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[PATCH] md: improve raid10 "IO Barrier" concept
[mirror_ubuntu-eoan-kernel.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
38#define HASH_PAGES 1
39#define HASH_PAGES_ORDER 0
40#define NR_HASH (HASH_PAGES * PAGE_SIZE / sizeof(struct stripe_head *))
41#define HASH_MASK (NR_HASH - 1)
42
43#define stripe_hash(conf, sect) ((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK])
44
45/* bio's attached to a stripe+device for I/O are linked together in bi_sector
46 * order without overlap. There may be several bio's per stripe+device, and
47 * a bio could span several devices.
48 * When walking this list for a particular stripe+device, we must never proceed
49 * beyond a bio that extends past this device, as the next bio might no longer
50 * be valid.
51 * This macro is used to determine the 'next' bio in the list, given the sector
52 * of the current stripe+device
53 */
54#define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL)
55/*
56 * The following can be used to debug the driver
57 */
58#define RAID5_DEBUG 0
59#define RAID5_PARANOIA 1
60#if RAID5_PARANOIA && defined(CONFIG_SMP)
61# define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
62#else
63# define CHECK_DEVLOCK()
64#endif
65
66#define PRINTK(x...) ((void)(RAID5_DEBUG && printk(x)))
67#if RAID5_DEBUG
68#define inline
69#define __inline__
70#endif
71
72static void print_raid5_conf (raid5_conf_t *conf);
73
74static inline void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
75{
76 if (atomic_dec_and_test(&sh->count)) {
77 if (!list_empty(&sh->lru))
78 BUG();
79 if (atomic_read(&conf->active_stripes)==0)
80 BUG();
81 if (test_bit(STRIPE_HANDLE, &sh->state)) {
82 if (test_bit(STRIPE_DELAYED, &sh->state))
83 list_add_tail(&sh->lru, &conf->delayed_list);
72626685
N		 84 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
85 conf->seq_write == sh->bm_seq)
86 list_add_tail(&sh->lru, &conf->bitmap_list);
87 else {
88 clear_bit(STRIPE_BIT_DELAY, &sh->state);
1da177e4 89 list_add_tail(&sh->lru, &conf->handle_list);
72626685 90 }
1da177e4
LT		 91 md_wakeup_thread(conf->mddev->thread);
92 } else {
93 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
94 atomic_dec(&conf->preread_active_stripes);
95 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
96 md_wakeup_thread(conf->mddev->thread);
97 }
98 list_add_tail(&sh->lru, &conf->inactive_list);
99 atomic_dec(&conf->active_stripes);
100 if (!conf->inactive_blocked ||
5036805b 101 atomic_read(&conf->active_stripes) < (conf->max_nr_stripes*3/4))
1da177e4
LT		 102 wake_up(&conf->wait_for_stripe);
103 }
104 }
105}
106static void release_stripe(struct stripe_head *sh)
107{
108 raid5_conf_t *conf = sh->raid_conf;
109 unsigned long flags;
110
111 spin_lock_irqsave(&conf->device_lock, flags);
112 __release_stripe(conf, sh);
113 spin_unlock_irqrestore(&conf->device_lock, flags);
114}
115
116static void remove_hash(struct stripe_head *sh)
117{
118 PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector);
119
120 if (sh->hash_pprev) {
121 if (sh->hash_next)
122 sh->hash_next->hash_pprev = sh->hash_pprev;
123 *sh->hash_pprev = sh->hash_next;
124 sh->hash_pprev = NULL;
125 }
126}
127
128static __inline__ void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
129{
130 struct stripe_head **shp = &stripe_hash(conf, sh->sector);
131
132 PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector);
133
134 CHECK_DEVLOCK();
135 if ((sh->hash_next = *shp) != NULL)
136 (*shp)->hash_pprev = &sh->hash_next;
137 *shp = sh;
138 sh->hash_pprev = shp;
139}
140
141
142/* find an idle stripe, make sure it is unhashed, and return it. */
143static struct stripe_head *get_free_stripe(raid5_conf_t *conf)
144{
145 struct stripe_head *sh = NULL;
146 struct list_head *first;
147
148 CHECK_DEVLOCK();
149 if (list_empty(&conf->inactive_list))
150 goto out;
151 first = conf->inactive_list.next;
152 sh = list_entry(first, struct stripe_head, lru);
153 list_del_init(first);
154 remove_hash(sh);
155 atomic_inc(&conf->active_stripes);
156out:
157 return sh;
158}
159
160static void shrink_buffers(struct stripe_head *sh, int num)
161{
162 struct page *p;
163 int i;
164
165 for (i=0; i<num ; i++) {
166 p = sh->dev[i].page;
167 if (!p)
168 continue;
169 sh->dev[i].page = NULL;
170 page_cache_release(p);
171 }
172}
173
174static int grow_buffers(struct stripe_head *sh, int num)
175{
176 int i;
177
178 for (i=0; i<num; i++) {
179 struct page *page;
180
181 if (!(page = alloc_page(GFP_KERNEL))) {
182 return 1;
183 }
184 sh->dev[i].page = page;
185 }
186 return 0;
187}
188
189static void raid5_build_block (struct stripe_head *sh, int i);
190
191static inline void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx)
192{
193 raid5_conf_t *conf = sh->raid_conf;
194 int disks = conf->raid_disks, i;
195
196 if (atomic_read(&sh->count) != 0)
197 BUG();
198 if (test_bit(STRIPE_HANDLE, &sh->state))
199 BUG();
200
201 CHECK_DEVLOCK();
202 PRINTK("init_stripe called, stripe %llu\n",
203 (unsigned long long)sh->sector);
204
205 remove_hash(sh);
206
207 sh->sector = sector;
208 sh->pd_idx = pd_idx;
209 sh->state = 0;
210
211 for (i=disks; i--; ) {
212 struct r5dev *dev = &sh->dev[i];
213
214 if (dev->toread || dev->towrite || dev->written ||
215 test_bit(R5_LOCKED, &dev->flags)) {
216 printk("sector=%llx i=%d %p %p %p %d\n",
217 (unsigned long long)sh->sector, i, dev->toread,
218 dev->towrite, dev->written,
219 test_bit(R5_LOCKED, &dev->flags));
220 BUG();
221 }
222 dev->flags = 0;
223 raid5_build_block(sh, i);
224 }
225 insert_hash(conf, sh);
226}
227
228static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector)
229{
230 struct stripe_head *sh;
231
232 CHECK_DEVLOCK();
233 PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector);
234 for (sh = stripe_hash(conf, sector); sh; sh = sh->hash_next)
235 if (sh->sector == sector)
236 return sh;
237 PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector);
238 return NULL;
239}
240
241static void unplug_slaves(mddev_t *mddev);
242static void raid5_unplug_device(request_queue_t *q);
243
244static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector,
245 int pd_idx, int noblock)
246{
247 struct stripe_head *sh;
248
249 PRINTK("get_stripe, sector %llu\n", (unsigned long long)sector);
250
251 spin_lock_irq(&conf->device_lock);
252
253 do {
72626685
N		 254 wait_event_lock_irq(conf->wait_for_stripe,
255 conf->quiesce == 0,
256 conf->device_lock, /* nothing */);
1da177e4
LT		 257 sh = __find_stripe(conf, sector);
258 if (!sh) {
259 if (!conf->inactive_blocked)
260 sh = get_free_stripe(conf);
261 if (noblock && sh == NULL)
262 break;
263 if (!sh) {
264 conf->inactive_blocked = 1;
265 wait_event_lock_irq(conf->wait_for_stripe,
266 !list_empty(&conf->inactive_list) &&
5036805b
N		 267 (atomic_read(&conf->active_stripes)
268 < (conf->max_nr_stripes *3/4)
1da177e4
LT		 269 || !conf->inactive_blocked),
270 conf->device_lock,
271 unplug_slaves(conf->mddev);
272 );
273 conf->inactive_blocked = 0;
274 } else
275 init_stripe(sh, sector, pd_idx);
276 } else {
277 if (atomic_read(&sh->count)) {
278 if (!list_empty(&sh->lru))
279 BUG();
280 } else {
281 if (!test_bit(STRIPE_HANDLE, &sh->state))
282 atomic_inc(&conf->active_stripes);
283 if (list_empty(&sh->lru))
284 BUG();
285 list_del_init(&sh->lru);
286 }
287 }
288 } while (sh == NULL);
289
290 if (sh)
291 atomic_inc(&sh->count);
292
293 spin_unlock_irq(&conf->device_lock);
294 return sh;
295}
296
3f294f4f 297static int grow_one_stripe(raid5_conf_t *conf)
1da177e4
LT		 298{
299 struct stripe_head *sh;
3f294f4f
N		 300 sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL);
301 if (!sh)
302 return 0;
303 memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev));
304 sh->raid_conf = conf;
305 spin_lock_init(&sh->lock);
306
307 if (grow_buffers(sh, conf->raid_disks)) {
308 shrink_buffers(sh, conf->raid_disks);
309 kmem_cache_free(conf->slab_cache, sh);
