh->count);
1393 bi->bi_sector = sh->sector + rdev->data_offset;
1394 bi->bi_flags = 1 << BIO_UPTODATE;
1395 bi->bi_vcnt = 1;
1396 bi->bi_max_vecs = 1;
1397 bi->bi_idx = 0;
1398 bi->bi_io_vec = &sh->dev[i].vec;
1399 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1400 bi->bi_io_vec[0].bv_offset = 0;
1401 bi->bi_size = STRIPE_SIZE;
1402 bi->bi_next = NULL;
4dbcdc75
N		 1403 if (rw == WRITE &&
1404 test_bit(R5_ReWrite, &sh->dev[i].flags))
1405 atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1da177e4
LT		 1406 generic_make_request(bi);
1407 } else {
72626685
N		 1408 if (rw == 1)
1409 set_bit(STRIPE_DEGRADED, &sh->state);
1da177e4
LT		 1410 PRINTK("skip op %ld on disc %d for sector %llu\n",
1411 bi->bi_rw, i, (unsigned long long)sh->sector);
1412 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1413 set_bit(STRIPE_HANDLE, &sh->state);
1414 }
1415 }
1416}
1417
1418static inline void raid5_activate_delayed(raid5_conf_t *conf)
1419{
1420 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
1421 while (!list_empty(&conf->delayed_list)) {
1422 struct list_head *l = conf->delayed_list.next;
1423 struct stripe_head *sh;
1424 sh = list_entry(l, struct stripe_head, lru);
1425 list_del_init(l);
1426 clear_bit(STRIPE_DELAYED, &sh->state);
1427 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1428 atomic_inc(&conf->preread_active_stripes);
1429 list_add_tail(&sh->lru, &conf->handle_list);
1430 }
1431 }
1432}
1433
72626685
N		 1434static inline void activate_bit_delay(raid5_conf_t *conf)
1435{
1436 /* device_lock is held */
1437 struct list_head head;
1438 list_add(&head, &conf->bitmap_list);
1439 list_del_init(&conf->bitmap_list);
1440 while (!list_empty(&head)) {
1441 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
1442 list_del_init(&sh->lru);
1443 atomic_inc(&sh->count);
1444 __release_stripe(conf, sh);
1445 }
1446}
1447
1da177e4
LT		 1448static void unplug_slaves(mddev_t *mddev)
1449{
1450 raid5_conf_t *conf = mddev_to_conf(mddev);
1451 int i;
1452
1453 rcu_read_lock();
1454 for (i=0; i<mddev->raid_disks; i++) {
d6065f7b 1455 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 1456 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
1da177e4
LT		 1457 request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
1458
1459 atomic_inc(&rdev->nr_pending);
1460 rcu_read_unlock();
1461
1462 if (r_queue->unplug_fn)
1463 r_queue->unplug_fn(r_queue);
1464
1465 rdev_dec_pending(rdev, mddev);
1466 rcu_read_lock();
1467 }
1468 }
1469 rcu_read_unlock();
1470}
1471
1472static void raid5_unplug_device(request_queue_t *q)
1473{
1474 mddev_t *mddev = q->queuedata;
1475 raid5_conf_t *conf = mddev_to_conf(mddev);
1476 unsigned long flags;
1477
1478 spin_lock_irqsave(&conf->device_lock, flags);
1479
72626685
N		 1480 if (blk_remove_plug(q)) {
1481 conf->seq_flush++;
1da177e4 1482 raid5_activate_delayed(conf);
72626685 1483 }
1da177e4
LT		 1484 md_wakeup_thread(mddev->thread);
1485
1486 spin_unlock_irqrestore(&conf->device_lock, flags);
1487
1488 unplug_slaves(mddev);
1489}
1490
1491static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk,
1492 sector_t *error_sector)
1493{
1494 mddev_t *mddev = q->queuedata;
1495 raid5_conf_t *conf = mddev_to_conf(mddev);
1496 int i, ret = 0;
1497
1498 rcu_read_lock();
1499 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
d6065f7b 1500 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 1501 if (rdev && !test_bit(Faulty, &rdev->flags)) {
1da177e4
LT		 1502 struct block_device *bdev = rdev->bdev;
1503 request_queue_t *r_queue = bdev_get_queue(bdev);
1504
1505 if (!r_queue->issue_flush_fn)
1506 ret = -EOPNOTSUPP;
1507 else {
1508 atomic_inc(&rdev->nr_pending);
1509 rcu_read_unlock();
1510 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
1511 error_sector);
1512 rdev_dec_pending(rdev, mddev);
1513 rcu_read_lock();
