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md: raid5_run_ops - run stripe operations outside sh->lock
[linux-2.6-block.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
16a53ecc 5 * Copyright (C) 2002, 2003 H. Peter Anvin
1da177e4 6 *
16a53ecc
N		 7 * RAID-4/5/6 management functions.
8 * Thanks to Penguin Computing for making the RAID-6 development possible
9 * by donating a test server!
1da177e4
LT		 10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2, or (at your option)
14 * any later version.
15 *
16 * You should have received a copy of the GNU General Public License
17 * (for example /usr/src/linux/COPYING); if not, write to the Free
18 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
ae3c20cc
N		 21/*
22 * BITMAP UNPLUGGING:
23 *
24 * The sequencing for updating the bitmap reliably is a little
25 * subtle (and I got it wrong the first time) so it deserves some
26 * explanation.
27 *
28 * We group bitmap updates into batches. Each batch has a number.
29 * We may write out several batches at once, but that isn't very important.
30 * conf->bm_write is the number of the last batch successfully written.
31 * conf->bm_flush is the number of the last batch that was closed to
32 * new additions.
33 * When we discover that we will need to write to any block in a stripe
34 * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
35 * the number of the batch it will be in. This is bm_flush+1.
36 * When we are ready to do a write, if that batch hasn't been written yet,
37 * we plug the array and queue the stripe for later.
38 * When an unplug happens, we increment bm_flush, thus closing the current
39 * batch.
40 * When we notice that bm_flush > bm_write, we write out all pending updates
41 * to the bitmap, and advance bm_write to where bm_flush was.
42 * This may occasionally write a bit out twice, but is sure never to
43 * miss any bits.
44 */
1da177e4 45
1da177e4
LT		 46#include <linux/module.h>
47#include <linux/slab.h>
1da177e4
LT		 48#include <linux/highmem.h>
49#include <linux/bitops.h>
f6705578 50#include <linux/kthread.h>
1da177e4 51#include <asm/atomic.h>
16a53ecc 52#include "raid6.h"
1da177e4 53
72626685 54#include <linux/raid/bitmap.h>
91c00924 55#include <linux/async_tx.h>
72626685 56
1da177e4
LT		 57/*
58 * Stripe cache
59 */
60
61#define NR_STRIPES 256
62#define STRIPE_SIZE PAGE_SIZE
63#define STRIPE_SHIFT (PAGE_SHIFT - 9)
64#define STRIPE_SECTORS (STRIPE_SIZE>>9)
65#define IO_THRESHOLD 1
fccddba0 66#define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
1da177e4
LT		 67#define HASH_MASK (NR_HASH - 1)
68
fccddba0 69#define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
1da177e4
LT		 70
71/* bio's attached to a stripe+device for I/O are linked together in bi_sector
72 * order without overlap. There may be several bio's per stripe+device, and
73 * a bio could span several devices.
74 * When walking this list for a particular stripe+device, we must never proceed
75 * beyond a bio that extends past this device, as the next bio might no longer
76 * be valid.
77 * This macro is used to determine the 'next' bio in the list, given the sector
78 * of the current stripe+device
79 */
80#define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL)
81/*
82 * The following can be used to debug the driver
83 */
1da177e4
LT		 84#define RAID5_PARANOIA 1
85#if RAID5_PARANOIA && defined(CONFIG_SMP)
86# define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
87#else
88# define CHECK_DEVLOCK()
89#endif
90
45b4233c 91#ifdef DEBUG
1da177e4
LT		 92#define inline
93#define __inline__
94#endif
95
16a53ecc
N		 96#if !RAID6_USE_EMPTY_ZERO_PAGE
97/* In .bss so it's zeroed */
98const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
99#endif
100
101static inline int raid6_next_disk(int disk, int raid_disks)
102{
103 disk++;
104 return (disk < raid_disks) ? disk : 0;
105}
a4456856
DW		 106
107static void return_io(struct bio *return_bi)
108{
109 struct bio *bi = return_bi;
110 while (bi) {
111 int bytes = bi->bi_size;
112
113 return_bi = bi->bi_next;
114 bi->bi_next = NULL;
115 bi->bi_size = 0;
116 bi->bi_end_io(bi, bytes,
117 test_bit(BIO_UPTODATE, &bi->bi_flags)
118 ? 0 : -EIO);
119 bi = return_bi;
120 }
121}
122
1da177e4
LT		 123static void print_raid5_conf (raid5_conf_t *conf);
124
858119e1 125static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
1da177e4
LT		 126{
127 if (atomic_dec_and_test(&sh->count)) {
78bafebd
ES		 128 BUG_ON(!list_empty(&sh->lru));
129 BUG_ON(atomic_read(&conf->active_stripes)==0);
1da177e4 130 if (test_bit(STRIPE_HANDLE, &sh->state)) {
7c785b7a 131 if (test_bit(STRIPE_DELAYED, &sh->state)) {
1da177e4 132 list_add_tail(&sh->lru, &conf->delayed_list);
7c785b7a
N		 133 blk_plug_device(conf->mddev->queue);
134 } else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
ae3c20cc 135 sh->bm_seq - conf->seq_write > 0) {
72626685 136 list_add_tail(&sh->lru, &conf->bitmap_list);
7c785b7a
N		 137 blk_plug_device(conf->mddev->queue);
138 } else {
72626685 139 clear_bit(STRIPE_BIT_DELAY, &sh->state);
1da177e4 140 list_add_tail(&sh->lru, &conf->handle_list);
72626685 141 }
1da177e4
LT		 142 md_wakeup_thread(conf->mddev->thread);
143 } else {
144 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
145 atomic_dec(&conf->preread_active_stripes);
146 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
147 md_wakeup_thread(conf->mddev->thread);
148 }
1da177e4 149 atomic_dec(&conf->active_stripes);
ccfcc3c1
N		 150 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
151 list_add_tail(&sh->lru, &conf->inactive_list);
1da177e4 152 wake_up(&conf->wait_for_stripe);
46031f9a
RBJ		 153 if (conf->retry_read_aligned)
154 md_wakeup_thread(conf->mddev->thread);
ccfcc3c1 155 }
1da177e4
LT		 156 }
157 }
158}
159static void release_stripe(struct stripe_head *sh)
160{
161 raid5_conf_t *conf = sh->raid_conf;
162 unsigned long flags;
16a53ecc 163
1da177e4
LT		 164 spin_lock_irqsave(&conf->device_lock, flags);
165 __release_stripe(conf, sh);
166 spin_unlock_irqrestore(&conf->device_lock, flags);
167}
168
fccddba0 169static inline void remove_hash(struct stripe_head *sh)
1da177e4 170{
45b4233c
DW		 171 pr_debug("remove_hash(), stripe %llu\n",
172 (unsigned long long)sh->sector);
1da177e4 173
fccddba0 174 hlist_del_init(&sh->hash);
1da177e4
LT		 175}
176
16a53ecc 177static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
1da177e4 178{
fccddba0 179 struct hlist_head *hp = stripe_hash(conf, sh->sector);
1da177e4 180
45b4233c
DW		 181 pr_debug("insert_hash(), stripe %llu\n",
182 (unsigned long long)sh->sector);
1da177e4
LT		 183
184 CHECK_DEVLOCK();
fccddba0 185 hlist_add_head(&sh->hash, hp);
1da177e4
LT		 186}
187
188
189/* find an idle stripe, make sure it is unhashed, and return it. */
190static struct stripe_head *get_free_stripe(raid5_conf_t *conf)
191{
192 struct stripe_head *sh = NULL;
193 struct list_head *first;
194
195 CHECK_DEVLOCK();
196 if (list_empty(&conf->inactive_list))
197 goto out;
198 first = conf->inactive_list.next;
199 sh = list_entry(first, struct stripe_head, lru);
200 list_del_init(first);
201 remove_hash(sh);
202 atomic_inc(&conf->active_stripes);
203out:
204 return sh;
205}
206
207static void shrink_buffers(struct stripe_head *sh, int num)
208{
209 struct page *p;
210 int i;
211
212 for (i=0; i<num ; i++) {
213 p = sh->dev[i].page;
214 if (!p)
215 continue;
216 sh->dev[i].page = NULL;
2d1f3b5d 217 put_page(p);
1da177e4
LT		 218 }
219}
220
221static int grow_buffers(struct stripe_head *sh, int num)
222{
223 int i;
224
225 for (i=0; i<num; i++) {
226 struct page *page;
227
228 if (!(page = alloc_page(GFP_KERNEL))) {
229 return 1;
230 }
231 sh->dev[i].page = page;
232 }
233 return 0;
234}
235
236static void raid5_build_block (struct stripe_head *sh, int i);
237
7ecaa1e6 238static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int disks)
1da177e4
LT		 239{
240 raid5_conf_t *conf = sh->raid_conf;
7ecaa1e6 241 int i;
1da177e4 242
78bafebd
ES		 243 BUG_ON(atomic_read(&sh->count) != 0);
244 BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
1da177e4
LT		 245
246 CHECK_DEVLOCK();
45b4233c 247 pr_debug("init_stripe called, stripe %llu\n",
1da177e4
LT		 248 (unsigned long long)sh->sector);
249
250 remove_hash(sh);
16a53ecc 251
1da177e4
LT		 252 sh->sector = sector;
253 sh->pd_idx = pd_idx;
254 sh->state = 0;
255
7ecaa1e6
N		 256 sh->disks = disks;
257
258 for (i = sh->disks; i--; ) {
1da177e4
LT		 259 struct r5dev *dev = &sh->dev[i];
260
261 if (dev->toread || dev->towrite || dev->written ||
262 test_bit(R5_LOCKED, &dev->flags)) {
263 printk("sector=%llx i=%d %p %p %p %d\n",
264 (unsigned long long)sh->sector, i, dev->toread,
265 dev->towrite, dev->written,
266 test_bit(R5_LOCKED, &dev->flags));
267 BUG();
268 }
269 dev->flags = 0;
270 raid5_build_block(sh, i);
271 }
272 insert_hash(conf, sh);
273}
274
7ecaa1e6 275static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, int disks)
1da177e4
LT		 276{
277 struct stripe_head *sh;
fccddba0 278 struct hlist_node *hn;
1da177e4
LT		 279
280 CHECK_DEVLOCK();
45b4233c 281 pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
fccddba0 282 hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
7ecaa1e6 283 if (sh->sector == sector && sh->disks == disks)
1da177e4 284 return sh;
45b4233c 285 pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
1da177e4
LT		 286 return NULL;
287}
288
289static void unplug_slaves(mddev_t *mddev);
290static void raid5_unplug_device(request_queue_t *q);
291
7ecaa1e6
N		 292static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector, int disks,
293 int pd_idx, int noblock)
1da177e4
LT		 294{
295 struct stripe_head *sh;
296
45b4233c 297 pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
1da177e4
LT		 298
299 spin_lock_irq(&conf->device_lock);
300
301 do {
72626685
N		 302 wait_event_lock_irq(conf->wait_for_stripe,
303 conf->quiesce == 0,
304 conf->device_lock, /* nothing */);
7ecaa1e6 305 sh = __find_stripe(conf, sector, disks);
1da177e4
LT		 306 if (!sh) {
307 if (!conf->inactive_blocked)
308 sh = get_free_stripe(conf);
309 if (noblock && sh == NULL)
310 break;
311 if (!sh) {
312 conf->inactive_blocked = 1;
313 wait_event_lock_irq(conf->wait_for_stripe,
314 !list_empty(&conf->inactive_list) &&
5036805b
N		 315 (atomic_read(&conf->active_stripes)
316 < (conf->max_nr_stripes *3/4)
1da177e4
LT		 317 || !conf->inactive_blocked),
318 conf->device_lock,
f4370781 319 raid5_unplug_device(conf->mddev->queue)
1da177e4
LT		 320 );
321 conf->inactive_blocked = 0;
322 } else
7ecaa1e6 323 init_stripe(sh, sector, pd_idx, disks);
1da177e4
LT		 324 } else {
325 if (atomic_read(&sh->count)) {
78bafebd 326 BUG_ON(!list_empty(&sh->lru));
1da177e4
LT		 327 } else {
328 if (!test_bit(STRIPE_HANDLE, &sh->state))
329 atomic_inc(&conf->active_stripes);
ff4e8d9a
N		 330 if (list_empty(&sh->lru) &&
331 !test_bit(STRIPE_EXPANDING, &sh->state))
16a53ecc
N		 332 BUG();
333 list_del_init(&sh->lru);
1da177e4
LT		 334 }
335 }
336 } while (sh == NULL);
337
338 if (sh)
339 atomic_inc(&sh->count);
340
341 spin_unlock_irq(&conf->device_lock);
342 return sh;
343}
344
91c00924
DW		 345static int
346raid5_end_read_request(struct bio *bi, unsigned int bytes_done, int error);
347static int
348raid5_end_write_request (struct bio *bi, unsigned int bytes_done, int error);
349
350static void ops_run_io(struct stripe_head *sh)
351{
352 raid5_conf_t *conf = sh->raid_conf;
353 int i, disks = sh->disks;
354
355 might_sleep();
356
357 for (i = disks; i--; ) {
358 int rw;
359 struct bio *bi;
360 mdk_rdev_t *rdev;
361 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
362 rw = WRITE;
363 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
364 rw = READ;
365 else
366 continue;
367
368 bi = &sh->dev[i].req;
369
370 bi->bi_rw = rw;
371 if (rw == WRITE)
372 bi->bi_end_io = raid5_end_write_request;
373 else
374 bi->bi_end_io = raid5_end_read_request;
375
376 rcu_read_lock();
377 rdev = rcu_dereference(conf->disks[i].rdev);
378 if (rdev && test_bit(Faulty, &rdev->flags))
379 rdev = NULL;
380 if (rdev)
381 atomic_inc(&rdev->nr_pending);
382 rcu_read_unlock();
383
384 if (rdev) {
385 if (test_bit(STRIPE_SYNCING, &sh->state) ||
386 test_bit(STRIPE_EXPAND_SOURCE, &sh->state) ||
387 test_bit(STRIPE_EXPAND_READY, &sh->state))
388 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
389
390 bi->bi_bdev = rdev->bdev;
391 pr_debug("%s: for %llu schedule op %ld on disc %d\n",
392 __FUNCTION__, (unsigned long long)sh->sector,
393 bi->bi_rw, i);
394 atomic_inc(&sh->count);
395 bi->bi_sector = sh->sector + rdev->data_offset;
396 bi->bi_flags = 1 << BIO_UPTODATE;
397 bi->bi_vcnt = 1;
398 bi->bi_max_vecs = 1;
399 bi->bi_idx = 0;
400 bi->bi_io_vec = &sh->dev[i].vec;
401 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
402 bi->bi_io_vec[0].bv_offset = 0;
403 bi->bi_size = STRIPE_SIZE;
404 bi->bi_next = NULL;
405 if (rw == WRITE &&
406 test_bit(R5_ReWrite, &sh->dev[i].flags))
407 atomic_add(STRIPE_SECTORS,
408 &rdev->corrected_errors);
409 generic_make_request(bi);
410 } else {
411 if (rw == WRITE)
412 set_bit(STRIPE_DEGRADED, &sh->state);
413 pr_debug("skip op %ld on disc %d for sector %llu\n",
414 bi->bi_rw, i, (unsigned long long)sh->sector);
415 clear_bit(R5_LOCKED, &sh->dev[i].flags);
416 set_bit(STRIPE_HANDLE, &sh->state);
417 }
418 }
419}
420
421static struct dma_async_tx_descriptor *
422async_copy_data(int frombio, struct bio *bio, struct page *page,
423 sector_t sector, struct dma_async_tx_descriptor *tx)
424{
425 struct bio_vec *bvl;
426 struct page *bio_page;
427 int i;
428 int page_offset;
429
430 if (bio->bi_sector >= sector)
431 page_offset = (signed)(bio->bi_sector - sector) * 512;
432 else
433 page_offset = (signed)(sector - bio->bi_sector) * -512;
434 bio_for_each_segment(bvl, bio, i) {
435 int len = bio_iovec_idx(bio, i)->bv_len;
436 int clen;
437 int b_offset = 0;
438
439 if (page_offset < 0) {
440 b_offset = -page_offset;
441 page_offset += b_offset;
442 len -= b_offset;
443 }
444
445 if (len > 0 && page_offset + len > STRIPE_SIZE)
446 clen = STRIPE_SIZE - page_offset;
447 else
448 clen = len;
449
450 if (clen > 0) {
451 b_offset += bio_iovec_idx(bio, i)->bv_offset;
452 bio_page = bio_iovec_idx(bio, i)->bv_page;
453 if (frombio)
454 tx = async_memcpy(page, bio_page, page_offset,
455 b_offset, clen,
456 ASYNC_TX_DEP_ACK | ASYNC_TX_KMAP_SRC,
457 tx, NULL, NULL);
458 else
459 tx = async_memcpy(bio_page, page, b_offset,
460 page_offset, clen,
461 ASYNC_TX_DEP_ACK | ASYNC_TX_KMAP_DST,
462 tx, NULL, NULL);
463 }
464 if (clen < len) /* hit end of page */
465 break;
466 page_offset += len;
467 }
468
469 return tx;
470}
471
472static void ops_complete_biofill(void *stripe_head_ref)
473{
474 struct stripe_head *sh = stripe_head_ref;
475 struct bio *return_bi = NULL;
476 raid5_conf_t *conf = sh->raid_conf;
477 int i, more_to_read = 0;
478
479 pr_debug("%s: stripe %llu\n", __FUNCTION__,
480 (unsigned long long)sh->sector);
481
482 /* clear completed biofills */
483 for (i = sh->disks; i--; ) {
484 struct r5dev *dev = &sh->dev[i];
485 /* check if this stripe has new incoming reads */
486 if (dev->toread)
487 more_to_read++;
488
489 /* acknowledge completion of a biofill operation */
490 /* and check if we need to reply to a read request
491 */
492 if (test_bit(R5_Wantfill, &dev->flags) && !dev->toread) {
493 struct bio *rbi, *rbi2;
494 clear_bit(R5_Wantfill, &dev->flags);
495
496 /* The access to dev->read is outside of the
497 * spin_lock_irq(&conf->device_lock), but is protected
498 * by the STRIPE_OP_BIOFILL pending bit
499 */
500 BUG_ON(!dev->read);
501 rbi = dev->read;
502 dev->read = NULL;
503 while (rbi && rbi->bi_sector <
504 dev->sector + STRIPE_SECTORS) {
505 rbi2 = r5_next_bio(rbi, dev->sector);
506 spin_lock_irq(&conf->device_lock);
507 if (--rbi->bi_phys_segments == 0) {
508 rbi->bi_next = return_bi;
509 return_bi = rbi;
510 }
511 spin_unlock_irq(&conf->device_lock);
512 rbi = rbi2;
513 }
514 }
515 }
516 clear_bit(STRIPE_OP_BIOFILL, &sh->ops.ack);
517 clear_bit(STRIPE_OP_BIOFILL, &sh->ops.pending);
518
519 return_io(return_bi);
520
521 if (more_to_read)
522 set_bit(STRIPE_HANDLE, &sh->state);
523 release_stripe(sh);
524}
525
526static void ops_run_biofill(struct stripe_head *sh)
527{
528 struct dma_async_tx_descriptor *tx = NULL;
529 raid5_conf_t *conf = sh->raid_conf;
530 int i;
531
532 pr_debug("%s: stripe %llu\n", __FUNCTION__,
533 (unsigned long long)sh->sector);
534
535 for (i = sh->disks; i--; ) {
536 struct r5dev *dev = &sh->dev[i];
537 if (test_bit(R5_Wantfill, &dev->flags)) {
538 struct bio *rbi;
539 spin_lock_irq(&conf->device_lock);
540 dev->read = rbi = dev->toread;
541 dev->toread = NULL;
542 spin_unlock_irq(&conf->device_lock);
543 while (rbi && rbi->bi_sector <
544 dev->sector + STRIPE_SECTORS) {
545 tx = async_copy_data(0, rbi, dev->page,
546 dev->sector, tx);
547 rbi = r5_next_bio(rbi, dev->sector);
548 }
549 }
550 }
551
552 atomic_inc(&sh->count);
553 async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx,
554 ops_complete_biofill, sh);
555}
556
557static void ops_complete_compute5(void *stripe_head_ref)
558{
559 struct stripe_head *sh = stripe_head_ref;
560 int target = sh->ops.target;
561 struct r5dev *tgt = &sh->dev[target];
562
563 pr_debug("%s: stripe %llu\n", __FUNCTION__,
564 (unsigned long long)sh->sector);
565
566 set_bit(R5_UPTODATE, &tgt->flags);
567 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
568 clear_bit(R5_Wantcompute, &tgt->flags);
569 set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
570 set_bit(STRIPE_HANDLE, &sh->state);
571 release_stripe(sh);
572}
573
574static struct dma_async_tx_descriptor *
575ops_run_compute5(struct stripe_head *sh, unsigned long pending)
576{
577 /* kernel stack size limits the total number of disks */
578 int disks = sh->disks;
579 struct page *xor_srcs[disks];
580 int target = sh->ops.target;
581 struct r5dev *tgt = &sh->dev[target];
582 struct page *xor_dest = tgt->page;
583 int count = 0;
584 struct dma_async_tx_descriptor *tx;
585 int i;
586
587 pr_debug("%s: stripe %llu block: %d\n",
588 __FUNCTION__, (unsigned long long)sh->sector, target);
589 BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
590
591 for (i = disks; i--; )
592 if (i != target)
593 xor_srcs[count++] = sh->dev[i].page;
594
595 atomic_inc(&sh->count);
596
597 if (unlikely(count == 1))
598 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE,
599 0, NULL, ops_complete_compute5, sh);
600 else
601 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
602 ASYNC_TX_XOR_ZERO_DST, NULL,
603 ops_complete_compute5, sh);
604
605 /* ack now if postxor is not set to be run */
606 if (tx && !test_bit(STRIPE_OP_POSTXOR, &pending))
607 async_tx_ack(tx);
608
609 return tx;
610}
611
612static void ops_complete_prexor(void *stripe_head_ref)
613{
614 struct stripe_head *sh = stripe_head_ref;
615
616 pr_debug("%s: stripe %llu\n", __FUNCTION__,
617 (unsigned long long)sh->sector);
618
619 set_bit(STRIPE_OP_PREXOR, &sh->ops.complete);
620}
621
622static struct dma_async_tx_descriptor *
623ops_run_prexor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
624{
625 /* kernel stack size limits the total number of disks */
626 int disks = sh->disks;
627 struct page *xor_srcs[disks];
628 int count = 0, pd_idx = sh->pd_idx, i;
629
630 /* existing parity data subtracted */
631 struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
632
633 pr_debug("%s: stripe %llu\n", __FUNCTION__,
634 (unsigned long long)sh->sector);
635
636 for (i = disks; i--; ) {
637 struct r5dev *dev = &sh->dev[i];
638 /* Only process blocks that are known to be uptodate */
639 if (dev->towrite && test_bit(R5_Wantprexor, &dev->flags))
640 xor_srcs[count++] = dev->page;
641 }
642
643 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
644 ASYNC_TX_DEP_ACK | ASYNC_TX_XOR_DROP_DST, tx,
645 ops_complete_prexor, sh);
646
647 return tx;
648}
649
650static struct dma_async_tx_descriptor *
651ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
652{
653 int disks = sh->disks;
654 int pd_idx = sh->pd_idx, i;
655
656 /* check if prexor is active which means only process blocks
657 * that are part of a read-modify-write (Wantprexor)
658 */
659 int prexor = test_bit(STRIPE_OP_PREXOR, &sh->ops.pending);
660
661 pr_debug("%s: stripe %llu\n", __FUNCTION__,
662 (unsigned long long)sh->sector);
663
664 for (i = disks; i--; ) {
665 struct r5dev *dev = &sh->dev[i];
666 struct bio *chosen;
667 int towrite;
668
669 towrite = 0;
670 if (prexor) { /* rmw */
671 if (dev->towrite &&
672 test_bit(R5_Wantprexor, &dev->flags))
673 towrite = 1;
674 } else { /* rcw */
675 if (i != pd_idx && dev->towrite &&
676 test_bit(R5_LOCKED, &dev->flags))
677 towrite = 1;
678 }
679
680 if (towrite) {
681 struct bio *wbi;
682
683 spin_lock(&sh->lock);
684 chosen = dev->towrite;
685 dev->towrite = NULL;
686 BUG_ON(dev->written);
687 wbi = dev->written = chosen;
688 spin_unlock(&sh->lock);
689
690 while (wbi && wbi->bi_sector <
691 dev->sector + STRIPE_SECTORS) {
692 tx = async_copy_data(1, wbi, dev->page,
693 dev->sector, tx);
694 wbi = r5_next_bio(wbi, dev->sector);
695 }
696 }
697 }
698
699 return tx;
700}
701
702static void ops_complete_postxor(void *stripe_head_ref)
703{
704 struct stripe_head *sh = stripe_head_ref;
705
706 pr_debug("%s: stripe %llu\n", __FUNCTION__,
707 (unsigned long long)sh->sector);
708
709 set_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
710 set_bit(STRIPE_HANDLE, &sh->state);
711 release_stripe(sh);
712}
713
714static void ops_complete_write(void *stripe_head_ref)
715{
716 struct stripe_head *sh = stripe_head_ref;
717 int disks = sh->disks, i, pd_idx = sh->pd_idx;
718
719 pr_debug("%s: stripe %llu\n", __FUNCTION__,
720 (unsigned long long)sh->sector);
721
722 for (i = disks; i--; ) {
723 struct r5dev *dev = &sh->dev[i];
724 if (dev->written || i == pd_idx)
725 set_bit(R5_UPTODATE, &dev->flags);
726 }
727
728 set_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete);
729 set_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
730
731 set_bit(STRIPE_HANDLE, &sh->state);
732 release_stripe(sh);
733}
734
735static void
736ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
737{
738 /* kernel stack size limits the total number of disks */
739 int disks = sh->disks;
740 struct page *xor_srcs[disks];
741
742 int count = 0, pd_idx = sh->pd_idx, i;
743 struct page *xor_dest;
744 int prexor = test_bit(STRIPE_OP_PREXOR, &sh->ops.pending);
745 unsigned long flags;
746 dma_async_tx_callback callback;
747
748 pr_debug("%s: stripe %llu\n", __FUNCTION__,
749 (unsigned long long)sh->sector);
750
751 /* check if prexor is active which means only process blocks
752 * that are part of a read-modify-write (written)
753 */
754 if (prexor) {
755 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
756 for (i = disks; i--; ) {
757 struct r5dev *dev = &sh->dev[i];
758 if (dev->written)
759 xor_srcs[count++] = dev->page;
760 }
761 } else {
762 xor_dest = sh->dev[pd_idx].page;
763 for (i = disks; i--; ) {
764 struct r5dev *dev = &sh->dev[i];
765 if (i != pd_idx)
766 xor_srcs[count++] = dev->page;
767 }
768 }
769
770 /* check whether this postxor is part of a write */
771 callback = test_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending) ?
