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[PATCH] md: Checkpoint and allow restart of raid5 reshape
[linux-2.6/kmemtrace.git] / drivers / md / raid5.c
blob20ae32d67e21786de09be86275583ab20819adbc
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 <linux/kthread.h>
26 #include <asm/atomic.h>
27
28 #include <linux/raid/bitmap.h>
29
30 /*
31 * Stripe cache
32 */
33
34 #define NR_STRIPES 256
35 #define STRIPE_SIZE PAGE_SIZE
36 #define STRIPE_SHIFT (PAGE_SHIFT - 9)
37 #define STRIPE_SECTORS (STRIPE_SIZE>>9)
38 #define IO_THRESHOLD 1
39 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
40 #define HASH_MASK (NR_HASH - 1)
41
42 #define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
43
44 /* bio's attached to a stripe+device for I/O are linked together in bi_sector
45 * order without overlap. There may be several bio's per stripe+device, and
46 * a bio could span several devices.
47 * When walking this list for a particular stripe+device, we must never proceed
48 * beyond a bio that extends past this device, as the next bio might no longer
49 * be valid.
50 * This macro is used to determine the 'next' bio in the list, given the sector
51 * of the current stripe+device
52 */
53 #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL)
54 /*
55 * The following can be used to debug the driver
56 */
57 #define RAID5_DEBUG 0
58 #define RAID5_PARANOIA 1
59 #if RAID5_PARANOIA && defined(CONFIG_SMP)
60 # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
61 #else
62 # define CHECK_DEVLOCK()
63 #endif
64
65 #define PRINTK(x...) ((void)(RAID5_DEBUG && printk(x)))
66 #if RAID5_DEBUG
67 #define inline
68 #define __inline__
69 #endif
70
71 static void print_raid5_conf (raid5_conf_t *conf);
72
73 static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
74 {
75 if (atomic_dec_and_test(&sh->count)) {
76 if (!list_empty(&sh->lru))
77 BUG();
78 if (atomic_read(&conf->active_stripes)==0)
79 BUG();
80 if (test_bit(STRIPE_HANDLE, &sh->state)) {
81 if (test_bit(STRIPE_DELAYED, &sh->state))
82 list_add_tail(&sh->lru, &conf->delayed_list);
83 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
84 conf->seq_write == sh->bm_seq)
85 list_add_tail(&sh->lru, &conf->bitmap_list);
86 else {
87 clear_bit(STRIPE_BIT_DELAY, &sh->state);
88 list_add_tail(&sh->lru, &conf->handle_list);
89 }
90 md_wakeup_thread(conf->mddev->thread);
91 } else {
92 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
93 atomic_dec(&conf->preread_active_stripes);
94 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
95 md_wakeup_thread(conf->mddev->thread);
96 }
97 atomic_dec(&conf->active_stripes);
98 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
99 list_add_tail(&sh->lru, &conf->inactive_list);
100 wake_up(&conf->wait_for_stripe);
101 }
102 }
103 }
104 }
105 static void release_stripe(struct stripe_head *sh)
106 {
107 raid5_conf_t *conf = sh->raid_conf;
108 unsigned long flags;
109
110 spin_lock_irqsave(&conf->device_lock, flags);
111 __release_stripe(conf, sh);
112 spin_unlock_irqrestore(&conf->device_lock, flags);
113 }
114
115 static inline void remove_hash(struct stripe_head *sh)
116 {
117 PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector);
118
119 hlist_del_init(&sh->hash);
120 }
121
122 static void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
123 {
124 struct hlist_head *hp = stripe_hash(conf, sh->sector);
125
126 PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector);
127
128 CHECK_DEVLOCK();
129 hlist_add_head(&sh->hash, hp);
130 }
131
132
133 /* find an idle stripe, make sure it is unhashed, and return it. */
134 static struct stripe_head *get_free_stripe(raid5_conf_t *conf)
135 {
136 struct stripe_head *sh = NULL;
137 struct list_head *first;
138
139 CHECK_DEVLOCK();
140 if (list_empty(&conf->inactive_list))
141 goto out;
142 first = conf->inactive_list.next;
143 sh = list_entry(first, struct stripe_head, lru);
144 list_del_init(first);
145 remove_hash(sh);
146 atomic_inc(&conf->active_stripes);
147 out:
148 return sh;
149 }
150
151 static void shrink_buffers(struct stripe_head *sh, int num)
152 {
153 struct page *p;
154 int i;
155
156 for (i=0; i<num ; i++) {
157 p = sh->dev[i].page;
158 if (!p)
159 continue;
160 sh->dev[i].page = NULL;
161 put_page(p);
162 }
163 }
164
165 static int grow_buffers(struct stripe_head *sh, int num)
166 {
167 int i;
168
169 for (i=0; i<num; i++) {
170 struct page *page;
171
172 if (!(page = alloc_page(GFP_KERNEL))) {
173 return 1;
174 }
175 sh->dev[i].page = page;
176 }
177 return 0;
178 }
179
180 static void raid5_build_block (struct stripe_head *sh, int i);
181
182 static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int disks)
183 {
184 raid5_conf_t *conf = sh->raid_conf;
185 int i;
186
187 if (atomic_read(&sh->count) != 0)
188 BUG();
189 if (test_bit(STRIPE_HANDLE, &sh->state))
190 BUG();
191
192 CHECK_DEVLOCK();
193 PRINTK("init_stripe called, stripe %llu\n",
194 (unsigned long long)sh->sector);
195
196 remove_hash(sh);
197
198 sh->sector = sector;
199 sh->pd_idx = pd_idx;
200 sh->state = 0;
201
202 sh->disks = disks;
203
204 for (i = sh->disks; i--; ) {
205 struct r5dev *dev = &sh->dev[i];
206
207 if (dev->toread || dev->towrite || dev->written ||
208 test_bit(R5_LOCKED, &dev->flags)) {
209 printk("sector=%llx i=%d %p %p %p %d\n",
210 (unsigned long long)sh->sector, i, dev->toread,
211 dev->towrite, dev->written,
212 test_bit(R5_LOCKED, &dev->flags));
213 BUG();
214 }
215 dev->flags = 0;
216 raid5_build_block(sh, i);
217 }
218 insert_hash(conf, sh);
219 }
220
221 static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, int disks)
222 {
223 struct stripe_head *sh;
224 struct hlist_node *hn;
225
226 CHECK_DEVLOCK();
227 PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector);
228 hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
229 if (sh->sector == sector && sh->disks == disks)
230 return sh;
231 PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector);
232 return NULL;
233 }
234
235 static void unplug_slaves(mddev_t *mddev);
236 static void raid5_unplug_device(request_queue_t *q);
237
238 static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector, int disks,
239 int pd_idx, int noblock)
240 {
241 struct stripe_head *sh;
242
243 PRINTK("get_stripe, sector %llu\n", (unsigned long long)sector);
244
245 spin_lock_irq(&conf->device_lock);
246
247 do {
248 wait_event_lock_irq(conf->wait_for_stripe,
249 conf->quiesce == 0,
250 conf->device_lock, /* nothing */);
251 sh = __find_stripe(conf, sector, disks);
252 if (!sh) {
253 if (!conf->inactive_blocked)
254 sh = get_free_stripe(conf);
255 if (noblock && sh == NULL)
256 break;
257 if (!sh) {
258 conf->inactive_blocked = 1;
259 wait_event_lock_irq(conf->wait_for_stripe,
260 !list_empty(&conf->inactive_list) &&
261 (atomic_read(&conf->active_stripes)
262 < (conf->max_nr_stripes *3/4)
263 || !conf->inactive_blocked),
264 conf->device_lock,
265 unplug_slaves(conf->mddev);
266 );
267 conf->inactive_blocked = 0;
268 } else
269 init_stripe(sh, sector, pd_idx, disks);
270 } else {
271 if (atomic_read(&sh->count)) {
272 if (!list_empty(&sh->lru))
273 BUG();
274 } else {
275 if (!test_bit(STRIPE_HANDLE, &sh->state))
276 atomic_inc(&conf->active_stripes);
277 if (!list_empty(&sh->lru))
278 list_del_init(&sh->lru);
279 }
280 }
281 } while (sh == NULL);
282
283 if (sh)
284 atomic_inc(&sh->count);
285
286 spin_unlock_irq(&conf->device_lock);
287 return sh;
288 }
289
290 static int grow_one_stripe(raid5_conf_t *conf)
291 {
292 struct stripe_head *sh;
293 sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL);
294 if (!sh)
295 return 0;
296 memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev));
297 sh->raid_conf = conf;
298 spin_lock_init(&sh->lock);
299
300 if (grow_buffers(sh, conf->raid_disks)) {
301 shrink_buffers(sh, conf->raid_disks);
302 kmem_cache_free(conf->slab_cache, sh);
303 return 0;
304 }
305 sh->disks = conf->raid_disks;
306 /* we just created an active stripe so... */
307 atomic_set(&sh->count, 1);
308 atomic_inc(&conf->active_stripes);
309 INIT_LIST_HEAD(&sh->lru);
310 release_stripe(sh);
311 return 1;
312 }
313
314 static int grow_stripes(raid5_conf_t *conf, int num)
315 {
316 kmem_cache_t *sc;
317 int devs = conf->raid_disks;
318
319 sprintf(conf->cache_name[0], "raid5/%s", mdname(conf->mddev));
320 sprintf(conf->cache_name[1], "raid5/%s-alt", mdname(conf->mddev));
321 conf->active_name = 0;
322 sc = kmem_cache_create(conf->cache_name[conf->active_name],
323 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
324 0, 0, NULL, NULL);
325 if (!sc)
326 return 1;
327 conf->slab_cache = sc;
328 conf->pool_size = devs;
329 while (num--) {
330 if (!grow_one_stripe(conf))
331 return 1;
332 }
333 return 0;
334 }
335
336 #ifdef CONFIG_MD_RAID5_RESHAPE
337 static int resize_stripes(raid5_conf_t *conf, int newsize)
338 {
339 /* Make all the stripes able to hold 'newsize' devices.
340 * New slots in each stripe get 'page' set to a new page.
341 *
342 * This happens in stages:
343 * 1/ create a new kmem_cache and allocate the required number of
344 * stripe_heads.
345 * 2/ gather all the old stripe_heads and tranfer the pages across
346 * to the new stripe_heads. This will have the side effect of
347 * freezing the array as once all stripe_heads have been collected,
348 * no IO will be possible. Old stripe heads are freed once their
349 * pages have been transferred over, and the old kmem_cache is
350 * freed when all stripes are done.
351 * 3/ reallocate conf->disks to be suitable bigger. If this fails,
352 * we simple return a failre status - no need to clean anything up.
353 * 4/ allocate new pages for the new slots in the new stripe_heads.
354 * If this fails, we don't bother trying the shrink the
355 * stripe_heads down again, we just leave them as they are.
356 * As each stripe_head is processed the new one is released into
357 * active service.
358 *
359 * Once step2 is started, we cannot afford to wait for a write,
360 * so we use GFP_NOIO allocations.
361 */
362 struct stripe_head *osh, *nsh;
363 LIST_HEAD(newstripes);
364 struct disk_info *ndisks;
365 int err = 0;
366 kmem_cache_t *sc;
367 int i;
368
369 if (newsize <= conf->pool_size)
370 return 0; /* never bother to shrink */
371
372 /* Step 1 */
373 sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
374 sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
375 0, 0, NULL, NULL);
376 if (!sc)
377 return -ENOMEM;
378
379 for (i = conf->max_nr_stripes; i; i--) {
380 nsh = kmem_cache_alloc(sc, GFP_KERNEL);
381 if (!nsh)
382 break;
383
384 memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev));
385
386 nsh->raid_conf = conf;
387 spin_lock_init(&nsh->lock);
388
389 list_add(&nsh->lru, &newstripes);
390 }
391 if (i) {
392 /* didn't get enough, give up */
393 while (!list_empty(&newstripes)) {
394 nsh = list_entry(newstripes.next, struct stripe_head, lru);
395 list_del(&nsh->lru);
396 kmem_cache_free(sc, nsh);
397 }
398 kmem_cache_destroy(sc);
399 return -ENOMEM;
400 }
401 /* Step 2 - Must use GFP_NOIO now.