310 return 0;
311 }
312 /* we just created an active stripe so... */
313 atomic_set(&sh->count, 1);
314 atomic_inc(&conf->active_stripes);
315 INIT_LIST_HEAD(&sh->lru);
316 release_stripe(sh);
317 return 1;
318}
319
320static int grow_stripes(raid5_conf_t *conf, int num)
321{
1da177e4
LT		 322 kmem_cache_t *sc;
323 int devs = conf->raid_disks;
324
325 sprintf(conf->cache_name, "raid5/%s", mdname(conf->mddev));
326
327 sc = kmem_cache_create(conf->cache_name,
328 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
329 0, 0, NULL, NULL);
330 if (!sc)
331 return 1;
332 conf->slab_cache = sc;
333 while (num--) {
3f294f4f 334 if (!grow_one_stripe(conf))
1da177e4 335 return 1;
1da177e4
LT		 336 }
337 return 0;
338}
339
3f294f4f 340static int drop_one_stripe(raid5_conf_t *conf)
1da177e4
LT		 341{
342 struct stripe_head *sh;
343
3f294f4f
N		 344 spin_lock_irq(&conf->device_lock);
345 sh = get_free_stripe(conf);
346 spin_unlock_irq(&conf->device_lock);
347 if (!sh)
348 return 0;
349 if (atomic_read(&sh->count))
350 BUG();
351 shrink_buffers(sh, conf->raid_disks);
352 kmem_cache_free(conf->slab_cache, sh);
353 atomic_dec(&conf->active_stripes);
354 return 1;
355}
356
357static void shrink_stripes(raid5_conf_t *conf)
358{
359 while (drop_one_stripe(conf))
360 ;
361
1da177e4
LT		 362 kmem_cache_destroy(conf->slab_cache);
363 conf->slab_cache = NULL;
364}
365
4e5314b5 366static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done,
1da177e4
LT		 367 int error)
368{
369 struct stripe_head *sh = bi->bi_private;
370 raid5_conf_t *conf = sh->raid_conf;
371 int disks = conf->raid_disks, i;
372 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
373
374 if (bi->bi_size)
375 return 1;
376
377 for (i=0 ; i<disks; i++)
378 if (bi == &sh->dev[i].req)
379 break;
380
381 PRINTK("end_read_request %llu/%d, count: %d, uptodate %d.\n",
382 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
383 uptodate);
384 if (i == disks) {
385 BUG();
386 return 0;
387 }
388
389 if (uptodate) {
390#if 0
391 struct bio *bio;
392 unsigned long flags;
393 spin_lock_irqsave(&conf->device_lock, flags);
394 /* we can return a buffer if we bypassed the cache or
395 * if the top buffer is not in highmem. If there are
396 * multiple buffers, leave the extra work to
397 * handle_stripe
398 */
399 buffer = sh->bh_read[i];
400 if (buffer &&
401 (!PageHighMem(buffer->b_page)
402 || buffer->b_page == bh->b_page )
403 ) {
404 sh->bh_read[i] = buffer->b_reqnext;
405 buffer->b_reqnext = NULL;
406 } else
407 buffer = NULL;
408 spin_unlock_irqrestore(&conf->device_lock, flags);
409 if (sh->bh_page[i]==bh->b_page)
410 set_buffer_uptodate(bh);
411 if (buffer) {
412 if (buffer->b_page != bh->b_page)
413 memcpy(buffer->b_data, bh->b_data, bh->b_size);
414 buffer->b_end_io(buffer, 1);
415 }
416#else
417 set_bit(R5_UPTODATE, &sh->dev[i].flags);
4e5314b5
N		 418#endif
419 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
420 printk("R5: read error corrected!!\n");
421 clear_bit(R5_ReadError, &sh->dev[i].flags);
422 clear_bit(R5_ReWrite, &sh->dev[i].flags);
423 }
ba22dcbf
N		 424 if (atomic_read(&conf->disks[i].rdev->read_errors))
425 atomic_set(&conf->disks[i].rdev->read_errors, 0);
1da177e4 426 } else {
ba22dcbf 427 int retry = 0;
1da177e4 428 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
ba22dcbf
N		 429 atomic_inc(&conf->disks[i].rdev->read_errors);
430 if (conf->mddev->degraded)
4e5314b5 431 printk("R5: read error not correctable.\n");
ba22dcbf 432 else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
4e5314b5
N		 433 /* Oh, no!!! */
434 printk("R5: read error NOT corrected!!\n");
ba22dcbf
N		 435 else if (atomic_read(&conf->disks[i].rdev->read_errors)
436 > conf->max_nr_stripes)
437 printk("raid5: Too many read errors, failing device.\n");
438 else
439 retry = 1;
440 if (retry)
441 set_bit(R5_ReadError, &sh->dev[i].flags);
442 else {
4e5314b5
N		 443 clear_bit(R5_ReadError, &sh->dev[i].flags);
444 clear_bit(R5_ReWrite, &sh->dev[i].flags);
445 md_error(conf->mddev, conf->disks[i].rdev);
ba22dcbf 446 }
1da177e4
LT		 447 }
448 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
449#if 0
450 /* must restore b_page before unlocking buffer... */
451 if (sh->bh_page[i] != bh->b_page) {
452 bh->b_page = sh->bh_page[i];
453 bh->b_data = page_address(bh->b_page);
454 clear_buffer_uptodate(bh);
455 }
456#endif
457 clear_bit(R5_LOCKED, &sh->dev[i].flags);
458 set_bit(STRIPE_HANDLE, &sh->state);
459 release_stripe(sh);
460 return 0;
461}
462
463static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done,
464 int error)
465{
466 struct stripe_head *sh = bi->bi_private;
467 raid5_conf_t *conf = sh->raid_conf;
468 int disks = conf->raid_disks, i;
469 unsigned long flags;
470 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
471
472 if (bi->bi_size)
473 return 1;
474
475 for (i=0 ; i<disks; i++)
476 if (bi == &sh->dev[i].req)
477 break;
478
479 PRINTK("end_write_request %llu/%d, count %d, uptodate: %d.\n",
480 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
481 uptodate);
482 if (i == disks) {
483 BUG();
484 return 0;
485 }
486
487 spin_lock_irqsave(&conf->device_lock, flags);
488 if (!uptodate)
489 md_error(conf->mddev, conf->disks[i].rdev);
490
491 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
492
493 clear_bit(R5_LOCKED, &sh->dev[i].flags);
494 set_bit(STRIPE_HANDLE, &sh->state);
495 __release_stripe(conf, sh);
496 spin_unlock_irqrestore(&conf->device_lock, flags);
497 return 0;
498}
499
500
501static sector_t compute_blocknr(struct stripe_head *sh, int i);
502
503static void raid5_build_block (struct stripe_head *sh, int i)
504{
505 struct r5dev *dev = &sh->dev[i];
506
507 bio_init(&dev->req);
508 dev->req.bi_io_vec = &dev->vec;
509 dev->req.bi_vcnt++;
510 dev->req.bi_max_vecs++;
511 dev->vec.bv_page = dev->page;
512 dev->vec.bv_len = STRIPE_SIZE;
513 dev->vec.bv_offset = 0;
514
515 dev->req.bi_sector = sh->sector;
516 dev->req.bi_private = sh;
517
518 dev->flags = 0;
519 if (i != sh->pd_idx)
520 dev->sector = compute_blocknr(sh, i);
521}
522
523static void error(mddev_t *mddev, mdk_rdev_t *rdev)
524{
525 char b[BDEVNAME_SIZE];
526 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
527 PRINTK("raid5: error called\n");
528
b2d444d7 529 if (!test_bit(Faulty, &rdev->flags)) {
1da177e4 530 mddev->sb_dirty = 1;
b2d444d7 531 if (test_bit(In_sync, &rdev->flags)) {
1da177e4
LT		 532 conf->working_disks--;
533 mddev->degraded++;
534 conf->failed_disks++;
b2d444d7 535 clear_bit(In_sync, &rdev->flags);
1da177e4
LT		 536 /*
537 * if recovery was running, make sure it aborts.
538 */
539 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
540 }
b2d444d7 541 set_bit(Faulty, &rdev->flags);
1da177e4
LT		 542 printk (KERN_ALERT
543 "raid5: Disk failure on %s, disabling device."
544 " Operation continuing on %d devices\n",
545 bdevname(rdev->bdev,b), conf->working_disks);
546 }
547}
548
549/*
550 * Input: a 'big' sector number,
551 * Output: index of the data and parity disk, and the sector # in them.
552 */
553static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks,
554 unsigned int data_disks, unsigned int * dd_idx,
555 unsigned int * pd_idx, raid5_conf_t *conf)
556{
557 long stripe;
558 unsigned long chunk_number;
559 unsigned int chunk_offset;
560 sector_t new_sector;
561 int sectors_per_chunk = conf->chunk_size >> 9;
562
563 /* First compute the information on this sector */
564
565 /*
566 * Compute the chunk number and the sector offset inside the chunk
567 */
568 chunk_offset = sector_div(r_sector, sectors_per_chunk);
569 chunk_number = r_sector;
570 BUG_ON(r_sector != chunk_number);
571
572 /*
573 * Compute the stripe number
574 */
575 stripe = chunk_number / data_disks;
576
577 /*
578 * Compute the data disk and parity disk indexes inside the stripe
579 */
580 *dd_idx = chunk_number % data_disks;
581
582 /*
583 * Select the parity disk based on the user selected algorithm.