772 ops_complete_write : ops_complete_postxor;
773
774 /* 1/ if we prexor'd then the dest is reused as a source
775 * 2/ if we did not prexor then we are redoing the parity
776 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
777 * for the synchronous xor case
778 */
779 flags = ASYNC_TX_DEP_ACK | ASYNC_TX_ACK |
780 (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
781
782 atomic_inc(&sh->count);
783
784 if (unlikely(count == 1)) {
785 flags &= ~(ASYNC_TX_XOR_DROP_DST | ASYNC_TX_XOR_ZERO_DST);
786 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE,
787 flags, tx, callback, sh);
788 } else
789 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
790 flags, tx, callback, sh);
791}
792
793static void ops_complete_check(void *stripe_head_ref)
794{
795 struct stripe_head *sh = stripe_head_ref;
796 int pd_idx = sh->pd_idx;
797
798 pr_debug("%s: stripe %llu\n", __FUNCTION__,
799 (unsigned long long)sh->sector);
800
801 if (test_and_clear_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending) &&
802 sh->ops.zero_sum_result == 0)
803 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
804
805 set_bit(STRIPE_OP_CHECK, &sh->ops.complete);
806 set_bit(STRIPE_HANDLE, &sh->state);
807 release_stripe(sh);
808}
809
810static void ops_run_check(struct stripe_head *sh)
811{
812 /* kernel stack size limits the total number of disks */
813 int disks = sh->disks;
814 struct page *xor_srcs[disks];
815 struct dma_async_tx_descriptor *tx;
816
817 int count = 0, pd_idx = sh->pd_idx, i;
818 struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
819
820 pr_debug("%s: stripe %llu\n", __FUNCTION__,
821 (unsigned long long)sh->sector);
822
823 for (i = disks; i--; ) {
824 struct r5dev *dev = &sh->dev[i];
825 if (i != pd_idx)
826 xor_srcs[count++] = dev->page;
827 }
828
829 tx = async_xor_zero_sum(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
830 &sh->ops.zero_sum_result, 0, NULL, NULL, NULL);
831
832 if (tx)
833 set_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending);
834 else
835 clear_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending);
836
837 atomic_inc(&sh->count);
838 tx = async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx,
839 ops_complete_check, sh);
840}
841
842static void raid5_run_ops(struct stripe_head *sh, unsigned long pending)
843{
844 int overlap_clear = 0, i, disks = sh->disks;
845 struct dma_async_tx_descriptor *tx = NULL;
846
847 if (test_bit(STRIPE_OP_BIOFILL, &pending)) {
848 ops_run_biofill(sh);
849 overlap_clear++;
850 }
851
852 if (test_bit(STRIPE_OP_COMPUTE_BLK, &pending))
853 tx = ops_run_compute5(sh, pending);
854
855 if (test_bit(STRIPE_OP_PREXOR, &pending))
856 tx = ops_run_prexor(sh, tx);
857
858 if (test_bit(STRIPE_OP_BIODRAIN, &pending)) {
859 tx = ops_run_biodrain(sh, tx);
860 overlap_clear++;
861 }
862
863 if (test_bit(STRIPE_OP_POSTXOR, &pending))
864 ops_run_postxor(sh, tx);
865
866 if (test_bit(STRIPE_OP_CHECK, &pending))
867 ops_run_check(sh);
868
869 if (test_bit(STRIPE_OP_IO, &pending))
870 ops_run_io(sh);
871
872 if (overlap_clear)
873 for (i = disks; i--; ) {
874 struct r5dev *dev = &sh->dev[i];
875 if (test_and_clear_bit(R5_Overlap, &dev->flags))
876 wake_up(&sh->raid_conf->wait_for_overlap);
877 }
878}
879
3f294f4f 880static int grow_one_stripe(raid5_conf_t *conf)
1da177e4
LT		 881{
882 struct stripe_head *sh;
3f294f4f
N		 883 sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL);
884 if (!sh)
885 return 0;
886 memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev));
887 sh->raid_conf = conf;
888 spin_lock_init(&sh->lock);
889
890 if (grow_buffers(sh, conf->raid_disks)) {
891 shrink_buffers(sh, conf->raid_disks);
892 kmem_cache_free(conf->slab_cache, sh);
893 return 0;
894 }
7ecaa1e6 895 sh->disks = conf->raid_disks;
3f294f4f
N		 896 /* we just created an active stripe so... */
897 atomic_set(&sh->count, 1);
898 atomic_inc(&conf->active_stripes);
899 INIT_LIST_HEAD(&sh->lru);
900 release_stripe(sh);
901 return 1;
902}
903
904static int grow_stripes(raid5_conf_t *conf, int num)
905{
e18b890b 906 struct kmem_cache *sc;
1da177e4
LT		 907 int devs = conf->raid_disks;
908
42b9bebe
N		 909 sprintf(conf->cache_name[0], "raid5-%s", mdname(conf->mddev));
910 sprintf(conf->cache_name[1], "raid5-%s-alt", mdname(conf->mddev));
ad01c9e3
N		 911 conf->active_name = 0;
912 sc = kmem_cache_create(conf->cache_name[conf->active_name],
1da177e4
LT		 913 sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
914 0, 0, NULL, NULL);
915 if (!sc)
916 return 1;
917 conf->slab_cache = sc;
ad01c9e3 918 conf->pool_size = devs;
16a53ecc 919 while (num--)
3f294f4f 920 if (!grow_one_stripe(conf))
1da177e4 921 return 1;
1da177e4
LT		 922 return 0;
923}
29269553
N		 924
925#ifdef CONFIG_MD_RAID5_RESHAPE
ad01c9e3
N		 926static int resize_stripes(raid5_conf_t *conf, int newsize)
927{
928 /* Make all the stripes able to hold 'newsize' devices.
929 * New slots in each stripe get 'page' set to a new page.
930 *
931 * This happens in stages:
932 * 1/ create a new kmem_cache and allocate the required number of
933 * stripe_heads.
934 * 2/ gather all the old stripe_heads and tranfer the pages across
935 * to the new stripe_heads. This will have the side effect of
936 * freezing the array as once all stripe_heads have been collected,
937 * no IO will be possible. Old stripe heads are freed once their
938 * pages have been transferred over, and the old kmem_cache is
939 * freed when all stripes are done.
940 * 3/ reallocate conf->disks to be suitable bigger. If this fails,
941 * we simple return a failre status - no need to clean anything up.
942 * 4/ allocate new pages for the new slots in the new stripe_heads.
943 * If this fails, we don't bother trying the shrink the
944 * stripe_heads down again, we just leave them as they are.
945 * As each stripe_head is processed the new one is released into
946 * active service.
947 *
948 * Once step2 is started, we cannot afford to wait for a write,
949 * so we use GFP_NOIO allocations.
950 */
951 struct stripe_head *osh, *nsh;
952 LIST_HEAD(newstripes);
953 struct disk_info *ndisks;
954 int err = 0;
e18b890b 955 struct kmem_cache *sc;
ad01c9e3
N		 956 int i;
957
958 if (newsize <= conf->pool_size)
959 return 0; /* never bother to shrink */
960
2a2275d6
N		 961 md_allow_write(conf->mddev);
962
ad01c9e3
N		 963 /* Step 1 */
964 sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
965 sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
966 0, 0, NULL, NULL);
967 if (!sc)
968 return -ENOMEM;
969
970 for (i = conf->max_nr_stripes; i; i--) {
971 nsh = kmem_cache_alloc(sc, GFP_KERNEL);
972 if (!nsh)
973 break;
974
975 memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev));
976
977 nsh->raid_conf = conf;
978 spin_lock_init(&nsh->lock);
979
980 list_add(&nsh->lru, &newstripes);
981 }
982 if (i) {
983 /* didn't get enough, give up */
984 while (!list_empty(&newstripes)) {
985 nsh = list_entry(newstripes.next, struct stripe_head, lru);
986 list_del(&nsh->lru);
987 kmem_cache_free(sc, nsh);
988 }
989 kmem_cache_destroy(sc);
990 return -ENOMEM;
991 }
992 /* Step 2 - Must use GFP_NOIO now.
993 * OK, we have enough stripes, start collecting inactive
994 * stripes and copying them over
995 */
996 list_for_each_entry(nsh, &newstripes, lru) {
997 spin_lock_irq(&conf->device_lock);
998 wait_event_lock_irq(conf->wait_for_stripe,
999 !list_empty(&conf->inactive_list),
1000 conf->device_lock,
b3b46be3 1001 unplug_slaves(conf->mddev)
ad01c9e3
N		 1002 );
1003 osh = get_free_stripe(conf);
1004 spin_unlock_irq(&conf->device_lock);
1005 atomic_set(&nsh->count, 1);
1006 for(i=0; i<conf->pool_size; i++)
1007 nsh->dev[i].page = osh->dev[i].page;
1008 for( ; i<newsize; i++)
1009 nsh->dev[i].page = NULL;
1010 kmem_cache_free(conf->slab_cache, osh);
1011 }
1012 kmem_cache_destroy(conf->slab_cache);
1013
1014 /* Step 3.
1015 * At this point, we are holding all the stripes so the array
1016 * is completely stalled, so now is a good time to resize
1017 * conf->disks.
1018 */
1019 ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
1020 if (ndisks) {
1021 for (i=0; i<conf->raid_disks; i++)
1022 ndisks[i] = conf->disks[i];
1023 kfree(conf->disks);
1024 conf->disks = ndisks;
1025 } else
1026 err = -ENOMEM;
1027
1028 /* Step 4, return new stripes to service */
1029 while(!list_empty(&newstripes)) {
1030 nsh = list_entry(newstripes.next, struct stripe_head, lru);
1031 list_del_init(&nsh->lru);
1032 for (i=conf->raid_disks; i < newsize; i++)
1033 if (nsh->dev[i].page == NULL) {
1034 struct page *p = alloc_page(GFP_NOIO);
1035 nsh->dev[i].page = p;
1036 if (!p)
1037 err = -ENOMEM;
1038 }
1039 release_stripe(nsh);
1040 }
1041 /* critical section pass, GFP_NOIO no longer needed */
1042
1043 conf->slab_cache = sc;
1044 conf->active_name = 1-conf->active_name;
1045 conf->pool_size = newsize;
1046 return err;
1047}
29269553 1048#endif
1da177e4 1049
3f294f4f 1050static int drop_one_stripe(raid5_conf_t *conf)
1da177e4
LT		 1051{
1052 struct stripe_head *sh;
1053
3f294f4f
N		 1054 spin_lock_irq(&conf->device_lock);
1055 sh = get_free_stripe(conf);
1056 spin_unlock_irq(&conf->device_lock);
1057 if (!sh)
1058 return 0;
78bafebd 1059 BUG_ON(atomic_read(&sh->count));
ad01c9e3 1060 shrink_buffers(sh, conf->pool_size);
3f294f4f
N		 1061 kmem_cache_free(conf->slab_cache, sh);
1062 atomic_dec(&conf->active_stripes);
1063 return 1;
1064}
1065
1066static void shrink_stripes(raid5_conf_t *conf)
1067{
1068 while (drop_one_stripe(conf))
1069 ;
1070
29fc7e3e
N		 1071 if (conf->slab_cache)
1072 kmem_cache_destroy(conf->slab_cache);
1da177e4
LT		 1073 conf->slab_cache = NULL;
1074}
1075
4e5314b5 1076static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done,
1da177e4
LT		 1077 int error)
1078{
1079 struct stripe_head *sh = bi->bi_private;
1080 raid5_conf_t *conf = sh->raid_conf;
7ecaa1e6 1081 int disks = sh->disks, i;
1da177e4 1082 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
d6950432
N		 1083 char b[BDEVNAME_SIZE];
1084 mdk_rdev_t *rdev;
1da177e4
LT		 1085
1086 if (bi->bi_size)
1087 return 1;
1088
1089 for (i=0 ; i<disks; i++)
1090 if (bi == &sh->dev[i].req)
1091 break;
1092
45b4233c
DW		 1093 pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n",
1094 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
1da177e4
LT		 1095 uptodate);
1096 if (i == disks) {
1097 BUG();
1098 return 0;
1099 }
1100
1101 if (uptodate) {
1da177e4 1102 set_bit(R5_UPTODATE, &sh->dev[i].flags);
4e5314b5 1103 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
d6950432
N		 1104 rdev = conf->disks[i].rdev;
1105 printk(KERN_INFO "raid5:%s: read error corrected (%lu sectors at %llu on %s)\n",
1106 mdname(conf->mddev), STRIPE_SECTORS,
1107 (unsigned long long)sh->sector + rdev->data_offset,
1108 bdevname(rdev->bdev, b));
4e5314b5
N		 1109 clear_bit(R5_ReadError, &sh->dev[i].flags);
1110 clear_bit(R5_ReWrite, &sh->dev[i].flags);
1111 }
ba22dcbf
N		 1112 if (atomic_read(&conf->disks[i].rdev->read_errors))
1113 atomic_set(&conf->disks[i].rdev->read_errors, 0);
1da177e4 1114 } else {
d6950432 1115 const char *bdn = bdevname(conf->disks[i].rdev->bdev, b);
ba22dcbf 1116 int retry = 0;
d6950432
N		 1117 rdev = conf->disks[i].rdev;
1118
1da177e4 1119 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
d6950432 1120 atomic_inc(&rdev->read_errors);
ba22dcbf 1121 if (conf->mddev->degraded)
d6950432
N		 1122 printk(KERN_WARNING "raid5:%s: read error not correctable (sector %llu on %s).\n",
1123 mdname(conf->mddev),
1124 (unsigned long long)sh->sector + rdev->data_offset,
1125 bdn);
ba22dcbf 1126 else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
4e5314b5 1127 /* Oh, no!!! */
d6950432
N		 1128 printk(KERN_WARNING "raid5:%s: read error NOT corrected!! (sector %llu on %s).\n",
1129 mdname(conf->mddev),
1130 (unsigned long long)sh->sector + rdev->data_offset,
1131 bdn);
1132 else if (atomic_read(&rdev->read_errors)
ba22dcbf 1133 > conf->max_nr_stripes)
14f8d26b 1134 printk(KERN_WARNING
d6950432
N		 1135 "raid5:%s: Too many read errors, failing device %s.\n",
1136 mdname(conf->mddev), bdn);
ba22dcbf
N		 1137 else
1138 retry = 1;
1139 if (retry)
1140 set_bit(R5_ReadError, &sh->dev[i].flags);
1141 else {
4e5314b5
N		 1142 clear_bit(R5_ReadError, &sh->dev[i].flags);
1143 clear_bit(R5_ReWrite, &sh->dev[i].flags);
d6950432 1144 md_error(conf->mddev, rdev);
ba22dcbf 1145 }
1da177e4
LT		 1146 }
1147 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
1da177e4
LT		 1148 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1149 set_bit(STRIPE_HANDLE, &sh->state);
1150 release_stripe(sh);
1151 return 0;
1152}
1153
1154static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done,
1155 int error)
1156{
1157 struct stripe_head *sh = bi->bi_private;
1158 raid5_conf_t *conf = sh->raid_conf;
7ecaa1e6 1159 int disks = sh->disks, i;
1da177e4
LT		 1160 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1161
1162 if (bi->bi_size)
1163 return 1;
1164
1165 for (i=0 ; i<disks; i++)
1166 if (bi == &sh->dev[i].req)
1167 break;
1168
45b4233c 1169 pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
1da177e4
LT		 1170 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
1171 uptodate);
1172 if (i == disks) {
1173 BUG();
1174 return 0;
1175 }
1176
1da177e4
LT		 1177 if (!uptodate)
1178 md_error(conf->mddev, conf->disks[i].rdev);
1179
1180 rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
1181
1182 clear_bit(R5_LOCKED, &sh->dev[i].flags);
1183 set_bit(STRIPE_HANDLE, &sh->state);
c04be0aa 1184 release_stripe(sh);
1da177e4
LT		 1185 return 0;
1186}
1187
1188
1189static sector_t compute_blocknr(struct stripe_head *sh, int i);
1190
1191static void raid5_build_block (struct stripe_head *sh, int i)
1192{
1193 struct r5dev *dev = &sh->dev[i];
1194
1195 bio_init(&dev->req);
1196 dev->req.bi_io_vec = &dev->vec;
1197 dev->req.bi_vcnt++;
1198 dev->req.bi_max_vecs++;
1199 dev->vec.bv_page = dev->page;
1200 dev->vec.bv_len = STRIPE_SIZE;
1201 dev->vec.bv_offset = 0;
1202
1203 dev->req.bi_sector = sh->sector;
1204 dev->req.bi_private = sh;
1205
1206 dev->flags = 0;
16a53ecc 1207 dev->sector = compute_blocknr(sh, i);
1da177e4
LT		 1208}
1209
1210static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1211{
1212 char b[BDEVNAME_SIZE];
1213 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
45b4233c 1214 pr_debug("raid5: error called\n");
1da177e4 1215
b2d444d7 1216 if (!test_bit(Faulty, &rdev->flags)) {
850b2b42 1217 set_bit(MD_CHANGE_DEVS, &mddev->flags);
c04be0aa
N		 1218 if (test_and_clear_bit(In_sync, &rdev->flags)) {
1219 unsigned long flags;
1220 spin_lock_irqsave(&conf->device_lock, flags);
1da177e4 1221 mddev->degraded++;
c04be0aa 1222 spin_unlock_irqrestore(&conf->device_lock, flags);
1da177e4
LT		 1223 /*
1224 * if recovery was running, make sure it aborts.
1225 */
1226 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
1227 }
b2d444d7 1228 set_bit(Faulty, &rdev->flags);
1da177e4
LT		 1229 printk (KERN_ALERT
1230 "raid5: Disk failure on %s, disabling device."
1231 " Operation continuing on %d devices\n",
02c2de8c 1232 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
1da177e4 1233 }
16a53ecc 1234}
1da177e4
LT		 1235
1236/*
1237 * Input: a 'big' sector number,
1238 * Output: index of the data and parity disk, and the sector # in them.
1239 */
1240static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks,
1241 unsigned int data_disks, unsigned int * dd_idx,
1242 unsigned int * pd_idx, raid5_conf_t *conf)
1243{
1244 long stripe;
1245 unsigned long chunk_number;
1246 unsigned int chunk_offset;
1247 sector_t new_sector;
1248 int sectors_per_chunk = conf->chunk_size >> 9;
1249
1250 /* First compute the information on this sector */
1251
1252 /*
1253 * Compute the chunk number and the sector offset inside the chunk
1254 */
1255 chunk_offset = sector_div(r_sector, sectors_per_chunk);
1256 chunk_number = r_sector;
1257 BUG_ON(r_sector != chunk_number);
1258
1259 /*
1260 * Compute the stripe number
1261 */
1262 stripe = chunk_number / data_disks;
1263
1264 /*
1265 * Compute the data disk and parity disk indexes inside the stripe
1266 */
1267 *dd_idx = chunk_number % data_disks;
1268
1269 /*
1270 * Select the parity disk based on the user selected algorithm.
