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1da177e4 LT |
1 | /* |
2 | * raid5.c : Multiple Devices driver for Linux | |
3 | * Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman | |
4 | * Copyright (C) 1999, 2000 Ingo Molnar | |
5 | * | |
6 | * RAID-5 management functions. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2, or (at your option) | |
11 | * any later version. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * (for example /usr/src/linux/COPYING); if not, write to the Free | |
15 | * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
16 | */ | |
17 | ||
18 | ||
19 | #include <linux/config.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/slab.h> | |
22 | #include <linux/raid/raid5.h> | |
23 | #include <linux/highmem.h> | |
24 | #include <linux/bitops.h> | |
25 | #include <asm/atomic.h> | |
26 | ||
72626685 N |
27 | #include <linux/raid/bitmap.h> |
28 | ||
1da177e4 LT |
29 | /* |
30 | * Stripe cache | |
31 | */ | |
32 | ||
33 | #define NR_STRIPES 256 | |
34 | #define STRIPE_SIZE PAGE_SIZE | |
35 | #define STRIPE_SHIFT (PAGE_SHIFT - 9) | |
36 | #define STRIPE_SECTORS (STRIPE_SIZE>>9) | |
37 | #define IO_THRESHOLD 1 | |
38 | #define HASH_PAGES 1 | |
39 | #define HASH_PAGES_ORDER 0 | |
40 | #define NR_HASH (HASH_PAGES * PAGE_SIZE / sizeof(struct stripe_head *)) | |
41 | #define HASH_MASK (NR_HASH - 1) | |
42 | ||
43 | #define stripe_hash(conf, sect) ((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]) | |
44 | ||
45 | /* bio's attached to a stripe+device for I/O are linked together in bi_sector | |
46 | * order without overlap. There may be several bio's per stripe+device, and | |
47 | * a bio could span several devices. | |
48 | * When walking this list for a particular stripe+device, we must never proceed | |
49 | * beyond a bio that extends past this device, as the next bio might no longer | |
50 | * be valid. | |
51 | * This macro is used to determine the 'next' bio in the list, given the sector | |
52 | * of the current stripe+device | |
53 | */ | |
54 | #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL) | |
55 | /* | |
56 | * The following can be used to debug the driver | |
57 | */ | |
58 | #define RAID5_DEBUG 0 | |
59 | #define RAID5_PARANOIA 1 | |
60 | #if RAID5_PARANOIA && defined(CONFIG_SMP) | |
61 | # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock) | |
62 | #else | |
63 | # define CHECK_DEVLOCK() | |
64 | #endif | |
65 | ||
66 | #define PRINTK(x...) ((void)(RAID5_DEBUG && printk(x))) | |
67 | #if RAID5_DEBUG | |
68 | #define inline | |
69 | #define __inline__ | |
70 | #endif | |
71 | ||
72 | static void print_raid5_conf (raid5_conf_t *conf); | |
73 | ||
74 | static inline void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh) | |
75 | { | |
76 | if (atomic_dec_and_test(&sh->count)) { | |
77 | if (!list_empty(&sh->lru)) | |
78 | BUG(); | |
79 | if (atomic_read(&conf->active_stripes)==0) | |
80 | BUG(); | |
81 | if (test_bit(STRIPE_HANDLE, &sh->state)) { | |
82 | if (test_bit(STRIPE_DELAYED, &sh->state)) | |
83 | list_add_tail(&sh->lru, &conf->delayed_list); | |
72626685 N |
84 | else if (test_bit(STRIPE_BIT_DELAY, &sh->state) && |
85 | conf->seq_write == sh->bm_seq) | |
86 | list_add_tail(&sh->lru, &conf->bitmap_list); | |
87 | else { | |
88 | clear_bit(STRIPE_BIT_DELAY, &sh->state); | |
1da177e4 | 89 | list_add_tail(&sh->lru, &conf->handle_list); |
72626685 | 90 | } |
1da177e4 LT |
91 | md_wakeup_thread(conf->mddev->thread); |
92 | } else { | |
93 | if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { | |
94 | atomic_dec(&conf->preread_active_stripes); | |
95 | if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) | |
96 | md_wakeup_thread(conf->mddev->thread); | |
97 | } | |
98 | list_add_tail(&sh->lru, &conf->inactive_list); | |