584 */
585 if (conf->level == 4)
586 *pd_idx = data_disks;
587 else switch (conf->algorithm) {
588 case ALGORITHM_LEFT_ASYMMETRIC:
589 *pd_idx = data_disks - stripe % raid_disks;
590 if (*dd_idx >= *pd_idx)
591 (*dd_idx)++;
592 break;
593 case ALGORITHM_RIGHT_ASYMMETRIC:
594 *pd_idx = stripe % raid_disks;
595 if (*dd_idx >= *pd_idx)
596 (*dd_idx)++;
597 break;
598 case ALGORITHM_LEFT_SYMMETRIC:
599 *pd_idx = data_disks - stripe % raid_disks;
600 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
601 break;
602 case ALGORITHM_RIGHT_SYMMETRIC:
603 *pd_idx = stripe % raid_disks;
604 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
605 break;
606 default:
607 printk("raid5: unsupported algorithm %d\n",
608 conf->algorithm);
609 }
610
611 /*
612 * Finally, compute the new sector number
613 */
614 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
615 return new_sector;
616}
617
618
619static sector_t compute_blocknr(struct stripe_head *sh, int i)
620{
621 raid5_conf_t *conf = sh->raid_conf;
622 int raid_disks = conf->raid_disks, data_disks = raid_disks - 1;
623 sector_t new_sector = sh->sector, check;
624 int sectors_per_chunk = conf->chunk_size >> 9;
625 sector_t stripe;
626 int chunk_offset;
627 int chunk_number, dummy1, dummy2, dd_idx = i;
628 sector_t r_sector;
629
630 chunk_offset = sector_div(new_sector, sectors_per_chunk);
631 stripe = new_sector;
632 BUG_ON(new_sector != stripe);
633
634
635 switch (conf->algorithm) {
636 case ALGORITHM_LEFT_ASYMMETRIC:
637 case ALGORITHM_RIGHT_ASYMMETRIC:
638 if (i > sh->pd_idx)
639 i--;
640 break;
641 case ALGORITHM_LEFT_SYMMETRIC:
642 case ALGORITHM_RIGHT_SYMMETRIC:
643 if (i < sh->pd_idx)
644 i += raid_disks;
645 i -= (sh->pd_idx + 1);
646 break;
647 default:
648 printk("raid5: unsupported algorithm %d\n",
649 conf->algorithm);
650 }
651
652 chunk_number = stripe * data_disks + i;
653 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
654
655 check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
656 if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
657 printk("compute_blocknr: map not correct\n");
658 return 0;
659 }
660 return r_sector;
661}
662
663
664
665/*
666 * Copy data between a page in the stripe cache, and a bio.
667 * There are no alignment or size guarantees between the page or the
668 * bio except that there is some overlap.
669 * All iovecs in the bio must be considered.
670 */
671static void copy_data(int frombio, struct bio *bio,
672 struct page *page,
673 sector_t sector)
674{
675 char *pa = page_address(page);
676 struct bio_vec *bvl;
677 int i;
678 int page_offset;
679
680 if (bio->bi_sector >= sector)
681 page_offset = (signed)(bio->bi_sector - sector) * 512;
682 else
683 page_offset = (signed)(sector - bio->bi_sector) * -512;
684 bio_for_each_segment(bvl, bio, i) {
685 int len = bio_iovec_idx(bio,i)->bv_len;
686 int clen;
687 int b_offset = 0;
688
689 if (page_offset < 0) {
690 b_offset = -page_offset;
691 page_offset += b_offset;
692 len -= b_offset;
693 }
694
695 if (len > 0 && page_offset + len > STRIPE_SIZE)
696 clen = STRIPE_SIZE - page_offset;
697 else clen = len;
698
699 if (clen > 0) {
700 char *ba = __bio_kmap_atomic(bio, i, KM_USER0);
701 if (frombio)
702 memcpy(pa+page_offset, ba+b_offset, clen);
703 else
704 memcpy(ba+b_offset, pa+page_offset, clen);
705 __bio_kunmap_atomic(ba, KM_USER0);
706 }
707 if (clen < len) /* hit end of page */
708 break;
709 page_offset += len;
710 }
711}
712
713#define check_xor() do { \
714 if (count == MAX_XOR_BLOCKS) { \
715 xor_block(count, STRIPE_SIZE, ptr); \
716 count = 1; \
717 } \
718 } while(0)
719
720
721static void compute_block(struct stripe_head *sh, int dd_idx)
722{
723 raid5_conf_t *conf = sh->raid_conf;
724 int i, count, disks = conf->raid_disks;
725 void *ptr[MAX_XOR_BLOCKS], *p;
726
727 PRINTK("compute_block, stripe %llu, idx %d\n",
728 (unsigned long long)sh->sector, dd_idx);
729
730 ptr[0] = page_address(sh->dev[dd_idx].page);
731 memset(ptr[0], 0, STRIPE_SIZE);
732 count = 1;
733 for (i = disks ; i--; ) {
734 if (i == dd_idx)
735 continue;
736 p = page_address(sh->dev[i].page);
737 if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
738 ptr[count++] = p;
739 else
740 printk("compute_block() %d, stripe %llu, %d"
741 " not present\n", dd_idx,
742 (unsigned long long)sh->sector, i);
743
744 check_xor();
745 }
746 if (count != 1)
747 xor_block(count, STRIPE_SIZE, ptr);
748 set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
749}
750
751static void compute_parity(struct stripe_head *sh, int method)
752{
753 raid5_conf_t *conf = sh->raid_conf;
754 int i, pd_idx = sh->pd_idx, disks = conf->raid_disks, count;
755 void *ptr[MAX_XOR_BLOCKS];
756 struct bio *chosen;
757
758 PRINTK("compute_parity, stripe %llu, method %d\n",
759 (unsigned long long)sh->sector, method);
760
761 count = 1;
762 ptr[0] = page_address(sh->dev[pd_idx].page);
763 switch(method) {
764 case READ_MODIFY_WRITE:
765 if (!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags))
766 BUG();
767 for (i=disks ; i-- ;) {
768 if (i==pd_idx)
769 continue;
770 if (sh->dev[i].towrite &&
771 test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
772 ptr[count++] = page_address(sh->dev[i].page);
773 chosen = sh->dev[i].towrite;
774 sh->dev[i].towrite = NULL;
775
776 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
777 wake_up(&conf->wait_for_overlap);
778
779 if (sh->dev[i].written) BUG();
780 sh->dev[i].written = chosen;
781 check_xor();
782 }
783 }
784 break;
785 case RECONSTRUCT_WRITE:
786 memset(ptr[0], 0, STRIPE_SIZE);
787 for (i= disks; i-- ;)
788 if (i!=pd_idx && sh->dev[i].towrite) {
789 chosen = sh->dev[i].towrite;
790 sh->dev[i].towrite = NULL;
791
792 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
793 wake_up(&conf->wait_for_overlap);
794
795 if (sh->dev[i].written) BUG();
796 sh->dev[i].written = chosen;
797 }
798 break;
799 case CHECK_PARITY:
800 break;
801 }
802 if (count>1) {
803 xor_block(count, STRIPE_SIZE, ptr);
804 count = 1;
805 }
806
807 for (i = disks; i--;)
808 if (sh->dev[i].written) {
809 sector_t sector = sh->dev[i].sector;
810 struct bio *wbi = sh->dev[i].written;
811 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
812 copy_data(1, wbi, sh->dev[i].page, sector);
813 wbi = r5_next_bio(wbi, sector);
814 }
815
816 set_bit(R5_LOCKED, &sh->dev[i].flags);
817 set_bit(R5_UPTODATE, &sh->dev[i].flags);
818 }
819
820 switch(method) {
821 case RECONSTRUCT_WRITE:
822 case CHECK_PARITY:
823 for (i=disks; i--;)
824 if (i != pd_idx) {
825 ptr[count++] = page_address(sh->dev[i].page);
826 check_xor();
827 }
828 break;
829 case READ_MODIFY_WRITE:
830 for (i = disks; i--;)
831 if (sh->dev[i].written) {
832 ptr[count++] = page_address(sh->dev[i].page);
833 check_xor();
834 }
835 }
836 if (count != 1)
837 xor_block(count, STRIPE_SIZE, ptr);
838
839 if (method != CHECK_PARITY) {
840 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
841 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
842 } else
843 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
844}
845
846/*
847 * Each stripe/dev can have one or more bion attached.
848 * toread/towrite point to the first in a chain.
849 * The bi_next chain must be in order.
850 */
851static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
852{
853 struct bio **bip;
854 raid5_conf_t *conf = sh->raid_conf;
72626685 855 int firstwrite=0;
1da177e4
LT		 856
857 PRINTK("adding bh b#%llu to stripe s#%llu\n",
858 (unsigned long long)bi->bi_sector,
859 (unsigned long long)sh->sector);
860
861
862 spin_lock(&sh->lock);
863 spin_lock_irq(&conf->device_lock);
72626685 864 if (forwrite) {
1da177e4 865 bip = &sh->dev[dd_idx].towrite;
72626685
N		 866 if (*bip == NULL && sh->dev[dd_idx].written == NULL)
867 firstwrite = 1;
868 } else
1da177e4
LT		 869 bip = &sh->dev[dd_idx].toread;
870 while (*bip && (*bip)->bi_sector < bi->bi_sector) {
871 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
872 goto overlap;
873 bip = & (*bip)->bi_next;
874 }
875 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
876 goto overlap;
877
878 if (*bip && bi->bi_next && (*bip) != bi->bi_next)
879 BUG();
880 if (*bip)
881 bi->bi_next = *bip;
882 *bip = bi;
883 bi->bi_phys_segments ++;
884 spin_unlock_irq(&conf->device_lock);
885 spin_unlock(&sh->lock);
886
887 PRINTK("added bi b#%llu to stripe s#%llu, disk %d.\n",
888 (unsigned long long)bi->bi_sector,
889 (unsigned long long)sh->sector, dd_idx);
890
72626685
N		 891 if (conf->mddev->bitmap && firstwrite) {
892 sh->bm_seq = conf->seq_write;
893 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
894 STRIPE_SECTORS, 0);
895 set_bit(STRIPE_BIT_DELAY, &sh->state);
896 }
897
1da177e4
LT		 898 if (forwrite) {
899 /* check if page is covered */
900 sector_t sector = sh->dev[dd_idx].sector;
901 for (bi=sh->dev[dd_idx].towrite;
902 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
903 bi && bi->bi_sector <= sector;
904 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
905 if (bi->bi_sector + (bi->bi_size>>9) >= sector)
906 sector = bi->bi_sector + (bi->bi_size>>9);
907 }
908 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
909 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
910 }
911 return 1;
912
913 overlap:
914 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
915 spin_unlock_irq(&conf->device_lock);
916 spin_unlock(&sh->lock);
917 return 0;
918}
919
920
921/*
922 * handle_stripe - do things to a stripe.
923 *
924 * We lock the stripe and then examine the state of various bits
925 * to see what needs to be done.