1514 }
1515 }
1516 }
1517 rcu_read_unlock();
1518 return ret;
1519}
1520
1521static inline void raid5_plug_device(raid5_conf_t *conf)
1522{
1523 spin_lock_irq(&conf->device_lock);
1524 blk_plug_device(conf->mddev->queue);
1525 spin_unlock_irq(&conf->device_lock);
1526}
1527
1528static int make_request (request_queue_t *q, struct bio * bi)
1529{
1530 mddev_t *mddev = q->queuedata;
1531 raid5_conf_t *conf = mddev_to_conf(mddev);
1532 const unsigned int raid_disks = conf->raid_disks;
1533 const unsigned int data_disks = raid_disks - 1;
1534 unsigned int dd_idx, pd_idx;
1535 sector_t new_sector;
1536 sector_t logical_sector, last_sector;
1537 struct stripe_head *sh;
a362357b 1538 const int rw = bio_data_dir(bi);
1da177e4 1539
e5dcdd80
N		 1540 if (unlikely(bio_barrier(bi))) {
1541 bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
1542 return 0;
1543 }
1544
3d310eb7 1545 md_write_start(mddev, bi);
06d91a5f 1546
a362357b
JA		 1547 disk_stat_inc(mddev->gendisk, ios[rw]);
1548 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
1da177e4
LT		 1549
1550 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
1551 last_sector = bi->bi_sector + (bi->bi_size>>9);
1552 bi->bi_next = NULL;
1553 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
06d91a5f 1554
1da177e4
LT		 1555 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
1556 DEFINE_WAIT(w);
1557
1558 new_sector = raid5_compute_sector(logical_sector,
1559 raid_disks, data_disks, &dd_idx, &pd_idx, conf);
1560
1561 PRINTK("raid5: make_request, sector %llu logical %llu\n",
1562 (unsigned long long)new_sector,
1563 (unsigned long long)logical_sector);
1564
1565 retry:
1566 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
1567 sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK));
1568 if (sh) {
1569 if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
1570 /* Add failed due to overlap. Flush everything
1571 * and wait a while
1572 */
1573 raid5_unplug_device(mddev->queue);
1574 release_stripe(sh);
1575 schedule();
1576 goto retry;
1577 }
1578 finish_wait(&conf->wait_for_overlap, &w);
1579 raid5_plug_device(conf);
1580 handle_stripe(sh);
1581 release_stripe(sh);
1582
1583 } else {
1584 /* cannot get stripe for read-ahead, just give-up */
1585 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1586 finish_wait(&conf->wait_for_overlap, &w);
1587 break;
1588 }
1589
1590 }
1591 spin_lock_irq(&conf->device_lock);
1592 if (--bi->bi_phys_segments == 0) {
1593 int bytes = bi->bi_size;
1594
1595 if ( bio_data_dir(bi) == WRITE )
1596 md_write_end(mddev);
1597 bi->bi_size = 0;
1598 bi->bi_end_io(bi, bytes, 0);
1599 }
1600 spin_unlock_irq(&conf->device_lock);
1601 return 0;
1602}
1603
1604/* FIXME go_faster isn't used */
57afd89f 1605static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1da177e4
LT		 1606{
1607 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
1608 struct stripe_head *sh;
1609 int sectors_per_chunk = conf->chunk_size >> 9;
1610 sector_t x;
1611 unsigned long stripe;
1612 int chunk_offset;
1613 int dd_idx, pd_idx;
1614 sector_t first_sector;
1615 int raid_disks = conf->raid_disks;
1616 int data_disks = raid_disks-1;
72626685
N		 1617 sector_t max_sector = mddev->size << 1;
1618 int sync_blocks;
1da177e4 1619
72626685 1620 if (sector_nr >= max_sector) {
1da177e4
LT		 1621 /* just being told to finish up .. nothing much to do */
1622 unplug_slaves(mddev);
72626685
N		 1623
1624 if (mddev->curr_resync < max_sector) /* aborted */
1625 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1626 &sync_blocks, 1);
1627 else /* compelted sync */
1628 conf->fullsync = 0;
1629 bitmap_close_sync(mddev->bitmap);
1630
1da177e4
LT		 1631 return 0;
1632 }
1633 /* if there is 1 or more failed drives and we are trying
1634 * to resync, then assert that we are finished, because there is
1635 * nothing we can do.