1271 */
16a53ecc
N		 1272 switch(conf->level) {
1273 case 4:
1da177e4 1274 *pd_idx = data_disks;
16a53ecc
N		 1275 break;
1276 case 5:
1277 switch (conf->algorithm) {
1da177e4
LT		 1278 case ALGORITHM_LEFT_ASYMMETRIC:
1279 *pd_idx = data_disks - stripe % raid_disks;
1280 if (*dd_idx >= *pd_idx)
1281 (*dd_idx)++;
1282 break;
1283 case ALGORITHM_RIGHT_ASYMMETRIC:
1284 *pd_idx = stripe % raid_disks;
1285 if (*dd_idx >= *pd_idx)
1286 (*dd_idx)++;
1287 break;
1288 case ALGORITHM_LEFT_SYMMETRIC:
1289 *pd_idx = data_disks - stripe % raid_disks;
1290 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
1291 break;
1292 case ALGORITHM_RIGHT_SYMMETRIC:
1293 *pd_idx = stripe % raid_disks;
1294 *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
1295 break;
1296 default:
14f8d26b 1297 printk(KERN_ERR "raid5: unsupported algorithm %d\n",
1da177e4 1298 conf->algorithm);
16a53ecc
N		 1299 }
1300 break;
1301 case 6:
1302
1303 /**** FIX THIS ****/
1304 switch (conf->algorithm) {
1305 case ALGORITHM_LEFT_ASYMMETRIC:
1306 *pd_idx = raid_disks - 1 - (stripe % raid_disks);
1307 if (*pd_idx == raid_disks-1)
1308 (*dd_idx)++; /* Q D D D P */
1309 else if (*dd_idx >= *pd_idx)
1310 (*dd_idx) += 2; /* D D P Q D */
1311 break;
1312 case ALGORITHM_RIGHT_ASYMMETRIC:
1313 *pd_idx = stripe % raid_disks;
1314 if (*pd_idx == raid_disks-1)
1315 (*dd_idx)++; /* Q D D D P */
1316 else if (*dd_idx >= *pd_idx)
1317 (*dd_idx) += 2; /* D D P Q D */
1318 break;
1319 case ALGORITHM_LEFT_SYMMETRIC:
1320 *pd_idx = raid_disks - 1 - (stripe % raid_disks);
1321 *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
1322 break;
1323 case ALGORITHM_RIGHT_SYMMETRIC:
1324 *pd_idx = stripe % raid_disks;
1325 *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
1326 break;
1327 default:
1328 printk (KERN_CRIT "raid6: unsupported algorithm %d\n",
1329 conf->algorithm);
1330 }
1331 break;
1da177e4
LT		 1332 }
1333
1334 /*
1335 * Finally, compute the new sector number
1336 */
1337 new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
1338 return new_sector;
1339}
1340
1341
1342static sector_t compute_blocknr(struct stripe_head *sh, int i)
1343{
1344 raid5_conf_t *conf = sh->raid_conf;
b875e531
N		 1345 int raid_disks = sh->disks;
1346 int data_disks = raid_disks - conf->max_degraded;
1da177e4
LT		 1347 sector_t new_sector = sh->sector, check;
1348 int sectors_per_chunk = conf->chunk_size >> 9;
1349 sector_t stripe;
1350 int chunk_offset;
1351 int chunk_number, dummy1, dummy2, dd_idx = i;
1352 sector_t r_sector;
1353
16a53ecc 1354
1da177e4
LT		 1355 chunk_offset = sector_div(new_sector, sectors_per_chunk);
1356 stripe = new_sector;
1357 BUG_ON(new_sector != stripe);
1358
16a53ecc
N		 1359 if (i == sh->pd_idx)
1360 return 0;
1361 switch(conf->level) {
1362 case 4: break;
1363 case 5:
1364 switch (conf->algorithm) {
1da177e4
LT		 1365 case ALGORITHM_LEFT_ASYMMETRIC:
1366 case ALGORITHM_RIGHT_ASYMMETRIC:
1367 if (i > sh->pd_idx)
1368 i--;
1369 break;
1370 case ALGORITHM_LEFT_SYMMETRIC:
1371 case ALGORITHM_RIGHT_SYMMETRIC:
1372 if (i < sh->pd_idx)
1373 i += raid_disks;
1374 i -= (sh->pd_idx + 1);
1375 break;
1376 default:
14f8d26b 1377 printk(KERN_ERR "raid5: unsupported algorithm %d\n",
16a53ecc
N		 1378 conf->algorithm);
1379 }
1380 break;
1381 case 6:
16a53ecc
N		 1382 if (i == raid6_next_disk(sh->pd_idx, raid_disks))
1383 return 0; /* It is the Q disk */
1384 switch (conf->algorithm) {
1385 case ALGORITHM_LEFT_ASYMMETRIC:
1386 case ALGORITHM_RIGHT_ASYMMETRIC:
1387 if (sh->pd_idx == raid_disks-1)
1388 i--; /* Q D D D P */
1389 else if (i > sh->pd_idx)
1390 i -= 2; /* D D P Q D */
1391 break;
1392 case ALGORITHM_LEFT_SYMMETRIC:
1393 case ALGORITHM_RIGHT_SYMMETRIC:
1394 if (sh->pd_idx == raid_disks-1)
1395 i--; /* Q D D D P */
1396 else {
1397 /* D D P Q D */
1398 if (i < sh->pd_idx)
1399 i += raid_disks;
1400 i -= (sh->pd_idx + 2);
1401 }
1402 break;
1403 default:
1404 printk (KERN_CRIT "raid6: unsupported algorithm %d\n",
1da177e4 1405 conf->algorithm);
16a53ecc
N		 1406 }
1407 break;
1da177e4
LT		 1408 }
1409
1410 chunk_number = stripe * data_disks + i;
1411 r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;
1412
1413 check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
1414 if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
14f8d26b 1415 printk(KERN_ERR "compute_blocknr: map not correct\n");
1da177e4
LT		 1416 return 0;
1417 }
1418 return r_sector;
1419}
1420
1421
1422
1423/*
16a53ecc
N		 1424 * Copy data between a page in the stripe cache, and one or more bion
1425 * The page could align with the middle of the bio, or there could be
1426 * several bion, each with several bio_vecs, which cover part of the page
1427 * Multiple bion are linked together on bi_next. There may be extras
1428 * at the end of this list. We ignore them.
1da177e4
LT		 1429 */
1430static void copy_data(int frombio, struct bio *bio,
1431 struct page *page,
1432 sector_t sector)
1433{
1434 char *pa = page_address(page);
1435 struct bio_vec *bvl;
1436 int i;
1437 int page_offset;
1438
1439 if (bio->bi_sector >= sector)
1440 page_offset = (signed)(bio->bi_sector - sector) * 512;
1441 else
1442 page_offset = (signed)(sector - bio->bi_sector) * -512;
1443 bio_for_each_segment(bvl, bio, i) {
1444 int len = bio_iovec_idx(bio,i)->bv_len;
1445 int clen;
1446 int b_offset = 0;
1447
1448 if (page_offset < 0) {
1449 b_offset = -page_offset;
1450 page_offset += b_offset;
1451 len -= b_offset;
1452 }
1453
1454 if (len > 0 && page_offset + len > STRIPE_SIZE)
1455 clen = STRIPE_SIZE - page_offset;
1456 else clen = len;
16a53ecc 1457
1da177e4
LT		 1458 if (clen > 0) {
1459 char *ba = __bio_kmap_atomic(bio, i, KM_USER0);
1460 if (frombio)
1461 memcpy(pa+page_offset, ba+b_offset, clen);
1462 else
1463 memcpy(ba+b_offset, pa+page_offset, clen);
1464 __bio_kunmap_atomic(ba, KM_USER0);
1465 }
1466 if (clen < len) /* hit end of page */
1467 break;
1468 page_offset += len;
1469 }
1470}
1471
9bc89cd8
DW		 1472#define check_xor() do { \
1473 if (count == MAX_XOR_BLOCKS) { \
1474 xor_blocks(count, STRIPE_SIZE, dest, ptr);\
1475 count = 0; \
1476 } \
1da177e4
LT		 1477 } while(0)
1478
1479
1480static void compute_block(struct stripe_head *sh, int dd_idx)
1481{
7ecaa1e6 1482 int i, count, disks = sh->disks;
9bc89cd8 1483 void *ptr[MAX_XOR_BLOCKS], *dest, *p;
1da177e4 1484
45b4233c 1485 pr_debug("compute_block, stripe %llu, idx %d\n",
1da177e4
LT		 1486 (unsigned long long)sh->sector, dd_idx);
1487
9bc89cd8
DW		 1488 dest = page_address(sh->dev[dd_idx].page);
1489 memset(dest, 0, STRIPE_SIZE);
1490 count = 0;
1da177e4
LT		 1491 for (i = disks ; i--; ) {
1492 if (i == dd_idx)
1493 continue;
1494 p = page_address(sh->dev[i].page);
1495 if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
1496 ptr[count++] = p;
1497 else
14f8d26b 1498 printk(KERN_ERR "compute_block() %d, stripe %llu, %d"
1da177e4
LT		 1499 " not present\n", dd_idx,
1500 (unsigned long long)sh->sector, i);
1501
1502 check_xor();
1503 }
9bc89cd8
DW		 1504 if (count)
1505 xor_blocks(count, STRIPE_SIZE, dest, ptr);
1da177e4
LT		 1506 set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
1507}
1508
16a53ecc 1509static void compute_parity5(struct stripe_head *sh, int method)
1da177e4
LT		 1510{
1511 raid5_conf_t *conf = sh->raid_conf;
7ecaa1e6 1512 int i, pd_idx = sh->pd_idx, disks = sh->disks, count;
9bc89cd8 1513 void *ptr[MAX_XOR_BLOCKS], *dest;
1da177e4
LT		 1514 struct bio *chosen;
1515
45b4233c 1516 pr_debug("compute_parity5, stripe %llu, method %d\n",
1da177e4
LT		 1517 (unsigned long long)sh->sector, method);
1518
9bc89cd8
DW		 1519 count = 0;
1520 dest = page_address(sh->dev[pd_idx].page);
1da177e4
LT		 1521 switch(method) {
1522 case READ_MODIFY_WRITE:
78bafebd 1523 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags));
1da177e4
LT		 1524 for (i=disks ; i-- ;) {
1525 if (i==pd_idx)
1526 continue;
1527 if (sh->dev[i].towrite &&
1528 test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
1529 ptr[count++] = page_address(sh->dev[i].page);
1530 chosen = sh->dev[i].towrite;
1531 sh->dev[i].towrite = NULL;
1532
1533 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1534 wake_up(&conf->wait_for_overlap);
1535
78bafebd 1536 BUG_ON(sh->dev[i].written);
1da177e4
LT		 1537 sh->dev[i].written = chosen;
1538 check_xor();
1539 }
1540 }
1541 break;
1542 case RECONSTRUCT_WRITE:
9bc89cd8 1543 memset(dest, 0, STRIPE_SIZE);
1da177e4
LT		 1544 for (i= disks; i-- ;)
1545 if (i!=pd_idx && sh->dev[i].towrite) {
1546 chosen = sh->dev[i].towrite;
1547 sh->dev[i].towrite = NULL;
1548
1549 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1550 wake_up(&conf->wait_for_overlap);
1551
78bafebd 1552 BUG_ON(sh->dev[i].written);
1da177e4
LT		 1553 sh->dev[i].written = chosen;
1554 }
1555 break;
1556 case CHECK_PARITY:
1557 break;
1558 }
9bc89cd8
DW		 1559 if (count) {
1560 xor_blocks(count, STRIPE_SIZE, dest, ptr);
1561 count = 0;
1da177e4
LT		 1562 }
1563
1564 for (i = disks; i--;)
1565 if (sh->dev[i].written) {
1566 sector_t sector = sh->dev[i].sector;
1567 struct bio *wbi = sh->dev[i].written;
1568 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
1569 copy_data(1, wbi, sh->dev[i].page, sector);
1570 wbi = r5_next_bio(wbi, sector);
1571 }
1572
1573 set_bit(R5_LOCKED, &sh->dev[i].flags);
1574 set_bit(R5_UPTODATE, &sh->dev[i].flags);
1575 }
1576
1577 switch(method) {
1578 case RECONSTRUCT_WRITE:
1579 case CHECK_PARITY:
1580 for (i=disks; i--;)
1581 if (i != pd_idx) {
1582 ptr[count++] = page_address(sh->dev[i].page);
1583 check_xor();
1584 }
1585 break;
1586 case READ_MODIFY_WRITE:
1587 for (i = disks; i--;)
1588 if (sh->dev[i].written) {
1589 ptr[count++] = page_address(sh->dev[i].page);
1590 check_xor();
1591 }
1592 }
9bc89cd8
DW		 1593 if (count)
1594 xor_blocks(count, STRIPE_SIZE, dest, ptr);
1595
1da177e4
LT		 1596 if (method != CHECK_PARITY) {
1597 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
1598 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
1599 } else
1600 clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
1601}
1602
16a53ecc
N		 1603static void compute_parity6(struct stripe_head *sh, int method)
1604{
1605 raid6_conf_t *conf = sh->raid_conf;
f416885e 1606 int i, pd_idx = sh->pd_idx, qd_idx, d0_idx, disks = sh->disks, count;
16a53ecc
N		 1607 struct bio *chosen;
1608 /**** FIX THIS: This could be very bad if disks is close to 256 ****/
1609 void *ptrs[disks];
1610
1611 qd_idx = raid6_next_disk(pd_idx, disks);
1612 d0_idx = raid6_next_disk(qd_idx, disks);
1613
45b4233c 1614 pr_debug("compute_parity, stripe %llu, method %d\n",
16a53ecc
N		 1615 (unsigned long long)sh->sector, method);
1616
1617 switch(method) {
1618 case READ_MODIFY_WRITE:
1619 BUG(); /* READ_MODIFY_WRITE N/A for RAID-6 */
1620 case RECONSTRUCT_WRITE:
1621 for (i= disks; i-- ;)
1622 if ( i != pd_idx && i != qd_idx && sh->dev[i].towrite ) {
1623 chosen = sh->dev[i].towrite;
1624 sh->dev[i].towrite = NULL;
1625
1626 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1627 wake_up(&conf->wait_for_overlap);
1628
52e5f9d1 1629 BUG_ON(sh->dev[i].written);
16a53ecc
N		 1630 sh->dev[i].written = chosen;
1631 }
1632 break;
1633 case CHECK_PARITY:
1634 BUG(); /* Not implemented yet */
1635 }
1636
1637 for (i = disks; i--;)
1638 if (sh->dev[i].written) {
1639 sector_t sector = sh->dev[i].sector;
1640 struct bio *wbi = sh->dev[i].written;
1641 while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
1642 copy_data(1, wbi, sh->dev[i].page, sector);
1643 wbi = r5_next_bio(wbi, sector);
1644 }
1645
1646 set_bit(R5_LOCKED, &sh->dev[i].flags);
1647 set_bit(R5_UPTODATE, &sh->dev[i].flags);
1648 }
1649
1650// switch(method) {
1651// case RECONSTRUCT_WRITE:
1652// case CHECK_PARITY:
1653// case UPDATE_PARITY:
1654 /* Note that unlike RAID-5, the ordering of the disks matters greatly. */
1655 /* FIX: Is this ordering of drives even remotely optimal? */
1656 count = 0;
1657 i = d0_idx;
1658 do {
1659 ptrs[count++] = page_address(sh->dev[i].page);
1660 if (count <= disks-2 && !test_bit(R5_UPTODATE, &sh->dev[i].flags))
1661 printk("block %d/%d not uptodate on parity calc\n", i,count);
1662 i = raid6_next_disk(i, disks);
1663 } while ( i != d0_idx );
1664// break;
1665// }
1666
1667 raid6_call.gen_syndrome(disks, STRIPE_SIZE, ptrs);
1668
1669 switch(method) {
1670 case RECONSTRUCT_WRITE:
1671 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
1672 set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
1673 set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
1674 set_bit(R5_LOCKED, &sh->dev[qd_idx].flags);
1675 break;
1676 case UPDATE_PARITY:
1677 set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
1678 set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
1679 break;
1680 }
1681}
1682
1683
1684/* Compute one missing block */
1685static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero)
1686{
f416885e 1687 int i, count, disks = sh->disks;
9bc89cd8 1688 void *ptr[MAX_XOR_BLOCKS], *dest, *p;
16a53ecc
N		 1689 int pd_idx = sh->pd_idx;
1690 int qd_idx = raid6_next_disk(pd_idx, disks);
1691
45b4233c 1692 pr_debug("compute_block_1, stripe %llu, idx %d\n",
16a53ecc
N		 1693 (unsigned long long)sh->sector, dd_idx);
1694
1695 if ( dd_idx == qd_idx ) {
1696 /* We're actually computing the Q drive */
1697 compute_parity6(sh, UPDATE_PARITY);
1698 } else {
9bc89cd8
DW		 1699 dest = page_address(sh->dev[dd_idx].page);
1700 if (!nozero) memset(dest, 0, STRIPE_SIZE);
1701 count = 0;
16a53ecc
N		 1702 for (i = disks ; i--; ) {
1703 if (i == dd_idx || i == qd_idx)
1704 continue;
1705 p = page_address(sh->dev[i].page);
1706 if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
1707 ptr[count++] = p;
1708 else
1709 printk("compute_block() %d, stripe %llu, %d"
1710 " not present\n", dd_idx,
1711 (unsigned long long)sh->sector, i);
1712
1713 check_xor();
1714 }
9bc89cd8
DW		 1715 if (count)
1716 xor_blocks(count, STRIPE_SIZE, dest, ptr);
16a53ecc
N		 1717 if (!nozero) set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
1718 else clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
1719 }
1720}
1721
1722/* Compute two missing blocks */
1723static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
1724{
f416885e 1725 int i, count, disks = sh->disks;
16a53ecc
N		 1726 int pd_idx = sh->pd_idx;
1727 int qd_idx = raid6_next_disk(pd_idx, disks);
1728 int d0_idx = raid6_next_disk(qd_idx, disks);
1729 int faila, failb;
1730
1731 /* faila and failb are disk numbers relative to d0_idx */
1732 /* pd_idx become disks-2 and qd_idx become disks-1 */
1733 faila = (dd_idx1 < d0_idx) ? dd_idx1+(disks-d0_idx) : dd_idx1-d0_idx;
1734 failb = (dd_idx2 < d0_idx) ? dd_idx2+(disks-d0_idx) : dd_idx2-d0_idx;
1735
1736 BUG_ON(faila == failb);
1737 if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; }
1738
45b4233c 1739 pr_debug("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n",
16a53ecc
N		 1740 (unsigned long long)sh->sector, dd_idx1, dd_idx2, faila, failb);
1741
1742 if ( failb == disks-1 ) {
1743 /* Q disk is one of the missing disks */
1744 if ( faila == disks-2 ) {
1745 /* Missing P+Q, just recompute */
1746 compute_parity6(sh, UPDATE_PARITY);
1747 return;
1748 } else {
1749 /* We're missing D+Q; recompute D from P */
1750 compute_block_1(sh, (dd_idx1 == qd_idx) ? dd_idx2 : dd_idx1, 0);
1751 compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */
1752 return;
1753 }
1754 }
1755
1756 /* We're missing D+P or D+D; build pointer table */
1757 {
1758 /**** FIX THIS: This could be very bad if disks is close to 256 ****/
1759 void *ptrs[disks];
1760
1761 count = 0;
1762 i = d0_idx;
1763 do {
1764 ptrs[count++] = page_address(sh->dev[i].page);
1765 i = raid6_next_disk(i, disks);
1766 if (i != dd_idx1 && i != dd_idx2 &&
1767 !test_bit(R5_UPTODATE, &sh->dev[i].flags))
1768 printk("compute_2 with missing block %d/%d\n", count, i);
1769 } while ( i != d0_idx );
1770
1771 if ( failb == disks-2 ) {
1772 /* We're missing D+P. */
1773 raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs);
1774 } else {
1775 /* We're missing D+D. */
1776 raid6_2data_recov(disks, STRIPE_SIZE, faila, failb, ptrs);
1777 }
1778
1779 /* Both the above update both missing blocks */
1780 set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags);
1781 set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags);
1782 }
1783}
1784
1785
1786
1da177e4
LT		 1787/*
1788 * Each stripe/dev can have one or more bion attached.
16a53ecc 1789 * toread/towrite point to the first in a chain.
1da177e4
LT		 1790 * The bi_next chain must be in order.