926 * Possible results:
927 * return some read request which now have data
928 * return some write requests which are safely on disc
929 * schedule a read on some buffers
930 * schedule a write of some buffers
931 * return confirmation of parity correctness
932 *
933 * Parity calculations are done inside the stripe lock
934 * buffers are taken off read_list or write_list, and bh_cache buffers
935 * get BH_Lock set before the stripe lock is released.
936 *
937 */
938
939static void handle_stripe(struct stripe_head *sh)
940{
941 raid5_conf_t *conf = sh->raid_conf;
942 int disks = conf->raid_disks;
943 struct bio *return_bi= NULL;
944 struct bio *bi;
945 int i;
946 int syncing;
947 int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
948 int non_overwrite = 0;
949 int failed_num=0;
950 struct r5dev *dev;
951
952 PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n",
953 (unsigned long long)sh->sector, atomic_read(&sh->count),
954 sh->pd_idx);
955
956 spin_lock(&sh->lock);
957 clear_bit(STRIPE_HANDLE, &sh->state);
958 clear_bit(STRIPE_DELAYED, &sh->state);
959
960 syncing = test_bit(STRIPE_SYNCING, &sh->state);
961 /* Now to look around and see what can be done */
962
963 for (i=disks; i--; ) {
964 mdk_rdev_t *rdev;
965 dev = &sh->dev[i];
966 clear_bit(R5_Insync, &dev->flags);
967 clear_bit(R5_Syncio, &dev->flags);
968
969 PRINTK("check %d: state 0x%lx read %p write %p written %p\n",
970 i, dev->flags, dev->toread, dev->towrite, dev->written);
971 /* maybe we can reply to a read */
972 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
973 struct bio *rbi, *rbi2;
974 PRINTK("Return read for disc %d\n", i);
975 spin_lock_irq(&conf->device_lock);
976 rbi = dev->toread;
977 dev->toread = NULL;
978 if (test_and_clear_bit(R5_Overlap, &dev->flags))
979 wake_up(&conf->wait_for_overlap);
980 spin_unlock_irq(&conf->device_lock);
981 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) {
982 copy_data(0, rbi, dev->page, dev->sector);
983 rbi2 = r5_next_bio(rbi, dev->sector);
984 spin_lock_irq(&conf->device_lock);
985 if (--rbi->bi_phys_segments == 0) {
986 rbi->bi_next = return_bi;
987 return_bi = rbi;
988 }
989 spin_unlock_irq(&conf->device_lock);
990 rbi = rbi2;
991 }
992 }
993
994 /* now count some things */
995 if (test_bit(R5_LOCKED, &dev->flags)) locked++;
996 if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
997
998
999 if (dev->toread) to_read++;
1000 if (dev->towrite) {
1001 to_write++;
1002 if (!test_bit(R5_OVERWRITE, &dev->flags))
1003 non_overwrite++;
1004 }
1005 if (dev->written) written++;
1006 rdev = conf->disks[i].rdev; /* FIXME, should I be looking rdev */
b2d444d7 1007 if (!rdev || !test_bit(In_sync, &rdev->flags)) {
4e5314b5
N		 1008 /* The ReadError flag wil just be confusing now */
1009 clear_bit(R5_ReadError, &dev->flags);
1010 clear_bit(R5_ReWrite, &dev->flags);
1011 }
b2d444d7 1012 if (!rdev || !test_bit(In_sync, &rdev->flags)
4e5314b5 1013 || test_bit(R5_ReadError, &dev->flags)) {
1da177e4
LT		 1014 failed++;
1015 failed_num = i;
1016 } else
1017 set_bit(R5_Insync, &dev->flags);
1018 }
1019 PRINTK("locked=%d uptodate=%d to_read=%d"
1020 " to_write=%d failed=%d failed_num=%d\n",
1021 locked, uptodate, to_read, to_write, failed, failed_num);
1022 /* check if the array has lost two devices and, if so, some requests might
1023 * need to be failed
1024 */
1025 if (failed > 1 && to_read+to_write+written) {
1da177e4 1026 for (i=disks; i--; ) {
72626685 1027 int bitmap_end = 0;
4e5314b5
N		 1028
1029 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1030 mdk_rdev_t *rdev = conf->disks[i].rdev;
b2d444d7 1031 if (rdev && test_bit(In_sync, &rdev->flags))
4e5314b5
N		 1032 /* multiple read failures in one stripe */
1033 md_error(conf->mddev, rdev);
1034 }
1035
72626685 1036 spin_lock_irq(&conf->device_lock);
1da177e4
LT		 1037 /* fail all writes first */
1038 bi = sh->dev[i].towrite;
1039 sh->dev[i].towrite = NULL;
72626685 1040 if (bi) { to_write--; bitmap_end = 1; }
1da177e4
LT		 1041
1042 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1043 wake_up(&conf->wait_for_overlap);
1044
1045 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
1046 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1047 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1048 if (--bi->bi_phys_segments == 0) {
1049 md_write_end(conf->mddev);
1050 bi->bi_next = return_bi;
1051 return_bi = bi;
1052 }
1053 bi = nextbi;
1054 }
1055 /* and fail all 'written' */
1056 bi = sh->dev[i].written;
1057 sh->dev[i].written = NULL;
72626685 1058 if (bi) bitmap_end = 1;
1da177e4
LT		 1059 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) {
1060 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
1061 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1062 if (--bi->bi_phys_segments == 0) {
1063 md_write_end(conf->mddev);
1064 bi->bi_next = return_bi;
1065 return_bi = bi;
1066 }
1067 bi = bi2;
1068 }
1069
1070 /* fail any reads if this device is non-operational */
4e5314b5
N		 1071 if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
1072 test_bit(R5_ReadError, &sh->dev[i].flags)) {
1da177e4
LT		 1073 bi = sh->dev[i].toread;
1074 sh->dev[i].toread = NULL;
1075 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1076 wake_up(&conf->wait_for_overlap);
1077 if (bi) to_read--;
1078 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
1079 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1080 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1081 if (--bi->bi_phys_segments == 0) {
1082 bi->bi_next = return_bi;
1083 return_bi = bi;
1084 }
1085 bi = nextbi;
1086 }
1087 }
72626685
N		 1088 spin_unlock_irq(&conf->device_lock);
1089 if (bitmap_end)
1090 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
1091 STRIPE_SECTORS, 0, 0);
1da177e4 1092 }
1da177e4
LT		 1093 }
1094 if (failed > 1 && syncing) {
1095 md_done_sync(conf->mddev, STRIPE_SECTORS,0);
1096 clear_bit(STRIPE_SYNCING, &sh->state);
1097 syncing = 0;
1098 }
1099
1100 /* might be able to return some write requests if the parity block
1101 * is safe, or on a failed drive
1102 */
1103 dev = &sh->dev[sh->pd_idx];
1104 if ( written &&
1105 ( (test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) &&
1106 test_bit(R5_UPTODATE, &dev->flags))
1107 || (failed == 1 && failed_num == sh->pd_idx))
1108 ) {
1109 /* any written block on an uptodate or failed drive can be returned.
1110 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
1111 * never LOCKED, so we don't need to test 'failed' directly.
1112 */
1113 for (i=disks; i--; )
1114 if (sh->dev[i].written) {
1115 dev = &sh->dev[i];
1116 if (!test_bit(R5_LOCKED, &dev->flags) &&
1117 test_bit(R5_UPTODATE, &dev->flags) ) {
1118 /* We can return any write requests */
1119 struct bio *wbi, *wbi2;
72626685 1120 int bitmap_end = 0;
1da177e4
LT		 1121 PRINTK("Return write for disc %d\n", i);
1122 spin_lock_irq(&conf->device_lock);
1123 wbi = dev->written;
1124 dev->written = NULL;
1125 while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) {
1126 wbi2 = r5_next_bio(wbi, dev->sector);
1127 if (--wbi->bi_phys_segments == 0) {
1128 md_write_end(conf->mddev);
1129 wbi->bi_next = return_bi;
1130 return_bi = wbi;
1131 }
1132 wbi = wbi2;
1133 }
72626685
N		 1134 if (dev->towrite == NULL)
1135 bitmap_end = 1;
1da177e4 1136 spin_unlock_irq(&conf->device_lock);
72626685
N		 1137 if (bitmap_end)
1138 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
1139 STRIPE_SECTORS,
1140 !test_bit(STRIPE_DEGRADED, &sh->state), 0);
1da177e4
LT		 1141 }
1142 }
1143 }
1144
1145 /* Now we might consider reading some blocks, either to check/generate
1146 * parity, or to satisfy requests
1147 * or to load a block that is being partially written.