1636 */
1637 if (mddev->degraded >= 1 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
57afd89f
N		 1638 sector_t rv = (mddev->size << 1) - sector_nr;
1639 *skipped = 1;
1da177e4
LT		 1640 return rv;
1641 }
72626685 1642 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
3855ad9f 1643 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
72626685
N		 1644 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
1645 /* we can skip this block, and probably more */
1646 sync_blocks /= STRIPE_SECTORS;
1647 *skipped = 1;
1648 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
1649 }
1da177e4
LT		 1650
1651 x = sector_nr;
1652 chunk_offset = sector_div(x, sectors_per_chunk);
1653 stripe = x;
1654 BUG_ON(x != stripe);
1655
1656 first_sector = raid5_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk
1657 + chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf);
1658 sh = get_active_stripe(conf, sector_nr, pd_idx, 1);
1659 if (sh == NULL) {
1660 sh = get_active_stripe(conf, sector_nr, pd_idx, 0);
1661 /* make sure we don't swamp the stripe cache if someone else
1662 * is trying to get access
1663 */
66c006a5 1664 schedule_timeout_uninterruptible(1);
1da177e4 1665 }
72626685 1666 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 0);
1da177e4
LT		 1667 spin_lock(&sh->lock);
1668 set_bit(STRIPE_SYNCING, &sh->state);
1669 clear_bit(STRIPE_INSYNC, &sh->state);
1670 spin_unlock(&sh->lock);
1671
1672 handle_stripe(sh);
1673 release_stripe(sh);
1674
1675 return STRIPE_SECTORS;
1676}
1677
1678/*
1679 * This is our raid5 kernel thread.
1680 *
1681 * We scan the hash table for stripes which can be handled now.
1682 * During the scan, completed stripes are saved for us by the interrupt
1683 * handler, so that they will not have to wait for our next wakeup.
1684 */
1685static void raid5d (mddev_t *mddev)
1686{
1687 struct stripe_head *sh;
1688 raid5_conf_t *conf = mddev_to_conf(mddev);
1689 int handled;
1690
1691 PRINTK("+++ raid5d active\n");
1692
1693 md_check_recovery(mddev);
1da177e4
LT		 1694
1695 handled = 0;
1696 spin_lock_irq(&conf->device_lock);
1697 while (1) {
1698 struct list_head *first;
1699
72626685
N		 1700 if (conf->seq_flush - conf->seq_write > 0) {
1701 int seq = conf->seq_flush;
700e432d 1702 spin_unlock_irq(&conf->device_lock);
72626685 1703 bitmap_unplug(mddev->bitmap);
700e432d 1704 spin_lock_irq(&conf->device_lock);
72626685
N		 1705 conf->seq_write = seq;
1706 activate_bit_delay(conf);
1707 }
1708
1da177e4
LT		 1709 if (list_empty(&conf->handle_list) &&
1710 atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
1711 !blk_queue_plugged(mddev->queue) &&
1712 !list_empty(&conf->delayed_list))
1713 raid5_activate_delayed(conf);
1714
1715 if (list_empty(&conf->handle_list))
1716 break;
1717
1718 first = conf->handle_list.next;
1719 sh = list_entry(first, struct stripe_head, lru);
1720
1721 list_del_init(first);
1722 atomic_inc(&sh->count);
1723 if (atomic_read(&sh->count)!= 1)
1724 BUG();
1725 spin_unlock_irq(&conf->device_lock);
1726
1727 handled++;
1728 handle_stripe(sh);
1729 release_stripe(sh);
1730
1731 spin_lock_irq(&conf->device_lock);
1732 }