1791 */
1792static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
1793{
1794 struct bio **bip;
1795 raid5_conf_t *conf = sh->raid_conf;
72626685 1796 int firstwrite=0;
1da177e4 1797
45b4233c 1798 pr_debug("adding bh b#%llu to stripe s#%llu\n",
1da177e4
LT		 1799 (unsigned long long)bi->bi_sector,
1800 (unsigned long long)sh->sector);
1801
1802
1803 spin_lock(&sh->lock);
1804 spin_lock_irq(&conf->device_lock);
72626685 1805 if (forwrite) {
1da177e4 1806 bip = &sh->dev[dd_idx].towrite;
72626685
N		 1807 if (*bip == NULL && sh->dev[dd_idx].written == NULL)
1808 firstwrite = 1;
1809 } else
1da177e4
LT		 1810 bip = &sh->dev[dd_idx].toread;
1811 while (*bip && (*bip)->bi_sector < bi->bi_sector) {
1812 if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
1813 goto overlap;
1814 bip = & (*bip)->bi_next;
1815 }
1816 if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
1817 goto overlap;
1818
78bafebd 1819 BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
1da177e4
LT		 1820 if (*bip)
1821 bi->bi_next = *bip;
1822 *bip = bi;
1823 bi->bi_phys_segments ++;
1824 spin_unlock_irq(&conf->device_lock);
1825 spin_unlock(&sh->lock);
1826
45b4233c 1827 pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
1da177e4
LT		 1828 (unsigned long long)bi->bi_sector,
1829 (unsigned long long)sh->sector, dd_idx);
1830
72626685 1831 if (conf->mddev->bitmap && firstwrite) {
72626685
N		 1832 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
1833 STRIPE_SECTORS, 0);
ae3c20cc 1834 sh->bm_seq = conf->seq_flush+1;
72626685
N		 1835 set_bit(STRIPE_BIT_DELAY, &sh->state);
1836 }
1837
1da177e4
LT		 1838 if (forwrite) {
1839 /* check if page is covered */
1840 sector_t sector = sh->dev[dd_idx].sector;
1841 for (bi=sh->dev[dd_idx].towrite;
1842 sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
1843 bi && bi->bi_sector <= sector;
1844 bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
1845 if (bi->bi_sector + (bi->bi_size>>9) >= sector)
1846 sector = bi->bi_sector + (bi->bi_size>>9);
1847 }
1848 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
1849 set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
1850 }
1851 return 1;
1852
1853 overlap:
1854 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
1855 spin_unlock_irq(&conf->device_lock);
1856 spin_unlock(&sh->lock);
1857 return 0;
1858}
1859
29269553
N		 1860static void end_reshape(raid5_conf_t *conf);
1861
16a53ecc
N		 1862static int page_is_zero(struct page *p)
1863{
1864 char *a = page_address(p);
1865 return ((*(u32*)a) == 0 &&
1866 memcmp(a, a+4, STRIPE_SIZE-4)==0);
1867}
1868
ccfcc3c1
N		 1869static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)
1870{
1871 int sectors_per_chunk = conf->chunk_size >> 9;
ccfcc3c1 1872 int pd_idx, dd_idx;
2d2063ce
CQH		 1873 int chunk_offset = sector_div(stripe, sectors_per_chunk);
1874
b875e531
N		 1875 raid5_compute_sector(stripe * (disks - conf->max_degraded)
1876 *sectors_per_chunk + chunk_offset,
1877 disks, disks - conf->max_degraded,
1878 &dd_idx, &pd_idx, conf);
ccfcc3c1
N		 1879 return pd_idx;
1880}
1881
a4456856
DW		 1882static void
1883handle_requests_to_failed_array(raid5_conf_t *conf, struct stripe_head *sh,
1884 struct stripe_head_state *s, int disks,
1885 struct bio **return_bi)
1886{
1887 int i;
1888 for (i = disks; i--; ) {
1889 struct bio *bi;
1890 int bitmap_end = 0;
1891
1892 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1893 mdk_rdev_t *rdev;
1894 rcu_read_lock();
1895 rdev = rcu_dereference(conf->disks[i].rdev);
1896 if (rdev && test_bit(In_sync, &rdev->flags))
1897 /* multiple read failures in one stripe */
1898 md_error(conf->mddev, rdev);
1899 rcu_read_unlock();
1900 }
1901 spin_lock_irq(&conf->device_lock);
1902 /* fail all writes first */
1903 bi = sh->dev[i].towrite;
1904 sh->dev[i].towrite = NULL;
1905 if (bi) {
1906 s->to_write--;
1907 bitmap_end = 1;
1908 }
1909
1910 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1911 wake_up(&conf->wait_for_overlap);
1912
1913 while (bi && bi->bi_sector <
1914 sh->dev[i].sector + STRIPE_SECTORS) {
1915 struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
1916 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1917 if (--bi->bi_phys_segments == 0) {
1918 md_write_end(conf->mddev);
1919 bi->bi_next = *return_bi;
1920 *return_bi = bi;
1921 }
1922 bi = nextbi;
1923 }
1924 /* and fail all 'written' */
1925 bi = sh->dev[i].written;
1926 sh->dev[i].written = NULL;
1927 if (bi) bitmap_end = 1;
1928 while (bi && bi->bi_sector <
1929 sh->dev[i].sector + STRIPE_SECTORS) {
1930 struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
1931 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1932 if (--bi->bi_phys_segments == 0) {
1933 md_write_end(conf->mddev);
1934 bi->bi_next = *return_bi;
1935 *return_bi = bi;
1936 }
1937 bi = bi2;
1938 }
1939
1940 /* fail any reads if this device is non-operational */
1941 if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
1942 test_bit(R5_ReadError, &sh->dev[i].flags)) {
1943 bi = sh->dev[i].toread;
1944 sh->dev[i].toread = NULL;
1945 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
1946 wake_up(&conf->wait_for_overlap);
1947 if (bi) s->to_read--;
1948 while (bi && bi->bi_sector <
1949 sh->dev[i].sector + STRIPE_SECTORS) {
1950 struct bio *nextbi =
1951 r5_next_bio(bi, sh->dev[i].sector);
1952 clear_bit(BIO_UPTODATE, &bi->bi_flags);
1953 if (--bi->bi_phys_segments == 0) {
1954 bi->bi_next = *return_bi;
1955 *return_bi = bi;
1956 }
1957 bi = nextbi;
1958 }
1959 }
1960 spin_unlock_irq(&conf->device_lock);
1961 if (bitmap_end)
1962 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
1963 STRIPE_SECTORS, 0, 0);
1964 }
1965
1966}
1967
1968static void handle_issuing_new_read_requests5(struct stripe_head *sh,
1969 struct stripe_head_state *s, int disks)
1970{
1971 int i;
1972 for (i = disks; i--; ) {
1973 struct r5dev *dev = &sh->dev[i];
1974 if (!test_bit(R5_LOCKED, &dev->flags) &&
1975 !test_bit(R5_UPTODATE, &dev->flags) &&
1976 (dev->toread ||
1977 (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
1978 s->syncing || s->expanding ||
1979 (s->failed && (sh->dev[s->failed_num].toread ||
1980 (sh->dev[s->failed_num].towrite &&
1981 !test_bit(R5_OVERWRITE, &sh->dev[s->failed_num].flags))
1982 )))) {
1983 /* we would like to get this block, possibly
1984 * by computing it, but we might not be able to
1985 */
1986 if (s->uptodate == disks-1) {
45b4233c 1987 pr_debug("Computing block %d\n", i);
a4456856
DW		 1988 compute_block(sh, i);
1989 s->uptodate++;
1990 } else if (test_bit(R5_Insync, &dev->flags)) {
1991 set_bit(R5_LOCKED, &dev->flags);
1992 set_bit(R5_Wantread, &dev->flags);
1993 s->locked++;
45b4233c 1994 pr_debug("Reading block %d (sync=%d)\n",
a4456856
DW		 1995 i, s->syncing);
1996 }
1997 }
1998 }
1999 set_bit(STRIPE_HANDLE, &sh->state);
2000}
2001
2002static void handle_issuing_new_read_requests6(struct stripe_head *sh,
2003 struct stripe_head_state *s, struct r6_state *r6s,
2004 int disks)
2005{
2006 int i;
2007 for (i = disks; i--; ) {
2008 struct r5dev *dev = &sh->dev[i];
2009 if (!test_bit(R5_LOCKED, &dev->flags) &&
2010 !test_bit(R5_UPTODATE, &dev->flags) &&
2011 (dev->toread || (dev->towrite &&
2012 !test_bit(R5_OVERWRITE, &dev->flags)) ||
2013 s->syncing || s->expanding ||
2014 (s->failed >= 1 &&
2015 (sh->dev[r6s->failed_num[0]].toread ||
2016 s->to_write)) ||
2017 (s->failed >= 2 &&
2018 (sh->dev[r6s->failed_num[1]].toread ||
2019 s->to_write)))) {
2020 /* we would like to get this block, possibly
2021 * by computing it, but we might not be able to
2022 */
2023 if (s->uptodate == disks-1) {
45b4233c 2024 pr_debug("Computing stripe %llu block %d\n",
a4456856
DW		 2025 (unsigned long long)sh->sector, i);
2026 compute_block_1(sh, i, 0);
2027 s->uptodate++;
2028 } else if ( s->uptodate == disks-2 && s->failed >= 2 ) {
2029 /* Computing 2-failure is *very* expensive; only
2030 * do it if failed >= 2
2031 */
2032 int other;
2033 for (other = disks; other--; ) {
2034 if (other == i)
2035 continue;
2036 if (!test_bit(R5_UPTODATE,
2037 &sh->dev[other].flags))
2038 break;
2039 }
2040 BUG_ON(other < 0);
45b4233c 2041 pr_debug("Computing stripe %llu blocks %d,%d\n",
a4456856
DW		 2042 (unsigned long long)sh->sector,
2043 i, other);
2044 compute_block_2(sh, i, other);
2045 s->uptodate += 2;
2046 } else if (test_bit(R5_Insync, &dev->flags)) {
2047 set_bit(R5_LOCKED, &dev->flags);
2048 set_bit(R5_Wantread, &dev->flags);
2049 s->locked++;
45b4233c 2050 pr_debug("Reading block %d (sync=%d)\n",
a4456856
DW		 2051 i, s->syncing);
2052 }
2053 }
2054 }
2055 set_bit(STRIPE_HANDLE, &sh->state);
2056}
2057
2058
2059/* handle_completed_write_requests
2060 * any written block on an uptodate or failed drive can be returned.
2061 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
2062 * never LOCKED, so we don't need to test 'failed' directly.
2063 */
2064static void handle_completed_write_requests(raid5_conf_t *conf,
2065 struct stripe_head *sh, int disks, struct bio **return_bi)
2066{
2067 int i;
2068 struct r5dev *dev;
2069
2070 for (i = disks; i--; )
2071 if (sh->dev[i].written) {
2072 dev = &sh->dev[i];
2073 if (!test_bit(R5_LOCKED, &dev->flags) &&
2074 test_bit(R5_UPTODATE, &dev->flags)) {
2075 /* We can return any write requests */
2076 struct bio *wbi, *wbi2;
2077 int bitmap_end = 0;
45b4233c 2078 pr_debug("Return write for disc %d\n", i);
a4456856
DW		 2079 spin_lock_irq(&conf->device_lock);
2080 wbi = dev->written;
2081 dev->written = NULL;
2082 while (wbi && wbi->bi_sector <
2083 dev->sector + STRIPE_SECTORS) {
2084 wbi2 = r5_next_bio(wbi, dev->sector);
2085 if (--wbi->bi_phys_segments == 0) {
2086 md_write_end(conf->mddev);
2087 wbi->bi_next = *return_bi;
2088 *return_bi = wbi;
2089 }
2090 wbi = wbi2;
2091 }
2092 if (dev->towrite == NULL)
2093 bitmap_end = 1;
2094 spin_unlock_irq(&conf->device_lock);
2095 if (bitmap_end)
2096 bitmap_endwrite(conf->mddev->bitmap,
2097 sh->sector,
2098 STRIPE_SECTORS,
2099 !test_bit(STRIPE_DEGRADED, &sh->state),
2100 0);
2101 }
2102 }
2103}
2104
2105static void handle_issuing_new_write_requests5(raid5_conf_t *conf,
2106 struct stripe_head *sh, struct stripe_head_state *s, int disks)
2107{
2108 int rmw = 0, rcw = 0, i;
2109 for (i = disks; i--; ) {
2110 /* would I have to read this buffer for read_modify_write */
2111 struct r5dev *dev = &sh->dev[i];
2112 if ((dev->towrite || i == sh->pd_idx) &&
2113 !test_bit(R5_LOCKED, &dev->flags) &&
2114 !test_bit(R5_UPTODATE, &dev->flags)) {
2115 if (test_bit(R5_Insync, &dev->flags))
2116 rmw++;
2117 else
2118 rmw += 2*disks; /* cannot read it */
2119 }
2120 /* Would I have to read this buffer for reconstruct_write */
2121 if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
2122 !test_bit(R5_LOCKED, &dev->flags) &&
2123 !test_bit(R5_UPTODATE, &dev->flags)) {
2124 if (test_bit(R5_Insync, &dev->flags))
2125 rcw++;
2126 else
2127 rcw += 2*disks;
2128 }
2129 }
45b4233c 2130 pr_debug("for sector %llu, rmw=%d rcw=%d\n",
a4456856
DW		 2131 (unsigned long long)sh->sector, rmw, rcw);
2132 set_bit(STRIPE_HANDLE, &sh->state);
2133 if (rmw < rcw && rmw > 0)
2134 /* prefer read-modify-write, but need to get some data */
2135 for (i = disks; i--; ) {
2136 struct r5dev *dev = &sh->dev[i];
2137 if ((dev->towrite || i == sh->pd_idx) &&
2138 !test_bit(R5_LOCKED, &dev->flags) &&
2139 !test_bit(R5_UPTODATE, &dev->flags) &&
2140 test_bit(R5_Insync, &dev->flags)) {
2141 if (
2142 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
45b4233c 2143 pr_debug("Read_old block "
a4456856
DW		 2144 "%d for r-m-w\n", i);
2145 set_bit(R5_LOCKED, &dev->flags);
2146 set_bit(R5_Wantread, &dev->flags);
2147 s->locked++;
2148 } else {
2149 set_bit(STRIPE_DELAYED, &sh->state);
2150 set_bit(STRIPE_HANDLE, &sh->state);
2151 }
2152 }
2153 }
2154 if (rcw <= rmw && rcw > 0)
2155 /* want reconstruct write, but need to get some data */
2156 for (i = disks; i--; ) {
2157 struct r5dev *dev = &sh->dev[i];
2158 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
2159 i != sh->pd_idx &&
2160 !test_bit(R5_LOCKED, &dev->flags) &&
2161 !test_bit(R5_UPTODATE, &dev->flags) &&
2162 test_bit(R5_Insync, &dev->flags)) {
2163 if (
2164 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
45b4233c 2165 pr_debug("Read_old block "
a4456856
DW		 2166 "%d for Reconstruct\n", i);
2167 set_bit(R5_LOCKED, &dev->flags);
2168 set_bit(R5_Wantread, &dev->flags);
2169 s->locked++;
2170 } else {
2171 set_bit(STRIPE_DELAYED, &sh->state);
2172 set_bit(STRIPE_HANDLE, &sh->state);
2173 }
2174 }
2175 }
2176 /* now if nothing is locked, and if we have enough data,
2177 * we can start a write request
2178 */
2179 if (s->locked == 0 && (rcw == 0 || rmw == 0) &&
2180 !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
45b4233c 2181 pr_debug("Computing parity...\n");
a4456856
DW		 2182 compute_parity5(sh, rcw == 0 ?
2183 RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
2184 /* now every locked buffer is ready to be written */
2185 for (i = disks; i--; )
2186 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
45b4233c 2187 pr_debug("Writing block %d\n", i);
a4456856
DW		 2188 s->locked++;
2189 set_bit(R5_Wantwrite, &sh->dev[i].flags);
2190 if (!test_bit(R5_Insync, &sh->dev[i].flags)
2191 || (i == sh->pd_idx && s->failed == 0))
2192 set_bit(STRIPE_INSYNC, &sh->state);
2193 }
2194 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2195 atomic_dec(&conf->preread_active_stripes);
2196 if (atomic_read(&conf->preread_active_stripes) <
2197 IO_THRESHOLD)
2198 md_wakeup_thread(conf->mddev->thread);
2199 }
2200 }
2201}
2202
2203static void handle_issuing_new_write_requests6(raid5_conf_t *conf,
2204 struct stripe_head *sh, struct stripe_head_state *s,
2205 struct r6_state *r6s, int disks)
2206{
2207 int rcw = 0, must_compute = 0, pd_idx = sh->pd_idx, i;
2208 int qd_idx = r6s->qd_idx;
2209 for (i = disks; i--; ) {
2210 struct r5dev *dev = &sh->dev[i];
2211 /* Would I have to read this buffer for reconstruct_write */
2212 if (!test_bit(R5_OVERWRITE, &dev->flags)
2213 && i != pd_idx && i != qd_idx
2214 && (!test_bit(R5_LOCKED, &dev->flags)
2215 ) &&
2216 !test_bit(R5_UPTODATE, &dev->flags)) {
2217 if (test_bit(R5_Insync, &dev->flags)) rcw++;
2218 else {
45b4233c 2219 pr_debug("raid6: must_compute: "
a4456856
DW		 2220 "disk %d flags=%#lx\n", i, dev->flags);
2221 must_compute++;
2222 }
2223 }
2224 }
45b4233c 2225 pr_debug("for sector %llu, rcw=%d, must_compute=%d\n",
a4456856
DW		 2226 (unsigned long long)sh->sector, rcw, must_compute);
2227 set_bit(STRIPE_HANDLE, &sh->state);
2228
2229 if (rcw > 0)
2230 /* want reconstruct write, but need to get some data */
2231 for (i = disks; i--; ) {
2232 struct r5dev *dev = &sh->dev[i];
2233 if (!test_bit(R5_OVERWRITE, &dev->flags)
2234 && !(s->failed == 0 && (i == pd_idx || i == qd_idx))
2235 && !test_bit(R5_LOCKED, &dev->flags) &&
2236 !test_bit(R5_UPTODATE, &dev->flags) &&
2237 test_bit(R5_Insync, &dev->flags)) {
2238 if (
2239 test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
45b4233c 2240 pr_debug("Read_old stripe %llu "
a4456856
DW		 2241 "block %d for Reconstruct\n",
2242 (unsigned long long)sh->sector, i);
2243 set_bit(R5_LOCKED, &dev->flags);
2244 set_bit(R5_Wantread, &dev->flags);
2245 s->locked++;
2246 } else {
45b4233c 2247 pr_debug("Request delayed stripe %llu "
a4456856
DW		 2248 "block %d for Reconstruct\n",
2249 (unsigned long long)sh->sector, i);
2250 set_bit(STRIPE_DELAYED, &sh->state);
2251 set_bit(STRIPE_HANDLE, &sh->state);
2252 }
2253 }
2254 }
2255 /* now if nothing is locked, and if we have enough data, we can start a
2256 * write request
2257 */
2258 if (s->locked == 0 && rcw == 0 &&
2259 !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
2260 if (must_compute > 0) {
2261 /* We have failed blocks and need to compute them */
2262 switch (s->failed) {
2263 case 0:
2264 BUG();
2265 case 1:
2266 compute_block_1(sh, r6s->failed_num[0], 0);
2267 break;
2268 case 2:
2269 compute_block_2(sh, r6s->failed_num[0],
2270 r6s->failed_num[1]);
2271 break;
2272 default: /* This request should have been failed? */
2273 BUG();
2274 }
2275 }
2276
45b4233c 2277 pr_debug("Computing parity for stripe %llu\n",
a4456856
DW		 2278 (unsigned long long)sh->sector);
2279 compute_parity6(sh, RECONSTRUCT_WRITE);
2280 /* now every locked buffer is ready to be written */
2281 for (i = disks; i--; )
2282 if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
45b4233c 2283 pr_debug("Writing stripe %llu block %d\n",
a4456856
DW		 2284 (unsigned long long)sh->sector, i);
2285 s->locked++;
2286 set_bit(R5_Wantwrite, &sh->dev[i].flags);
2287 }
2288 /* after a RECONSTRUCT_WRITE, the stripe MUST be in-sync */
2289 set_bit(STRIPE_INSYNC, &sh->state);
2290
2291 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2292 atomic_dec(&conf->preread_active_stripes);
2293 if (atomic_read(&conf->preread_active_stripes) <
2294 IO_THRESHOLD)
2295 md_wakeup_thread(conf->mddev->thread);
2296 }
2297 }
2298}
2299
2300static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
2301 struct stripe_head_state *s, int disks)
2302{
2303 set_bit(STRIPE_HANDLE, &sh->state);
2304 if (s->failed == 0) {
2305 BUG_ON(s->uptodate != disks);
2306 compute_parity5(sh, CHECK_PARITY);
2307 s->uptodate--;
2308 if (page_is_zero(sh->dev[sh->pd_idx].page)) {
2309 /* parity is correct (on disc, not in buffer any more)
2310 */
2311 set_bit(STRIPE_INSYNC, &sh->state);
2312 } else {
2313 conf->mddev->resync_mismatches += STRIPE_SECTORS;
2314 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
2315 /* don't try to repair!! */
2316 set_bit(STRIPE_INSYNC, &sh->state);
2317 else {
2318 compute_block(sh, sh->pd_idx);
2319 s->uptodate++;
2320 }
2321 }
2322 }
2323 if (!test_bit(STRIPE_INSYNC, &sh->state)) {
2324 struct r5dev *dev;
2325 /* either failed parity check, or recovery is happening */
2326 if (s->failed == 0)
2327 s->failed_num = sh->pd_idx;
2328 dev = &sh->dev[s->failed_num];
2329 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
2330 BUG_ON(s->uptodate != disks);
2331
2332 set_bit(R5_LOCKED, &dev->flags);
2333 set_bit(R5_Wantwrite, &dev->flags);
2334 clear_bit(STRIPE_DEGRADED, &sh->state);
2335 s->locked++;
2336 set_bit(STRIPE_INSYNC, &sh->state);
2337 }
2338}
2339
2340
2341static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh,
2342 struct stripe_head_state *s,
2343 struct r6_state *r6s, struct page *tmp_page,
2344 int disks)
2345{
2346 int update_p = 0, update_q = 0;
2347 struct r5dev *dev;
2348 int pd_idx = sh->pd_idx;
2349 int qd_idx = r6s->qd_idx;
2350
2351 set_bit(STRIPE_HANDLE, &sh->state);
2352
2353 BUG_ON(s->failed > 2);
2354 BUG_ON(s->uptodate < disks);
2355 /* Want to check and possibly repair P and Q.
2356 * However there could be one 'failed' device, in which
2357 * case we can only check one of them, possibly using the
2358 * other to generate missing data
2359 */
2360
2361 /* If !tmp_page, we cannot do the calculations,
2362 * but as we have set STRIPE_HANDLE, we will soon be called
2363 * by stripe_handle with a tmp_page - just wait until then.
2364 */
2365 if (tmp_page) {
2366 if (s->failed == r6s->q_failed) {
2367 /* The only possible failed device holds 'Q', so it
2368 * makes sense to check P (If anything else were failed,
2369 * we would have used P to recreate it).
2370 */
2371 compute_block_1(sh, pd_idx, 1);
2372 if (!page_is_zero(sh->dev[pd_idx].page)) {
2373 compute_block_1(sh, pd_idx, 0);
2374 update_p = 1;
2375 }
2376 }
2377 if (!r6s->q_failed && s->failed < 2) {
2378 /* q is not failed, and we didn't use it to generate
2379 * anything, so it makes sense to check it
2380 */
2381 memcpy(page_address(tmp_page),
2382 page_address(sh->dev[qd_idx].page),
2383 STRIPE_SIZE);
2384 compute_parity6(sh, UPDATE_PARITY);
2385 if (memcmp(page_address(tmp_page),
2386 page_address(sh->dev[qd_idx].page),
2387 STRIPE_SIZE) != 0) {
2388 clear_bit(STRIPE_INSYNC, &sh->state);
2389 update_q = 1;
2390 }
2391 }
2392 if (update_p || update_q) {
2393 conf->mddev->resync_mismatches += STRIPE_SECTORS;
2394 if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
2395 /* don't try to repair!! */
2396 update_p = update_q = 0;
2397 }
2398
2399 /* now write out any block on a failed drive,
2400 * or P or Q if they need it
2401 */
2402
2403 if (s->failed == 2) {
2404 dev = &sh->dev[r6s->failed_num[1]];
2405 s->locked++;
2406 set_bit(R5_LOCKED, &dev->flags);
2407 set_bit(R5_Wantwrite, &dev->flags);
2408 }
2409 if (s->failed >= 1) {
2410 dev = &sh->dev[r6s->failed_num[0]];
2411 s->locked++;
2412 set_bit(R5_LOCKED, &dev->flags);
2413 set_bit(R5_Wantwrite, &dev->flags);
2414 }
2415
2416 if (update_p) {
2417 dev = &sh->dev[pd_idx];
2418 s->locked++;
2419 set_bit(R5_LOCKED, &dev->flags);
2420 set_bit(R5_Wantwrite, &dev->flags);
2421 }
2422 if (update_q) {
2423 dev = &sh->dev[qd_idx];
2424 s->locked++;
2425 set_bit(R5_LOCKED, &dev->flags);
2426 set_bit(R5_Wantwrite, &dev->flags);
2427 }
2428 clear_bit(STRIPE_DEGRADED, &sh->state);
2429
2430 set_bit(STRIPE_INSYNC, &sh->state);
2431 }
2432}
2433
2434static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
2435 struct r6_state *r6s)
2436{
2437 int i;
2438
2439 /* We have read all the blocks in this stripe and now we need to
2440 * copy some of them into a target stripe for expand.