1148 */
1149 if (to_read || non_overwrite || (syncing && (uptodate < disks))) {
1150 for (i=disks; i--;) {
1151 dev = &sh->dev[i];
1152 if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1153 (dev->toread ||
1154 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
1155 syncing ||
1156 (failed && (sh->dev[failed_num].toread ||
1157 (sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags))))
1158 )
1159 ) {
1160 /* we would like to get this block, possibly
1161 * by computing it, but we might not be able to
1162 */
1163 if (uptodate == disks-1) {
1164 PRINTK("Computing block %d\n", i);
1165 compute_block(sh, i);
1166 uptodate++;
1167 } else if (test_bit(R5_Insync, &dev->flags)) {
1168 set_bit(R5_LOCKED, &dev->flags);
1169 set_bit(R5_Wantread, &dev->flags);
1170#if 0
1171 /* if I am just reading this block and we don't have
1172 a failed drive, or any pending writes then sidestep the cache */
1173 if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext &&
1174 ! syncing && !failed && !to_write) {
1175 sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page;
1176 sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data;
1177 }
1178#endif
1179 locked++;
1180 PRINTK("Reading block %d (sync=%d)\n",
1181 i, syncing);
1182 if (syncing)
1183 md_sync_acct(conf->disks[i].rdev->bdev,
1184 STRIPE_SECTORS);
1185 }
1186 }
1187 }
1188 set_bit(STRIPE_HANDLE, &sh->state);
1189 }
1190
1191 /* now to consider writing and what else, if anything should be read */
1192 if (to_write) {
1193 int rmw=0, rcw=0;
1194 for (i=disks ; i--;) {
1195 /* would I have to read this buffer for read_modify_write */
1196 dev = &sh->dev[i];
1197 if ((dev->towrite || i == sh->pd_idx) &&
1198 (!test_bit(R5_LOCKED, &dev->flags)
1199#if 0
1200|| sh->bh_page[i]!=bh->b_page
1201#endif
1202 ) &&
1203 !test_bit(R5_UPTODATE, &dev->flags)) {
1204 if (test_bit(R5_Insync, &dev->flags)
1205/* && !(!mddev->insync && i == sh->pd_idx) */
1206 )
1207 rmw++;
1208 else rmw += 2*disks; /* cannot read it */
1209 }
1210 /* Would I have to read this buffer for reconstruct_write */
1211 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
1212 (!test_bit(R5_LOCKED, &dev->flags)
1213#if 0
1214|| sh->bh_page[i] != bh->b_page
1215#endif
1216 ) &&
1217 !test_bit(R5_UPTODATE, &dev->flags)) {
1218 if (test_bit(R5_Insync, &dev->flags)) rcw++;
1219 else rcw += 2*disks;
1220 }
1221 }
1222 PRINTK("for sector %llu, rmw=%d rcw=%d\n",
1223 (unsigned long long)sh->sector, rmw, rcw);
1224 set_bit(STRIPE_HANDLE, &sh->state);
1225 if (rmw < rcw && rmw > 0)
1226 /* prefer read-modify-write, but need to get some data */
1227 for (i=disks; i--;) {
1228 dev = &sh->dev[i];
1229 if ((dev->towrite || i == sh->pd_idx) &&
1230 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1231 test_bit(R5_Insync, &dev->flags)) {
1232 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1233 {
1234 PRINTK("Read_old block %d for r-m-w\n", i);
1235 set_bit(R5_LOCKED, &dev->flags);
1236 set_bit(R5_Wantread, &dev->flags);
1237 locked++;
1238 } else {
1239 set_bit(STRIPE_DELAYED, &sh->state);
1240 set_bit(STRIPE_HANDLE, &sh->state);
1241 }
1242 }
1243 }
1244 if (rcw <= rmw && rcw > 0)
1245 /* want reconstruct write, but need to get some data */
1246 for (i=disks; i--;) {
1247 dev = &sh->dev[i];
1248 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
1249 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1250 test_bit(R5_Insync, &dev->flags)) {
1251 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1252 {
1253 PRINTK("Read_old block %d for Reconstruct\n", i);
1254 set_bit(R5_LOCKED, &dev->flags);
1255 set_bit(R5_Wantread, &dev->flags);
1256 locked++;
1257 } else {
1258 set_bit(STRIPE_DELAYED, &sh->state);
1259 set_bit(STRIPE_HANDLE, &sh->state);
1260 }
1261 }
1262 }
1263 /* now if nothing is locked, and if we have enough data, we can start a write request */
72626685
N		 1264 if (locked == 0 && (rcw == 0 ||rmw == 0) &&
1265 !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
1da177e4
LT		 1266 PRINTK("Computing parity...\n");
1267 compute_parity(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
1268 /* now every locked buffer is ready to be written */
1269 for (i=disks; i--;)
1270 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
1271 PRINTK("Writing block %d\n", i);
1272 locked++;
1273 set_bit(R5_Wantwrite, &sh->dev[i].flags);
1274 if (!test_bit(R5_Insync, &sh->dev[i].flags)
1275 || (i==sh->pd_idx && failed == 0))
1276 set_bit(STRIPE_INSYNC, &sh->state);
1277 }
1278 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
1279 atomic_dec(&conf->preread_active_stripes);
1280 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
1281 md_wakeup_thread(conf->mddev->thread);
1282 }
1283 }
1284 }
1285
1286 /* maybe we need to check and possibly fix the parity for this stripe
1287 * Any reads will already have been scheduled, so we just see if enough data
1288 * is available
1289 */
1290 if (syncing && locked == 0 &&
1291 !test_bit(STRIPE_INSYNC, &sh->state) && failed <= 1) {
1292 set_bit(STRIPE_HANDLE, &sh->state);
1293 if (failed == 0) {
1294 char *pagea;
1295 if (uptodate != disks)
1296 BUG();
1297 compute_parity(sh, CHECK_PARITY);
1298 uptodate--;
1299 pagea = page_address(sh->dev[sh->pd_idx].page);
1300 if ((*(u32*)pagea) == 0 &&
1301 !memcmp(pagea, pagea+4, STRIPE_SIZE-4)) {
1302 /* parity is correct (on disc, not in buffer any more) */
1303 set_bit(STRIPE_INSYNC, &sh->state);
9d88883e
N		 1304 } else {
1305 conf->mddev->resync_mismatches += STRIPE_SECTORS;
1306 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
1307 /* don't try to repair!! */
1308 set_bit(STRIPE_INSYNC, &sh->state);
1da177e4
LT		 1309 }
1310 }
1311 if (!test_bit(STRIPE_INSYNC, &sh->state)) {
1312 if (failed==0)
1313 failed_num = sh->pd_idx;
1314 /* should be able to compute the missing block and write it to spare */
1315 if (!test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)) {
1316 if (uptodate+1 != disks)
1317 BUG();
1318 compute_block(sh, failed_num);
1319 uptodate++;
1320 }
1321 if (uptodate != disks)
1322 BUG();
1323 dev = &sh->dev[failed_num];
1324 set_bit(R5_LOCKED, &dev->flags);
1325 set_bit(R5_Wantwrite, &dev->flags);
72626685 1326 clear_bit(STRIPE_DEGRADED, &sh->state);
1da177e4
LT		 1327 locked++;
1328 set_bit(STRIPE_INSYNC, &sh->state);
1329 set_bit(R5_Syncio, &dev->flags);
1330 }
1331 }
1332 if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
1333 md_done_sync(conf->mddev, STRIPE_SECTORS,1);
1334 clear_bit(STRIPE_SYNCING, &sh->state);
1335 }
4e5314b5
N		 1336
1337 /* If the failed drive is just a ReadError, then we might need to progress
1338 * the repair/check process
1339 */
ba22dcbf
N		 1340 if (failed == 1 && ! conf->mddev->ro &&
1341 test_bit(R5_ReadError, &sh->dev[failed_num].flags)
4e5314b5
N		 1342 && !test_bit(R5_LOCKED, &sh->dev[failed_num].flags)
1343 && test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)
1344 ) {
1345 dev = &sh->dev[failed_num];
1346 if (!test_bit(R5_ReWrite, &dev->flags)) {
1347 set_bit(R5_Wantwrite, &dev->flags);
1348 set_bit(R5_ReWrite, &dev->flags);
1349 set_bit(R5_LOCKED, &dev->flags);
1350 } else {
1351 /* let's read it back */
1352 set_bit(R5_Wantread, &dev->flags);
1353 set_bit(R5_LOCKED, &dev->flags);
1354 }
1355 }
1356
1da177e4
LT		 1357 spin_unlock(&sh->lock);
1358
1359 while ((bi=return_bi)) {
1360 int bytes = bi->bi_size;
1361
1362 return_bi = bi->bi_next;
1363 bi->bi_next = NULL;
1364 bi->bi_size = 0;
1365 bi->bi_end_io(bi, bytes, 0);
1366 }
1367 for (i=disks; i-- ;) {
1368 int rw;
1369 struct bio *bi;
1370 mdk_rdev_t *rdev;
1371 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
1372 rw = 1;
1373 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1374 rw = 0;
1375 else
1376 continue;
1377
1378 bi = &sh->dev[i].req;
1379
1380 bi->bi_rw = rw;
1381 if (rw)
1382 bi->bi_end_io = raid5_end_write_request;
1383 else
1384 bi->bi_end_io = raid5_end_read_request;
1385
1386 rcu_read_lock();
d6065f7b 1387 rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 1388 if (rdev && test_bit(Faulty, &rdev->flags))
1da177e4
LT		 1389 rdev = NULL;
1390 if (rdev)
1391 atomic_inc(&rdev->nr_pending);
1392 rcu_read_unlock();
1393
1394 if (rdev) {
1395 if (test_bit(R5_Syncio, &sh->dev[i].flags))
1396 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1397
1398 bi->bi_bdev = rdev->bdev;
1399 PRINTK("for %llu schedule op %ld on disc %d\n",
1400 (unsigned long long)sh->sector, bi->bi_rw, i);
1401 atomic_inc(&sh->count);
1402 bi->bi_sector = sh->sector + rdev->data_offset;
1403 bi->bi_flags = 1 << BIO_UPTODATE;
1404 bi->bi_vcnt = 1;
1405 bi->bi_max_vecs = 1;
1406 bi->bi_idx = 0;
1407 bi->bi_io_vec = &sh->dev[i].vec;
1408 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1409 bi->bi_io_vec[0].bv_offset = 0;
1410 bi->bi_size = STRIPE_SIZE;
1411 bi->bi_next = NULL;
1412 generic_make_request(bi);
1413 } else {
72626685
N		 1414 if (rw == 1)