1733 PRINTK("%d stripes handled\n", handled);
1734
1735 spin_unlock_irq(&conf->device_lock);
1736
1737 unplug_slaves(mddev);
1738
1739 PRINTK("--- raid5d inactive\n");
1740}
1741
3f294f4f 1742static ssize_t
007583c9 1743raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
3f294f4f 1744{
007583c9 1745 raid5_conf_t *conf = mddev_to_conf(mddev);
96de1e66
N		 1746 if (conf)
1747 return sprintf(page, "%d\n", conf->max_nr_stripes);
1748 else
1749 return 0;
3f294f4f
N		 1750}
1751
1752static ssize_t
007583c9 1753raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
3f294f4f 1754{
007583c9 1755 raid5_conf_t *conf = mddev_to_conf(mddev);
3f294f4f
N		 1756 char *end;
1757 int new;
1758 if (len >= PAGE_SIZE)
1759 return -EINVAL;
96de1e66
N		 1760 if (!conf)
1761 return -ENODEV;
3f294f4f
N		 1762
1763 new = simple_strtoul(page, &end, 10);
1764 if (!*page || (*end && *end != '\n') )
1765 return -EINVAL;
1766 if (new <= 16 || new > 32768)
1767 return -EINVAL;
1768 while (new < conf->max_nr_stripes) {
1769 if (drop_one_stripe(conf))
1770 conf->max_nr_stripes--;
1771 else
1772 break;
1773 }
1774 while (new > conf->max_nr_stripes) {
1775 if (grow_one_stripe(conf))
1776 conf->max_nr_stripes++;
1777 else break;
1778 }
1779 return len;
1780}
007583c9 1781
96de1e66
N		 1782static struct md_sysfs_entry
1783raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
1784 raid5_show_stripe_cache_size,
1785 raid5_store_stripe_cache_size);
3f294f4f
N		 1786
1787static ssize_t
96de1e66 1788stripe_cache_active_show(mddev_t *mddev, char *page)
3f294f4f 1789{
007583c9 1790 raid5_conf_t *conf = mddev_to_conf(mddev);
96de1e66
N		 1791 if (conf)
1792 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
1793 else
1794 return 0;
3f294f4f
N		 1795}
1796
96de1e66
N		 1797static struct md_sysfs_entry
1798raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
3f294f4f 1799
007583c9 1800static struct attribute *raid5_attrs[] = {
3f294f4f
N		 1801 &raid5_stripecache_size.attr,
1802 &raid5_stripecache_active.attr,
1803 NULL,
1804};
007583c9
N		 1805static struct attribute_group raid5_attrs_group = {
1806 .name = NULL,
1807 .attrs = raid5_attrs,
3f294f4f
N		 1808};
1809
72626685 1810static int run(mddev_t *mddev)
1da177e4
LT		 1811{
1812 raid5_conf_t *conf;
1813 int raid_disk, memory;
1814 mdk_rdev_t *rdev;
1815 struct disk_info *disk;
1816 struct list_head *tmp;
1817
1818 if (mddev->level != 5 && mddev->level != 4) {
14f8d26b
N		 1819 printk(KERN_ERR "raid5: %s: raid level not set to 4/5 (%d)\n",
1820 mdname(mddev), mddev->level);
1da177e4
LT		 1821 return -EIO;
1822 }
1823
9ffae0cf
N		 1824 mddev->private = kzalloc(sizeof (raid5_conf_t)
1825 + mddev->raid_disks * sizeof(struct disk_info),
1826 GFP_KERNEL);
1da177e4
LT		 1827 if ((conf = mddev->private) == NULL)
1828 goto abort;
9ffae0cf 1829
1da177e4
LT		 1830 conf->mddev = mddev;
1831
fccddba0 1832 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
1da177e4 1833 goto abort;
1da177e4
LT		 1834
1835 spin_lock_init(&conf->device_lock);
1836 init_waitqueue_head(&conf->wait_for_stripe);
1837 init_waitqueue_head(&conf->wait_for_overlap);
1838 INIT_LIST_HEAD(&conf->handle_list);