2441 */
2442 clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
2443 for (i = 0; i < sh->disks; i++)
2444 if (i != sh->pd_idx && (r6s && i != r6s->qd_idx)) {
2445 int dd_idx, pd_idx, j;
2446 struct stripe_head *sh2;
2447
2448 sector_t bn = compute_blocknr(sh, i);
2449 sector_t s = raid5_compute_sector(bn, conf->raid_disks,
2450 conf->raid_disks -
2451 conf->max_degraded, &dd_idx,
2452 &pd_idx, conf);
2453 sh2 = get_active_stripe(conf, s, conf->raid_disks,
2454 pd_idx, 1);
2455 if (sh2 == NULL)
2456 /* so far only the early blocks of this stripe
2457 * have been requested. When later blocks
2458 * get requested, we will try again
2459 */
2460 continue;
2461 if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
2462 test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
2463 /* must have already done this block */
2464 release_stripe(sh2);
2465 continue;
2466 }
2467 memcpy(page_address(sh2->dev[dd_idx].page),
2468 page_address(sh->dev[i].page),
2469 STRIPE_SIZE);
2470 set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
2471 set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
2472 for (j = 0; j < conf->raid_disks; j++)
2473 if (j != sh2->pd_idx &&
2474 (r6s && j != r6s->qd_idx) &&
2475 !test_bit(R5_Expanded, &sh2->dev[j].flags))
2476 break;
2477 if (j == conf->raid_disks) {
2478 set_bit(STRIPE_EXPAND_READY, &sh2->state);
2479 set_bit(STRIPE_HANDLE, &sh2->state);
2480 }
2481 release_stripe(sh2);
2482 }
2483}
1da177e4
LT		 2484
2485/*
2486 * handle_stripe - do things to a stripe.
2487 *
2488 * We lock the stripe and then examine the state of various bits
2489 * to see what needs to be done.
2490 * Possible results:
2491 * return some read request which now have data
2492 * return some write requests which are safely on disc
2493 * schedule a read on some buffers
2494 * schedule a write of some buffers
2495 * return confirmation of parity correctness
2496 *
2497 * Parity calculations are done inside the stripe lock
2498 * buffers are taken off read_list or write_list, and bh_cache buffers
2499 * get BH_Lock set before the stripe lock is released.
2500 *
2501 */
a4456856 2502
16a53ecc 2503static void handle_stripe5(struct stripe_head *sh)
1da177e4
LT		 2504{
2505 raid5_conf_t *conf = sh->raid_conf;
a4456856
DW		 2506 int disks = sh->disks, i;
2507 struct bio *return_bi = NULL;
2508 struct stripe_head_state s;
1da177e4
LT		 2509 struct r5dev *dev;
2510
a4456856 2511 memset(&s, 0, sizeof(s));
45b4233c 2512 pr_debug("handling stripe %llu, cnt=%d, pd_idx=%d\n",
1da177e4
LT		 2513 (unsigned long long)sh->sector, atomic_read(&sh->count),
2514 sh->pd_idx);
2515
2516 spin_lock(&sh->lock);
2517 clear_bit(STRIPE_HANDLE, &sh->state);
2518 clear_bit(STRIPE_DELAYED, &sh->state);
2519
a4456856
DW		 2520 s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
2521 s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
2522 s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
1da177e4
LT		 2523 /* Now to look around and see what can be done */
2524
9910f16a 2525 rcu_read_lock();
1da177e4
LT		 2526 for (i=disks; i--; ) {
2527 mdk_rdev_t *rdev;
a4456856 2528 struct r5dev *dev = &sh->dev[i];
1da177e4 2529 clear_bit(R5_Insync, &dev->flags);
1da177e4 2530
45b4233c 2531 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
1da177e4
LT		 2532 i, dev->flags, dev->toread, dev->towrite, dev->written);
2533 /* maybe we can reply to a read */
2534 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
2535 struct bio *rbi, *rbi2;
45b4233c 2536 pr_debug("Return read for disc %d\n", i);
1da177e4
LT		 2537 spin_lock_irq(&conf->device_lock);
2538 rbi = dev->toread;
2539 dev->toread = NULL;
2540 if (test_and_clear_bit(R5_Overlap, &dev->flags))
2541 wake_up(&conf->wait_for_overlap);
2542 spin_unlock_irq(&conf->device_lock);
2543 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) {
2544 copy_data(0, rbi, dev->page, dev->sector);
2545 rbi2 = r5_next_bio(rbi, dev->sector);
2546 spin_lock_irq(&conf->device_lock);
2547 if (--rbi->bi_phys_segments == 0) {
2548 rbi->bi_next = return_bi;
2549 return_bi = rbi;
2550 }
2551 spin_unlock_irq(&conf->device_lock);
2552 rbi = rbi2;
2553 }
2554 }
2555
2556 /* now count some things */
a4456856
DW		 2557 if (test_bit(R5_LOCKED, &dev->flags)) s.locked++;
2558 if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++;
1da177e4 2559
a4456856
DW		 2560 if (dev->toread)
2561 s.to_read++;
1da177e4 2562 if (dev->towrite) {
a4456856 2563 s.to_write++;
1da177e4 2564 if (!test_bit(R5_OVERWRITE, &dev->flags))
a4456856 2565 s.non_overwrite++;
1da177e4 2566 }
a4456856
DW		 2567 if (dev->written)
2568 s.written++;
9910f16a 2569 rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 2570 if (!rdev || !test_bit(In_sync, &rdev->flags)) {
14f8d26b 2571 /* The ReadError flag will just be confusing now */
4e5314b5
N		 2572 clear_bit(R5_ReadError, &dev->flags);
2573 clear_bit(R5_ReWrite, &dev->flags);
2574 }
b2d444d7 2575 if (!rdev || !test_bit(In_sync, &rdev->flags)
4e5314b5 2576 || test_bit(R5_ReadError, &dev->flags)) {
a4456856
DW		 2577 s.failed++;
2578 s.failed_num = i;
1da177e4
LT		 2579 } else
2580 set_bit(R5_Insync, &dev->flags);
2581 }
9910f16a 2582 rcu_read_unlock();
45b4233c 2583 pr_debug("locked=%d uptodate=%d to_read=%d"
1da177e4 2584 " to_write=%d failed=%d failed_num=%d\n",
a4456856
DW		 2585 s.locked, s.uptodate, s.to_read, s.to_write,
2586 s.failed, s.failed_num);
1da177e4
LT		 2587 /* check if the array has lost two devices and, if so, some requests might
2588 * need to be failed
2589 */
a4456856
DW		 2590 if (s.failed > 1 && s.to_read+s.to_write+s.written)
2591 handle_requests_to_failed_array(conf, sh, &s, disks,
2592 &return_bi);
2593 if (s.failed > 1 && s.syncing) {
1da177e4
LT		 2594 md_done_sync(conf->mddev, STRIPE_SECTORS,0);
2595 clear_bit(STRIPE_SYNCING, &sh->state);
a4456856 2596 s.syncing = 0;
1da177e4
LT		 2597 }
2598
2599 /* might be able to return some write requests if the parity block
2600 * is safe, or on a failed drive
2601 */
2602 dev = &sh->dev[sh->pd_idx];
a4456856
DW		 2603 if ( s.written &&
2604 ((test_bit(R5_Insync, &dev->flags) &&
2605 !test_bit(R5_LOCKED, &dev->flags) &&
2606 test_bit(R5_UPTODATE, &dev->flags)) ||
2607 (s.failed == 1 && s.failed_num == sh->pd_idx)))
2608 handle_completed_write_requests(conf, sh, disks, &return_bi);
1da177e4
LT		 2609
2610 /* Now we might consider reading some blocks, either to check/generate
2611 * parity, or to satisfy requests
2612 * or to load a block that is being partially written.
2613 */
a4456856
DW		 2614 if (s.to_read || s.non_overwrite ||
2615 (s.syncing && (s.uptodate < disks)) || s.expanding)
2616 handle_issuing_new_read_requests5(sh, &s, disks);
1da177e4
LT		 2617
2618 /* now to consider writing and what else, if anything should be read */
a4456856
DW		 2619 if (s.to_write)
2620 handle_issuing_new_write_requests5(conf, sh, &s, disks);
1da177e4
LT		 2621
2622 /* maybe we need to check and possibly fix the parity for this stripe
2623 * Any reads will already have been scheduled, so we just see if enough data
2624 * is available
2625 */
a4456856
DW		 2626 if (s.syncing && s.locked == 0 &&
2627 !test_bit(STRIPE_INSYNC, &sh->state))
2628 handle_parity_checks5(conf, sh, &s, disks);
2629 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
1da177e4
LT		 2630 md_done_sync(conf->mddev, STRIPE_SECTORS,1);
2631 clear_bit(STRIPE_SYNCING, &sh->state);
2632 }
4e5314b5
N		 2633
2634 /* If the failed drive is just a ReadError, then we might need to progress
2635 * the repair/check process
2636 */
a4456856
DW		 2637 if (s.failed == 1 && !conf->mddev->ro &&
2638 test_bit(R5_ReadError, &sh->dev[s.failed_num].flags)
2639 && !test_bit(R5_LOCKED, &sh->dev[s.failed_num].flags)
2640 && test_bit(R5_UPTODATE, &sh->dev[s.failed_num].flags)
4e5314b5 2641 ) {
a4456856 2642 dev = &sh->dev[s.failed_num];
4e5314b5
N		 2643 if (!test_bit(R5_ReWrite, &dev->flags)) {
2644 set_bit(R5_Wantwrite, &dev->flags);
2645 set_bit(R5_ReWrite, &dev->flags);
2646 set_bit(R5_LOCKED, &dev->flags);
a4456856 2647 s.locked++;
4e5314b5
N		 2648 } else {
2649 /* let's read it back */
2650 set_bit(R5_Wantread, &dev->flags);
2651 set_bit(R5_LOCKED, &dev->flags);
a4456856 2652 s.locked++;
4e5314b5
N		 2653 }
2654 }
2655
a4456856 2656 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
ccfcc3c1
N		 2657 /* Need to write out all blocks after computing parity */
2658 sh->disks = conf->raid_disks;
2659 sh->pd_idx = stripe_to_pdidx(sh->sector, conf, conf->raid_disks);
16a53ecc 2660 compute_parity5(sh, RECONSTRUCT_WRITE);
a4456856 2661 for (i = conf->raid_disks; i--; ) {
ccfcc3c1 2662 set_bit(R5_LOCKED, &sh->dev[i].flags);
a4456856 2663 s.locked++;
ccfcc3c1
N		 2664 set_bit(R5_Wantwrite, &sh->dev[i].flags);
2665 }
2666 clear_bit(STRIPE_EXPANDING, &sh->state);
a4456856 2667 } else if (s.expanded) {
ccfcc3c1 2668 clear_bit(STRIPE_EXPAND_READY, &sh->state);
f6705578 2669 atomic_dec(&conf->reshape_stripes);
ccfcc3c1
N		 2670 wake_up(&conf->wait_for_overlap);
2671 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
2672 }
2673
a4456856
DW		 2674 if (s.expanding && s.locked == 0)
2675 handle_stripe_expansion(conf, sh, NULL);
ccfcc3c1 2676
1da177e4
LT		 2677 spin_unlock(&sh->lock);
2678
a4456856 2679 return_io(return_bi);
1da177e4 2680
1da177e4
LT		 2681 for (i=disks; i-- ;) {
2682 int rw;
2683 struct bio *bi;
2684 mdk_rdev_t *rdev;
2685 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
802ba064 2686 rw = WRITE;
1da177e4 2687 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
802ba064 2688 rw = READ;
1da177e4
LT		 2689 else
2690 continue;
2691
2692 bi = &sh->dev[i].req;
2693
2694 bi->bi_rw = rw;
802ba064 2695 if (rw == WRITE)
1da177e4
LT		 2696 bi->bi_end_io = raid5_end_write_request;
2697 else
2698 bi->bi_end_io = raid5_end_read_request;
2699
2700 rcu_read_lock();
d6065f7b 2701 rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 2702 if (rdev && test_bit(Faulty, &rdev->flags))
1da177e4
LT		 2703 rdev = NULL;
2704 if (rdev)
2705 atomic_inc(&rdev->nr_pending);
2706 rcu_read_unlock();
2707
2708 if (rdev) {
a4456856 2709 if (s.syncing || s.expanding || s.expanded)
1da177e4
LT		 2710 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
2711
2712 bi->bi_bdev = rdev->bdev;
45b4233c 2713 pr_debug("for %llu schedule op %ld on disc %d\n",
1da177e4
LT		 2714 (unsigned long long)sh->sector, bi->bi_rw, i);
2715 atomic_inc(&sh->count);
2716 bi->bi_sector = sh->sector + rdev->data_offset;
2717 bi->bi_flags = 1 << BIO_UPTODATE;
2718 bi->bi_vcnt = 1;
2719 bi->bi_max_vecs = 1;
2720 bi->bi_idx = 0;
2721 bi->bi_io_vec = &sh->dev[i].vec;
2722 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
2723 bi->bi_io_vec[0].bv_offset = 0;
2724 bi->bi_size = STRIPE_SIZE;
2725 bi->bi_next = NULL;
4dbcdc75
N		 2726 if (rw == WRITE &&
2727 test_bit(R5_ReWrite, &sh->dev[i].flags))
2728 atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1da177e4
LT		 2729 generic_make_request(bi);
2730 } else {
802ba064 2731 if (rw == WRITE)
72626685 2732 set_bit(STRIPE_DEGRADED, &sh->state);
45b4233c 2733 pr_debug("skip op %ld on disc %d for sector %llu\n",
1da177e4
LT		 2734 bi->bi_rw, i, (unsigned long long)sh->sector);
2735 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2736 set_bit(STRIPE_HANDLE, &sh->state);
2737 }
2738 }
2739}
2740
16a53ecc 2741static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
1da177e4 2742{
16a53ecc 2743 raid6_conf_t *conf = sh->raid_conf;
f416885e 2744 int disks = sh->disks;
a4456856
DW		 2745 struct bio *return_bi = NULL;
2746 int i, pd_idx = sh->pd_idx;
2747 struct stripe_head_state s;
2748 struct r6_state r6s;
16a53ecc 2749 struct r5dev *dev, *pdev, *qdev;
1da177e4 2750
a4456856 2751 r6s.qd_idx = raid6_next_disk(pd_idx, disks);
45b4233c 2752 pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
a4456856
DW		 2753 "pd_idx=%d, qd_idx=%d\n",
2754 (unsigned long long)sh->sector, sh->state,
2755 atomic_read(&sh->count), pd_idx, r6s.qd_idx);
2756 memset(&s, 0, sizeof(s));
72626685 2757
16a53ecc
N		 2758 spin_lock(&sh->lock);
2759 clear_bit(STRIPE_HANDLE, &sh->state);
2760 clear_bit(STRIPE_DELAYED, &sh->state);
2761
a4456856
DW		 2762 s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
2763 s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
2764 s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
16a53ecc 2765 /* Now to look around and see what can be done */
1da177e4
LT		 2766
2767 rcu_read_lock();
16a53ecc
N		 2768 for (i=disks; i--; ) {
2769 mdk_rdev_t *rdev;
2770 dev = &sh->dev[i];
2771 clear_bit(R5_Insync, &dev->flags);
1da177e4 2772
45b4233c 2773 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
16a53ecc
N		 2774 i, dev->flags, dev->toread, dev->towrite, dev->written);
2775 /* maybe we can reply to a read */
2776 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
2777 struct bio *rbi, *rbi2;
45b4233c 2778 pr_debug("Return read for disc %d\n", i);
16a53ecc
N		 2779 spin_lock_irq(&conf->device_lock);
2780 rbi = dev->toread;
2781 dev->toread = NULL;
2782 if (test_and_clear_bit(R5_Overlap, &dev->flags))
2783 wake_up(&conf->wait_for_overlap);
2784 spin_unlock_irq(&conf->device_lock);
2785 while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) {
2786 copy_data(0, rbi, dev->page, dev->sector);
2787 rbi2 = r5_next_bio(rbi, dev->sector);
2788 spin_lock_irq(&conf->device_lock);
2789 if (--rbi->bi_phys_segments == 0) {
2790 rbi->bi_next = return_bi;
2791 return_bi = rbi;
2792 }
2793 spin_unlock_irq(&conf->device_lock);
2794 rbi = rbi2;
2795 }
2796 }
1da177e4 2797
16a53ecc 2798 /* now count some things */
a4456856
DW		 2799 if (test_bit(R5_LOCKED, &dev->flags)) s.locked++;
2800 if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++;
1da177e4 2801
16a53ecc 2802
a4456856
DW		 2803 if (dev->toread)
2804 s.to_read++;
16a53ecc 2805 if (dev->towrite) {
a4456856 2806 s.to_write++;
16a53ecc 2807 if (!test_bit(R5_OVERWRITE, &dev->flags))
a4456856 2808 s.non_overwrite++;
16a53ecc 2809 }
a4456856
DW		 2810 if (dev->written)
2811 s.written++;
16a53ecc
N		 2812 rdev = rcu_dereference(conf->disks[i].rdev);
2813 if (!rdev || !test_bit(In_sync, &rdev->flags)) {
2814 /* The ReadError flag will just be confusing now */
2815 clear_bit(R5_ReadError, &dev->flags);
2816 clear_bit(R5_ReWrite, &dev->flags);
1da177e4 2817 }
16a53ecc
N		 2818 if (!rdev || !test_bit(In_sync, &rdev->flags)
2819 || test_bit(R5_ReadError, &dev->flags)) {
a4456856
DW		 2820 if (s.failed < 2)
2821 r6s.failed_num[s.failed] = i;
2822 s.failed++;
16a53ecc
N		 2823 } else
2824 set_bit(R5_Insync, &dev->flags);
1da177e4
LT		 2825 }
2826 rcu_read_unlock();
45b4233c 2827 pr_debug("locked=%d uptodate=%d to_read=%d"
16a53ecc 2828 " to_write=%d failed=%d failed_num=%d,%d\n",
a4456856
DW		 2829 s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
2830 r6s.failed_num[0], r6s.failed_num[1]);
2831 /* check if the array has lost >2 devices and, if so, some requests
2832 * might need to be failed
16a53ecc 2833 */
a4456856
DW		 2834 if (s.failed > 2 && s.to_read+s.to_write+s.written)
2835 handle_requests_to_failed_array(conf, sh, &s, disks,
2836 &return_bi);
2837 if (s.failed > 2 && s.syncing) {
16a53ecc
N		 2838 md_done_sync(conf->mddev, STRIPE_SECTORS,0);
2839 clear_bit(STRIPE_SYNCING, &sh->state);
a4456856 2840 s.syncing = 0;
16a53ecc
N		 2841 }
2842
2843 /*
2844 * might be able to return some write requests if the parity blocks
2845 * are safe, or on a failed drive
2846 */
2847 pdev = &sh->dev[pd_idx];
a4456856
DW		 2848 r6s.p_failed = (s.failed >= 1 && r6s.failed_num[0] == pd_idx)
2849 || (s.failed >= 2 && r6s.failed_num[1] == pd_idx);
2850 qdev = &sh->dev[r6s.qd_idx];
2851 r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == r6s.qd_idx)
2852 || (s.failed >= 2 && r6s.failed_num[1] == r6s.qd_idx);
2853
2854 if ( s.written &&
2855 ( r6s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
16a53ecc 2856 && !test_bit(R5_LOCKED, &pdev->flags)
a4456856
DW		 2857 && test_bit(R5_UPTODATE, &pdev->flags)))) &&
2858 ( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
16a53ecc 2859 && !test_bit(R5_LOCKED, &qdev->flags)
a4456856
DW		 2860 && test_bit(R5_UPTODATE, &qdev->flags)))))
2861 handle_completed_write_requests(conf, sh, disks, &return_bi);
16a53ecc
N		 2862
2863 /* Now we might consider reading some blocks, either to check/generate
2864 * parity, or to satisfy requests
2865 * or to load a block that is being partially written.