402 * OK, we have enough stripes, start collecting inactive
403 * stripes and copying them over
404 */
405 list_for_each_entry(nsh, &newstripes, lru) {
406 spin_lock_irq(&conf->device_lock);
407 wait_event_lock_irq(conf->wait_for_stripe,
408 !list_empty(&conf->inactive_list),
409 conf->device_lock,
410 unplug_slaves(conf->mddev);
411 );
412 osh = get_free_stripe(conf);
413 spin_unlock_irq(&conf->device_lock);
414 atomic_set(&nsh->count, 1);
415 for(i=0; i<conf->pool_size; i++)
416 nsh->dev[i].page = osh->dev[i].page;
417 for( ; i<newsize; i++)
418 nsh->dev[i].page = NULL;
419 kmem_cache_free(conf->slab_cache, osh);
420 }
421 kmem_cache_destroy(conf->slab_cache);
422
423 /* Step 3.
424 * At this point, we are holding all the stripes so the array
425 * is completely stalled, so now is a good time to resize
426 * conf->disks.
427 */
428 ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
429 if (ndisks) {
430 for (i=0; i<conf->raid_disks; i++)
431 ndisks[i] = conf->disks[i];
432 kfree(conf->disks);
433 conf->disks = ndisks;
434 } else
435 err = -ENOMEM;
436
437 /* Step 4, return new stripes to service */
438 while(!list_empty(&newstripes)) {
439 nsh = list_entry(newstripes.next, struct stripe_head, lru);
440 list_del_init(&nsh->lru);
441 for (i=conf->raid_disks; i < newsize; i++)
442 if (nsh->dev[i].page == NULL) {
443 struct page *p = alloc_page(GFP_NOIO);
444 nsh->dev[i].page = p;
445 if (!p)
446 err = -ENOMEM;
447 }
448 release_stripe(nsh);
449 }
450 /* critical section pass, GFP_NOIO no longer needed */
451
452 conf->slab_cache = sc;
453 conf->active_name = 1-conf->active_name;
454 conf->pool_size = newsize;
455 return err;
456 }
457 #endif
458
459 static int drop_one_stripe(raid5_conf_t *conf)
460 {
461 struct stripe_head *sh;
462
463 spin_lock_irq(&conf->device_lock);
464 sh = get_free_stripe(conf);
465 spin_unlock_irq(&conf->device_lock);
466 if (!sh)
467 return 0;
468 if (atomic_read(&sh->count))
469 BUG();
470 shrink_buffers(sh, conf->pool_size);
471 kmem_cache_free(conf->slab_cache, sh);
472 atomic_dec(&conf->active_stripes);
473 return 1;
474 }
475
476 static void shrink_stripes(raid5_conf_t *conf)
477 {
478 while (drop_one_stripe(conf))
479 ;
480
481 if (conf->slab_cache)
482 kmem_cache_destroy(conf->slab_cache);
483 conf->slab_cache = NULL;
484 }
485
486 static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done,
487 int error)
488 {
489 struct stripe_head *sh = bi->bi_private;
490 raid5_conf_t *conf = sh->raid_conf;
491 int disks = sh->disks, i;
492 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
493
494 if (bi->bi_size)
495 return 1;
496
497 for (i=0 ; i<disks; i++)
498 if (bi == &sh->dev[i].req)
499 break;
500
501 PRINTK("end_read_request %llu/%d, count: %d, uptodate %d.\n",
502 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
503 uptodate);
504 if (i == disks) {
505 BUG();
506 return 0;
507 }
508
509 if (uptodate) {
510 #if 0
511 struct bio *bio;
512 unsigned long flags;
513 spin_lock_irqsave(&conf->device_lock, flags);
514 /* we can return a buffer if we bypassed the cache or
515 * if the top buffer is not in highmem. If there are
516 * multiple buffers, leave the extra work to
517 * handle_stripe
518 */
519 buffer = sh->bh_read[i];
520 if (buffer &&
521 (!PageHighMem(buffer->b_page)
522 || buffer->b_page == bh->b_page )
523 ) {
524 sh->bh_read[i] = buffer->b_reqnext;
525 buffer->b_reqnext = NULL;
526 } else
527 buffer = NULL;
528 spin_unlock_irqrestore(&conf->device_lock, flags);
529 if (sh->bh_page[i]==bh->b_page)
530 set_buffer_uptodate(bh);
531 if (buffer) {
532 if (buffer->b_page != bh->b_page)
533 memcpy(buffer->b_data, bh->b_data, bh->b_size);
534 buffer->b_end_io(buffer, 1);
535 }
536 #else
537 set_bit(R5_UPTODATE, &sh->dev[i].flags);
538 #endif
539 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
540 printk(KERN_INFO "raid5: read error corrected!!\n");
541 clear_bit(R5_ReadError, &sh->dev[i].flags);
542 clear_bit(R5_ReWrite, &sh->dev[i].flags);
543 }
544 if (atomic_read(&conf->disks[i].rdev->read_errors))
545 atomic_set(&conf->disks[i].rdev->read_errors, 0);
546 } else {
547 int retry = 0;
548 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
549 atomic_inc(&conf->disks[i].rdev->read_errors);
550 if (conf->mddev->degraded)
551 printk(KERN_WARNING "raid5: read error not correctable.\n");
552 else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
553 /* Oh, no!!! */
554 printk(KERN_WARNING "raid5: read error NOT corrected!!\n");
555 else if (atomic_read(&conf->disks[i].rdev->read_errors)
556 > conf->max_nr_stripes)
557 printk(KERN_WARNING
558 "raid5: Too many read errors, failing device.\n");
559 else
560 retry = 1;
561 if (retry)
562 set_bit(R5_ReadError, &sh->dev[i].flags);
563 else {
564 clear_bit(R5_ReadError, &sh->dev[i].flags);
565 clear_bit(R5_ReWrite, &sh->dev[i].flags);
566 md_error(conf->mddev, conf->disks[i].rdev);
567 }
568 }
569 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
570 #if 0
571 /* must restore b_page before unlocking buffer... */
572 if (sh->bh_page[i] != bh->b_page) {
573 bh->b_page = sh->bh_page[i];
574 bh->b_data = page_address(bh->b_page);
575 clear_buffer_uptodate(bh);
576 }
577 #endif
578 clear_bit(R5_LOCKED, &sh->dev[i].flags);
579 set_bit(STRIPE_HANDLE, &sh->state);
580 release_stripe(sh);
581 return 0;
582 }
583
584 static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done,
585 int error)
586 {
587 struct stripe_head *sh = bi->bi_private;
588 raid5_conf_t *conf = sh->raid_conf;
589 int disks = sh->disks, i;
590 unsigned long flags;
591 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
592
593 if (bi->bi_size)
594 return 1;
595
596 for (i=0 ; i<disks; i++)
597 if (bi == &sh->dev[i].req)
598 break;
599
600 PRINTK("end_write_request %llu/%d, count %d, uptodate: %d.\n",
601 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
602 uptodate);
603 if (i == disks) {
604 BUG();
605 return 0;
606 }
607
608 spin_lock_irqsave(&conf->device_lock, flags);
609 if (!uptodate)
610 md_error(conf->mddev, conf->disks[i].rdev);
611
612 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
613
614 clear_bit(R5_LOCKED, &sh->dev[i].flags);
615 set_bit(STRIPE_HANDLE, &sh->state);
616 __release_stripe(conf, sh);
617 spin_unlock_irqrestore(&conf->device_lock, flags);
618 return 0;
619 }
620
621
622 static sector_t compute_blocknr(struct stripe_head *sh, int i);
623
624 static void raid5_build_block (struct stripe_head *sh, int i)
625 {
626 struct r5dev *dev = &sh->dev[i];
627
628 bio_init(&dev->req);
629 dev->req.bi_io_vec = &dev->vec;
630 dev->req.bi_vcnt++;
631 dev->req.bi_max_vecs++;
632 dev->vec.bv_page = dev->page;
633 dev->vec.bv_len = STRIPE_SIZE;
634 dev->vec.bv_offset = 0;
635
636 dev->req.bi_sector = sh->sector;
637 dev->req.bi_private = sh;
638
639 dev->flags = 0;
640 if (i != sh->pd_idx)
641 dev->sector = compute_blocknr(sh, i);
642 }
643
644 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
645 {
646 char b[BDEVNAME_SIZE];
647 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
648 PRINTK("raid5: error called\n");
649
650 if (!test_bit(Faulty, &rdev->flags)) {
651 mddev->sb_dirty = 1;
652 if (test_bit(In_sync, &rdev->flags)) {
653 conf->working_disks--;
654 mddev->degraded++;
655 conf->failed_disks++;
656 clear_bit(In_sync, &rdev->flags);
657 /*
658 * if recovery was running, make sure it aborts.
659 */
660 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
661 }
662 set_bit(Faulty, &rdev->flags);
663 printk (KERN_ALERT
664 "raid5: Disk failure on %s, disabling device."
665 " Operation continuing on %d devices\n",
666 bdevname(rdev->bdev,b), conf->working_disks);
667 }
668 }
669
670 /*
671 * Input: a 'big' sector number,
672 * Output: index of the data and parity disk, and the sector # in them.
673 */
674 static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks,
675 unsigned int data_disks, unsigned int * dd_idx,
676 unsigned int * pd_idx, raid5_conf_t *conf)
677 {
678 long stripe;
679 unsigned long chunk_number;
680 unsigned int chunk_offset;
681 sector_t new_sector;
682 int sectors_per_chunk = conf->chunk_size >> 9;
683
684 /* First compute the information on this sector */
685
686 /*
687 * Compute the chunk number and the sector offset inside the chunk
688 */
689 chunk_offset = sector_div(r_sector, sectors_per_chunk);
690 chunk_number = r_sector;
691 BUG_ON(r_sector != chunk_number);
692
693 /*
694 * Compute the stripe number
695 */
696 stripe = chunk_number / data_disks;
697
698 /*
699 * Compute the data disk and parity disk indexes inside the stripe
700 */
701 *dd_idx = chunk_number % data_disks;
702
703 /*
704 * Select the parity disk based on the user selected algorithm.
705 */
706 if (conf->level == 4)
707 *pd_idx = data_disks;
708 else switch (conf->algorithm) {
709 case ALGORITHM_LEFT_ASYMMETRIC:
710 *pd_idx = data_disks - stripe % raid_disks;
711 if (*dd_idx >= *pd_idx)
712 (*dd_idx)++;
713 break;
714 case ALGORITHM_RIGHT_ASYMMETRIC:
715 *pd_idx = stripe % raid_disks;
716 if (*dd_idx >= *pd_idx)
717 (*dd_idx)++;
718 break;
719 case ALGORITHM_LEFT_SYMMETRIC:
720 *pd_idx = data_disks - stripe % raid_disks;
721 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
722 break;
723 case ALGORITHM_RIGHT_SYMMETRIC:
724 *pd_idx = stripe % raid_disks;
725 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
726 break;
727 default:
728 printk(KERN_ERR "raid5: unsupported algorithm %d\n",
729 conf->algorithm);
730 }
731
732 /*
733 * Finally, compute the new sector number
734 */
735 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
736 return new_sector;
737 }
738
739
740 static sector_t compute_blocknr(struct stripe_head *sh, int i)
741 {
742 raid5_conf_t *conf = sh->raid_conf;
743 int raid_disks = sh->disks, data_disks = raid_disks - 1;
744 sector_t new_sector = sh->sector, check;
745 int sectors_per_chunk = conf->chunk_size >> 9;
746 sector_t stripe;
747 int chunk_offset;
748 int chunk_number, dummy1, dummy2, dd_idx = i;
749 sector_t r_sector;
750
751 chunk_offset = sector_div(new_sector, sectors_per_chunk);
752 stripe = new_sector;
753 BUG_ON(new_sector != stripe);
754
755
756 switch (conf->algorithm) {
757 case ALGORITHM_LEFT_ASYMMETRIC:
758 case ALGORITHM_RIGHT_ASYMMETRIC:
759 if (i > sh->pd_idx)
760 i--;
761 break;
762 case ALGORITHM_LEFT_SYMMETRIC:
763 case ALGORITHM_RIGHT_SYMMETRIC:
764 if (i < sh->pd_idx)
765 i += raid_disks;
766 i -= (sh->pd_idx + 1);
767 break;
768 default:
769 printk(KERN_ERR "raid5: unsupported algorithm %d\n",
770 conf->algorithm);
771 }
772
773 chunk_number = stripe * data_disks + i;
774 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
775
776 check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
777 if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
778 printk(KERN_ERR "compute_blocknr: map not correct\n");
779 return 0;
780 }
781 return r_sector;
782 }
783
784
785
786 /*
787 * Copy data between a page in the stripe cache, and a bio.