1839 INIT_LIST_HEAD(&conf->delayed_list);
72626685 1840 INIT_LIST_HEAD(&conf->bitmap_list);
1da177e4
LT		 1841 INIT_LIST_HEAD(&conf->inactive_list);
1842 atomic_set(&conf->active_stripes, 0);
1843 atomic_set(&conf->preread_active_stripes, 0);
1844
1da177e4
LT		 1845 PRINTK("raid5: run(%s) called.\n", mdname(mddev));
1846
1847 ITERATE_RDEV(mddev,rdev,tmp) {
1848 raid_disk = rdev->raid_disk;
1849 if (raid_disk >= mddev->raid_disks
1850 || raid_disk < 0)
1851 continue;
1852 disk = conf->disks + raid_disk;
1853
1854 disk->rdev = rdev;
1855
b2d444d7 1856 if (test_bit(In_sync, &rdev->flags)) {
1da177e4
LT		 1857 char b[BDEVNAME_SIZE];
1858 printk(KERN_INFO "raid5: device %s operational as raid"
1859 " disk %d\n", bdevname(rdev->bdev,b),
1860 raid_disk);
1861 conf->working_disks++;
1862 }
1863 }
1864
1865 conf->raid_disks = mddev->raid_disks;
1866 /*
1867 * 0 for a fully functional array, 1 for a degraded array.
1868 */
1869 mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks;
1870 conf->mddev = mddev;
1871 conf->chunk_size = mddev->chunk_size;
1872 conf->level = mddev->level;
1873 conf->algorithm = mddev->layout;
1874 conf->max_nr_stripes = NR_STRIPES;
1875
1876 /* device size must be a multiple of chunk size */
1877 mddev->size &= ~(mddev->chunk_size/1024 -1);
b1581566 1878 mddev->resync_max_sectors = mddev->size << 1;
1da177e4
LT		 1879
1880 if (!conf->chunk_size || conf->chunk_size % 4) {
1881 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
1882 conf->chunk_size, mdname(mddev));
1883 goto abort;
1884 }
1885 if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) {
1886 printk(KERN_ERR
1887 "raid5: unsupported parity algorithm %d for %s\n",
1888 conf->algorithm, mdname(mddev));
1889 goto abort;
1890 }
1891 if (mddev->degraded > 1) {
1892 printk(KERN_ERR "raid5: not enough operational devices for %s"
1893 " (%d/%d failed)\n",
1894 mdname(mddev), conf->failed_disks, conf->raid_disks);
1895 goto abort;
1896 }
1897
1898 if (mddev->degraded == 1 &&
1899 mddev->recovery_cp != MaxSector) {
6ff8d8ec
N		 1900 if (mddev->ok_start_degraded)
1901 printk(KERN_WARNING
1902 "raid5: starting dirty degraded array: %s"
1903 "- data corruption possible.\n",
1904 mdname(mddev));
1905 else {
1906 printk(KERN_ERR
1907 "raid5: cannot start dirty degraded array for %s\n",
1908 mdname(mddev));
1909 goto abort;
1910 }
1da177e4
LT		 1911 }
1912
1913 {
1914 mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5");
1915 if (!mddev->thread) {
1916 printk(KERN_ERR
1917 "raid5: couldn't allocate thread for %s\n",
1918 mdname(mddev));
1919 goto abort;
1920 }
1921 }
5036805b 1922 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
1da177e4
LT		 1923 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
1924 if (grow_stripes(conf, conf->max_nr_stripes)) {
1925 printk(KERN_ERR
1926 "raid5: couldn't allocate %dkB for buffers\n", memory);
1927 shrink_stripes(conf);
1928 md_unregister_thread(mddev->thread);
1929 goto abort;
1930 } else
1931 printk(KERN_INFO "raid5: allocated %dkB for %s\n",
1932 memory, mdname(mddev));
1933
1934 if (mddev->degraded == 0)
1935 printk("raid5: raid level %d set %s active with %d out of %d"