2866 */
a4456856
DW		 2867 if (s.to_read || s.non_overwrite || (s.to_write && s.failed) ||
2868 (s.syncing && (s.uptodate < disks)) || s.expanding)
2869 handle_issuing_new_read_requests6(sh, &s, &r6s, disks);
16a53ecc
N		 2870
2871 /* now to consider writing and what else, if anything should be read */
a4456856
DW		 2872 if (s.to_write)
2873 handle_issuing_new_write_requests6(conf, sh, &s, &r6s, disks);
16a53ecc
N		 2874
2875 /* maybe we need to check and possibly fix the parity for this stripe
a4456856
DW		 2876 * Any reads will already have been scheduled, so we just see if enough
2877 * data is available
16a53ecc 2878 */
a4456856
DW		 2879 if (s.syncing && s.locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state))
2880 handle_parity_checks6(conf, sh, &s, &r6s, tmp_page, disks);
16a53ecc 2881
a4456856 2882 if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
16a53ecc
N		 2883 md_done_sync(conf->mddev, STRIPE_SECTORS,1);
2884 clear_bit(STRIPE_SYNCING, &sh->state);
2885 }
2886
2887 /* If the failed drives are just a ReadError, then we might need
2888 * to progress the repair/check process
2889 */
a4456856
DW		 2890 if (s.failed <= 2 && !conf->mddev->ro)
2891 for (i = 0; i < s.failed; i++) {
2892 dev = &sh->dev[r6s.failed_num[i]];
16a53ecc
N		 2893 if (test_bit(R5_ReadError, &dev->flags)
2894 && !test_bit(R5_LOCKED, &dev->flags)
2895 && test_bit(R5_UPTODATE, &dev->flags)
2896 ) {
2897 if (!test_bit(R5_ReWrite, &dev->flags)) {
2898 set_bit(R5_Wantwrite, &dev->flags);
2899 set_bit(R5_ReWrite, &dev->flags);
2900 set_bit(R5_LOCKED, &dev->flags);
2901 } else {
2902 /* let's read it back */
2903 set_bit(R5_Wantread, &dev->flags);
2904 set_bit(R5_LOCKED, &dev->flags);
2905 }
2906 }
2907 }
f416885e 2908
a4456856 2909 if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
f416885e
N		 2910 /* Need to write out all blocks after computing P&Q */
2911 sh->disks = conf->raid_disks;
2912 sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
2913 conf->raid_disks);
2914 compute_parity6(sh, RECONSTRUCT_WRITE);
2915 for (i = conf->raid_disks ; i-- ; ) {
2916 set_bit(R5_LOCKED, &sh->dev[i].flags);
a4456856 2917 s.locked++;
f416885e
N		 2918 set_bit(R5_Wantwrite, &sh->dev[i].flags);
2919 }
2920 clear_bit(STRIPE_EXPANDING, &sh->state);
a4456856 2921 } else if (s.expanded) {
f416885e
N		 2922 clear_bit(STRIPE_EXPAND_READY, &sh->state);
2923 atomic_dec(&conf->reshape_stripes);
2924 wake_up(&conf->wait_for_overlap);
2925 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
2926 }
2927
a4456856
DW		 2928 if (s.expanding && s.locked == 0)
2929 handle_stripe_expansion(conf, sh, &r6s);
f416885e 2930
16a53ecc
N		 2931 spin_unlock(&sh->lock);
2932
a4456856 2933 return_io(return_bi);
16a53ecc 2934
16a53ecc
N		 2935 for (i=disks; i-- ;) {
2936 int rw;
2937 struct bio *bi;
2938 mdk_rdev_t *rdev;
2939 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
802ba064 2940 rw = WRITE;
16a53ecc 2941 else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
802ba064 2942 rw = READ;
16a53ecc
N		 2943 else
2944 continue;
2945
2946 bi = &sh->dev[i].req;
2947
2948 bi->bi_rw = rw;
802ba064 2949 if (rw == WRITE)
16a53ecc
N		 2950 bi->bi_end_io = raid5_end_write_request;
2951 else
2952 bi->bi_end_io = raid5_end_read_request;
2953
2954 rcu_read_lock();
2955 rdev = rcu_dereference(conf->disks[i].rdev);
2956 if (rdev && test_bit(Faulty, &rdev->flags))
2957 rdev = NULL;
2958 if (rdev)
2959 atomic_inc(&rdev->nr_pending);
2960 rcu_read_unlock();
2961
2962 if (rdev) {
a4456856 2963 if (s.syncing || s.expanding || s.expanded)
16a53ecc
N		 2964 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
2965
2966 bi->bi_bdev = rdev->bdev;
45b4233c 2967 pr_debug("for %llu schedule op %ld on disc %d\n",
16a53ecc
N		 2968 (unsigned long long)sh->sector, bi->bi_rw, i);
2969 atomic_inc(&sh->count);
2970 bi->bi_sector = sh->sector + rdev->data_offset;
2971 bi->bi_flags = 1 << BIO_UPTODATE;
2972 bi->bi_vcnt = 1;
2973 bi->bi_max_vecs = 1;
2974 bi->bi_idx = 0;
2975 bi->bi_io_vec = &sh->dev[i].vec;
2976 bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
2977 bi->bi_io_vec[0].bv_offset = 0;
2978 bi->bi_size = STRIPE_SIZE;
2979 bi->bi_next = NULL;
2980 if (rw == WRITE &&
2981 test_bit(R5_ReWrite, &sh->dev[i].flags))
2982 atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
2983 generic_make_request(bi);
2984 } else {
802ba064 2985 if (rw == WRITE)
16a53ecc 2986 set_bit(STRIPE_DEGRADED, &sh->state);
45b4233c 2987 pr_debug("skip op %ld on disc %d for sector %llu\n",
16a53ecc
N		 2988 bi->bi_rw, i, (unsigned long long)sh->sector);
2989 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2990 set_bit(STRIPE_HANDLE, &sh->state);
2991 }
2992 }
2993}
2994
2995static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
2996{
2997 if (sh->raid_conf->level == 6)
2998 handle_stripe6(sh, tmp_page);
2999 else
3000 handle_stripe5(sh);
3001}
3002
3003
3004
3005static void raid5_activate_delayed(raid5_conf_t *conf)
3006{
3007 if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
3008 while (!list_empty(&conf->delayed_list)) {
3009 struct list_head *l = conf->delayed_list.next;
3010 struct stripe_head *sh;
3011 sh = list_entry(l, struct stripe_head, lru);
3012 list_del_init(l);
3013 clear_bit(STRIPE_DELAYED, &sh->state);
3014 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3015 atomic_inc(&conf->preread_active_stripes);
3016 list_add_tail(&sh->lru, &conf->handle_list);
3017 }
3018 }
3019}
3020
3021static void activate_bit_delay(raid5_conf_t *conf)
3022{
3023 /* device_lock is held */
3024 struct list_head head;
3025 list_add(&head, &conf->bitmap_list);
3026 list_del_init(&conf->bitmap_list);
3027 while (!list_empty(&head)) {
3028 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
3029 list_del_init(&sh->lru);
3030 atomic_inc(&sh->count);
3031 __release_stripe(conf, sh);
3032 }
3033}
3034
3035static void unplug_slaves(mddev_t *mddev)
3036{
3037 raid5_conf_t *conf = mddev_to_conf(mddev);
3038 int i;
3039
3040 rcu_read_lock();
3041 for (i=0; i<mddev->raid_disks; i++) {
3042 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
3043 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
3044 request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
3045
3046 atomic_inc(&rdev->nr_pending);
3047 rcu_read_unlock();
3048
3049 if (r_queue->unplug_fn)
3050 r_queue->unplug_fn(r_queue);
3051
3052 rdev_dec_pending(rdev, mddev);
3053 rcu_read_lock();
3054 }
3055 }
3056 rcu_read_unlock();
3057}
3058
3059static void raid5_unplug_device(request_queue_t *q)
3060{
3061 mddev_t *mddev = q->queuedata;
3062 raid5_conf_t *conf = mddev_to_conf(mddev);
3063 unsigned long flags;
3064
3065 spin_lock_irqsave(&conf->device_lock, flags);
3066
3067 if (blk_remove_plug(q)) {
3068 conf->seq_flush++;
3069 raid5_activate_delayed(conf);
72626685 3070 }
1da177e4
LT		 3071 md_wakeup_thread(mddev->thread);
3072
3073 spin_unlock_irqrestore(&conf->device_lock, flags);
3074
3075 unplug_slaves(mddev);
3076}
3077
3078static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk,
3079 sector_t *error_sector)
3080{
3081 mddev_t *mddev = q->queuedata;
3082 raid5_conf_t *conf = mddev_to_conf(mddev);
3083 int i, ret = 0;
3084
3085 rcu_read_lock();
3086 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
d6065f7b 3087 mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
b2d444d7 3088 if (rdev && !test_bit(Faulty, &rdev->flags)) {
1da177e4
LT		 3089 struct block_device *bdev = rdev->bdev;
3090 request_queue_t *r_queue = bdev_get_queue(bdev);
3091
3092 if (!r_queue->issue_flush_fn)
3093 ret = -EOPNOTSUPP;
3094 else {
3095 atomic_inc(&rdev->nr_pending);
3096 rcu_read_unlock();
3097 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
3098 error_sector);
3099 rdev_dec_pending(rdev, mddev);
3100 rcu_read_lock();
3101 }
3102 }
3103 }
3104 rcu_read_unlock();
3105 return ret;
3106}
3107
f022b2fd
N		 3108static int raid5_congested(void *data, int bits)
3109{
3110 mddev_t *mddev = data;
3111 raid5_conf_t *conf = mddev_to_conf(mddev);
3112
3113 /* No difference between reads and writes. Just check
3114 * how busy the stripe_cache is
3115 */
3116 if (conf->inactive_blocked)
3117 return 1;
3118 if (conf->quiesce)
3119 return 1;
3120 if (list_empty_careful(&conf->inactive_list))
3121 return 1;
3122
3123 return 0;
3124}
3125
23032a0e
RBJ		 3126/* We want read requests to align with chunks where possible,
3127 * but write requests don't need to.
3128 */
3129static int raid5_mergeable_bvec(request_queue_t *q, struct bio *bio, struct bio_vec *biovec)
3130{
3131 mddev_t *mddev = q->queuedata;
3132 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3133 int max;
3134 unsigned int chunk_sectors = mddev->chunk_size >> 9;
3135 unsigned int bio_sectors = bio->bi_size >> 9;
3136
802ba064 3137 if (bio_data_dir(bio) == WRITE)
23032a0e
RBJ		 3138 return biovec->bv_len; /* always allow writes to be mergeable */
3139
3140 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
3141 if (max < 0) max = 0;
3142 if (max <= biovec->bv_len && bio_sectors == 0)
3143 return biovec->bv_len;
3144 else
3145 return max;
3146}
3147
f679623f
RBJ		 3148
3149static int in_chunk_boundary(mddev_t *mddev, struct bio *bio)
3150{
3151 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3152 unsigned int chunk_sectors = mddev->chunk_size >> 9;
3153 unsigned int bio_sectors = bio->bi_size >> 9;
3154
3155 return chunk_sectors >=
3156 ((sector & (chunk_sectors - 1)) + bio_sectors);
3157}
3158
46031f9a
RBJ		 3159/*
3160 * add bio to the retry LIFO ( in O(1) ... we are in interrupt )
3161 * later sampled by raid5d.
3162 */
3163static void add_bio_to_retry(struct bio *bi,raid5_conf_t *conf)
3164{
3165 unsigned long flags;
3166
3167 spin_lock_irqsave(&conf->device_lock, flags);
3168
3169 bi->bi_next = conf->retry_read_aligned_list;
3170 conf->retry_read_aligned_list = bi;
3171
3172 spin_unlock_irqrestore(&conf->device_lock, flags);
3173 md_wakeup_thread(conf->mddev->thread);
3174}
3175
3176
3177static struct bio *remove_bio_from_retry(raid5_conf_t *conf)
3178{
3179 struct bio *bi;
3180
3181 bi = conf->retry_read_aligned;
3182 if (bi) {
3183 conf->retry_read_aligned = NULL;
3184 return bi;
3185 }
3186 bi = conf->retry_read_aligned_list;
3187 if(bi) {
387bb173 3188 conf->retry_read_aligned_list = bi->bi_next;
46031f9a
RBJ		 3189 bi->bi_next = NULL;
3190 bi->bi_phys_segments = 1; /* biased count of active stripes */
3191 bi->bi_hw_segments = 0; /* count of processed stripes */
3192 }
3193
3194 return bi;
3195}
3196
3197
f679623f
RBJ		 3198/*
3199 * The "raid5_align_endio" should check if the read succeeded and if it
3200 * did, call bio_endio on the original bio (having bio_put the new bio
3201 * first).
3202 * If the read failed..
3203 */
46031f9a 3204static int raid5_align_endio(struct bio *bi, unsigned int bytes, int error)
f679623f
RBJ		 3205{
3206 struct bio* raid_bi = bi->bi_private;
46031f9a
RBJ		 3207 mddev_t *mddev;
3208 raid5_conf_t *conf;
3209 int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
3210 mdk_rdev_t *rdev;
3211
f679623f
RBJ		 3212 if (bi->bi_size)
3213 return 1;
3214 bio_put(bi);
46031f9a
RBJ		 3215
3216 mddev = raid_bi->bi_bdev->bd_disk->queue->queuedata;
3217 conf = mddev_to_conf(mddev);
3218 rdev = (void*)raid_bi->bi_next;
3219 raid_bi->bi_next = NULL;
3220
3221 rdev_dec_pending(rdev, conf->mddev);
3222
3223 if (!error && uptodate) {
3224 bio_endio(raid_bi, bytes, 0);
3225 if (atomic_dec_and_test(&conf->active_aligned_reads))
3226 wake_up(&conf->wait_for_stripe);
3227 return 0;
3228 }
3229
3230
45b4233c 3231 pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
46031f9a
RBJ		 3232
3233 add_bio_to_retry(raid_bi, conf);
f679623f
RBJ		 3234 return 0;
3235}
3236
387bb173
NB		 3237static int bio_fits_rdev(struct bio *bi)
3238{
3239 request_queue_t *q = bdev_get_queue(bi->bi_bdev);
3240
3241 if ((bi->bi_size>>9) > q->max_sectors)
3242 return 0;
3243 blk_recount_segments(q, bi);
3244 if (bi->bi_phys_segments > q->max_phys_segments ||
3245 bi->bi_hw_segments > q->max_hw_segments)
3246 return 0;
3247
3248 if (q->merge_bvec_fn)
3249 /* it's too hard to apply the merge_bvec_fn at this stage,
3250 * just just give up
3251 */
3252 return 0;
3253
3254 return 1;
3255}
3256
3257
f679623f
RBJ		 3258static int chunk_aligned_read(request_queue_t *q, struct bio * raid_bio)
3259{
3260 mddev_t *mddev = q->queuedata;
3261 raid5_conf_t *conf = mddev_to_conf(mddev);
3262 const unsigned int raid_disks = conf->raid_disks;
46031f9a 3263 const unsigned int data_disks = raid_disks - conf->max_degraded;
f679623f
RBJ		 3264 unsigned int dd_idx, pd_idx;
3265 struct bio* align_bi;
3266 mdk_rdev_t *rdev;
3267
3268 if (!in_chunk_boundary(mddev, raid_bio)) {
45b4233c 3269 pr_debug("chunk_aligned_read : non aligned\n");
f679623f
RBJ		 3270 return 0;
3271 }
3272 /*
3273 * use bio_clone to make a copy of the bio
3274 */
3275 align_bi = bio_clone(raid_bio, GFP_NOIO);
3276 if (!align_bi)
3277 return 0;
3278 /*
3279 * set bi_end_io to a new function, and set bi_private to the
3280 * original bio.
3281 */
3282 align_bi->bi_end_io = raid5_align_endio;
3283 align_bi->bi_private = raid_bio;
3284 /*
3285 * compute position
3286 */
3287 align_bi->bi_sector = raid5_compute_sector(raid_bio->bi_sector,
3288 raid_disks,
3289 data_disks,
3290 &dd_idx,
3291 &pd_idx,
3292 conf);
3293
3294 rcu_read_lock();
3295 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
3296 if (rdev && test_bit(In_sync, &rdev->flags)) {
f679623f
RBJ		 3297 atomic_inc(&rdev->nr_pending);
3298 rcu_read_unlock();
46031f9a
RBJ		 3299 raid_bio->bi_next = (void*)rdev;
3300 align_bi->bi_bdev = rdev->bdev;
3301 align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);
3302 align_bi->bi_sector += rdev->data_offset;
3303
387bb173
NB		 3304 if (!bio_fits_rdev(align_bi)) {
3305 /* too big in some way */
3306 bio_put(align_bi);
3307 rdev_dec_pending(rdev, mddev);
3308 return 0;
3309 }
3310
46031f9a
RBJ		 3311 spin_lock_irq(&conf->device_lock);
3312 wait_event_lock_irq(conf->wait_for_stripe,
3313 conf->quiesce == 0,
3314 conf->device_lock, /* nothing */);
3315 atomic_inc(&conf->active_aligned_reads);
3316 spin_unlock_irq(&conf->device_lock);
3317
f679623f
RBJ		 3318 generic_make_request(align_bi);
3319 return 1;
3320 } else {
3321 rcu_read_unlock();
46031f9a 3322 bio_put(align_bi);
f679623f
RBJ		 3323 return 0;
3324 }
3325}
3326
3327
7ecaa1e6 3328static int make_request(request_queue_t *q, struct bio * bi)
1da177e4
LT		 3329{
3330 mddev_t *mddev = q->queuedata;
3331 raid5_conf_t *conf = mddev_to_conf(mddev);
1da177e4
LT		 3332 unsigned int dd_idx, pd_idx;
3333 sector_t new_sector;
3334 sector_t logical_sector, last_sector;
3335 struct stripe_head *sh;
a362357b 3336 const int rw = bio_data_dir(bi);
f6344757 3337 int remaining;
1da177e4 3338
e5dcdd80
N		 3339 if (unlikely(bio_barrier(bi))) {
3340 bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
3341 return 0;
3342 }
3343
3d310eb7 3344 md_write_start(mddev, bi);
06d91a5f 3345
a362357b
JA		 3346 disk_stat_inc(mddev->gendisk, ios[rw]);
3347 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
1da177e4 3348
802ba064 3349 if (rw == READ &&
52488615
RBJ		 3350 mddev->reshape_position == MaxSector &&
3351 chunk_aligned_read(q,bi))
3352 return 0;
3353
1da177e4
LT		 3354 logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
3355 last_sector = bi->bi_sector + (bi->bi_size>>9);
3356 bi->bi_next = NULL;
3357 bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
06d91a5f 3358
1da177e4
LT		 3359 for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
3360 DEFINE_WAIT(w);
16a53ecc 3361 int disks, data_disks;
b578d55f 3362
7ecaa1e6 3363 retry:
b578d55f 3364 prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
7ecaa1e6
N		 3365 if (likely(conf->expand_progress == MaxSector))
3366 disks = conf->raid_disks;
3367 else {
df8e7f76
N		 3368 /* spinlock is needed as expand_progress may be
3369 * 64bit on a 32bit platform, and so it might be
3370 * possible to see a half-updated value
3371 * Ofcourse expand_progress could change after
3372 * the lock is dropped, so once we get a reference
3373 * to the stripe that we think it is, we will have
3374 * to check again.
3375 */
7ecaa1e6
N		 3376 spin_lock_irq(&conf->device_lock);
3377 disks = conf->raid_disks;
3378 if (logical_sector >= conf->expand_progress)
3379 disks = conf->previous_raid_disks;
b578d55f
N		 3380 else {
3381 if (logical_sector >= conf->expand_lo) {
3382 spin_unlock_irq(&conf->device_lock);
3383 schedule();
3384 goto retry;
3385 }
3386 }
7ecaa1e6
N		 3387 spin_unlock_irq(&conf->device_lock);
3388 }
16a53ecc
N		 3389 data_disks = disks - conf->max_degraded;
3390
3391 new_sector = raid5_compute_sector(logical_sector, disks, data_disks,
7ecaa1e6 3392 &dd_idx, &pd_idx, conf);
45b4233c 3393 pr_debug("raid5: make_request, sector %llu logical %llu\n",
1da177e4
LT		 3394 (unsigned long long)new_sector,
3395 (unsigned long long)logical_sector);
3396
7ecaa1e6 3397 sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK));
1da177e4 3398 if (sh) {
7ecaa1e6
N		 3399 if (unlikely(conf->expand_progress != MaxSector)) {
3400 /* expansion might have moved on while waiting for a
df8e7f76
N		 3401 * stripe, so we must do the range check again.
3402 * Expansion could still move past after this
3403 * test, but as we are holding a reference to
3404 * 'sh', we know that if that happens,
3405 * STRIPE_EXPANDING will get set and the expansion
3406 * won't proceed until we finish with the stripe.
7ecaa1e6
N		 3407 */
3408 int must_retry = 0;
3409 spin_lock_irq(&conf->device_lock);
3410 if (logical_sector < conf->expand_progress &&
3411 disks == conf->previous_raid_disks)
3412 /* mismatch, need to try again */
3413 must_retry = 1;
3414 spin_unlock_irq(&conf->device_lock);
3415 if (must_retry) {
3416 release_stripe(sh);
3417 goto retry;
3418 }
3419 }
e464eafd
N		 3420 /* FIXME what if we get a false positive because these
3421 * are being updated.
3422 */
3423 if (logical_sector >= mddev->suspend_lo &&
3424 logical_sector < mddev->suspend_hi) {
3425 release_stripe(sh);
3426 schedule();
3427 goto retry;
3428 }
7ecaa1e6
N		 3429
3430 if (test_bit(STRIPE_EXPANDING, &sh->state) ||
3431 !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
3432 /* Stripe is busy expanding or
3433 * add failed due to overlap. Flush everything
1da177e4
LT		 3434 * and wait a while
3435 */
3436 raid5_unplug_device(mddev->queue);
3437 release_stripe(sh);
3438 schedule();
3439 goto retry;
3440 }
3441 finish_wait(&conf->wait_for_overlap, &w);
16a53ecc 3442 handle_stripe(sh, NULL);
1da177e4 3443 release_stripe(sh);
1da177e4
LT		 3444 } else {
3445 /* cannot get stripe for read-ahead, just give-up */
3446 clear_bit(BIO_UPTODATE, &bi->bi_flags);
3447 finish_wait(&conf->wait_for_overlap, &w);
3448 break;
3449 }
3450
3451 }
3452 spin_lock_irq(&conf->device_lock);
f6344757
N		 3453 remaining = --bi->bi_phys_segments;
3454 spin_unlock_irq(&conf->device_lock);
3455 if (remaining == 0) {
1da177e4
LT		 3456 int bytes = bi->bi_size;
3457
16a53ecc 3458 if ( rw == WRITE )
1da177e4
LT		 3459 md_write_end(mddev);
3460 bi->bi_size = 0;
c2b00852
N		 3461 bi->bi_end_io(bi, bytes,
3462 test_bit(BIO_UPTODATE, &bi->bi_flags)
3463 ? 0 : -EIO);
1da177e4 3464 }
1da177e4
LT		 3465 return 0;
3466}
3467
52c03291 3468static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped)
1da177e4 3469{
52c03291
N		 3470 /* reshaping is quite different to recovery/resync so it is
3471 * handled quite separately ... here.
3472 *
3473 * On each call to sync_request, we gather one chunk worth of
3474 * destination stripes and flag them as expanding.
3475 * Then we find all the source stripes and request reads.
3476 * As the reads complete, handle_stripe will copy the data
3477 * into the destination stripe and release that stripe.
3478 */
1da177e4
LT		 3479 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
3480 struct stripe_head *sh;
ccfcc3c1
N		 3481 int pd_idx;
3482 sector_t first_sector, last_sector;
f416885e
N		 3483 int raid_disks = conf->previous_raid_disks;
3484 int data_disks = raid_disks - conf->max_degraded;
3485 int new_data_disks = conf->raid_disks - conf->max_degraded;
52c03291
N		 3486 int i;
3487 int dd_idx;
3488 sector_t writepos, safepos, gap;
3489
3490 if (sector_nr == 0 &&
3491 conf->expand_progress != 0) {
3492 /* restarting in the middle, skip the initial sectors */
3493 sector_nr = conf->expand_progress;
f416885e 3494 sector_div(sector_nr, new_data_disks);
52c03291
N		 3495 *skipped = 1;
3496 return sector_nr;
3497 }
3498
3499 /* we update the metadata when there is more than 3Meg
3500 * in the block range (that is rather arbitrary, should
3501 * probably be time based) or when the data about to be
3502 * copied would over-write the source of the data at
3503 * the front of the range.