788 * There are no alignment or size guarantees between the page or the
789 * bio except that there is some overlap.
790 * All iovecs in the bio must be considered.
791 */
792 static void copy_data(int frombio, struct bio *bio,
793 struct page *page,
794 sector_t sector)
795 {
796 char *pa = page_address(page);
797 struct bio_vec *bvl;
798 int i;
799 int page_offset;
800
801 if (bio->bi_sector >= sector)
802 page_offset = (signed)(bio->bi_sector - sector) * 512;
803 else
804 page_offset = (signed)(sector - bio->bi_sector) * -512;
805 bio_for_each_segment(bvl, bio, i) {
806 int len = bio_iovec_idx(bio,i)->bv_len;
807 int clen;
808 int b_offset = 0;
809
810 if (page_offset < 0) {
811 b_offset = -page_offset;
812 page_offset += b_offset;
813 len -= b_offset;
814 }
815
816 if (len > 0 && page_offset + len > STRIPE_SIZE)
817 clen = STRIPE_SIZE - page_offset;
818 else clen = len;
819
820 if (clen > 0) {
821 char *ba = __bio_kmap_atomic(bio, i, KM_USER0);
822 if (frombio)
823 memcpy(pa+page_offset, ba+b_offset, clen);
824 else
825 memcpy(ba+b_offset, pa+page_offset, clen);
826 __bio_kunmap_atomic(ba, KM_USER0);
827 }
828 if (clen < len) /* hit end of page */
829 break;
830 page_offset += len;
831 }
832 }
833
834 #define check_xor() do { \
835 if (count == MAX_XOR_BLOCKS) { \
836 xor_block(count, STRIPE_SIZE, ptr); \
837 count = 1; \
838 } \
839 } while(0)
840
841
842 static void compute_block(struct stripe_head *sh, int dd_idx)
843 {
844 int i, count, disks = sh->disks;
845 void *ptr[MAX_XOR_BLOCKS], *p;
846
847 PRINTK("compute_block, stripe %llu, idx %d\n",
848 (unsigned long long)sh->sector, dd_idx);
849
850 ptr[0] = page_address(sh->dev[dd_idx].page);
851 memset(ptr[0], 0, STRIPE_SIZE);
852 count = 1;
853 for (i = disks ; i--; ) {
854 if (i == dd_idx)
855 continue;
856 p = page_address(sh->dev[i].page);
857 if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
858 ptr[count++] = p;
859 else
860 printk(KERN_ERR "compute_block() %d, stripe %llu, %d"
861 " not present\n", dd_idx,
862 (unsigned long long)sh->sector, i);
863
864 check_xor();
865 }
866 if (count != 1)
867 xor_block(count, STRIPE_SIZE, ptr);
868 set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
869 }
870
871 static void compute_parity(struct stripe_head *sh, int method)
872 {
873 raid5_conf_t *conf = sh->raid_conf;
874 int i, pd_idx = sh->pd_idx, disks = sh->disks, count;
875 void *ptr[MAX_XOR_BLOCKS];
876 struct bio *chosen;
877
878 PRINTK("compute_parity, stripe %llu, method %d\n",
879 (unsigned long long)sh->sector, method);
880
881 count = 1;
882 ptr[0] = page_address(sh->dev[pd_idx].page);
883 switch(method) {
884 case READ_MODIFY_WRITE:
885 if (!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags))
886 BUG();
887 for (i=disks ; i-- ;) {
888 if (i==pd_idx)
889 continue;
890 if (sh->dev[i].towrite &&
891 test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
892 ptr[count++] = page_address(sh->dev[i].page);
893 chosen = sh->dev[i].towrite;
894 sh->dev[i].towrite = NULL;
895
896 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
897 wake_up(&conf->wait_for_overlap);
898
899 if (sh->dev[i].written) BUG();
900 sh->dev[i].written = chosen;
901 check_xor();
902 }
903 }
904 break;
905 case RECONSTRUCT_WRITE:
906 memset(ptr[0], 0, STRIPE_SIZE);
907 for (i= disks; i-- ;)
908 if (i!=pd_idx && sh->dev[i].towrite) {
909 chosen = sh->dev[i].towrite;
910 sh->dev[i].towrite = NULL;
911
912 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
913 wake_up(&conf->wait_for_overlap);
914
915 if (sh->dev[i].written) BUG();
916 sh->dev[i].written = chosen;
917 }
918 break;
919 case CHECK_PARITY:
920 break;
921 }
922 if (count>1) {
923 xor_block(count, STRIPE_SIZE, ptr);
924 count = 1;
925 }
926
927 for (i = disks; i--;)
928 if (sh->dev[i].written) {
929 sector_t sector = sh->dev[i].sector;
930 struct bio *wbi = sh->dev[i].written;
931 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
932 copy_data(1, wbi, sh->dev[i].page, sector);
933 wbi = r5_next_bio(wbi, sector);
934 }
935
936 set_bit(R5_LOCKED, &sh->dev[i].flags);
937 set_bit(R5_UPTODATE, &sh->dev[i].flags);
938 }
939
940 switch(method) {
941 case RECONSTRUCT_WRITE:
942 case CHECK_PARITY:
943 for (i=disks; i--;)
944 if (i != pd_idx) {
945 ptr[count++] = page_address(sh->dev[i].page);
946 check_xor();
947 }
948 break;
949 case READ_MODIFY_WRITE:
950 for (i = disks; i--;)
951 if (sh->dev[i].written) {
952 ptr[count++] = page_address(sh->dev[i].page);
953 check_xor();
954 }
955 }
956 if (count != 1)
957 xor_block(count, STRIPE_SIZE, ptr);
958
959 if (method != CHECK_PARITY) {
960 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
961 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
962 } else
963 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
964 }
965
966 /*
967 * Each stripe/dev can have one or more bion attached.
968 * toread/towrite point to the first in a chain.
969 * The bi_next chain must be in order.
970 */
971 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
972 {
973 struct bio **bip;
974 raid5_conf_t *conf = sh->raid_conf;
975 int firstwrite=0;
976
977 PRINTK("adding bh b#%llu to stripe s#%llu\n",
978 (unsigned long long)bi->bi_sector,
979 (unsigned long long)sh->sector);
980
981
982 spin_lock(&sh->lock);
983 spin_lock_irq(&conf->device_lock);
984 if (forwrite) {
985 bip = &sh->dev[dd_idx].towrite;
986 if (*bip == NULL && sh->dev[dd_idx].written == NULL)
987 firstwrite = 1;
988 } else
989 bip = &sh->dev[dd_idx].toread;
990 while (*bip && (*bip)->bi_sector < bi->bi_sector) {
991 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
992 goto overlap;
993 bip = & (*bip)->bi_next;
994 }
995 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
996 goto overlap;
997
998 if (*bip && bi->bi_next && (*bip) != bi->bi_next)
999 BUG();
1000 if (*bip)
1001 bi->bi_next = *bip;
1002 *bip = bi;
1003 bi->bi_phys_segments ++;
1004 spin_unlock_irq(&conf->device_lock);
1005 spin_unlock(&sh->lock);
1006
1007 PRINTK("added bi b#%llu to stripe s#%llu, disk %d.\n",
1008 (unsigned long long)bi->bi_sector,
1009 (unsigned long long)sh->sector, dd_idx);
1010
1011 if (conf->mddev->bitmap && firstwrite) {
1012 sh->bm_seq = conf->seq_write;
1013 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
1014 STRIPE_SECTORS, 0);
1015 set_bit(STRIPE_BIT_DELAY, &sh->state);
1016 }
1017
1018 if (forwrite) {
1019 /* check if page is covered */
1020 sector_t sector = sh->dev[dd_idx].sector;
1021 for (bi=sh->dev[dd_idx].towrite;
1022 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
1023 bi && bi->bi_sector <= sector;
1024 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
1025 if (bi->bi_sector + (bi->bi_size>>9) >= sector)
1026 sector = bi->bi_sector + (bi->bi_size>>9);
1027 }
1028 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
1029 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
1030 }
1031 return 1;
1032
1033 overlap:
1034 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
1035 spin_unlock_irq(&conf->device_lock);
1036 spin_unlock(&sh->lock);
1037 return 0;
1038 }
1039
1040 static void end_reshape(raid5_conf_t *conf);
1041
1042 static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)
1043 {
1044 int sectors_per_chunk = conf->chunk_size >> 9;
1045 sector_t x = stripe;
1046 int pd_idx, dd_idx;
1047 int chunk_offset = sector_div(x, sectors_per_chunk);
1048 stripe = x;
1049 raid5_compute_sector(stripe*(disks-1)*sectors_per_chunk
1050 + chunk_offset, disks, disks-1, &dd_idx, &pd_idx, conf);
1051 return pd_idx;
1052 }
1053
1054
1055 /*
1056 * handle_stripe - do things to a stripe.
1057 *
1058 * We lock the stripe and then examine the state of various bits
1059 * to see what needs to be done.
1060 * Possible results:
1061 * return some read request which now have data
1062 * return some write requests which are safely on disc
1063 * schedule a read on some buffers
1064 * schedule a write of some buffers
1065 * return confirmation of parity correctness
1066 *
1067 * Parity calculations are done inside the stripe lock
1068 * buffers are taken off read_list or write_list, and bh_cache buffers
1069 * get BH_Lock set before the stripe lock is released.