1936 " devices, algorithm %d\n", conf->level, mdname(mddev),
1937 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
1938 conf->algorithm);
1939 else
1940 printk(KERN_ALERT "raid5: raid level %d set %s active with %d"
1941 " out of %d devices, algorithm %d\n", conf->level,
1942 mdname(mddev), mddev->raid_disks - mddev->degraded,
1943 mddev->raid_disks, conf->algorithm);
1944
1945 print_raid5_conf(conf);
1946
1947 /* read-ahead size must cover two whole stripes, which is
1948 * 2 * (n-1) * chunksize where 'n' is the number of raid devices
1949 */
1950 {
1951 int stripe = (mddev->raid_disks-1) * mddev->chunk_size
2d1f3b5d 1952 / PAGE_SIZE;
1da177e4
LT		 1953 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
1954 mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
1955 }
1956
1957 /* Ok, everything is just fine now */
007583c9 1958 sysfs_create_group(&mddev->kobj, &raid5_attrs_group);
7a5febe9
N		 1959
1960 mddev->queue->unplug_fn = raid5_unplug_device;
1961 mddev->queue->issue_flush_fn = raid5_issue_flush;
1962
1da177e4
LT		 1963 mddev->array_size = mddev->size * (mddev->raid_disks - 1);
1964 return 0;
1965abort:
1966 if (conf) {
1967 print_raid5_conf(conf);
fccddba0 1968 kfree(conf->stripe_hashtbl);
1da177e4
LT		 1969 kfree(conf);
1970 }
1971 mddev->private = NULL;
1972 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev));
1973 return -EIO;
1974}
1975
1976
1977
3f294f4f 1978static int stop(mddev_t *mddev)
1da177e4
LT		 1979{
1980 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
1981
1982 md_unregister_thread(mddev->thread);
1983 mddev->thread = NULL;
1984 shrink_stripes(conf);
fccddba0 1985 kfree(conf->stripe_hashtbl);
1da177e4 1986 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
007583c9 1987 sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
96de1e66 1988 kfree(conf);
1da177e4
LT		 1989 mddev->private = NULL;
1990 return 0;
1991}
1992
1993#if RAID5_DEBUG
1994static void print_sh (struct stripe_head *sh)
1995{
1996 int i;
1997
1998 printk("sh %llu, pd_idx %d, state %ld.\n",
1999 (unsigned long long)sh->sector, sh->pd_idx, sh->state);
2000 printk("sh %llu, count %d.\n",
2001 (unsigned long long)sh->sector, atomic_read(&sh->count));
2002 printk("sh %llu, ", (unsigned long long)sh->sector);
2003 for (i = 0; i < sh->raid_conf->raid_disks; i++) {
2004 printk("(cache%d: %p %ld) ",
2005 i, sh->dev[i].page, sh->dev[i].flags);
2006 }
2007 printk("\n");
2008}
2009
2010static void printall (raid5_conf_t *conf)
2011{
2012 struct stripe_head *sh;
fccddba0 2013 struct hlist_node *hn;
1da177e4
LT		 2014 int i;
2015
2016 spin_lock_irq(&conf->device_lock);
2017 for (i = 0; i < NR_HASH; i++) {
fccddba0 2018 hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
1da177e4
LT		 2019 if (sh->raid_conf != conf)
2020 continue;
2021 print_sh(sh);
2022 }
2023 }
2024 spin_unlock_irq(&conf->device_lock);
2025}
2026#endif
2027
2028static void status (struct seq_file *seq, mddev_t *mddev)
2029{
2030 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
2031 int i;
2032
2033 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout);
2034 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks);