3504 * i.e. one new_stripe forward from expand_progress new_maps
3505 * to after where expand_lo old_maps to
3506 */
3507 writepos = conf->expand_progress +
f416885e
N		 3508 conf->chunk_size/512*(new_data_disks);
3509 sector_div(writepos, new_data_disks);
52c03291 3510 safepos = conf->expand_lo;
f416885e 3511 sector_div(safepos, data_disks);
52c03291
N		 3512 gap = conf->expand_progress - conf->expand_lo;
3513
3514 if (writepos >= safepos ||
f416885e 3515 gap > (new_data_disks)*3000*2 /*3Meg*/) {
52c03291
N		 3516 /* Cannot proceed until we've updated the superblock... */
3517 wait_event(conf->wait_for_overlap,
3518 atomic_read(&conf->reshape_stripes)==0);
3519 mddev->reshape_position = conf->expand_progress;
850b2b42 3520 set_bit(MD_CHANGE_DEVS, &mddev->flags);
52c03291 3521 md_wakeup_thread(mddev->thread);
850b2b42 3522 wait_event(mddev->sb_wait, mddev->flags == 0 ||
52c03291
N		 3523 kthread_should_stop());
3524 spin_lock_irq(&conf->device_lock);
3525 conf->expand_lo = mddev->reshape_position;
3526 spin_unlock_irq(&conf->device_lock);
3527 wake_up(&conf->wait_for_overlap);
3528 }
3529
3530 for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) {
3531 int j;
3532 int skipped = 0;
3533 pd_idx = stripe_to_pdidx(sector_nr+i, conf, conf->raid_disks);
3534 sh = get_active_stripe(conf, sector_nr+i,
3535 conf->raid_disks, pd_idx, 0);
3536 set_bit(STRIPE_EXPANDING, &sh->state);
3537 atomic_inc(&conf->reshape_stripes);
3538 /* If any of this stripe is beyond the end of the old
3539 * array, then we need to zero those blocks
3540 */
3541 for (j=sh->disks; j--;) {
3542 sector_t s;
3543 if (j == sh->pd_idx)
3544 continue;
f416885e
N		 3545 if (conf->level == 6 &&
3546 j == raid6_next_disk(sh->pd_idx, sh->disks))
3547 continue;
52c03291
N		 3548 s = compute_blocknr(sh, j);
3549 if (s < (mddev->array_size<<1)) {
3550 skipped = 1;
3551 continue;
3552 }
3553 memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
3554 set_bit(R5_Expanded, &sh->dev[j].flags);
3555 set_bit(R5_UPTODATE, &sh->dev[j].flags);
3556 }
3557 if (!skipped) {
3558 set_bit(STRIPE_EXPAND_READY, &sh->state);
3559 set_bit(STRIPE_HANDLE, &sh->state);
3560 }
3561 release_stripe(sh);
3562 }
3563 spin_lock_irq(&conf->device_lock);
6d3baf2e 3564 conf->expand_progress = (sector_nr + i) * new_data_disks;
52c03291
N		 3565 spin_unlock_irq(&conf->device_lock);
3566 /* Ok, those stripe are ready. We can start scheduling
3567 * reads on the source stripes.
3568 * The source stripes are determined by mapping the first and last
3569 * block on the destination stripes.
3570 */
52c03291 3571 first_sector =
f416885e 3572 raid5_compute_sector(sector_nr*(new_data_disks),
52c03291
N		 3573 raid_disks, data_disks,
3574 &dd_idx, &pd_idx, conf);
3575 last_sector =
3576 raid5_compute_sector((sector_nr+conf->chunk_size/512)
f416885e 3577 *(new_data_disks) -1,
52c03291
N		 3578 raid_disks, data_disks,
3579 &dd_idx, &pd_idx, conf);
3580 if (last_sector >= (mddev->size<<1))
3581 last_sector = (mddev->size<<1)-1;
3582 while (first_sector <= last_sector) {
f416885e
N		 3583 pd_idx = stripe_to_pdidx(first_sector, conf,
3584 conf->previous_raid_disks);
52c03291
N		 3585 sh = get_active_stripe(conf, first_sector,
3586 conf->previous_raid_disks, pd_idx, 0);
3587 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
3588 set_bit(STRIPE_HANDLE, &sh->state);
3589 release_stripe(sh);
3590 first_sector += STRIPE_SECTORS;
3591 }
3592 return conf->chunk_size>>9;
3593}
3594
3595/* FIXME go_faster isn't used */
3596static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
3597{
3598 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
3599 struct stripe_head *sh;
3600 int pd_idx;
1da177e4 3601 int raid_disks = conf->raid_disks;
72626685
N		 3602 sector_t max_sector = mddev->size << 1;
3603 int sync_blocks;
16a53ecc
N		 3604 int still_degraded = 0;
3605 int i;
1da177e4 3606
72626685 3607 if (sector_nr >= max_sector) {
1da177e4
LT		 3608 /* just being told to finish up .. nothing much to do */
3609 unplug_slaves(mddev);
29269553
N		 3610 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
3611 end_reshape(conf);
3612 return 0;
3613 }
72626685
N		 3614
3615 if (mddev->curr_resync < max_sector) /* aborted */
3616 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
3617 &sync_blocks, 1);
16a53ecc 3618 else /* completed sync */
72626685
N		 3619 conf->fullsync = 0;
3620 bitmap_close_sync(mddev->bitmap);
3621
1da177e4
LT		 3622 return 0;
3623 }
ccfcc3c1 3624
52c03291
N		 3625 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3626 return reshape_request(mddev, sector_nr, skipped);
f6705578 3627
16a53ecc 3628 /* if there is too many failed drives and we are trying
1da177e4
LT		 3629 * to resync, then assert that we are finished, because there is
3630 * nothing we can do.
3631 */
3285edf1 3632 if (mddev->degraded >= conf->max_degraded &&
16a53ecc 3633 test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
57afd89f
N		 3634 sector_t rv = (mddev->size << 1) - sector_nr;
3635 *skipped = 1;
1da177e4
LT		 3636 return rv;
3637 }
72626685 3638 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
3855ad9f 3639 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
72626685
N		 3640 !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
3641 /* we can skip this block, and probably more */
3642 sync_blocks /= STRIPE_SECTORS;
3643 *skipped = 1;
3644 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
3645 }
1da177e4 3646
ccfcc3c1 3647 pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks);
7ecaa1e6 3648 sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1);
1da177e4 3649 if (sh == NULL) {
7ecaa1e6 3650 sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0);
1da177e4 3651 /* make sure we don't swamp the stripe cache if someone else
16a53ecc 3652 * is trying to get access
1da177e4 3653 */
66c006a5 3654 schedule_timeout_uninterruptible(1);
1da177e4 3655 }
16a53ecc
N		 3656 /* Need to check if array will still be degraded after recovery/resync
3657 * We don't need to check the 'failed' flag as when that gets set,
3658 * recovery aborts.
3659 */
3660 for (i=0; i<mddev->raid_disks; i++)
3661 if (conf->disks[i].rdev == NULL)
3662 still_degraded = 1;
3663
3664 bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
3665
3666 spin_lock(&sh->lock);
1da177e4
LT		 3667 set_bit(STRIPE_SYNCING, &sh->state);
3668 clear_bit(STRIPE_INSYNC, &sh->state);
3669 spin_unlock(&sh->lock);
3670
16a53ecc 3671 handle_stripe(sh, NULL);
1da177e4
LT		 3672 release_stripe(sh);
3673
3674 return STRIPE_SECTORS;
3675}
3676
46031f9a
RBJ		 3677static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
3678{
3679 /* We may not be able to submit a whole bio at once as there
3680 * may not be enough stripe_heads available.
3681 * We cannot pre-allocate enough stripe_heads as we may need
3682 * more than exist in the cache (if we allow ever large chunks).
3683 * So we do one stripe head at a time and record in
3684 * ->bi_hw_segments how many have been done.
3685 *
3686 * We *know* that this entire raid_bio is in one chunk, so
3687 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
3688 */
3689 struct stripe_head *sh;
3690 int dd_idx, pd_idx;
3691 sector_t sector, logical_sector, last_sector;
3692 int scnt = 0;
3693 int remaining;
3694 int handled = 0;
3695
3696 logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
3697 sector = raid5_compute_sector( logical_sector,
3698 conf->raid_disks,
3699 conf->raid_disks - conf->max_degraded,
3700 &dd_idx,
3701 &pd_idx,
3702 conf);
3703 last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);
3704
3705 for (; logical_sector < last_sector;
387bb173
NB		 3706 logical_sector += STRIPE_SECTORS,
3707 sector += STRIPE_SECTORS,
3708 scnt++) {
46031f9a
RBJ		 3709
3710 if (scnt < raid_bio->bi_hw_segments)
3711 /* already done this stripe */
3712 continue;
3713
3714 sh = get_active_stripe(conf, sector, conf->raid_disks, pd_idx, 1);
3715
3716 if (!sh) {
3717 /* failed to get a stripe - must wait */
3718 raid_bio->bi_hw_segments = scnt;
3719 conf->retry_read_aligned = raid_bio;
3720 return handled;
3721 }
3722
3723 set_bit(R5_ReadError, &sh->dev[dd_idx].flags);
387bb173
NB		 3724 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
3725 release_stripe(sh);
3726 raid_bio->bi_hw_segments = scnt;
3727 conf->retry_read_aligned = raid_bio;
3728 return handled;
3729 }
3730
46031f9a
RBJ		 3731 handle_stripe(sh, NULL);
3732 release_stripe(sh);
3733 handled++;
3734 }
3735 spin_lock_irq(&conf->device_lock);
3736 remaining = --raid_bio->bi_phys_segments;
3737 spin_unlock_irq(&conf->device_lock);
3738 if (remaining == 0) {
3739 int bytes = raid_bio->bi_size;
3740
3741 raid_bio->bi_size = 0;
c2b00852
N		 3742 raid_bio->bi_end_io(raid_bio, bytes,
3743 test_bit(BIO_UPTODATE, &raid_bio->bi_flags)
3744 ? 0 : -EIO);
46031f9a
RBJ		 3745 }
3746 if (atomic_dec_and_test(&conf->active_aligned_reads))
3747 wake_up(&conf->wait_for_stripe);
3748 return handled;
3749}
3750
3751
3752
1da177e4
LT		 3753/*
3754 * This is our raid5 kernel thread.
3755 *
3756 * We scan the hash table for stripes which can be handled now.
3757 * During the scan, completed stripes are saved for us by the interrupt
3758 * handler, so that they will not have to wait for our next wakeup.
3759 */
3760static void raid5d (mddev_t *mddev)
3761{
3762 struct stripe_head *sh;
3763 raid5_conf_t *conf = mddev_to_conf(mddev);
3764 int handled;
3765
45b4233c 3766 pr_debug("+++ raid5d active\n");
1da177e4
LT		 3767
3768 md_check_recovery(mddev);
1da177e4
LT		 3769
3770 handled = 0;
3771 spin_lock_irq(&conf->device_lock);
3772 while (1) {
3773 struct list_head *first;
46031f9a 3774 struct bio *bio;
1da177e4 3775
ae3c20cc 3776 if (conf->seq_flush != conf->seq_write) {
72626685 3777 int seq = conf->seq_flush;
700e432d 3778 spin_unlock_irq(&conf->device_lock);
72626685 3779 bitmap_unplug(mddev->bitmap);
700e432d 3780 spin_lock_irq(&conf->device_lock);
72626685
N		 3781 conf->seq_write = seq;
3782 activate_bit_delay(conf);
3783 }
3784
1da177e4
LT		 3785 if (list_empty(&conf->handle_list) &&
3786 atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
3787 !blk_queue_plugged(mddev->queue) &&
3788 !list_empty(&conf->delayed_list))
3789 raid5_activate_delayed(conf);
3790
46031f9a
RBJ		 3791 while ((bio = remove_bio_from_retry(conf))) {
3792 int ok;
3793 spin_unlock_irq(&conf->device_lock);
3794 ok = retry_aligned_read(conf, bio);
3795 spin_lock_irq(&conf->device_lock);
3796 if (!ok)
3797 break;
3798 handled++;
3799 }
3800
1da177e4
LT		 3801 if (list_empty(&conf->handle_list))
3802 break;
3803
3804 first = conf->handle_list.next;
3805 sh = list_entry(first, struct stripe_head, lru);
3806
3807 list_del_init(first);
3808 atomic_inc(&sh->count);
78bafebd 3809 BUG_ON(atomic_read(&sh->count)!= 1);
1da177e4
LT		 3810 spin_unlock_irq(&conf->device_lock);
3811
3812 handled++;
16a53ecc 3813 handle_stripe(sh, conf->spare_page);
1da177e4
LT		 3814 release_stripe(sh);
3815
3816 spin_lock_irq(&conf->device_lock);
3817 }
45b4233c 3818 pr_debug("%d stripes handled\n", handled);
1da177e4
LT		 3819
3820 spin_unlock_irq(&conf->device_lock);
3821
3822 unplug_slaves(mddev);
3823
45b4233c 3824 pr_debug("--- raid5d inactive\n");
1da177e4
LT		 3825}
3826
3f294f4f 3827static ssize_t
007583c9 3828raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
3f294f4f 3829{
007583c9 3830 raid5_conf_t *conf = mddev_to_conf(mddev);
96de1e66
N		 3831 if (conf)
3832 return sprintf(page, "%d\n", conf->max_nr_stripes);
3833 else
3834 return 0;
3f294f4f
N		 3835}
3836
3837static ssize_t
007583c9 3838raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
3f294f4f 3839{
007583c9 3840 raid5_conf_t *conf = mddev_to_conf(mddev);
3f294f4f
N		 3841 char *end;
3842 int new;
3843 if (len >= PAGE_SIZE)
3844 return -EINVAL;
96de1e66
N		 3845 if (!conf)
3846 return -ENODEV;
3f294f4f
N		 3847
3848 new = simple_strtoul(page, &end, 10);
3849 if (!*page || (*end && *end != '\n') )
3850 return -EINVAL;
3851 if (new <= 16 || new > 32768)
3852 return -EINVAL;
3853 while (new < conf->max_nr_stripes) {
3854 if (drop_one_stripe(conf))
3855 conf->max_nr_stripes--;
3856 else
3857 break;
3858 }
2a2275d6 3859 md_allow_write(mddev);
3f294f4f
N		 3860 while (new > conf->max_nr_stripes) {
3861 if (grow_one_stripe(conf))
3862 conf->max_nr_stripes++;
3863 else break;
3864 }
3865 return len;
3866}
007583c9 3867
96de1e66
N		 3868static struct md_sysfs_entry
3869raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
3870 raid5_show_stripe_cache_size,
3871 raid5_store_stripe_cache_size);
3f294f4f
N		 3872
3873static ssize_t
96de1e66 3874stripe_cache_active_show(mddev_t *mddev, char *page)
3f294f4f 3875{
007583c9 3876 raid5_conf_t *conf = mddev_to_conf(mddev);
96de1e66
N		 3877 if (conf)
3878 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
3879 else
3880 return 0;
3f294f4f
N		 3881}
3882
96de1e66
N		 3883static struct md_sysfs_entry
3884raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
3f294f4f 3885
007583c9 3886static struct attribute *raid5_attrs[] = {
3f294f4f
N		 3887 &raid5_stripecache_size.attr,
3888 &raid5_stripecache_active.attr,
3889 NULL,
3890};
007583c9
N		 3891static struct attribute_group raid5_attrs_group = {
3892 .name = NULL,
3893 .attrs = raid5_attrs,
3f294f4f
N		 3894};
3895
72626685 3896static int run(mddev_t *mddev)
1da177e4
LT		 3897{
3898 raid5_conf_t *conf;
3899 int raid_disk, memory;
3900 mdk_rdev_t *rdev;
3901 struct disk_info *disk;
3902 struct list_head *tmp;
02c2de8c 3903 int working_disks = 0;
1da177e4 3904
16a53ecc
N		 3905 if (mddev->level != 5 && mddev->level != 4 && mddev->level != 6) {
3906 printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n",
14f8d26b 3907 mdname(mddev), mddev->level);
1da177e4
LT		 3908 return -EIO;
3909 }
3910
f6705578
N		 3911 if (mddev->reshape_position != MaxSector) {
3912 /* Check that we can continue the reshape.
3913 * Currently only disks can change, it must
3914 * increase, and we must be past the point where
3915 * a stripe over-writes itself
3916 */
3917 sector_t here_new, here_old;
3918 int old_disks;
f416885e 3919 int max_degraded = (mddev->level == 5 ? 1 : 2);
f6705578
N		 3920
3921 if (mddev->new_level != mddev->level ||
3922 mddev->new_layout != mddev->layout ||
3923 mddev->new_chunk != mddev->chunk_size) {
f416885e
N		 3924 printk(KERN_ERR "raid5: %s: unsupported reshape "
3925 "required - aborting.\n",
f6705578
N		 3926 mdname(mddev));
3927 return -EINVAL;
3928 }
3929 if (mddev->delta_disks <= 0) {
f416885e
N		 3930 printk(KERN_ERR "raid5: %s: unsupported reshape "
3931 "(reduce disks) required - aborting.\n",
f6705578
N		 3932 mdname(mddev));
3933 return -EINVAL;
3934 }
3935 old_disks = mddev->raid_disks - mddev->delta_disks;
3936 /* reshape_position must be on a new-stripe boundary, and one
f416885e
N		 3937 * further up in new geometry must map after here in old
3938 * geometry.
f6705578
N		 3939 */
3940 here_new = mddev->reshape_position;
f416885e
N		 3941 if (sector_div(here_new, (mddev->chunk_size>>9)*
3942 (mddev->raid_disks - max_degraded))) {
3943 printk(KERN_ERR "raid5: reshape_position not "
3944 "on a stripe boundary\n");
f6705578
N		 3945 return -EINVAL;
3946 }
3947 /* here_new is the stripe we will write to */
3948 here_old = mddev->reshape_position;
f416885e
N		 3949 sector_div(here_old, (mddev->chunk_size>>9)*
3950 (old_disks-max_degraded));
3951 /* here_old is the first stripe that we might need to read
3952 * from */
f6705578
N		 3953 if (here_new >= here_old) {
3954 /* Reading from the same stripe as writing to - bad */
f416885e
N		 3955 printk(KERN_ERR "raid5: reshape_position too early for "
3956 "auto-recovery - aborting.\n");
f6705578
N		 3957 return -EINVAL;
3958 }
3959 printk(KERN_INFO "raid5: reshape will continue\n");
3960 /* OK, we should be able to continue; */
3961 }
3962
3963
b55e6bfc 3964 mddev->private = kzalloc(sizeof (raid5_conf_t), GFP_KERNEL);
1da177e4
LT		 3965 if ((conf = mddev->private) == NULL)
3966 goto abort;
f6705578
N		 3967 if (mddev->reshape_position == MaxSector) {
3968 conf->previous_raid_disks = conf->raid_disks = mddev->raid_disks;
3969 } else {
3970 conf->raid_disks = mddev->raid_disks;
3971 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
3972 }
3973
3974 conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info),
b55e6bfc
N		 3975 GFP_KERNEL);
3976 if (!conf->disks)
3977 goto abort;
9ffae0cf 3978
1da177e4
LT		 3979 conf->mddev = mddev;
3980
fccddba0 3981 if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
1da177e4 3982 goto abort;
1da177e4 3983
16a53ecc
N		 3984 if (mddev->level == 6) {
3985 conf->spare_page = alloc_page(GFP_KERNEL);
3986 if (!conf->spare_page)
3987 goto abort;
3988 }
1da177e4
LT		 3989 spin_lock_init(&conf->device_lock);
3990 init_waitqueue_head(&conf->wait_for_stripe);
3991 init_waitqueue_head(&conf->wait_for_overlap);
3992 INIT_LIST_HEAD(&conf->handle_list);
3993 INIT_LIST_HEAD(&conf->delayed_list);
72626685 3994 INIT_LIST_HEAD(&conf->bitmap_list);
1da177e4
LT		 3995 INIT_LIST_HEAD(&conf->inactive_list);
3996 atomic_set(&conf->active_stripes, 0);
3997 atomic_set(&conf->preread_active_stripes, 0);
46031f9a 3998 atomic_set(&conf->active_aligned_reads, 0);
1da177e4 3999
45b4233c 4000 pr_debug("raid5: run(%s) called.\n", mdname(mddev));
1da177e4
LT		 4001
4002 ITERATE_RDEV(mddev,rdev,tmp) {
4003 raid_disk = rdev->raid_disk;
f6705578 4004 if (raid_disk >= conf->raid_disks
1da177e4
LT		 4005 || raid_disk < 0)
4006 continue;
4007 disk = conf->disks + raid_disk;
4008
4009 disk->rdev = rdev;
4010
b2d444d7 4011 if (test_bit(In_sync, &rdev->flags)) {
1da177e4
LT		 4012 char b[BDEVNAME_SIZE];
4013 printk(KERN_INFO "raid5: device %s operational as raid"
4014 " disk %d\n", bdevname(rdev->bdev,b),
4015 raid_disk);
02c2de8c 4016 working_disks++;
1da177e4
LT		 4017 }
4018 }
4019
1da177e4 4020 /*
16a53ecc 4021 * 0 for a fully functional array, 1 or 2 for a degraded array.