1070 *
1071 */
1072
1073 static void handle_stripe(struct stripe_head *sh)
1074 {
1075 raid5_conf_t *conf = sh->raid_conf;
1076 int disks = sh->disks;
1077 struct bio *return_bi= NULL;
1078 struct bio *bi;
1079 int i;
1080 int syncing, expanding, expanded;
1081 int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
1082 int non_overwrite = 0;
1083 int failed_num=0;
1084 struct r5dev *dev;
1085
1086 PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n",
1087 (unsigned long long)sh->sector, atomic_read(&sh->count),
1088 sh->pd_idx);
1089
1090 spin_lock(&sh->lock);
1091 clear_bit(STRIPE_HANDLE, &sh->state);
1092 clear_bit(STRIPE_DELAYED, &sh->state);
1093
1094 syncing = test_bit(STRIPE_SYNCING, &sh->state);
1095 expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
1096 expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
1097 /* Now to look around and see what can be done */
1098
1099 rcu_read_lock();
1100 for (i=disks; i--; ) {
1101 mdk_rdev_t *rdev;
1102 dev = &sh->dev[i];
1103 clear_bit(R5_Insync, &dev->flags);
1104
1105 PRINTK("check %d: state 0x%lx read %p write %p written %p\n",
1106 i, dev->flags, dev->toread, dev->towrite, dev->written);
1107 /* maybe we can reply to a read */
1108 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
1109 struct bio *rbi, *rbi2;
1110 PRINTK("Return read for disc %d\n", i);
1111 spin_lock_irq(&conf->device_lock);
1112 rbi = dev->toread;
1113 dev->toread = NULL;
1114 if (test_and_clear_bit(R5_Overlap, &dev->flags))
1115 wake_up(&conf->wait_for_overlap);
1116 spin_unlock_irq(&conf->device_lock);
1117 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) {
1118 copy_data(0, rbi, dev->page, dev->sector);
1119 rbi2 = r5_next_bio(rbi, dev->sector);
1120 spin_lock_irq(&conf->device_lock);
1121 if (--rbi->bi_phys_segments == 0) {
1122 rbi->bi_next = return_bi;
1123 return_bi = rbi;
1124 }
1125 spin_unlock_irq(&conf->device_lock);
1126 rbi = rbi2;
1127 }
1128 }
1129
1130 /* now count some things */
1131 if (test_bit(R5_LOCKED, &dev->flags)) locked++;
1132 if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
1133
1134
1135 if (dev->toread) to_read++;
1136 if (dev->towrite) {
1137 to_write++;
1138 if (!test_bit(R5_OVERWRITE, &dev->flags))
1139 non_overwrite++;
1140 }
1141 if (dev->written) written++;
1142 rdev = rcu_dereference(conf->disks[i].rdev);
1143 if (!rdev || !test_bit(In_sync, &rdev->flags)) {
1144 /* The ReadError flag will just be confusing now */
1145 clear_bit(R5_ReadError, &dev->flags);
1146 clear_bit(R5_ReWrite, &dev->flags);
1147 }
1148 if (!rdev || !test_bit(In_sync, &rdev->flags)
1149 || test_bit(R5_ReadError, &dev->flags)) {
1150 failed++;
1151 failed_num = i;
1152 } else
1153 set_bit(R5_Insync, &dev->flags);
1154 }
1155 rcu_read_unlock();
1156 PRINTK("locked=%d uptodate=%d to_read=%d"
1157 " to_write=%d failed=%d failed_num=%d\n",
1158 locked, uptodate, to_read, to_write, failed, failed_num);
1159 /* check if the array has lost two devices and, if so, some requests might
1160 * need to be failed
1161 */
1162 if (failed > 1 && to_read+to_write+written) {
1163 for (i=disks; i--; ) {
1164 int bitmap_end = 0;
1165
1166 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1167 mdk_rdev_t *rdev;
1168 rcu_read_lock();
1169 rdev = rcu_dereference(conf->disks[i].rdev);
1170 if (rdev && test_bit(In_sync, &rdev->flags))
1171 /* multiple read failures in one stripe */
1172 md_error(conf->mddev, rdev);
1173 rcu_read_unlock();
1174 }
1175
1176 spin_lock_irq(&conf->device_lock);
1177 /* fail all writes first */
1178 bi = sh->dev[i].towrite;
1179 sh->dev[i].towrite = NULL;
1180 if (bi) { to_write--; bitmap_end = 1; }
1181
1182 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1183 wake_up(&conf->wait_for_overlap);
1184
1185 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
1186 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1187 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1188 if (--bi->bi_phys_segments == 0) {
1189 md_write_end(conf->mddev);
1190 bi->bi_next = return_bi;
1191 return_bi = bi;
1192 }
1193 bi = nextbi;
1194 }
1195 /* and fail all 'written' */
1196 bi = sh->dev[i].written;
1197 sh->dev[i].written = NULL;
1198 if (bi) bitmap_end = 1;
1199 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) {
1200 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
1201 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1202 if (--bi->bi_phys_segments == 0) {
1203 md_write_end(conf->mddev);
1204 bi->bi_next = return_bi;
1205 return_bi = bi;
1206 }
1207 bi = bi2;
1208 }
1209
1210 /* fail any reads if this device is non-operational */
1211 if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
1212 test_bit(R5_ReadError, &sh->dev[i].flags)) {
1213 bi = sh->dev[i].toread;
1214 sh->dev[i].toread = NULL;
1215 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1216 wake_up(&conf->wait_for_overlap);
1217 if (bi) to_read--;
1218 while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){
1219 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1220 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1221 if (--bi->bi_phys_segments == 0) {
1222 bi->bi_next = return_bi;
1223 return_bi = bi;
1224 }
1225 bi = nextbi;
1226 }
1227 }
1228 spin_unlock_irq(&conf->device_lock);
1229 if (bitmap_end)
1230 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
1231 STRIPE_SECTORS, 0, 0);
1232 }
1233 }
1234 if (failed > 1 && syncing) {
1235 md_done_sync(conf->mddev, STRIPE_SECTORS,0);
1236 clear_bit(STRIPE_SYNCING, &sh->state);
1237 syncing = 0;
1238 }
1239
1240 /* might be able to return some write requests if the parity block
1241 * is safe, or on a failed drive
1242 */
1243 dev = &sh->dev[sh->pd_idx];
1244 if ( written &&
1245 ( (test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) &&
1246 test_bit(R5_UPTODATE, &dev->flags))
1247 || (failed == 1 && failed_num == sh->pd_idx))
1248 ) {
1249 /* any written block on an uptodate or failed drive can be returned.
1250 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
1251 * never LOCKED, so we don't need to test 'failed' directly.
1252 */
1253 for (i=disks; i--; )
1254 if (sh->dev[i].written) {
1255 dev = &sh->dev[i];
1256 if (!test_bit(R5_LOCKED, &dev->flags) &&
1257 test_bit(R5_UPTODATE, &dev->flags) ) {
1258 /* We can return any write requests */
1259 struct bio *wbi, *wbi2;
1260 int bitmap_end = 0;
1261 PRINTK("Return write for disc %d\n", i);
1262 spin_lock_irq(&conf->device_lock);
1263 wbi = dev->written;
1264 dev->written = NULL;
1265 while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) {
1266 wbi2 = r5_next_bio(wbi, dev->sector);
1267 if (--wbi->bi_phys_segments == 0) {
1268 md_write_end(conf->mddev);
1269 wbi->bi_next = return_bi;
1270 return_bi = wbi;
1271 }
1272 wbi = wbi2;
1273 }
1274 if (dev->towrite == NULL)
1275 bitmap_end = 1;
1276 spin_unlock_irq(&conf->device_lock);
1277 if (bitmap_end)
1278 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
1279 STRIPE_SECTORS,
1280 !test_bit(STRIPE_DEGRADED, &sh->state), 0);
1281 }
1282 }
1283 }
1284
1285 /* Now we might consider reading some blocks, either to check/generate
1286 * parity, or to satisfy requests
1287 * or to load a block that is being partially written.
1288 */
1289 if (to_read || non_overwrite || (syncing && (uptodate < disks)) || expanding) {
1290 for (i=disks; i--;) {
1291 dev = &sh->dev[i];
1292 if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1293 (dev->toread ||
1294 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
1295 syncing ||
1296 expanding ||
1297 (failed && (sh->dev[failed_num].toread ||
1298 (sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags))))
1299 )
1300 ) {
1301 /* we would like to get this block, possibly
1302 * by computing it, but we might not be able to
1303 */
1304 if (uptodate == disks-1) {
1305 PRINTK("Computing block %d\n", i);
1306 compute_block(sh, i);
1307 uptodate++;
1308 } else if (test_bit(R5_Insync, &dev->flags)) {
1309 set_bit(R5_LOCKED, &dev->flags);
1310 set_bit(R5_Wantread, &dev->flags);
1311 #if 0
1312 /* if I am just reading this block and we don't have
1313 a failed drive, or any pending writes then sidestep the cache */
1314 if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext &&
1315 ! syncing && !failed && !to_write) {
1316 sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page;
1317 sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data;
1318 }
1319 #endif
1320 locked++;
1321 PRINTK("Reading block %d (sync=%d)\n",
1322 i, syncing);
1323 }
1324 }
1325 }
1326 set_bit(STRIPE_HANDLE, &sh->state);
1327 }
1328
1329 /* now to consider writing and what else, if anything should be read */
1330 if (to_write) {
1331 int rmw=0, rcw=0;
1332 for (i=disks ; i--;) {
1333 /* would I have to read this buffer for read_modify_write */
1334 dev = &sh->dev[i];
1335 if ((dev->towrite || i == sh->pd_idx) &&
1336 (!test_bit(R5_LOCKED, &dev->flags)
1337 #if 0
1338 || sh->bh_page[i]!=bh->b_page
1339 #endif
1340 ) &&
1341 !test_bit(R5_UPTODATE, &dev->flags)) {
1342 if (test_bit(R5_Insync, &dev->flags)
1343 /* && !(!mddev->insync && i == sh->pd_idx) */
1344 )
1345 rmw++;
1346 else rmw += 2*disks; /* cannot read it */
1347 }
1348 /* Would I have to read this buffer for reconstruct_write */
1349 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
1350 (!test_bit(R5_LOCKED, &dev->flags)
1351 #if 0
1352 || sh->bh_page[i] != bh->b_page
1353 #endif
1354 ) &&
1355 !test_bit(R5_UPTODATE, &dev->flags)) {
1356 if (test_bit(R5_Insync, &dev->flags)) rcw++;
1357 else rcw += 2*disks;
1358 }
1359 }
1360 PRINTK("for sector %llu, rmw=%d rcw=%d\n",
1361 (unsigned long long)sh->sector, rmw, rcw);
1362 set_bit(STRIPE_HANDLE, &sh->state);
1363 if (rmw < rcw && rmw > 0)
1364 /* prefer read-modify-write, but need to get some data */
1365 for (i=disks; i--;) {
1366 dev = &sh->dev[i];
1367 if ((dev->towrite || i == sh->pd_idx) &&
1368 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1369 test_bit(R5_Insync, &dev->flags)) {
1370 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1371 {
1372 PRINTK("Read_old block %d for r-m-w\n", i);
1373 set_bit(R5_LOCKED, &dev->flags);
1374 set_bit(R5_Wantread, &dev->flags);
1375 locked++;
1376 } else {
1377 set_bit(STRIPE_DELAYED, &sh->state);
1378 set_bit(STRIPE_HANDLE, &sh->state);
1379 }
1380 }
1381 }
1382 if (rcw <= rmw && rcw > 0)
1383 /* want reconstruct write, but need to get some data */
1384 for (i=disks; i--;) {
1385 dev = &sh->dev[i];
1386 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
1387 !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) &&
1388 test_bit(R5_Insync, &dev->flags)) {
1389 if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1390 {
1391 PRINTK("Read_old block %d for Reconstruct\n", i);
1392 set_bit(R5_LOCKED, &dev->flags);
1393 set_bit(R5_Wantread, &dev->flags);
1394 locked++;
1395 } else {
1396 set_bit(STRIPE_DELAYED, &sh->state);
1397 set_bit(STRIPE_HANDLE, &sh->state);
1398 }
1399 }
1400 }
1401 /* now if nothing is locked, and if we have enough data, we can start a write request */
1402 if (locked == 0 && (rcw == 0 ||rmw == 0) &&
1403 !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
1404 PRINTK("Computing parity...\n");
1405 compute_parity(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
1406 /* now every locked buffer is ready to be written */
1407 for (i=disks; i--;)
1408 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
1409 PRINTK("Writing block %d\n", i);
1410 locked++;
1411 set_bit(R5_Wantwrite, &sh->dev[i].flags);
1412 if (!test_bit(R5_Insync, &sh->dev[i].flags)
1413 || (i==sh->pd_idx && failed == 0))
1414 set_bit(STRIPE_INSYNC, &sh->state);
1415 }