2035 for (i = 0; i < conf->raid_disks; i++)
2036 seq_printf (seq, "%s",
2037 conf->disks[i].rdev &&
b2d444d7 2038 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
1da177e4
LT		 2039 seq_printf (seq, "]");
2040#if RAID5_DEBUG
2041#define D(x) \
2042 seq_printf (seq, "<"#x":%d>", atomic_read(&conf->x))
2043 printall(conf);
2044#endif
2045}
2046
2047static void print_raid5_conf (raid5_conf_t *conf)
2048{
2049 int i;
2050 struct disk_info *tmp;
2051
2052 printk("RAID5 conf printout:\n");
2053 if (!conf) {
2054 printk("(conf==NULL)\n");
2055 return;
2056 }
2057 printk(" --- rd:%d wd:%d fd:%d\n", conf->raid_disks,
2058 conf->working_disks, conf->failed_disks);
2059
2060 for (i = 0; i < conf->raid_disks; i++) {
2061 char b[BDEVNAME_SIZE];
2062 tmp = conf->disks + i;
2063 if (tmp->rdev)
2064 printk(" disk %d, o:%d, dev:%s\n",
b2d444d7 2065 i, !test_bit(Faulty, &tmp->rdev->flags),
1da177e4
LT		 2066 bdevname(tmp->rdev->bdev,b));
2067 }
2068}
2069
2070static int raid5_spare_active(mddev_t *mddev)
2071{
2072 int i;
2073 raid5_conf_t *conf = mddev->private;
2074 struct disk_info *tmp;
2075
2076 for (i = 0; i < conf->raid_disks; i++) {
2077 tmp = conf->disks + i;
2078 if (tmp->rdev
b2d444d7
N		 2079 && !test_bit(Faulty, &tmp->rdev->flags)
2080 && !test_bit(In_sync, &tmp->rdev->flags)) {
1da177e4
LT		 2081 mddev->degraded--;
2082 conf->failed_disks--;
2083 conf->working_disks++;
b2d444d7 2084 set_bit(In_sync, &tmp->rdev->flags);
1da177e4
LT		 2085 }
2086 }
2087 print_raid5_conf(conf);
2088 return 0;
2089}
2090
2091static int raid5_remove_disk(mddev_t *mddev, int number)
2092{
2093 raid5_conf_t *conf = mddev->private;
2094 int err = 0;
2095 mdk_rdev_t *rdev;
2096 struct disk_info *p = conf->disks + number;
2097
2098 print_raid5_conf(conf);
2099 rdev = p->rdev;
2100 if (rdev) {
b2d444d7 2101 if (test_bit(In_sync, &rdev->flags) ||
1da177e4
LT		 2102 atomic_read(&rdev->nr_pending)) {
2103 err = -EBUSY;
2104 goto abort;
2105 }
2106 p->rdev = NULL;
fbd568a3 2107 synchronize_rcu();
1da177e4
LT		 2108 if (atomic_read(&rdev->nr_pending)) {
2109 /* lost the race, try later */
2110 err = -EBUSY;
2111 p->rdev = rdev;
2112 }
2113 }
2114abort:
2115
2116 print_raid5_conf(conf);
2117 return err;
2118}
2119
2120static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
2121{
2122 raid5_conf_t *conf = mddev->private;
2123 int found = 0;
2124 int disk;
2125 struct disk_info *p;
2126
2127 if (mddev->degraded > 1)
2128 /* no point adding a device */
2129 return 0;
2130
2131 /*
2132 * find the disk ...
2133 */
2134 for (disk=0; disk < mddev->raid_disks; disk++)
2135 if ((p=conf->disks + disk)->rdev == NULL) {
b2d444d7 2136 clear_bit(In_sync, &rdev->flags);
1da177e4
LT		 2137 rdev->raid_disk = disk;
2138 found = 1;
72626685
N		 2139 if (rdev->saved_raid_disk != disk)
2140 conf->fullsync = 1;
d6065f7b 2141 rcu_assign_pointer(p->rdev, rdev);
1da177e4
LT		 2142 break;
2143 }
2144 print_raid5_conf(conf);
2145 return found;
2146}
2147
2148static int raid5_resize(mddev_t *mddev, sector_t sectors)
2149{
2150 /* no resync is happening, and there is enough space
2151 * on all devices, so we can resize.