1415 set_bit(STRIPE_DEGRADED, &sh->state);
1da177e4
LT		 1416 PRINTK("skip op %ld on disc %d for sector %llu\n",
1417 bi->bi_rw, i, (unsigned long long)sh->sector);
1418 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1419 set_bit(STRIPE_HANDLE, &sh->state);
1420 }
1421 }
1422}
1423
1424static inline void raid5_activate_delayed(raid5_conf_t *conf)
1425{
1426 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
1427 while (!list_empty(&conf->delayed_list)) {
1428 struct list_head *l = conf->delayed_list.next;
1429 struct stripe_head *sh;
1430 sh = list_entry(l, struct stripe_head, lru);
1431 list_del_init(l);
1432 clear_bit(STRIPE_DELAYED, &sh->state);
1433 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1434 atomic_inc(&conf->preread_active_stripes);
1435 list_add_tail(&sh->lru, &conf->handle_list);
1436 }
1437 }
1438}
1439
72626685
N		 1440static inline void activate_bit_delay(raid5_conf_t *conf)
1441{
1442 /* device_lock is held */
1443 struct list_head head;
1444 list_add(&head, &conf->bitmap_list);
1445 list_del_init(&conf->bitmap_list);
1446 while (!list_empty(&head)) {
1447 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
1448 list_del_init(&sh->lru);
1449 atomic_inc(&sh->count);
1450 __release_stripe(conf, sh);
1451 }
1452}
1453
1da177e4
LT		 1454static void unplug_slaves(mddev_t *mddev)
1455{
1456 raid5_conf_t *conf = mddev_to_conf(mddev);
1457 int i;
1458
1459 rcu_read_lock();
1460 for (i=0; i<mddev->raid_disks; i++) {
d6065f7b 1461 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 1462 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
1da177e4
LT		 1463 request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
1464
1465 atomic_inc(&rdev->nr_pending);
1466 rcu_read_unlock();
1467
1468 if (r_queue->unplug_fn)
1469 r_queue->unplug_fn(r_queue);
1470
1471 rdev_dec_pending(rdev, mddev);
1472 rcu_read_lock();
1473 }
1474 }
1475 rcu_read_unlock();
1476}
1477
1478static void raid5_unplug_device(request_queue_t *q)
1479{
1480 mddev_t *mddev = q->queuedata;
1481 raid5_conf_t *conf = mddev_to_conf(mddev);
1482 unsigned long flags;
1483
1484 spin_lock_irqsave(&conf->device_lock, flags);
1485
72626685
N		 1486 if (blk_remove_plug(q)) {
1487 conf->seq_flush++;
1da177e4 1488 raid5_activate_delayed(conf);
72626685 1489 }
1da177e4
LT		 1490 md_wakeup_thread(mddev->thread);
1491
1492 spin_unlock_irqrestore(&conf->device_lock, flags);
1493
1494 unplug_slaves(mddev);
1495}
1496
1497static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk,
1498 sector_t *error_sector)
1499{
1500 mddev_t *mddev = q->queuedata;
1501 raid5_conf_t *conf = mddev_to_conf(mddev);
1502 int i, ret = 0;
1503
1504 rcu_read_lock();
1505 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
d6065f7b 1506 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 1507 if (rdev && !test_bit(Faulty, &rdev->flags)) {
1da177e4
LT		 1508 struct block_device *bdev = rdev->bdev;
1509 request_queue_t *r_queue = bdev_get_queue(bdev);
1510
1511 if (!r_queue->issue_flush_fn)
1512 ret = -EOPNOTSUPP;
1513 else {
1514 atomic_inc(&rdev->nr_pending);
1515 rcu_read_unlock();
1516 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
1517 error_sector);
1518 rdev_dec_pending(rdev, mddev);
1519 rcu_read_lock();
1520 }
1521 }
1522 }
1523 rcu_read_unlock();
1524 return ret;
1525}
1526
1527static inline void raid5_plug_device(raid5_conf_t *conf)
1528{
1529 spin_lock_irq(&conf->device_lock);
1530 blk_plug_device(conf->mddev->queue);
1531 spin_unlock_irq(&conf->device_lock);
1532}
1533
1534static int make_request (request_queue_t *q, struct bio * bi)
1535{
1536 mddev_t *mddev = q->queuedata;
1537 raid5_conf_t *conf = mddev_to_conf(mddev);
1538 const unsigned int raid_disks = conf->raid_disks;
1539 const unsigned int data_disks = raid_disks - 1;
1540 unsigned int dd_idx, pd_idx;
1541 sector_t new_sector;
1542 sector_t logical_sector, last_sector;
1543 struct stripe_head *sh;
a362357b 1544 const int rw = bio_data_dir(bi);
1da177e4 1545
e5dcdd80
N		 1546 if (unlikely(bio_barrier(bi))) {
1547 bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
1548 return 0;
1549 }
1550
3d310eb7 1551 md_write_start(mddev, bi);
06d91a5f 1552
a362357b
JA		 1553 disk_stat_inc(mddev->gendisk, ios[rw]);
1554 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
1da177e4
LT		 1555
1556 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
1557 last_sector = bi->bi_sector + (bi->bi_size>>9);
1558 bi->bi_next = NULL;
1559 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
06d91a5f 1560
1da177e4
LT		 1561 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
1562 DEFINE_WAIT(w);
1563
1564 new_sector = raid5_compute_sector(logical_sector,
1565 raid_disks, data_disks, &dd_idx, &pd_idx, conf);
1566
1567 PRINTK("raid5: make_request, sector %llu logical %llu\n",
1568 (unsigned long long)new_sector,
1569 (unsigned long long)logical_sector);
1570
1571 retry:
1572 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
1573 sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK));
1574 if (sh) {
1575 if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
1576 /* Add failed due to overlap. Flush everything
1577 * and wait a while
1578 */
1579 raid5_unplug_device(mddev->queue);
1580 release_stripe(sh);
1581 schedule();
1582 goto retry;
1583 }
1584 finish_wait(&conf->wait_for_overlap, &w);
1585 raid5_plug_device(conf);
1586 handle_stripe(sh);
1587 release_stripe(sh);
1588
1589 } else {
1590 /* cannot get stripe for read-ahead, just give-up */
1591 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1592 finish_wait(&conf->wait_for_overlap, &w);
1593 break;
1594 }
1595
1596 }
1597 spin_lock_irq(&conf->device_lock);
1598 if (--bi->bi_phys_segments == 0) {
1599 int bytes = bi->bi_size;
1600
1601 if ( bio_data_dir(bi) == WRITE )
1602 md_write_end(mddev);
1603 bi->bi_size = 0;
1604 bi->bi_end_io(bi, bytes, 0);
1605 }
1606 spin_unlock_irq(&conf->device_lock);
1607 return 0;
1608}
1609
1610/* FIXME go_faster isn't used */
57afd89f 1611static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1da177e4
LT		 1612{
1613 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
1614 struct stripe_head *sh;
1615 int sectors_per_chunk = conf->chunk_size >> 9;
1616 sector_t x;
1617 unsigned long stripe;
1618 int chunk_offset;
1619 int dd_idx, pd_idx;
1620 sector_t first_sector;
1621 int raid_disks = conf->raid_disks;
1622 int data_disks = raid_disks-1;
72626685
N		 1623 sector_t max_sector = mddev->size << 1;
1624 int sync_blocks;
1da177e4 1625
72626685 1626 if (sector_nr >= max_sector) {
1da177e4
LT		 1627 /* just being told to finish up .. nothing much to do */
1628 unplug_slaves(mddev);
72626685
N		 1629
1630 if (mddev->curr_resync < max_sector) /* aborted */
1631 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1632 &sync_blocks, 1);
1633 else /* compelted sync */
1634 conf->fullsync = 0;
1635 bitmap_close_sync(mddev->bitmap);
1636
1da177e4
LT		 1637 return 0;
1638 }
1639 /* if there is 1 or more failed drives and we are trying
1640 * to resync, then assert that we are finished, because there is
1641 * nothing we can do.
1642 */
1643 if (mddev->degraded >= 1 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
57afd89f
N		 1644 sector_t rv = (mddev->size << 1) - sector_nr;
1645 *skipped = 1;
1da177e4
LT		 1646 return rv;
1647 }
72626685 1648 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
3855ad9f 1649 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
72626685
N		 1650 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
1651 /* we can skip this block, and probably more */
1652 sync_blocks /= STRIPE_SECTORS;
1653 *skipped = 1;
1654 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
1655 }
1da177e4
LT		 1656
1657 x = sector_nr;
1658 chunk_offset = sector_div(x, sectors_per_chunk);
1659 stripe = x;
1660 BUG_ON(x != stripe);
1661
1662 first_sector = raid5_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk
1663 + chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf);
1664 sh = get_active_stripe(conf, sector_nr, pd_idx, 1);
1665 if (sh == NULL) {
1666 sh = get_active_stripe(conf, sector_nr, pd_idx, 0);
1667 /* make sure we don't swamp the stripe cache if someone else
1668 * is trying to get access
1669 */
66c006a5 1670 schedule_timeout_uninterruptible(1);
1da177e4 1671 }
72626685 1672 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 0);
1da177e4
LT		 1673 spin_lock(&sh->lock);
1674 set_bit(STRIPE_SYNCING, &sh->state);
1675 clear_bit(STRIPE_INSYNC, &sh->state);
1676 spin_unlock(&sh->lock);
1677
1678 handle_stripe(sh);
1679 release_stripe(sh);
1680
1681 return STRIPE_SECTORS;
1682}
1683
1684/*
1685 * This is our raid5 kernel thread.
1686 *
1687 * We scan the hash table for stripes which can be handled now.
1688 * During the scan, completed stripes are saved for us by the interrupt
1689 * handler, so that they will not have to wait for our next wakeup.