1416 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
1417 atomic_dec(&conf->preread_active_stripes);
1418 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
1419 md_wakeup_thread(conf->mddev->thread);
1420 }
1421 }
1422 }
1423
1424 /* maybe we need to check and possibly fix the parity for this stripe
1425 * Any reads will already have been scheduled, so we just see if enough data
1426 * is available
1427 */
1428 if (syncing && locked == 0 &&
1429 !test_bit(STRIPE_INSYNC, &sh->state)) {
1430 set_bit(STRIPE_HANDLE, &sh->state);
1431 if (failed == 0) {
1432 char *pagea;
1433 if (uptodate != disks)
1434 BUG();
1435 compute_parity(sh, CHECK_PARITY);
1436 uptodate--;
1437 pagea = page_address(sh->dev[sh->pd_idx].page);
1438 if ((*(u32*)pagea) == 0 &&
1439 !memcmp(pagea, pagea+4, STRIPE_SIZE-4)) {
1440 /* parity is correct (on disc, not in buffer any more) */
1441 set_bit(STRIPE_INSYNC, &sh->state);
1442 } else {
1443 conf->mddev->resync_mismatches += STRIPE_SECTORS;
1444 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
1445 /* don't try to repair!! */
1446 set_bit(STRIPE_INSYNC, &sh->state);
1447 else {
1448 compute_block(sh, sh->pd_idx);
1449 uptodate++;
1450 }
1451 }
1452 }
1453 if (!test_bit(STRIPE_INSYNC, &sh->state)) {
1454 /* either failed parity check, or recovery is happening */
1455 if (failed==0)
1456 failed_num = sh->pd_idx;
1457 dev = &sh->dev[failed_num];
1458 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
1459 BUG_ON(uptodate != disks);
1460
1461 set_bit(R5_LOCKED, &dev->flags);
1462 set_bit(R5_Wantwrite, &dev->flags);
1463 clear_bit(STRIPE_DEGRADED, &sh->state);
1464 locked++;
1465 set_bit(STRIPE_INSYNC, &sh->state);
1466 }
1467 }
1468 if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
1469 md_done_sync(conf->mddev, STRIPE_SECTORS,1);
1470 clear_bit(STRIPE_SYNCING, &sh->state);
1471 }
1472
1473 /* If the failed drive is just a ReadError, then we might need to progress
1474 * the repair/check process
1475 */
1476 if (failed == 1 && ! conf->mddev->ro &&
1477 test_bit(R5_ReadError, &sh->dev[failed_num].flags)
1478 && !test_bit(R5_LOCKED, &sh->dev[failed_num].flags)
1479 && test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)
1480 ) {
1481 dev = &sh->dev[failed_num];
1482 if (!test_bit(R5_ReWrite, &dev->flags)) {
1483 set_bit(R5_Wantwrite, &dev->flags);
1484 set_bit(R5_ReWrite, &dev->flags);
1485 set_bit(R5_LOCKED, &dev->flags);
1486 locked++;
1487 } else {
1488 /* let's read it back */
1489 set_bit(R5_Wantread, &dev->flags);
1490 set_bit(R5_LOCKED, &dev->flags);
1491 locked++;
1492 }
1493 }
1494
1495 if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
1496 /* Need to write out all blocks after computing parity */
1497 sh->disks = conf->raid_disks;
1498 sh->pd_idx = stripe_to_pdidx(sh->sector, conf, conf->raid_disks);
1499 compute_parity(sh, RECONSTRUCT_WRITE);
1500 for (i= conf->raid_disks; i--;) {
1501 set_bit(R5_LOCKED, &sh->dev[i].flags);
1502 locked++;
1503 set_bit(R5_Wantwrite, &sh->dev[i].flags);
1504 }
1505 clear_bit(STRIPE_EXPANDING, &sh->state);
1506 } else if (expanded) {
1507 clear_bit(STRIPE_EXPAND_READY, &sh->state);
1508 atomic_dec(&conf->reshape_stripes);
1509 wake_up(&conf->wait_for_overlap);
1510 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
1511 }
1512
1513 if (expanding && locked == 0) {
1514 /* We have read all the blocks in this stripe and now we need to
1515 * copy some of them into a target stripe for expand.
1516 */
1517 clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
1518 for (i=0; i< sh->disks; i++)
1519 if (i != sh->pd_idx) {
1520 int dd_idx, pd_idx, j;
1521 struct stripe_head *sh2;
1522
1523 sector_t bn = compute_blocknr(sh, i);
1524 sector_t s = raid5_compute_sector(bn, conf->raid_disks,
1525 conf->raid_disks-1,
1526 &dd_idx, &pd_idx, conf);
1527 sh2 = get_active_stripe(conf, s, conf->raid_disks, pd_idx, 1);
1528 if (sh2 == NULL)
1529 /* so far only the early blocks of this stripe
1530 * have been requested. When later blocks
1531 * get requested, we will try again
1532 */
1533 continue;
1534 if(!test_bit(STRIPE_EXPANDING, &sh2->state) ||
1535 test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
1536 /* must have already done this block */
1537 release_stripe(sh2);
1538 continue;
1539 }
1540 memcpy(page_address(sh2->dev[dd_idx].page),
1541 page_address(sh->dev[i].page),
1542 STRIPE_SIZE);
1543 set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
1544 set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
1545 for (j=0; j<conf->raid_disks; j++)
1546 if (j != sh2->pd_idx &&
1547 !test_bit(R5_Expanded, &sh2->dev[j].flags))
1548 break;
1549 if (j == conf->raid_disks) {
1550 set_bit(STRIPE_EXPAND_READY, &sh2->state);
1551 set_bit(STRIPE_HANDLE, &sh2->state);
1552 }
1553 release_stripe(sh2);
1554 }
1555 }
1556
1557 spin_unlock(&sh->lock);
1558
1559 while ((bi=return_bi)) {
1560 int bytes = bi->bi_size;
1561
1562 return_bi = bi->bi_next;
1563 bi->bi_next = NULL;
1564 bi->bi_size = 0;
1565 bi->bi_end_io(bi, bytes, 0);
1566 }
1567 for (i=disks; i-- ;) {
1568 int rw;
1569 struct bio *bi;
1570 mdk_rdev_t *rdev;
1571 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
1572 rw = 1;
1573 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1574 rw = 0;
1575 else
1576 continue;
1577
1578 bi = &sh->dev[i].req;
1579
1580 bi->bi_rw = rw;
1581 if (rw)
1582 bi->bi_end_io = raid5_end_write_request;
1583 else
1584 bi->bi_end_io = raid5_end_read_request;
1585
1586 rcu_read_lock();
1587 rdev = rcu_dereference(conf->disks[i].rdev);
1588 if (rdev && test_bit(Faulty, &rdev->flags))
1589 rdev = NULL;
1590 if (rdev)
1591 atomic_inc(&rdev->nr_pending);
1592 rcu_read_unlock();
1593
1594 if (rdev) {
1595 if (syncing || expanding || expanded)
1596 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1597
1598 bi->bi_bdev = rdev->bdev;
1599 PRINTK("for %llu schedule op %ld on disc %d\n",
1600 (unsigned long long)sh->sector, bi->bi_rw, i);
1601 atomic_inc(&sh->count);
1602 bi->bi_sector = sh->sector + rdev->data_offset;
1603 bi->bi_flags = 1 << BIO_UPTODATE;
1604 bi->bi_vcnt = 1;
1605 bi->bi_max_vecs = 1;
1606 bi->bi_idx = 0;
1607 bi->bi_io_vec = &sh->dev[i].vec;
1608 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1609 bi->bi_io_vec[0].bv_offset = 0;
1610 bi->bi_size = STRIPE_SIZE;
1611 bi->bi_next = NULL;
1612 if (rw == WRITE &&
1613 test_bit(R5_ReWrite, &sh->dev[i].flags))
1614 atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1615 generic_make_request(bi);
1616 } else {
1617 if (rw == 1)
1618 set_bit(STRIPE_DEGRADED, &sh->state);
1619 PRINTK("skip op %ld on disc %d for sector %llu\n",
1620 bi->bi_rw, i, (unsigned long long)sh->sector);
1621 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1622 set_bit(STRIPE_HANDLE, &sh->state);
1623 }
1624 }
1625 }
1626
1627 static void raid5_activate_delayed(raid5_conf_t *conf)
1628 {
1629 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
1630 while (!list_empty(&conf->delayed_list)) {
1631 struct list_head *l = conf->delayed_list.next;
1632 struct stripe_head *sh;
1633 sh = list_entry(l, struct stripe_head, lru);
1634 list_del_init(l);
1635 clear_bit(STRIPE_DELAYED, &sh->state);
1636 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
1637 atomic_inc(&conf->preread_active_stripes);
1638 list_add_tail(&sh->lru, &conf->handle_list);
1639 }
1640 }
1641 }
1642
1643 static void activate_bit_delay(raid5_conf_t *conf)
1644 {
1645 /* device_lock is held */
1646 struct list_head head;
1647 list_add(&head, &conf->bitmap_list);
1648 list_del_init(&conf->bitmap_list);
1649 while (!list_empty(&head)) {
1650 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
1651 list_del_init(&sh->lru);
1652 atomic_inc(&sh->count);
1653 __release_stripe(conf, sh);
1654 }
1655 }
1656
1657 static void unplug_slaves(mddev_t *mddev)
1658 {
1659 raid5_conf_t *conf = mddev_to_conf(mddev);
1660 int i;
1661
1662 rcu_read_lock();
1663 for (i=0; i<mddev->raid_disks; i++) {
1664 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
1665 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
1666 request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
1667
1668 atomic_inc(&rdev->nr_pending);
1669 rcu_read_unlock();
1670
1671 if (r_queue->unplug_fn)
1672 r_queue->unplug_fn(r_queue);
1673
1674 rdev_dec_pending(rdev, mddev);
1675 rcu_read_lock();
1676 }
1677 }
1678 rcu_read_unlock();
1679 }
1680
1681 static void raid5_unplug_device(request_queue_t *q)
1682 {
1683 mddev_t *mddev = q->queuedata;
1684 raid5_conf_t *conf = mddev_to_conf(mddev);
1685 unsigned long flags;
1686
1687 spin_lock_irqsave(&conf->device_lock, flags);
1688
1689 if (blk_remove_plug(q)) {
1690 conf->seq_flush++;
1691 raid5_activate_delayed(conf);
1692 }
1693 md_wakeup_thread(mddev->thread);
1694
1695 spin_unlock_irqrestore(&conf->device_lock, flags);
1696
1697 unplug_slaves(mddev);
1698 }
1699
1700 static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk,
1701 sector_t *error_sector)
1702 {
1703 mddev_t *mddev = q->queuedata;
1704 raid5_conf_t *conf = mddev_to_conf(mddev);
1705 int i, ret = 0;
1706
1707 rcu_read_lock();
1708 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
1709 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
1710 if (rdev && !test_bit(Faulty, &rdev->flags)) {
1711 struct block_device *bdev = rdev->bdev;
1712 request_queue_t *r_queue = bdev_get_queue(bdev);
1713
1714 if (!r_queue->issue_flush_fn)
1715 ret = -EOPNOTSUPP;
1716 else {
1717 atomic_inc(&rdev->nr_pending);
1718 rcu_read_unlock();
1719 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
1720 error_sector);
1721 rdev_dec_pending(rdev, mddev);
1722 rcu_read_lock();
1723 }
1724 }
1725 }
1726 rcu_read_unlock();
1727 return ret;
1728 }
1729
1730 static inline void raid5_plug_device(raid5_conf_t *conf)
1731 {
1732 spin_lock_irq(&conf->device_lock);
1733 blk_plug_device(conf->mddev->queue);
1734 spin_unlock_irq(&conf->device_lock);
1735 }
1736
1737 static int make_request(request_queue_t *q, struct bio * bi)
1738 {
1739 mddev_t *mddev = q->queuedata;
1740 raid5_conf_t *conf = mddev_to_conf(mddev);
1741 unsigned int dd_idx, pd_idx;
1742 sector_t new_sector;
1743 sector_t logical_sector, last_sector;
1744 struct stripe_head *sh;
1745 const int rw = bio_data_dir(bi);
1746
1747 if (unlikely(bio_barrier(bi))) {
1748 bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
1749 return 0;
1750 }
1751
1752 md_write_start(mddev, bi);
1753
1754 disk_stat_inc(mddev->gendisk, ios[rw]);
1755 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
1756
1757 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
1758 last_sector = bi->bi_sector + (bi->bi_size>>9);
1759 bi->bi_next = NULL;
1760 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
1761
1762 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
1763 DEFINE_WAIT(w);
1764 int disks;
1765
1766 retry:
1767 if (likely(conf->expand_progress == MaxSector))
1768 disks = conf->raid_disks;
1769 else {
1770 spin_lock_irq(&conf->device_lock);
1771 disks = conf->raid_disks;
1772 if (logical_sector >= conf->expand_progress)
1773 disks = conf->previous_raid_disks;
1774 spin_unlock_irq(&conf->device_lock);
1775 }
1776 new_sector = raid5_compute_sector(logical_sector, disks, disks - 1,
1777 &dd_idx, &pd_idx, conf);
1778 PRINTK("raid5: make_request, sector %llu logical %llu\n",
1779 (unsigned long long)new_sector,
1780 (unsigned long long)logical_sector);
1781
1782 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
1783 sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK));
1784 if (sh) {
1785 if (unlikely(conf->expand_progress != MaxSector)) {
1786 /* expansion might have moved on while waiting for a
1787 * stripe, so we much do the range check again.