2152 * We need to make sure resync covers any new space.
2153 * If the array is shrinking we should possibly wait until
2154 * any io in the removed space completes, but it hardly seems
2155 * worth it.
2156 */
2157 sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
2158 mddev->array_size = (sectors * (mddev->raid_disks-1))>>1;
2159 set_capacity(mddev->gendisk, mddev->array_size << 1);
2160 mddev->changed = 1;
2161 if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) {
2162 mddev->recovery_cp = mddev->size << 1;
2163 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2164 }
2165 mddev->size = sectors /2;
4b5c7ae8 2166 mddev->resync_max_sectors = sectors;
1da177e4
LT		 2167 return 0;
2168}
2169
72626685
N		 2170static void raid5_quiesce(mddev_t *mddev, int state)
2171{
2172 raid5_conf_t *conf = mddev_to_conf(mddev);
2173
2174 switch(state) {
2175 case 1: /* stop all writes */
2176 spin_lock_irq(&conf->device_lock);
2177 conf->quiesce = 1;
2178 wait_event_lock_irq(conf->wait_for_stripe,
2179 atomic_read(&conf->active_stripes) == 0,
2180 conf->device_lock, /* nothing */);
2181 spin_unlock_irq(&conf->device_lock);
2182 break;
2183
2184 case 0: /* re-enable writes */
2185 spin_lock_irq(&conf->device_lock);
2186 conf->quiesce = 0;
2187 wake_up(&conf->wait_for_stripe);
2188 spin_unlock_irq(&conf->device_lock);
2189 break;
2190 }
72626685 2191}
b15c2e57 2192
2604b703 2193static struct mdk_personality raid5_personality =
1da177e4
LT		 2194{
2195 .name = "raid5",
2604b703 2196 .level = 5,
1da177e4
LT		 2197 .owner = THIS_MODULE,
2198 .make_request = make_request,
2199 .run = run,
2200 .stop = stop,
2201 .status = status,
2202 .error_handler = error,
2203 .hot_add_disk = raid5_add_disk,
2204 .hot_remove_disk= raid5_remove_disk,
2205 .spare_active = raid5_spare_active,
2206 .sync_request = sync_request,
2207 .resize = raid5_resize,
72626685 2208 .quiesce = raid5_quiesce,
1da177e4
LT		 2209};
2210
2604b703 2211static struct mdk_personality raid4_personality =
1da177e4 2212{
2604b703
N		 2213 .name = "raid4",
2214 .level = 4,
2215 .owner = THIS_MODULE,
2216 .make_request = make_request,
2217 .run = run,
2218 .stop = stop,
2219 .status = status,
2220 .error_handler = error,
2221 .hot_add_disk = raid5_add_disk,
2222 .hot_remove_disk= raid5_remove_disk,
2223 .spare_active = raid5_spare_active,
2224 .sync_request = sync_request,
2225 .resize = raid5_resize,
2226 .quiesce = raid5_quiesce,
2227};
2228
2229static int __init raid5_init(void)
2230{
2231 register_md_personality(&raid5_personality);
2232 register_md_personality(&raid4_personality);
2233 return 0;
1da177e4
LT		 2234}
2235
2604b703 2236static void raid5_exit(void)
1da177e4 2237{
2604b703
N		 2238 unregister_md_personality(&raid5_personality);
2239 unregister_md_personality(&raid4_personality);
1da177e4
LT		 2240}
2241
2242module_init(raid5_init);
2243module_exit(raid5_exit);
2244MODULE_LICENSE("GPL");
2245MODULE_ALIAS("md-personality-4"); /* RAID5 */
d9d166c2
N		 2246MODULE_ALIAS("md-raid5");
2247MODULE_ALIAS("md-raid4");
2604b703
N		 2248MODULE_ALIAS("md-level-5");
2249MODULE_ALIAS("md-level-4");
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