1da177e4 4022 */
02c2de8c 4023 mddev->degraded = conf->raid_disks - working_disks;
1da177e4
LT		 4024 conf->mddev = mddev;
4025 conf->chunk_size = mddev->chunk_size;
4026 conf->level = mddev->level;
16a53ecc
N		 4027 if (conf->level == 6)
4028 conf->max_degraded = 2;
4029 else
4030 conf->max_degraded = 1;
1da177e4
LT		 4031 conf->algorithm = mddev->layout;
4032 conf->max_nr_stripes = NR_STRIPES;
f6705578 4033 conf->expand_progress = mddev->reshape_position;
1da177e4
LT		 4034
4035 /* device size must be a multiple of chunk size */
4036 mddev->size &= ~(mddev->chunk_size/1024 -1);
b1581566 4037 mddev->resync_max_sectors = mddev->size << 1;
1da177e4 4038
16a53ecc
N		 4039 if (conf->level == 6 && conf->raid_disks < 4) {
4040 printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
4041 mdname(mddev), conf->raid_disks);
4042 goto abort;
4043 }
1da177e4
LT		 4044 if (!conf->chunk_size || conf->chunk_size % 4) {
4045 printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
4046 conf->chunk_size, mdname(mddev));
4047 goto abort;
4048 }
4049 if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) {
4050 printk(KERN_ERR
4051 "raid5: unsupported parity algorithm %d for %s\n",
4052 conf->algorithm, mdname(mddev));
4053 goto abort;
4054 }
16a53ecc 4055 if (mddev->degraded > conf->max_degraded) {
1da177e4
LT		 4056 printk(KERN_ERR "raid5: not enough operational devices for %s"
4057 " (%d/%d failed)\n",
02c2de8c 4058 mdname(mddev), mddev->degraded, conf->raid_disks);
1da177e4
LT		 4059 goto abort;
4060 }
4061
16a53ecc 4062 if (mddev->degraded > 0 &&
1da177e4 4063 mddev->recovery_cp != MaxSector) {
6ff8d8ec
N		 4064 if (mddev->ok_start_degraded)
4065 printk(KERN_WARNING
4066 "raid5: starting dirty degraded array: %s"
4067 "- data corruption possible.\n",
4068 mdname(mddev));
4069 else {
4070 printk(KERN_ERR
4071 "raid5: cannot start dirty degraded array for %s\n",
4072 mdname(mddev));
4073 goto abort;
4074 }
1da177e4
LT		 4075 }
4076
4077 {
4078 mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5");
4079 if (!mddev->thread) {
4080 printk(KERN_ERR
4081 "raid5: couldn't allocate thread for %s\n",
4082 mdname(mddev));
4083 goto abort;
4084 }
4085 }
5036805b 4086 memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
1da177e4
LT		 4087 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
4088 if (grow_stripes(conf, conf->max_nr_stripes)) {
4089 printk(KERN_ERR
4090 "raid5: couldn't allocate %dkB for buffers\n", memory);
4091 shrink_stripes(conf);
4092 md_unregister_thread(mddev->thread);
4093 goto abort;
4094 } else
4095 printk(KERN_INFO "raid5: allocated %dkB for %s\n",
4096 memory, mdname(mddev));
4097
4098 if (mddev->degraded == 0)
4099 printk("raid5: raid level %d set %s active with %d out of %d"
4100 " devices, algorithm %d\n", conf->level, mdname(mddev),
4101 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
4102 conf->algorithm);
4103 else
4104 printk(KERN_ALERT "raid5: raid level %d set %s active with %d"
4105 " out of %d devices, algorithm %d\n", conf->level,
4106 mdname(mddev), mddev->raid_disks - mddev->degraded,
4107 mddev->raid_disks, conf->algorithm);
4108
4109 print_raid5_conf(conf);
4110
f6705578
N		 4111 if (conf->expand_progress != MaxSector) {
4112 printk("...ok start reshape thread\n");
b578d55f 4113 conf->expand_lo = conf->expand_progress;
f6705578
N		 4114 atomic_set(&conf->reshape_stripes, 0);
4115 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4116 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4117 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4118 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4119 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4120 "%s_reshape");
f6705578
N		 4121 }
4122
1da177e4 4123 /* read-ahead size must cover two whole stripes, which is
16a53ecc 4124 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
1da177e4
LT		 4125 */
4126 {
16a53ecc
N		 4127 int data_disks = conf->previous_raid_disks - conf->max_degraded;
4128 int stripe = data_disks *
8932c2e0 4129 (mddev->chunk_size / PAGE_SIZE);
1da177e4
LT		 4130 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
4131 mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
4132 }
4133
4134 /* Ok, everything is just fine now */
5e55e2f5
N		 4135 if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
4136 printk(KERN_WARNING
4137 "raid5: failed to create sysfs attributes for %s\n",
4138 mdname(mddev));
7a5febe9
N		 4139
4140 mddev->queue->unplug_fn = raid5_unplug_device;
4141 mddev->queue->issue_flush_fn = raid5_issue_flush;
f022b2fd 4142 mddev->queue->backing_dev_info.congested_data = mddev;
041ae52e 4143 mddev->queue->backing_dev_info.congested_fn = raid5_congested;
f022b2fd 4144
16a53ecc
N		 4145 mddev->array_size = mddev->size * (conf->previous_raid_disks -
4146 conf->max_degraded);
7a5febe9 4147
23032a0e
RBJ		 4148 blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
4149
1da177e4
LT		 4150 return 0;
4151abort:
4152 if (conf) {
4153 print_raid5_conf(conf);
16a53ecc 4154 safe_put_page(conf->spare_page);
b55e6bfc 4155 kfree(conf->disks);
fccddba0 4156 kfree(conf->stripe_hashtbl);
1da177e4
LT		 4157 kfree(conf);
4158 }
4159 mddev->private = NULL;
4160 printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev));
4161 return -EIO;
4162}
4163
4164
4165
3f294f4f 4166static int stop(mddev_t *mddev)
1da177e4
LT		 4167{
4168 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
4169
4170 md_unregister_thread(mddev->thread);
4171 mddev->thread = NULL;
4172 shrink_stripes(conf);
fccddba0 4173 kfree(conf->stripe_hashtbl);
041ae52e 4174 mddev->queue->backing_dev_info.congested_fn = NULL;
1da177e4 4175 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
007583c9 4176 sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
b55e6bfc 4177 kfree(conf->disks);
96de1e66 4178 kfree(conf);
1da177e4
LT		 4179 mddev->private = NULL;
4180 return 0;
4181}
4182
45b4233c 4183#ifdef DEBUG
16a53ecc 4184static void print_sh (struct seq_file *seq, struct stripe_head *sh)
1da177e4
LT		 4185{
4186 int i;
4187
16a53ecc
N		 4188 seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n",
4189 (unsigned long long)sh->sector, sh->pd_idx, sh->state);
4190 seq_printf(seq, "sh %llu, count %d.\n",
4191 (unsigned long long)sh->sector, atomic_read(&sh->count));
4192 seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector);
7ecaa1e6 4193 for (i = 0; i < sh->disks; i++) {
16a53ecc
N		 4194 seq_printf(seq, "(cache%d: %p %ld) ",
4195 i, sh->dev[i].page, sh->dev[i].flags);
1da177e4 4196 }
16a53ecc 4197 seq_printf(seq, "\n");
1da177e4
LT		 4198}
4199
16a53ecc 4200static void printall (struct seq_file *seq, raid5_conf_t *conf)
1da177e4
LT		 4201{
4202 struct stripe_head *sh;
fccddba0 4203 struct hlist_node *hn;
1da177e4
LT		 4204 int i;
4205
4206 spin_lock_irq(&conf->device_lock);
4207 for (i = 0; i < NR_HASH; i++) {
fccddba0 4208 hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
1da177e4
LT		 4209 if (sh->raid_conf != conf)
4210 continue;
16a53ecc 4211 print_sh(seq, sh);
1da177e4
LT		 4212 }
4213 }
4214 spin_unlock_irq(&conf->device_lock);
4215}
4216#endif
4217
4218static void status (struct seq_file *seq, mddev_t *mddev)
4219{
4220 raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
4221 int i;
4222
4223 seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout);
02c2de8c 4224 seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
1da177e4
LT		 4225 for (i = 0; i < conf->raid_disks; i++)
4226 seq_printf (seq, "%s",
4227 conf->disks[i].rdev &&
b2d444d7 4228 test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
1da177e4 4229 seq_printf (seq, "]");
45b4233c 4230#ifdef DEBUG
16a53ecc
N		 4231 seq_printf (seq, "\n");
4232 printall(seq, conf);
1da177e4
LT		 4233#endif
4234}
4235
4236static void print_raid5_conf (raid5_conf_t *conf)
4237{
4238 int i;
4239 struct disk_info *tmp;
4240
4241 printk("RAID5 conf printout:\n");
4242 if (!conf) {
4243 printk("(conf==NULL)\n");
4244 return;
4245 }
02c2de8c
N		 4246 printk(" --- rd:%d wd:%d\n", conf->raid_disks,
4247 conf->raid_disks - conf->mddev->degraded);
1da177e4
LT		 4248
4249 for (i = 0; i < conf->raid_disks; i++) {
4250 char b[BDEVNAME_SIZE];
4251 tmp = conf->disks + i;
4252 if (tmp->rdev)
4253 printk(" disk %d, o:%d, dev:%s\n",
b2d444d7 4254 i, !test_bit(Faulty, &tmp->rdev->flags),
1da177e4
LT		 4255 bdevname(tmp->rdev->bdev,b));
4256 }
4257}
4258
4259static int raid5_spare_active(mddev_t *mddev)
4260{
4261 int i;
4262 raid5_conf_t *conf = mddev->private;
4263 struct disk_info *tmp;
4264
4265 for (i = 0; i < conf->raid_disks; i++) {
4266 tmp = conf->disks + i;
4267 if (tmp->rdev
b2d444d7 4268 && !test_bit(Faulty, &tmp->rdev->flags)
c04be0aa
N		 4269 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
4270 unsigned long flags;
4271 spin_lock_irqsave(&conf->device_lock, flags);
1da177e4 4272 mddev->degraded--;
c04be0aa 4273 spin_unlock_irqrestore(&conf->device_lock, flags);
1da177e4
LT		 4274 }
4275 }
4276 print_raid5_conf(conf);
4277 return 0;
4278}
4279
4280static int raid5_remove_disk(mddev_t *mddev, int number)
4281{
4282 raid5_conf_t *conf = mddev->private;
4283 int err = 0;
4284 mdk_rdev_t *rdev;
4285 struct disk_info *p = conf->disks + number;
4286
4287 print_raid5_conf(conf);
4288 rdev = p->rdev;
4289 if (rdev) {
b2d444d7 4290 if (test_bit(In_sync, &rdev->flags) ||
1da177e4
LT		 4291 atomic_read(&rdev->nr_pending)) {
4292 err = -EBUSY;
4293 goto abort;
4294 }
4295 p->rdev = NULL;
fbd568a3 4296 synchronize_rcu();
1da177e4
LT		 4297 if (atomic_read(&rdev->nr_pending)) {
4298 /* lost the race, try later */
4299 err = -EBUSY;
4300 p->rdev = rdev;
4301 }
4302 }
4303abort:
4304
4305 print_raid5_conf(conf);
4306 return err;
4307}
4308
4309static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
4310{
4311 raid5_conf_t *conf = mddev->private;
4312 int found = 0;
4313 int disk;
4314 struct disk_info *p;
4315
16a53ecc 4316 if (mddev->degraded > conf->max_degraded)
1da177e4
LT		 4317 /* no point adding a device */
4318 return 0;
4319
4320 /*
16a53ecc
N		 4321 * find the disk ... but prefer rdev->saved_raid_disk
4322 * if possible.
1da177e4 4323 */
16a53ecc
N		 4324 if (rdev->saved_raid_disk >= 0 &&
4325 conf->disks[rdev->saved_raid_disk].rdev == NULL)
4326 disk = rdev->saved_raid_disk;
4327 else
4328 disk = 0;
4329 for ( ; disk < conf->raid_disks; disk++)
1da177e4 4330 if ((p=conf->disks + disk)->rdev == NULL) {
b2d444d7 4331 clear_bit(In_sync, &rdev->flags);
1da177e4
LT		 4332 rdev->raid_disk = disk;
4333 found = 1;
72626685
N		 4334 if (rdev->saved_raid_disk != disk)
4335 conf->fullsync = 1;
d6065f7b 4336 rcu_assign_pointer(p->rdev, rdev);
1da177e4
LT		 4337 break;
4338 }
4339 print_raid5_conf(conf);
4340 return found;
4341}
4342
4343static int raid5_resize(mddev_t *mddev, sector_t sectors)
4344{
4345 /* no resync is happening, and there is enough space
4346 * on all devices, so we can resize.
4347 * We need to make sure resync covers any new space.
4348 * If the array is shrinking we should possibly wait until
4349 * any io in the removed space completes, but it hardly seems
4350 * worth it.
4351 */
16a53ecc
N		 4352 raid5_conf_t *conf = mddev_to_conf(mddev);
4353
1da177e4 4354 sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
16a53ecc 4355 mddev->array_size = (sectors * (mddev->raid_disks-conf->max_degraded))>>1;
1da177e4 4356 set_capacity(mddev->gendisk, mddev->array_size << 1);
44ce6294 4357 mddev->changed = 1;
1da177e4
LT		 4358 if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) {
4359 mddev->recovery_cp = mddev->size << 1;
4360 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4361 }
4362 mddev->size = sectors /2;
4b5c7ae8 4363 mddev->resync_max_sectors = sectors;
1da177e4
LT		 4364 return 0;
4365}
4366
29269553 4367#ifdef CONFIG_MD_RAID5_RESHAPE
63c70c4f 4368static int raid5_check_reshape(mddev_t *mddev)
29269553
N		 4369{
4370 raid5_conf_t *conf = mddev_to_conf(mddev);
4371 int err;
29269553 4372
63c70c4f
N		 4373 if (mddev->delta_disks < 0 ||
4374 mddev->new_level != mddev->level)
4375 return -EINVAL; /* Cannot shrink array or change level yet */
4376 if (mddev->delta_disks == 0)
29269553
N		 4377 return 0; /* nothing to do */
4378
4379 /* Can only proceed if there are plenty of stripe_heads.
4380 * We need a minimum of one full stripe,, and for sensible progress
4381 * it is best to have about 4 times that.
4382 * If we require 4 times, then the default 256 4K stripe_heads will
4383 * allow for chunk sizes up to 256K, which is probably OK.
4384 * If the chunk size is greater, user-space should request more
4385 * stripe_heads first.
4386 */
63c70c4f
N		 4387 if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes ||
4388 (mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) {
29269553
N		 4389 printk(KERN_WARNING "raid5: reshape: not enough stripes. Needed %lu\n",
4390 (mddev->chunk_size / STRIPE_SIZE)*4);
4391 return -ENOSPC;
4392 }
4393
63c70c4f
N		 4394 err = resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
4395 if (err)
4396 return err;
4397
b4c4c7b8
N		 4398 if (mddev->degraded > conf->max_degraded)
4399 return -EINVAL;
63c70c4f
N		 4400 /* looks like we might be able to manage this */
4401 return 0;
4402}
4403
4404static int raid5_start_reshape(mddev_t *mddev)
4405{
4406 raid5_conf_t *conf = mddev_to_conf(mddev);
4407 mdk_rdev_t *rdev;
4408 struct list_head *rtmp;
4409 int spares = 0;
4410 int added_devices = 0;
c04be0aa 4411 unsigned long flags;
63c70c4f 4412
f416885e 4413 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
63c70c4f
N		 4414 return -EBUSY;
4415
29269553
N		 4416 ITERATE_RDEV(mddev, rdev, rtmp)
4417 if (rdev->raid_disk < 0 &&
4418 !test_bit(Faulty, &rdev->flags))
4419 spares++;
63c70c4f 4420
f416885e 4421 if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
29269553
N		 4422 /* Not enough devices even to make a degraded array
4423 * of that size
4424 */
4425 return -EINVAL;
4426
f6705578 4427 atomic_set(&conf->reshape_stripes, 0);
29269553
N		 4428 spin_lock_irq(&conf->device_lock);
4429 conf->previous_raid_disks = conf->raid_disks;
63c70c4f 4430 conf->raid_disks += mddev->delta_disks;
29269553 4431 conf->expand_progress = 0;
b578d55f 4432 conf->expand_lo = 0;
29269553
N		 4433 spin_unlock_irq(&conf->device_lock);
4434
4435 /* Add some new drives, as many as will fit.
4436 * We know there are enough to make the newly sized array work.
4437 */
4438 ITERATE_RDEV(mddev, rdev, rtmp)
4439 if (rdev->raid_disk < 0 &&
4440 !test_bit(Faulty, &rdev->flags)) {
4441 if (raid5_add_disk(mddev, rdev)) {
4442 char nm[20];
4443 set_bit(In_sync, &rdev->flags);
29269553 4444 added_devices++;
5fd6c1dc 4445 rdev->recovery_offset = 0;
29269553 4446 sprintf(nm, "rd%d", rdev->raid_disk);
5e55e2f5
N		 4447 if (sysfs_create_link(&mddev->kobj,
4448 &rdev->kobj, nm))
4449 printk(KERN_WARNING
4450 "raid5: failed to create "
4451 " link %s for %s\n",
4452 nm, mdname(mddev));
29269553
N		 4453 } else
4454 break;
4455 }
4456
c04be0aa 4457 spin_lock_irqsave(&conf->device_lock, flags);
63c70c4f 4458 mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) - added_devices;
c04be0aa 4459 spin_unlock_irqrestore(&conf->device_lock, flags);
63c70c4f 4460 mddev->raid_disks = conf->raid_disks;
f6705578 4461 mddev->reshape_position = 0;
850b2b42 4462 set_bit(MD_CHANGE_DEVS, &mddev->flags);
f6705578 4463
29269553
N		 4464 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4465 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4466 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4467 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4468 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4469 "%s_reshape");
4470 if (!mddev->sync_thread) {
4471 mddev->recovery = 0;
4472 spin_lock_irq(&conf->device_lock);
4473 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
4474 conf->expand_progress = MaxSector;
4475 spin_unlock_irq(&conf->device_lock);
4476 return -EAGAIN;
4477 }
4478 md_wakeup_thread(mddev->sync_thread);
4479 md_new_event(mddev);
4480 return 0;
4481}
4482#endif
4483
4484static void end_reshape(raid5_conf_t *conf)
4485{
4486 struct block_device *bdev;
4487
f6705578 4488 if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
f416885e
N		 4489 conf->mddev->array_size = conf->mddev->size *
4490 (conf->raid_disks - conf->max_degraded);
f6705578 4491 set_capacity(conf->mddev->gendisk, conf->mddev->array_size << 1);
44ce6294 4492 conf->mddev->changed = 1;
f6705578
N		 4493
4494 bdev = bdget_disk(conf->mddev->gendisk, 0);
4495 if (bdev) {
4496 mutex_lock(&bdev->bd_inode->i_mutex);
0692c6b1 4497 i_size_write(bdev->bd_inode, (loff_t)conf->mddev->array_size << 10);
f6705578
N		 4498 mutex_unlock(&bdev->bd_inode->i_mutex);
4499 bdput(bdev);
4500 }
4501 spin_lock_irq(&conf->device_lock);
4502 conf->expand_progress = MaxSector;
4503 spin_unlock_irq(&conf->device_lock);
4504 conf->mddev->reshape_position = MaxSector;
16a53ecc
N		 4505
4506 /* read-ahead size must cover two whole stripes, which is
4507 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
4508 */
4509 {
4510 int data_disks = conf->previous_raid_disks - conf->max_degraded;
4511 int stripe = data_disks *
4512 (conf->mddev->chunk_size / PAGE_SIZE);
4513 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
4514 conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
4515 }
29269553 4516 }
29269553
N		 4517}
4518
72626685
N		 4519static void raid5_quiesce(mddev_t *mddev, int state)
4520{
4521 raid5_conf_t *conf = mddev_to_conf(mddev);
4522
4523 switch(state) {
e464eafd
N		 4524 case 2: /* resume for a suspend */
4525 wake_up(&conf->wait_for_overlap);
4526 break;
4527
72626685
N		 4528 case 1: /* stop all writes */
4529 spin_lock_irq(&conf->device_lock);
4530 conf->quiesce = 1;
4531 wait_event_lock_irq(conf->wait_for_stripe,
46031f9a
RBJ		 4532 atomic_read(&conf->active_stripes) == 0 &&
4533 atomic_read(&conf->active_aligned_reads) == 0,
72626685
N		 4534 conf->device_lock, /* nothing */);
4535 spin_unlock_irq(&conf->device_lock);
4536 break;
4537
4538 case 0: /* re-enable writes */
4539 spin_lock_irq(&conf->device_lock);
4540 conf->quiesce = 0;
4541 wake_up(&conf->wait_for_stripe);
e464eafd 4542 wake_up(&conf->wait_for_overlap);
72626685
N		 4543 spin_unlock_irq(&conf->device_lock);
4544 break;
4545 }
72626685 4546}
b15c2e57 4547
16a53ecc
N		 4548static struct mdk_personality raid6_personality =
4549{
4550 .name = "raid6",
4551 .level = 6,
4552 .owner = THIS_MODULE,
4553 .make_request = make_request,
4554 .run = run,
4555 .stop = stop,
4556 .status = status,
4557 .error_handler = error,
4558 .hot_add_disk = raid5_add_disk,
4559 .hot_remove_disk= raid5_remove_disk,
4560 .spare_active = raid5_spare_active,
4561 .sync_request = sync_request,
4562 .resize = raid5_resize,
f416885e
N		 4563#ifdef CONFIG_MD_RAID5_RESHAPE
4564 .check_reshape = raid5_check_reshape,
4565 .start_reshape = raid5_start_reshape,
4566#endif
16a53ecc
N		 4567 .quiesce = raid5_quiesce,
4568};
2604b703 4569static struct mdk_personality raid5_personality =
1da177e4
LT		 4570{
4571 .name = "raid5",
2604b703 4572 .level = 5,
1da177e4
LT		 4573 .owner = THIS_MODULE,
4574 .make_request = make_request,
4575 .run = run,
4576 .stop = stop,
4577 .status = status,
4578 .error_handler = error,
4579 .hot_add_disk = raid5_add_disk,
4580 .hot_remove_disk= raid5_remove_disk,
4581 .spare_active = raid5_spare_active,
4582 .sync_request = sync_request,
4583 .resize = raid5_resize,
29269553 4584#ifdef CONFIG_MD_RAID5_RESHAPE
63c70c4f
N		 4585 .check_reshape = raid5_check_reshape,
4586 .start_reshape = raid5_start_reshape,
29269553 4587#endif
72626685 4588 .quiesce = raid5_quiesce,
1da177e4
LT		 4589};
4590
2604b703 4591static struct mdk_personality raid4_personality =
1da177e4 4592{
2604b703
N		 4593 .name = "raid4",
4594 .level = 4,
4595 .owner = THIS_MODULE,
4596 .make_request = make_request,
4597 .run = run,
4598 .stop = stop,
4599 .status = status,
4600 .error_handler = error,
4601 .hot_add_disk = raid5_add_disk,
4602 .hot_remove_disk= raid5_remove_disk,
4603 .spare_active = raid5_spare_active,
4604 .sync_request = sync_request,
4605 .resize = raid5_resize,
3d37890b
N		 4606#ifdef CONFIG_MD_RAID5_RESHAPE
4607 .check_reshape = raid5_check_reshape,
4608 .start_reshape = raid5_start_reshape,
4609#endif
2604b703
N		 4610 .quiesce = raid5_quiesce,
4611};
4612
4613static int __init raid5_init(void)
4614{
16a53ecc
N		 4615 int e;
4616
4617 e = raid6_select_algo();
4618 if ( e )
4619 return e;
4620 register_md_personality(&raid6_personality);
2604b703
N		 4621 register_md_personality(&raid5_personality);
4622 register_md_personality(&raid4_personality);
4623 return 0;
1da177e4
LT		 4624}
4625
2604b703 4626static void raid5_exit(void)
1da177e4 4627{
16a53ecc 4628 unregister_md_personality(&raid6_personality);
2604b703
N		 4629 unregister_md_personality(&raid5_personality);
4630 unregister_md_personality(&raid4_personality);
1da177e4
LT		 4631}
4632
4633module_init(raid5_init);
4634module_exit(raid5_exit);
4635MODULE_LICENSE("GPL");
4636MODULE_ALIAS("md-personality-4"); /* RAID5 */
d9d166c2
N		 4637MODULE_ALIAS("md-raid5");
4638MODULE_ALIAS("md-raid4");
2604b703
N		 4639MODULE_ALIAS("md-level-5");
4640MODULE_ALIAS("md-level-4");
16a53ecc
N		 4641MODULE_ALIAS("md-personality-8"); /* RAID6 */
4642MODULE_ALIAS("md-raid6");
4643MODULE_ALIAS("md-level-6");
4644
4645/* This used to be two separate modules, they were: */
4646MODULE_ALIAS("raid5");
4647MODULE_ALIAS("raid6");
Linux 6.x block layer and io_uring tree(s)