1788 */
1789 int must_retry = 0;
1790 spin_lock_irq(&conf->device_lock);
1791 if (logical_sector < conf->expand_progress &&
1792 disks == conf->previous_raid_disks)
1793 /* mismatch, need to try again */
1794 must_retry = 1;
1795 spin_unlock_irq(&conf->device_lock);
1796 if (must_retry) {
1797 release_stripe(sh);
1798 goto retry;
1799 }
1800 }
1801
1802 if (test_bit(STRIPE_EXPANDING, &sh->state) ||
1803 !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
1804 /* Stripe is busy expanding or
1805 * add failed due to overlap. Flush everything
1806 * and wait a while
1807 */
1808 raid5_unplug_device(mddev->queue);
1809 release_stripe(sh);
1810 schedule();
1811 goto retry;
1812 }
1813 finish_wait(&conf->wait_for_overlap, &w);
1814 raid5_plug_device(conf);
1815 handle_stripe(sh);
1816 release_stripe(sh);
1817 } else {
1818 /* cannot get stripe for read-ahead, just give-up */
1819 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1820 finish_wait(&conf->wait_for_overlap, &w);
1821 break;
1822 }
1823
1824 }
1825 spin_lock_irq(&conf->device_lock);
1826 if (--bi->bi_phys_segments == 0) {
1827 int bytes = bi->bi_size;
1828
1829 if ( bio_data_dir(bi) == WRITE )
1830 md_write_end(mddev);
1831 bi->bi_size = 0;
1832 bi->bi_end_io(bi, bytes, 0);
1833 }
1834 spin_unlock_irq(&conf->device_lock);
1835 return 0;
1836 }
1837
1838 /* FIXME go_faster isn't used */
1839 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1840 {
1841 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
1842 struct stripe_head *sh;
1843 int pd_idx;
1844 sector_t first_sector, last_sector;
1845 int raid_disks = conf->raid_disks;
1846 int data_disks = raid_disks-1;
1847 sector_t max_sector = mddev->size << 1;
1848 int sync_blocks;
1849
1850 if (sector_nr >= max_sector) {
1851 /* just being told to finish up .. nothing much to do */
1852 unplug_slaves(mddev);
1853 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
1854 end_reshape(conf);
1855 return 0;
1856 }
1857
1858 if (mddev->curr_resync < max_sector) /* aborted */
1859 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1860 &sync_blocks, 1);
1861 else /* compelted sync */
1862 conf->fullsync = 0;
1863 bitmap_close_sync(mddev->bitmap);
1864
1865 return 0;
1866 }
1867
1868 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
1869 /* reshaping is quite different to recovery/resync so it is
1870 * handled quite separately ... here.
1871 *
1872 * On each call to sync_request, we gather one chunk worth of
1873 * destination stripes and flag them as expanding.
1874 * Then we find all the source stripes and request reads.
1875 * As the reads complete, handle_stripe will copy the data
1876 * into the destination stripe and release that stripe.
1877 */
1878 int i;
1879 int dd_idx;
1880
1881 if (sector_nr == 0 &&
1882 conf->expand_progress != 0) {
1883 /* restarting in the middle, skip the initial sectors */
1884 sector_nr = conf->expand_progress;
1885 sector_div(sector_nr, conf->raid_disks-1);
1886 *skipped = 1;
1887 return sector_nr;
1888 }
1889
1890 /* Cannot proceed until we've updated the superblock... */
1891 wait_event(conf->wait_for_overlap,
1892 atomic_read(&conf->reshape_stripes)==0);
1893 mddev->reshape_position = conf->expand_progress;
1894
1895 mddev->sb_dirty = 1;
1896 md_wakeup_thread(mddev->thread);
1897 wait_event(mddev->sb_wait, mddev->sb_dirty == 0 ||
1898 kthread_should_stop());
1899
1900 for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) {
1901 int j;
1902 int skipped = 0;
1903 pd_idx = stripe_to_pdidx(sector_nr+i, conf, conf->raid_disks);
1904 sh = get_active_stripe(conf, sector_nr+i,
1905 conf->raid_disks, pd_idx, 0);
1906 set_bit(STRIPE_EXPANDING, &sh->state);
1907 atomic_inc(&conf->reshape_stripes);
1908 /* If any of this stripe is beyond the end of the old
1909 * array, then we need to zero those blocks
1910 */
1911 for (j=sh->disks; j--;) {
1912 sector_t s;
1913 if (j == sh->pd_idx)
1914 continue;
1915 s = compute_blocknr(sh, j);
1916 if (s < (mddev->array_size<<1)) {
1917 skipped = 1;
1918 continue;
1919 }
1920 memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
1921 set_bit(R5_Expanded, &sh->dev[j].flags);
1922 set_bit(R5_UPTODATE, &sh->dev[j].flags);
1923 }
1924 if (!skipped) {
1925 set_bit(STRIPE_EXPAND_READY, &sh->state);
1926 set_bit(STRIPE_HANDLE, &sh->state);
1927 }
1928 release_stripe(sh);
1929 }
1930 spin_lock_irq(&conf->device_lock);
1931 conf->expand_progress = (sector_nr + i)*(conf->raid_disks-1);
1932 spin_unlock_irq(&conf->device_lock);
1933 /* Ok, those stripe are ready. We can start scheduling
1934 * reads on the source stripes.
1935 * The source stripes are determined by mapping the first and last
1936 * block on the destination stripes.
1937 */
1938 raid_disks = conf->previous_raid_disks;
1939 data_disks = raid_disks - 1;
1940 first_sector =
1941 raid5_compute_sector(sector_nr*(conf->raid_disks-1),
1942 raid_disks, data_disks,
1943 &dd_idx, &pd_idx, conf);
1944 last_sector =
1945 raid5_compute_sector((sector_nr+conf->chunk_size/512)
1946 *(conf->raid_disks-1) -1,
1947 raid_disks, data_disks,
1948 &dd_idx, &pd_idx, conf);
1949 if (last_sector >= (mddev->size<<1))
1950 last_sector = (mddev->size<<1)-1;
1951 while (first_sector <= last_sector) {
1952 pd_idx = stripe_to_pdidx(first_sector, conf, conf->previous_raid_disks);
1953 sh = get_active_stripe(conf, first_sector,
1954 conf->previous_raid_disks, pd_idx, 0);
1955 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
1956 set_bit(STRIPE_HANDLE, &sh->state);
1957 release_stripe(sh);
1958 first_sector += STRIPE_SECTORS;
1959 }
1960 return conf->chunk_size>>9;
1961 }
1962 /* if there is 1 or more failed drives and we are trying
1963 * to resync, then assert that we are finished, because there is
1964 * nothing we can do.
1965 */
1966 if (mddev->degraded >= 1 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
1967 sector_t rv = (mddev->size << 1) - sector_nr;
1968 *skipped = 1;
1969 return rv;
1970 }
1971 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1972 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1973 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
1974 /* we can skip this block, and probably more */
1975 sync_blocks /= STRIPE_SECTORS;
1976 *skipped = 1;
1977 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
1978 }
1979
1980 pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks);
1981 sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1);
1982 if (sh == NULL) {
1983 sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0);
1984 /* make sure we don't swamp the stripe cache if someone else
1985 * is trying to get access
1986 */
1987 schedule_timeout_uninterruptible(1);
1988 }
1989 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 0);
1990 spin_lock(&sh->lock);
1991 set_bit(STRIPE_SYNCING, &sh->state);
1992 clear_bit(STRIPE_INSYNC, &sh->state);
1993 spin_unlock(&sh->lock);
1994
1995 handle_stripe(sh);
1996 release_stripe(sh);
1997
1998 return STRIPE_SECTORS;
1999 }
2000
2001 /*
2002 * This is our raid5 kernel thread.
2003 *
2004 * We scan the hash table for stripes which can be handled now.
2005 * During the scan, completed stripes are saved for us by the interrupt
2006 * handler, so that they will not have to wait for our next wakeup.
2007 */
2008 static void raid5d (mddev_t *mddev)
2009 {
2010 struct stripe_head *sh;
2011 raid5_conf_t *conf = mddev_to_conf(mddev);
2012 int handled;
2013
2014 PRINTK("+++ raid5d active\n");
2015
2016 md_check_recovery(mddev);
2017
2018 handled = 0;
2019 spin_lock_irq(&conf->device_lock);
2020 while (1) {
2021 struct list_head *first;
2022
2023 if (conf->seq_flush - conf->seq_write > 0) {
2024 int seq = conf->seq_flush;
2025 spin_unlock_irq(&conf->device_lock);
2026 bitmap_unplug(mddev->bitmap);
2027 spin_lock_irq(&conf->device_lock);
2028 conf->seq_write = seq;
2029 activate_bit_delay(conf);
2030 }
2031
2032 if (list_empty(&conf->handle_list) &&
2033 atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
2034 !blk_queue_plugged(mddev->queue) &&
2035 !list_empty(&conf->delayed_list))
2036 raid5_activate_delayed(conf);
2037
2038 if (list_empty(&conf->handle_list))
2039 break;
2040
2041 first = conf->handle_list.next;
2042 sh = list_entry(first, struct stripe_head, lru);
2043
2044 list_del_init(first);
2045 atomic_inc(&sh->count);
2046 if (atomic_read(&sh->count)!= 1)
2047 BUG();
2048 spin_unlock_irq(&conf->device_lock);
2049
2050 handled++;
2051 handle_stripe(sh);
2052 release_stripe(sh);
2053
2054 spin_lock_irq(&conf->device_lock);
2055 }
2056 PRINTK("%d stripes handled\n", handled);
2057
2058 spin_unlock_irq(&conf->device_lock);
2059
2060 unplug_slaves(mddev);
2061
2062 PRINTK("--- raid5d inactive\n");
2063 }
2064
2065 static ssize_t
2066 raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
2067 {
2068 raid5_conf_t *conf = mddev_to_conf(mddev);
2069 if (conf)
2070 return sprintf(page, "%d\n", conf->max_nr_stripes);
2071 else
2072 return 0;
2073 }
2074
2075 static ssize_t
2076 raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
2077 {
2078 raid5_conf_t *conf = mddev_to_conf(mddev);
2079 char *end;
2080 int new;
2081 if (len >= PAGE_SIZE)
2082 return -EINVAL;
2083 if (!conf)
2084 return -ENODEV;
2085
2086 new = simple_strtoul(page, &end, 10);
2087 if (!*page || (*end && *end != '\n') )
2088 return -EINVAL;
2089 if (new <= 16 || new > 32768)
2090 return -EINVAL;
2091 while (new < conf->max_nr_stripes) {
2092 if (drop_one_stripe(conf))
2093 conf->max_nr_stripes--;
2094 else
2095 break;
2096 }
2097 while (new > conf->max_nr_stripes) {
2098 if (grow_one_stripe(conf))
2099 conf->max_nr_stripes++;
2100 else break;
2101 }
2102 return len;
2103 }
2104
2105 static struct md_sysfs_entry
2106 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
2107 raid5_show_stripe_cache_size,
2108 raid5_store_stripe_cache_size);
2109
2110 static ssize_t
2111 stripe_cache_active_show(mddev_t *mddev, char *page)
2112 {
2113 raid5_conf_t *conf = mddev_to_conf(mddev);
2114 if (conf)
2115 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
2116 else
2117 return 0;
2118 }
2119
2120 static struct md_sysfs_entry
2121 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
2122
2123 static struct attribute *raid5_attrs[] = {
2124 &raid5_stripecache_size.attr,
2125 &raid5_stripecache_active.attr,
2126 NULL,
2127 };
2128 static struct attribute_group raid5_attrs_group = {
2129 .name = NULL,
2130 .attrs = raid5_attrs,
2131 };
2132
2133 static int run(mddev_t *mddev)
2134 {
2135 raid5_conf_t *conf;
2136 int raid_disk, memory;
2137 mdk_rdev_t *rdev;
2138 struct disk_info *disk;
2139 struct list_head *tmp;
2140
2141 if (mddev->level != 5 && mddev->level != 4) {
2142 printk(KERN_ERR "raid5: %s: raid level not set to 4/5 (%d)\n",
2143 mdname(mddev), mddev->level);
2144 return -EIO;
2145 }
2146
2147 if (mddev->reshape_position != MaxSector) {
2148 /* Check that we can continue the reshape.