1690 */
1691static void raid5d (mddev_t *mddev)
1692{
1693 struct stripe_head *sh;
1694 raid5_conf_t *conf = mddev_to_conf(mddev);
1695 int handled;
1696
1697 PRINTK("+++ raid5d active\n");
1698
1699 md_check_recovery(mddev);
1da177e4
LT		 1700
1701 handled = 0;
1702 spin_lock_irq(&conf->device_lock);
1703 while (1) {
1704 struct list_head *first;
1705
72626685
N		 1706 if (conf->seq_flush - conf->seq_write > 0) {
1707 int seq = conf->seq_flush;
700e432d 1708 spin_unlock_irq(&conf->device_lock);
72626685 1709 bitmap_unplug(mddev->bitmap);
700e432d 1710 spin_lock_irq(&conf->device_lock);
72626685
N		 1711 conf->seq_write = seq;
1712 activate_bit_delay(conf);
1713 }
1714
1da177e4
LT		 1715 if (list_empty(&conf->handle_list) &&
1716 atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
1717 !blk_queue_plugged(mddev->queue) &&
1718 !list_empty(&conf->delayed_list))
1719 raid5_activate_delayed(conf);
1720
1721 if (list_empty(&conf->handle_list))
1722 break;
1723
1724 first = conf->handle_list.next;
1725 sh = list_entry(first, struct stripe_head, lru);
1726
1727 list_del_init(first);
1728 atomic_inc(&sh->count);
1729 if (atomic_read(&sh->count)!= 1)
1730 BUG();
1731 spin_unlock_irq(&conf->device_lock);
1732
1733 handled++;
1734 handle_stripe(sh);
1735 release_stripe(sh);
1736
1737 spin_lock_irq(&conf->device_lock);
1738 }
1739 PRINTK("%d stripes handled\n", handled);
1740
1741 spin_unlock_irq(&conf->device_lock);
1742
1743 unplug_slaves(mddev);
1744
1745 PRINTK("--- raid5d inactive\n");
1746}
1747
3f294f4f 1748static ssize_t
007583c9 1749raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
3f294f4f 1750{
007583c9 1751 raid5_conf_t *conf = mddev_to_conf(mddev);
96de1e66
N		 1752 if (conf)
1753 return sprintf(page, "%d\n", conf->max_nr_stripes);
1754 else
1755 return 0;
3f294f4f
N		 1756}
1757
1758static ssize_t
007583c9 1759raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
3f294f4f 1760{
007583c9 1761 raid5_conf_t *conf = mddev_to_conf(mddev);
3f294f4f
N		 1762 char *end;
1763 int new;
1764 if (len >= PAGE_SIZE)
1765 return -EINVAL;
96de1e66
N		 1766 if (!conf)
1767 return -ENODEV;
3f294f4f
N		 1768
1769 new = simple_strtoul(page, &end, 10);
1770 if (!*page || (*end && *end != '\n') )
1771 return -EINVAL;
1772 if (new <= 16 || new > 32768)
1773 return -EINVAL;
1774 while (new < conf->max_nr_stripes) {
1775 if (drop_one_stripe(conf))
1776 conf->max_nr_stripes--;
1777 else
1778 break;
1779 }
1780 while (new > conf->max_nr_stripes) {
1781 if (grow_one_stripe(conf))
1782 conf->max_nr_stripes++;
1783 else break;
1784 }
1785 return len;
1786}
007583c9 1787
96de1e66
N		 1788static struct md_sysfs_entry
1789raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
1790 raid5_show_stripe_cache_size,
1791 raid5_store_stripe_cache_size);
3f294f4f
N		 1792
1793static ssize_t
96de1e66 1794stripe_cache_active_show(mddev_t *mddev, char *page)
3f294f4f 1795{
007583c9 1796 raid5_conf_t *conf = mddev_to_conf(mddev);
96de1e66
N		 1797 if (conf)
1798 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
1799 else
1800 return 0;
3f294f4f
N		 1801}
1802
96de1e66
N		 1803static struct md_sysfs_entry
1804raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
3f294f4f 1805
007583c9 1806static struct attribute *raid5_attrs[] = {
3f294f4f
N		 1807 &raid5_stripecache_size.attr,
1808 &raid5_stripecache_active.attr,
1809 NULL,
1810};
007583c9
N		 1811static struct attribute_group raid5_attrs_group = {
1812 .name = NULL,
1813 .attrs = raid5_attrs,
3f294f4f
N		 1814};
1815
72626685 1816static int run(mddev_t *mddev)
1da177e4
LT		 1817{
1818 raid5_conf_t *conf;
1819 int raid_disk, memory;
1820 mdk_rdev_t *rdev;
1821 struct disk_info *disk;
1822 struct list_head *tmp;
1823
1824 if (mddev->level != 5 && mddev->level != 4) {
1825 printk("raid5: %s: raid level not set to 4/5 (%d)\n", mdname(mddev), mddev->level);
1826 return -EIO;
1827 }
1828
1829 mddev->private = kmalloc (sizeof (raid5_conf_t)
1830 + mddev->raid_disks * sizeof(struct disk_info),
1831 GFP_KERNEL);
1832 if ((conf = mddev->private) == NULL)
1833 goto abort;
1834 memset (conf, 0, sizeof (*conf) + mddev->raid_disks * sizeof(struct disk_info) );
1835 conf->mddev = mddev;
1836
1837 if ((conf->stripe_hashtbl = (struct stripe_head **) __get_free_pages(GFP_ATOMIC, HASH_PAGES_ORDER)) == NULL)
1838 goto abort;
1839 memset(conf->stripe_hashtbl, 0, HASH_PAGES * PAGE_SIZE);
1840
1841 spin_lock_init(&conf->device_lock);
1842 init_waitqueue_head(&conf->wait_for_stripe);
1843 init_waitqueue_head(&conf->wait_for_overlap);
1844 INIT_LIST_HEAD(&conf->handle_list);
1845 INIT_LIST_HEAD(&conf->delayed_list);
72626685 1846 INIT_LIST_HEAD(&conf->bitmap_list);
1da177e4
LT		 1847 INIT_LIST_HEAD(&conf->inactive_list);
1848 atomic_set(&conf->active_stripes, 0);
1849 atomic_set(&conf->preread_active_stripes, 0);
1850
1da177e4
LT		 1851 PRINTK("raid5: run(%s) called.\n", mdname(mddev));
1852
1853 ITERATE_RDEV(mddev,rdev,tmp) {
1854 raid_disk = rdev->raid_disk;
1855 if (raid_disk >= mddev->raid_disks
1856 || raid_disk < 0)
1857 continue;
1858 disk = conf->disks + raid_disk;
1859
1860 disk->rdev = rdev;
1861
b2d444d7 1862 if (test_bit(In_sync, &rdev->flags)) {
1da177e4
LT		 1863 char b[BDEVNAME_SIZE];
1864 printk(KERN_INFO "raid5: device %s operational as raid"
1865 " disk %d\n", bdevname(rdev->bdev,b),
1866 raid_disk);
1867 conf->working_disks++;
1868 }
1869 }
1870
1871 conf->raid_disks = mddev->raid_disks;
1872 /*
1873 * 0 for a fully functional array, 1 for a degraded array.
1874 */
1875 mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks;
1876 conf->mddev = mddev;
1877 conf->chunk_size = mddev->chunk_size;
1878 conf->level = mddev->level;
1879 conf->algorithm = mddev->layout;
1880 conf->max_nr_stripes = NR_STRIPES;
1881
1882 /* device size must be a multiple of chunk size */
1883 mddev->size &= ~(mddev->chunk_size/1024 -1);
b1581566 1884 mddev->resync_max_sectors = mddev->size << 1;
1da177e4
LT		 1885
1886 if (!conf->chunk_size || conf->chunk_size % 4) {
1887 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
1888 conf->chunk_size, mdname(mddev));
1889 goto abort;
1890 }
1891 if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) {
1892 printk(KERN_ERR
1893 "raid5: unsupported parity algorithm %d for %s\n",
1894 conf->algorithm, mdname(mddev));
1895 goto abort;
1896 }
1897 if (mddev->degraded > 1) {
1898 printk(KERN_ERR "raid5: not enough operational devices for %s"
1899 " (%d/%d failed)\n",
1900 mdname(mddev), conf->failed_disks, conf->raid_disks);
1901 goto abort;
1902 }
1903
1904 if (mddev->degraded == 1 &&
1905 mddev->recovery_cp != MaxSector) {
1906 printk(KERN_ERR
1907 "raid5: cannot start dirty degraded array for %s\n",
1908 mdname(mddev));
1909 goto abort;
1910 }
1911
1912 {
1913 mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5");
1914 if (!mddev->thread) {
1915 printk(KERN_ERR
1916 "raid5: couldn't allocate thread for %s\n",
1917 mdname(mddev));
1918 goto abort;
1919 }
1920 }
5036805b 1921 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
1da177e4
LT		 1922 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
1923 if (grow_stripes(conf, conf->max_nr_stripes)) {
1924 printk(KERN_ERR
1925 "raid5: couldn't allocate %dkB for buffers\n", memory);
1926 shrink_stripes(conf);
1927 md_unregister_thread(mddev->thread);
1928 goto abort;
1929 } else
1930 printk(KERN_INFO "raid5: allocated %dkB for %s\n",
1931 memory, mdname(mddev));
1932
1933 if (mddev->degraded == 0)
1934 printk("raid5: raid level %d set %s active with %d out of %d"
1935 " devices, algorithm %d\n", conf->level, mdname(mddev),
1936 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
1937 conf->algorithm);
1938 else
1939 printk(KERN_ALERT "raid5: raid level %d set %s active with %d"
1940 " out of %d devices, algorithm %d\n", conf->level,
1941 mdname(mddev), mddev->raid_disks - mddev->degraded,
1942 mddev->raid_disks, conf->algorithm);
1943
1944 print_raid5_conf(conf);
1945
1946 /* read-ahead size must cover two whole stripes, which is
1947 * 2 * (n-1) * chunksize where 'n' is the number of raid devices
1948 */
1949 {
1950 int stripe = (mddev->raid_disks-1) * mddev->chunk_size
1951 / PAGE_CACHE_SIZE;