2149 * Currently only disks can change, it must
2150 * increase, and we must be past the point where
2151 * a stripe over-writes itself
2152 */
2153 sector_t here_new, here_old;
2154 int old_disks;
2155
2156 if (mddev->new_level != mddev->level ||
2157 mddev->new_layout != mddev->layout ||
2158 mddev->new_chunk != mddev->chunk_size) {
2159 printk(KERN_ERR "raid5: %s: unsupported reshape required - aborting.\n",
2160 mdname(mddev));
2161 return -EINVAL;
2162 }
2163 if (mddev->delta_disks <= 0) {
2164 printk(KERN_ERR "raid5: %s: unsupported reshape (reduce disks) required - aborting.\n",
2165 mdname(mddev));
2166 return -EINVAL;
2167 }
2168 old_disks = mddev->raid_disks - mddev->delta_disks;
2169 /* reshape_position must be on a new-stripe boundary, and one
2170 * further up in new geometry must map after here in old geometry.
2171 */
2172 here_new = mddev->reshape_position;
2173 if (sector_div(here_new, (mddev->chunk_size>>9)*(mddev->raid_disks-1))) {
2174 printk(KERN_ERR "raid5: reshape_position not on a stripe boundary\n");
2175 return -EINVAL;
2176 }
2177 /* here_new is the stripe we will write to */
2178 here_old = mddev->reshape_position;
2179 sector_div(here_old, (mddev->chunk_size>>9)*(old_disks-1));
2180 /* here_old is the first stripe that we might need to read from */
2181 if (here_new >= here_old) {
2182 /* Reading from the same stripe as writing to - bad */
2183 printk(KERN_ERR "raid5: reshape_position too early for auto-recovery - aborting.\n");
2184 return -EINVAL;
2185 }
2186 printk(KERN_INFO "raid5: reshape will continue\n");
2187 /* OK, we should be able to continue; */
2188 }
2189
2190
2191 mddev->private = kzalloc(sizeof (raid5_conf_t), GFP_KERNEL);
2192 if ((conf = mddev->private) == NULL)
2193 goto abort;
2194 if (mddev->reshape_position == MaxSector) {
2195 conf->previous_raid_disks = conf->raid_disks = mddev->raid_disks;
2196 } else {
2197 conf->raid_disks = mddev->raid_disks;
2198 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
2199 }
2200
2201 conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info),
2202 GFP_KERNEL);
2203 if (!conf->disks)
2204 goto abort;
2205
2206 conf->mddev = mddev;
2207
2208 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
2209 goto abort;
2210
2211 spin_lock_init(&conf->device_lock);
2212 init_waitqueue_head(&conf->wait_for_stripe);
2213 init_waitqueue_head(&conf->wait_for_overlap);
2214 INIT_LIST_HEAD(&conf->handle_list);
2215 INIT_LIST_HEAD(&conf->delayed_list);
2216 INIT_LIST_HEAD(&conf->bitmap_list);
2217 INIT_LIST_HEAD(&conf->inactive_list);
2218 atomic_set(&conf->active_stripes, 0);
2219 atomic_set(&conf->preread_active_stripes, 0);
2220
2221 PRINTK("raid5: run(%s) called.\n", mdname(mddev));
2222
2223 ITERATE_RDEV(mddev,rdev,tmp) {
2224 raid_disk = rdev->raid_disk;
2225 if (raid_disk >= conf->raid_disks
2226 || raid_disk < 0)
2227 continue;
2228 disk = conf->disks + raid_disk;
2229
2230 disk->rdev = rdev;
2231
2232 if (test_bit(In_sync, &rdev->flags)) {
2233 char b[BDEVNAME_SIZE];
2234 printk(KERN_INFO "raid5: device %s operational as raid"
2235 " disk %d\n", bdevname(rdev->bdev,b),
2236 raid_disk);
2237 conf->working_disks++;
2238 }
2239 }
2240
2241 /*
2242 * 0 for a fully functional array, 1 for a degraded array.
2243 */
2244 mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks;
2245 conf->mddev = mddev;
2246 conf->chunk_size = mddev->chunk_size;
2247 conf->level = mddev->level;
2248 conf->algorithm = mddev->layout;
2249 conf->max_nr_stripes = NR_STRIPES;
2250 conf->expand_progress = mddev->reshape_position;
2251
2252 /* device size must be a multiple of chunk size */
2253 mddev->size &= ~(mddev->chunk_size/1024 -1);
2254 mddev->resync_max_sectors = mddev->size << 1;
2255
2256 if (!conf->chunk_size || conf->chunk_size % 4) {
2257 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
2258 conf->chunk_size, mdname(mddev));
2259 goto abort;
2260 }
2261 if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) {
2262 printk(KERN_ERR
2263 "raid5: unsupported parity algorithm %d for %s\n",
2264 conf->algorithm, mdname(mddev));
2265 goto abort;
2266 }
2267 if (mddev->degraded > 1) {
2268 printk(KERN_ERR "raid5: not enough operational devices for %s"
2269 " (%d/%d failed)\n",
2270 mdname(mddev), conf->failed_disks, conf->raid_disks);
2271 goto abort;
2272 }
2273
2274 if (mddev->degraded == 1 &&
2275 mddev->recovery_cp != MaxSector) {
2276 if (mddev->ok_start_degraded)
2277 printk(KERN_WARNING
2278 "raid5: starting dirty degraded array: %s"
2279 "- data corruption possible.\n",
2280 mdname(mddev));
2281 else {
2282 printk(KERN_ERR
2283 "raid5: cannot start dirty degraded array for %s\n",
2284 mdname(mddev));
2285 goto abort;
2286 }
2287 }
2288
2289 {
2290 mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5");
2291 if (!mddev->thread) {
2292 printk(KERN_ERR
2293 "raid5: couldn't allocate thread for %s\n",
2294 mdname(mddev));
2295 goto abort;
2296 }
2297 }
2298 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
2299 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
2300 if (grow_stripes(conf, conf->max_nr_stripes)) {
2301 printk(KERN_ERR
2302 "raid5: couldn't allocate %dkB for buffers\n", memory);
2303 shrink_stripes(conf);
2304 md_unregister_thread(mddev->thread);
2305 goto abort;
2306 } else
2307 printk(KERN_INFO "raid5: allocated %dkB for %s\n",
2308 memory, mdname(mddev));
2309
2310 if (mddev->degraded == 0)
2311 printk("raid5: raid level %d set %s active with %d out of %d"
2312 " devices, algorithm %d\n", conf->level, mdname(mddev),
2313 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
2314 conf->algorithm);
2315 else
2316 printk(KERN_ALERT "raid5: raid level %d set %s active with %d"
2317 " out of %d devices, algorithm %d\n", conf->level,
2318 mdname(mddev), mddev->raid_disks - mddev->degraded,
2319 mddev->raid_disks, conf->algorithm);
2320
2321 print_raid5_conf(conf);
2322
2323 if (conf->expand_progress != MaxSector) {
2324 printk("...ok start reshape thread\n");
2325 atomic_set(&conf->reshape_stripes, 0);
2326 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
2327 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
2328 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
2329 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
2330 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
2331 "%s_reshape");
2332 /* FIXME if md_register_thread fails?? */
2333 md_wakeup_thread(mddev->sync_thread);
2334
2335 }
2336
2337 /* read-ahead size must cover two whole stripes, which is
2338 * 2 * (n-1) * chunksize where 'n' is the number of raid devices
2339 */
2340 {
2341 int stripe = (mddev->raid_disks-1) * mddev->chunk_size
2342 / PAGE_SIZE;
2343 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
2344 mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
2345 }
2346
2347 /* Ok, everything is just fine now */
2348 sysfs_create_group(&mddev->kobj, &raid5_attrs_group);
2349
2350 mddev->queue->unplug_fn = raid5_unplug_device;
2351 mddev->queue->issue_flush_fn = raid5_issue_flush;
2352 mddev->array_size = mddev->size * (conf->previous_raid_disks - 1);
2353
2354 return 0;
2355 abort:
2356 if (conf) {
2357 print_raid5_conf(conf);
2358 kfree(conf->disks);
2359 kfree(conf->stripe_hashtbl);
2360 kfree(conf);
2361 }
2362 mddev->private = NULL;
2363 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev));
2364 return -EIO;
2365 }
2366
2367
2368
2369 static int stop(mddev_t *mddev)
2370 {
2371 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
2372
2373 md_unregister_thread(mddev->thread);
2374 mddev->thread = NULL;
2375 shrink_stripes(conf);
2376 kfree(conf->stripe_hashtbl);
2377 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2378 sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
2379 kfree(conf->disks);
2380 kfree(conf);
2381 mddev->private = NULL;
2382 return 0;
2383 }
2384
2385 #if RAID5_DEBUG
2386 static void print_sh (struct stripe_head *sh)
2387 {
2388 int i;
2389
2390 printk("sh %llu, pd_idx %d, state %ld.\n",
2391 (unsigned long long)sh->sector, sh->pd_idx, sh->state);
2392 printk("sh %llu, count %d.\n",
2393 (unsigned long long)sh->sector, atomic_read(&sh->count));
2394 printk("sh %llu, ", (unsigned long long)sh->sector);
2395 for (i = 0; i < sh->disks; i++) {
2396 printk("(cache%d: %p %ld) ",
2397 i, sh->dev[i].page, sh->dev[i].flags);
2398 }
2399 printk("\n");
2400 }
2401
2402 static void printall (raid5_conf_t *conf)
2403 {
2404 struct stripe_head *sh;
2405 struct hlist_node *hn;
2406 int i;
2407
2408 spin_lock_irq(&conf->device_lock);
2409 for (i = 0; i < NR_HASH; i++) {
2410 hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
2411 if (sh->raid_conf != conf)
2412 continue;
2413 print_sh(sh);
2414 }
2415 }
2416 spin_unlock_irq(&conf->device_lock);
2417 }
2418 #endif
2419
2420 static void status (struct seq_file *seq, mddev_t *mddev)
2421 {
2422 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
2423 int i;
2424
2425 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout);
2426 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks);
2427 for (i = 0; i < conf->raid_disks; i++)
2428 seq_printf (seq, "%s",
2429 conf->disks[i].rdev &&
2430 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
2431 seq_printf (seq, "]");
2432 #if RAID5_DEBUG
2433 #define D(x) \
2434 seq_printf (seq, "<"#x":%d>", atomic_read(&conf->x))
2435 printall(conf);
2436 #endif
2437 }
2438
2439 static void print_raid5_conf (raid5_conf_t *conf)
2440 {
2441 int i;
2442 struct disk_info *tmp;
2443
2444 printk("RAID5 conf printout:\n");
2445 if (!conf) {
2446 printk("(conf==NULL)\n");
2447 return;
2448 }
2449 printk(" --- rd:%d wd:%d fd:%d\n", conf->raid_disks,
2450 conf->working_disks, conf->failed_disks);
2451
2452 for (i = 0; i < conf->raid_disks; i++) {
2453 char b[BDEVNAME_SIZE];
2454 tmp = conf->disks + i;
2455 if (tmp->rdev)
2456 printk(" disk %d, o:%d, dev:%s\n",
2457 i, !test_bit(Faulty, &tmp->rdev->flags),
2458 bdevname(tmp->rdev->bdev,b));
2459 }
2460 }
2461
2462 static int raid5_spare_active(mddev_t *mddev)
2463 {
2464 int i;
2465 raid5_conf_t *conf = mddev->private;
2466 struct disk_info *tmp;
2467
2468 for (i = 0; i < conf->raid_disks; i++) {
2469 tmp = conf->disks + i;
2470 if (tmp->rdev
2471 && !test_bit(Faulty, &tmp->rdev->flags)
2472 && !test_bit(In_sync, &tmp->rdev->flags)) {
2473 mddev->degraded--;
2474 conf->failed_disks--;
2475 conf->working_disks++;
2476 set_bit(In_sync, &tmp->rdev->flags);
2477 }
2478 }
2479 print_raid5_conf(conf);
2480 return 0;
2481 }
2482
2483 static int raid5_remove_disk(mddev_t *mddev, int number)
2484 {
2485 raid5_conf_t *conf = mddev->private;
2486 int err = 0;
2487 mdk_rdev_t *rdev;
2488 struct disk_info *p = conf->disks + number;
2489
2490 print_raid5_conf(conf);
2491 rdev = p->rdev;
2492 if (rdev) {
2493 if (test_bit(In_sync, &rdev->flags) ||
2494 atomic_read(&rdev->nr_pending)) {
2495 err = -EBUSY;
2496 goto abort;
2497 }
2498 p->rdev = NULL;
2499 synchronize_rcu();
2500 if (atomic_read(&rdev->nr_pending)) {
2501 /* lost the race, try later */
2502 err = -EBUSY;
2503 p->rdev = rdev;
2504 }
2505 }
2506 abort:
2507
2508 print_raid5_conf(conf);
2509 return err;
2510 }
2511
2512 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
2513 {
2514 raid5_conf_t *conf = mddev->private;
2515 int found = 0;
2516 int disk;
2517 struct disk_info *p;
2518
2519 if (mddev->degraded > 1)
2520 /* no point adding a device */
2521 return 0;
2522
2523 /*
2524 * find the disk ...