1952 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
1953 mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
1954 }
1955
1956 /* Ok, everything is just fine now */
007583c9 1957 sysfs_create_group(&mddev->kobj, &raid5_attrs_group);
7a5febe9 1958
72626685
N		 1959 if (mddev->bitmap)
1960 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
1961
7a5febe9
N		 1962 mddev->queue->unplug_fn = raid5_unplug_device;
1963 mddev->queue->issue_flush_fn = raid5_issue_flush;
1964
1da177e4
LT		 1965 mddev->array_size = mddev->size * (mddev->raid_disks - 1);
1966 return 0;
1967abort:
1968 if (conf) {
1969 print_raid5_conf(conf);
1970 if (conf->stripe_hashtbl)
1971 free_pages((unsigned long) conf->stripe_hashtbl,
1972 HASH_PAGES_ORDER);
1973 kfree(conf);
1974 }
1975 mddev->private = NULL;
1976 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev));
1977 return -EIO;
1978}
1979
1980
1981
3f294f4f 1982static int stop(mddev_t *mddev)
1da177e4
LT		 1983{
1984 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
1985
1986 md_unregister_thread(mddev->thread);
1987 mddev->thread = NULL;
1988 shrink_stripes(conf);
1989 free_pages((unsigned long) conf->stripe_hashtbl, HASH_PAGES_ORDER);
1990 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
007583c9 1991 sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
96de1e66 1992 kfree(conf);
1da177e4
LT		 1993 mddev->private = NULL;
1994 return 0;
1995}
1996
1997#if RAID5_DEBUG
1998static void print_sh (struct stripe_head *sh)
1999{
2000 int i;
2001
2002 printk("sh %llu, pd_idx %d, state %ld.\n",
2003 (unsigned long long)sh->sector, sh->pd_idx, sh->state);
2004 printk("sh %llu, count %d.\n",
2005 (unsigned long long)sh->sector, atomic_read(&sh->count));
2006 printk("sh %llu, ", (unsigned long long)sh->sector);
2007 for (i = 0; i < sh->raid_conf->raid_disks; i++) {
2008 printk("(cache%d: %p %ld) ",
2009 i, sh->dev[i].page, sh->dev[i].flags);
2010 }
2011 printk("\n");
2012}
2013
2014static void printall (raid5_conf_t *conf)
2015{
2016 struct stripe_head *sh;
2017 int i;
2018
2019 spin_lock_irq(&conf->device_lock);
2020 for (i = 0; i < NR_HASH; i++) {
2021 sh = conf->stripe_hashtbl[i];
2022 for (; sh; sh = sh->hash_next) {
2023 if (sh->raid_conf != conf)
2024 continue;
2025 print_sh(sh);
2026 }
2027 }
2028 spin_unlock_irq(&conf->device_lock);
2029}
2030#endif
2031
2032static void status (struct seq_file *seq, mddev_t *mddev)
2033{
2034 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
2035 int i;
2036
2037 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout);
2038 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks);
2039 for (i = 0; i < conf->raid_disks; i++)
2040 seq_printf (seq, "%s",
2041 conf->disks[i].rdev &&
b2d444d7 2042 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
1da177e4
LT		 2043 seq_printf (seq, "]");
2044#if RAID5_DEBUG
2045#define D(x) \
2046 seq_printf (seq, "<"#x":%d>", atomic_read(&conf->x))
2047 printall(conf);
2048#endif
2049}
2050
2051static void print_raid5_conf (raid5_conf_t *conf)
2052{
2053 int i;
2054 struct disk_info *tmp;
2055
2056 printk("RAID5 conf printout:\n");
2057 if (!conf) {
2058 printk("(conf==NULL)\n");
2059 return;
2060 }
2061 printk(" --- rd:%d wd:%d fd:%d\n", conf->raid_disks,
2062 conf->working_disks, conf->failed_disks);
2063
2064 for (i = 0; i < conf->raid_disks; i++) {
2065 char b[BDEVNAME_SIZE];
2066 tmp = conf->disks + i;
2067 if (tmp->rdev)
2068 printk(" disk %d, o:%d, dev:%s\n",
b2d444d7 2069 i, !test_bit(Faulty, &tmp->rdev->flags),
1da177e4
LT		 2070 bdevname(tmp->rdev->bdev,b));
2071 }
2072}
2073
2074static int raid5_spare_active(mddev_t *mddev)
2075{
2076 int i;
2077 raid5_conf_t *conf = mddev->private;
2078 struct disk_info *tmp;
2079
2080 for (i = 0; i < conf->raid_disks; i++) {
2081 tmp = conf->disks + i;
2082 if (tmp->rdev
b2d444d7
N		 2083 && !test_bit(Faulty, &tmp->rdev->flags)
2084 && !test_bit(In_sync, &tmp->rdev->flags)) {
1da177e4
LT		 2085 mddev->degraded--;
2086 conf->failed_disks--;
2087 conf->working_disks++;
b2d444d7 2088 set_bit(In_sync, &tmp->rdev->flags);
1da177e4
LT		 2089 }
2090 }
2091 print_raid5_conf(conf);
2092 return 0;
2093}
2094
2095static int raid5_remove_disk(mddev_t *mddev, int number)
2096{
2097 raid5_conf_t *conf = mddev->private;
2098 int err = 0;
2099 mdk_rdev_t *rdev;
2100 struct disk_info *p = conf->disks + number;
2101
2102 print_raid5_conf(conf);
2103 rdev = p->rdev;
2104 if (rdev) {
b2d444d7 2105 if (test_bit(In_sync, &rdev->flags) ||
1da177e4
LT		 2106 atomic_read(&rdev->nr_pending)) {
2107 err = -EBUSY;
2108 goto abort;
2109 }
2110 p->rdev = NULL;
fbd568a3 2111 synchronize_rcu();
1da177e4
LT		 2112 if (atomic_read(&rdev->nr_pending)) {
2113 /* lost the race, try later */
2114 err = -EBUSY;
2115 p->rdev = rdev;
2116 }
2117 }
2118abort:
2119
2120 print_raid5_conf(conf);
2121 return err;
2122}
2123
2124static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
2125{
2126 raid5_conf_t *conf = mddev->private;
2127 int found = 0;
2128 int disk;
2129 struct disk_info *p;
2130
2131 if (mddev->degraded > 1)
2132 /* no point adding a device */
2133 return 0;
2134
2135 /*
2136 * find the disk ...
2137 */
2138 for (disk=0; disk < mddev->raid_disks; disk++)
2139 if ((p=conf->disks + disk)->rdev == NULL) {
b2d444d7 2140 clear_bit(In_sync, &rdev->flags);
1da177e4
LT		 2141 rdev->raid_disk = disk;
2142 found = 1;
72626685
N		 2143 if (rdev->saved_raid_disk != disk)
2144 conf->fullsync = 1;
d6065f7b 2145 rcu_assign_pointer(p->rdev, rdev);
1da177e4
LT		 2146 break;
2147 }
2148 print_raid5_conf(conf);
2149 return found;
2150}
2151
2152static int raid5_resize(mddev_t *mddev, sector_t sectors)
2153{
2154 /* no resync is happening, and there is enough space
2155 * on all devices, so we can resize.
2156 * We need to make sure resync covers any new space.
2157 * If the array is shrinking we should possibly wait until
2158 * any io in the removed space completes, but it hardly seems
2159 * worth it.
2160 */
2161 sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
2162 mddev->array_size = (sectors * (mddev->raid_disks-1))>>1;
2163 set_capacity(mddev->gendisk, mddev->array_size << 1);
2164 mddev->changed = 1;
2165 if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) {
2166 mddev->recovery_cp = mddev->size << 1;
2167 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2168 }
2169 mddev->size = sectors /2;
4b5c7ae8 2170 mddev->resync_max_sectors = sectors;
1da177e4
LT		 2171 return 0;
2172}
2173
72626685
N		 2174static void raid5_quiesce(mddev_t *mddev, int state)
2175{
2176 raid5_conf_t *conf = mddev_to_conf(mddev);
2177
2178 switch(state) {
2179 case 1: /* stop all writes */
2180 spin_lock_irq(&conf->device_lock);
2181 conf->quiesce = 1;
2182 wait_event_lock_irq(conf->wait_for_stripe,
2183 atomic_read(&conf->active_stripes) == 0,
2184 conf->device_lock, /* nothing */);
2185 spin_unlock_irq(&conf->device_lock);
2186 break;
2187
2188 case 0: /* re-enable writes */
2189 spin_lock_irq(&conf->device_lock);
2190 conf->quiesce = 0;
2191 wake_up(&conf->wait_for_stripe);
2192 spin_unlock_irq(&conf->device_lock);
2193 break;
2194 }
2195 if (mddev->thread) {
2196 if (mddev->bitmap)
2197 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
2198 else
2199 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
2200 md_wakeup_thread(mddev->thread);
2201 }
2202}
1da177e4
LT		 2203static mdk_personality_t raid5_personality=
2204{
2205 .name = "raid5",
2206 .owner = THIS_MODULE,
2207 .make_request = make_request,
2208 .run = run,
2209 .stop = stop,
2210 .status = status,
2211 .error_handler = error,
2212 .hot_add_disk = raid5_add_disk,
2213 .hot_remove_disk= raid5_remove_disk,
2214 .spare_active = raid5_spare_active,
2215 .sync_request = sync_request,
2216 .resize = raid5_resize,
72626685 2217 .quiesce = raid5_quiesce,
1da177e4
LT		 2218};
2219
2220static int __init raid5_init (void)
2221{
2222 return register_md_personality (RAID5, &raid5_personality);
2223}
2224
2225static void raid5_exit (void)
2226{
2227 unregister_md_personality (RAID5);
2228}
2229
2230module_init(raid5_init);
2231module_exit(raid5_exit);
2232MODULE_LICENSE("GPL");
2233MODULE_ALIAS("md-personality-4"); /* RAID5 */
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