2525 */
2526 for (disk=0; disk < conf->raid_disks; disk++)
2527 if ((p=conf->disks + disk)->rdev == NULL) {
2528 clear_bit(In_sync, &rdev->flags);
2529 rdev->raid_disk = disk;
2530 found = 1;
2531 if (rdev->saved_raid_disk != disk)
2532 conf->fullsync = 1;
2533 rcu_assign_pointer(p->rdev, rdev);
2534 break;
2535 }
2536 print_raid5_conf(conf);
2537 return found;
2538 }
2539
2540 static int raid5_resize(mddev_t *mddev, sector_t sectors)
2541 {
2542 /* no resync is happening, and there is enough space
2543 * on all devices, so we can resize.
2544 * We need to make sure resync covers any new space.
2545 * If the array is shrinking we should possibly wait until
2546 * any io in the removed space completes, but it hardly seems
2547 * worth it.
2548 */
2549 sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
2550 mddev->array_size = (sectors * (mddev->raid_disks-1))>>1;
2551 set_capacity(mddev->gendisk, mddev->array_size << 1);
2552 mddev->changed = 1;
2553 if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) {
2554 mddev->recovery_cp = mddev->size << 1;
2555 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2556 }
2557 mddev->size = sectors /2;
2558 mddev->resync_max_sectors = sectors;
2559 return 0;
2560 }
2561
2562 #ifdef CONFIG_MD_RAID5_RESHAPE
2563 static int raid5_reshape(mddev_t *mddev, int raid_disks)
2564 {
2565 raid5_conf_t *conf = mddev_to_conf(mddev);
2566 int err;
2567 mdk_rdev_t *rdev;
2568 struct list_head *rtmp;
2569 int spares = 0;
2570 int added_devices = 0;
2571
2572 if (mddev->degraded ||
2573 test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
2574 return -EBUSY;
2575 if (conf->raid_disks > raid_disks)
2576 return -EINVAL; /* Cannot shrink array yet */
2577 if (conf->raid_disks == raid_disks)
2578 return 0; /* nothing to do */
2579
2580 /* Can only proceed if there are plenty of stripe_heads.
2581 * We need a minimum of one full stripe,, and for sensible progress
2582 * it is best to have about 4 times that.
2583 * If we require 4 times, then the default 256 4K stripe_heads will
2584 * allow for chunk sizes up to 256K, which is probably OK.
2585 * If the chunk size is greater, user-space should request more
2586 * stripe_heads first.
2587 */
2588 if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes) {
2589 printk(KERN_WARNING "raid5: reshape: not enough stripes. Needed %lu\n",
2590 (mddev->chunk_size / STRIPE_SIZE)*4);
2591 return -ENOSPC;
2592 }
2593
2594 ITERATE_RDEV(mddev, rdev, rtmp)
2595 if (rdev->raid_disk < 0 &&
2596 !test_bit(Faulty, &rdev->flags))
2597 spares++;
2598 if (conf->raid_disks + spares < raid_disks-1)
2599 /* Not enough devices even to make a degraded array
2600 * of that size
2601 */
2602 return -EINVAL;
2603
2604 err = resize_stripes(conf, raid_disks);
2605 if (err)
2606 return err;
2607
2608 atomic_set(&conf->reshape_stripes, 0);
2609 spin_lock_irq(&conf->device_lock);
2610 conf->previous_raid_disks = conf->raid_disks;
2611 conf->raid_disks = raid_disks;
2612 conf->expand_progress = 0;
2613 spin_unlock_irq(&conf->device_lock);
2614
2615 /* Add some new drives, as many as will fit.
2616 * We know there are enough to make the newly sized array work.
2617 */
2618 ITERATE_RDEV(mddev, rdev, rtmp)
2619 if (rdev->raid_disk < 0 &&
2620 !test_bit(Faulty, &rdev->flags)) {
2621 if (raid5_add_disk(mddev, rdev)) {
2622 char nm[20];
2623 set_bit(In_sync, &rdev->flags);
2624 conf->working_disks++;
2625 added_devices++;
2626 sprintf(nm, "rd%d", rdev->raid_disk);
2627 sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
2628 } else
2629 break;
2630 }
2631
2632 mddev->degraded = (raid_disks - conf->previous_raid_disks) - added_devices;
2633 mddev->new_chunk = mddev->chunk_size;
2634 mddev->new_layout = mddev->layout;
2635 mddev->new_level = mddev->level;
2636 mddev->raid_disks = raid_disks;
2637 mddev->delta_disks = raid_disks - conf->previous_raid_disks;
2638 mddev->reshape_position = 0;
2639 mddev->sb_dirty = 1;
2640
2641 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
2642 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
2643 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
2644 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
2645 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
2646 "%s_reshape");
2647 if (!mddev->sync_thread) {
2648 mddev->recovery = 0;
2649 spin_lock_irq(&conf->device_lock);
2650 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
2651 mddev->delta_disks = 0;
2652 conf->expand_progress = MaxSector;
2653 spin_unlock_irq(&conf->device_lock);
2654 return -EAGAIN;
2655 }
2656 md_wakeup_thread(mddev->sync_thread);
2657 md_new_event(mddev);
2658 return 0;
2659 }
2660 #endif
2661
2662 static void end_reshape(raid5_conf_t *conf)
2663 {
2664 struct block_device *bdev;
2665
2666 if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
2667 conf->mddev->array_size = conf->mddev->size * (conf->raid_disks-1);
2668 set_capacity(conf->mddev->gendisk, conf->mddev->array_size << 1);
2669 conf->mddev->changed = 1;
2670
2671 bdev = bdget_disk(conf->mddev->gendisk, 0);
2672 if (bdev) {
2673 mutex_lock(&bdev->bd_inode->i_mutex);
2674 i_size_write(bdev->bd_inode, conf->mddev->array_size << 10);
2675 mutex_unlock(&bdev->bd_inode->i_mutex);
2676 bdput(bdev);
2677 }
2678 spin_lock_irq(&conf->device_lock);
2679 conf->expand_progress = MaxSector;
2680 spin_unlock_irq(&conf->device_lock);
2681 conf->mddev->reshape_position = MaxSector;
2682 }
2683 }
2684
2685 static void raid5_quiesce(mddev_t *mddev, int state)
2686 {
2687 raid5_conf_t *conf = mddev_to_conf(mddev);
2688
2689 switch(state) {
2690 case 1: /* stop all writes */
2691 spin_lock_irq(&conf->device_lock);
2692 conf->quiesce = 1;
2693 wait_event_lock_irq(conf->wait_for_stripe,
2694 atomic_read(&conf->active_stripes) == 0,
2695 conf->device_lock, /* nothing */);
2696 spin_unlock_irq(&conf->device_lock);
2697 break;
2698
2699 case 0: /* re-enable writes */
2700 spin_lock_irq(&conf->device_lock);
2701 conf->quiesce = 0;
2702 wake_up(&conf->wait_for_stripe);
2703 spin_unlock_irq(&conf->device_lock);
2704 break;
2705 }
2706 }
2707
2708 static struct mdk_personality raid5_personality =
2709 {
2710 .name = "raid5",
2711 .level = 5,
2712 .owner = THIS_MODULE,
2713 .make_request = make_request,
2714 .run = run,
2715 .stop = stop,
2716 .status = status,
2717 .error_handler = error,
2718 .hot_add_disk = raid5_add_disk,
2719 .hot_remove_disk= raid5_remove_disk,
2720 .spare_active = raid5_spare_active,
2721 .sync_request = sync_request,
2722 .resize = raid5_resize,
2723 #ifdef CONFIG_MD_RAID5_RESHAPE
2724 .reshape = raid5_reshape,
2725 #endif
2726 .quiesce = raid5_quiesce,
2727 };
2728
2729 static struct mdk_personality raid4_personality =
2730 {
2731 .name = "raid4",
2732 .level = 4,
2733 .owner = THIS_MODULE,
2734 .make_request = make_request,
2735 .run = run,
2736 .stop = stop,
2737 .status = status,
2738 .error_handler = error,
2739 .hot_add_disk = raid5_add_disk,
2740 .hot_remove_disk= raid5_remove_disk,
2741 .spare_active = raid5_spare_active,
2742 .sync_request = sync_request,
2743 .resize = raid5_resize,
2744 .quiesce = raid5_quiesce,
2745 };
2746
2747 static int __init raid5_init(void)
2748 {
2749 register_md_personality(&raid5_personality);
2750 register_md_personality(&raid4_personality);
2751 return 0;
2752 }
2753
2754 static void raid5_exit(void)
2755 {
2756 unregister_md_personality(&raid5_personality);
2757 unregister_md_personality(&raid4_personality);
2758 }
2759
2760 module_init(raid5_init);
2761 module_exit(raid5_exit);
2762 MODULE_LICENSE("GPL");
2763 MODULE_ALIAS("md-personality-4"); /* RAID5 */
2764 MODULE_ALIAS("md-raid5");
2765 MODULE_ALIAS("md-raid4");
2766 MODULE_ALIAS("md-level-5");
2767 MODULE_ALIAS("md-level-4");
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