99 | atomic_dec(&conf->active_stripes); | |
100 | if (!conf->inactive_blocked || | |
101 | atomic_read(&conf->active_stripes) < (NR_STRIPES*3/4)) | |
102 | wake_up(&conf->wait_for_stripe); | |
103 | } | |
104 | } | |
105 | } | |
106 | static void release_stripe(struct stripe_head *sh) | |
107 | { | |
108 | raid5_conf_t *conf = sh->raid_conf; | |
109 | unsigned long flags; | |
110 | ||
111 | spin_lock_irqsave(&conf->device_lock, flags); | |
112 | __release_stripe(conf, sh); | |
113 | spin_unlock_irqrestore(&conf->device_lock, flags); | |
114 | } | |
115 | ||
116 | static void remove_hash(struct stripe_head *sh) | |
117 | { | |
118 | PRINTK("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector); | |
119 | ||
120 | if (sh->hash_pprev) { | |
121 | if (sh->hash_next) | |
122 | sh->hash_next->hash_pprev = sh->hash_pprev; | |
123 | *sh->hash_pprev = sh->hash_next; | |
124 | sh->hash_pprev = NULL; | |
125 | } | |
126 | } | |
127 | ||
128 | static __inline__ void insert_hash(raid5_conf_t *conf, struct stripe_head *sh) | |
129 | { | |
130 | struct stripe_head **shp = &stripe_hash(conf, sh->sector); | |
131 | ||
132 | PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector); | |
133 | ||
134 | CHECK_DEVLOCK(); | |
135 | if ((sh->hash_next = *shp) != NULL) | |
136 | (*shp)->hash_pprev = &sh->hash_next; | |
137 | *shp = sh; | |
138 | sh->hash_pprev = shp; | |
139 | } | |
140 | ||
141 | ||
142 | /* find an idle stripe, make sure it is unhashed, and return it. */ | |
143 | static struct stripe_head *get_free_stripe(raid5_conf_t *conf) | |
144 | { | |
145 | struct stripe_head *sh = NULL; | |
146 | struct list_head *first; | |
147 | ||
148 | CHECK_DEVLOCK(); | |
149 | if (list_empty(&conf->inactive_list)) | |
150 | goto out; | |
151 | first = conf->inactive_list.next; | |
152 | sh = list_entry(first, struct stripe_head, lru); | |
153 | list_del_init(first); | |
154 | remove_hash(sh); | |
155 | atomic_inc(&conf->active_stripes); | |
156 | out: | |
157 | return sh; | |
158 | } | |
159 | ||
160 | static void shrink_buffers(struct stripe_head *sh, int num) | |
161 | { | |
162 | struct page *p; | |
163 | int i; | |
164 | ||
165 | for (i=0; i<num ; i++) { | |
166 | p = sh->dev[i].page; | |
167 | if (!p) | |
168 | continue; | |
169 | sh->dev[i].page = NULL; | |
170 | page_cache_release(p); | |
171 | } | |
172 | } | |
173 | ||
174 | static int grow_buffers(struct stripe_head *sh, int num) | |
175 | { | |
176 | int i; | |
177 | ||
178 | for (i=0; i<num; i++) { | |
179 | struct page *page; | |
180 | ||
181 | if (!(page = alloc_page(GFP_KERNEL))) { | |
182 | return 1; | |
183 | } | |
184 | sh->dev[i].page = page; | |
185 | } | |
186 | return 0; | |
187 | } | |
188 | ||
189 | static void raid5_build_block (struct stripe_head *sh, int i); | |
190 | ||
191 | static inline void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx) | |
192 | { | |
193 | raid5_conf_t *conf = sh->raid_conf; | |
194 | int disks = conf->raid_disks, i; | |
195 | ||
196 | if (atomic_read(&sh->count) != 0) | |
197 | BUG(); | |
198 | if (test_bit(STRIPE_HANDLE, &sh->state)) | |
199 | BUG(); | |
200 | ||
201 | CHECK_DEVLOCK(); | |
202 | PRINTK("init_stripe called, stripe %llu\n", | |
203 | (unsigned long long)sh->sector); | |
204 | ||
205 | remove_hash(sh); | |
206 | ||
207 | sh->sector = sector; | |
208 | sh->pd_idx = pd_idx; | |
209 | sh->state = 0; | |
210 | ||
211 | for (i=disks; i--; ) { | |
212 | struct r5dev *dev = &sh->dev[i]; | |
213 | ||
214 | if (dev->toread || dev->towrite || dev->written || | |
215 | test_bit(R5_LOCKED, &dev->flags)) { | |
216 | printk("sector=%llx i=%d %p %p %p %d\n", | |
217 | (unsigned long long)sh->sector, i, dev->toread, | |
218 | dev->towrite, dev->written, | |
219 | test_bit(R5_LOCKED, &dev->flags)); | |
220 | BUG(); | |
221 | } | |
222 | dev->flags = 0; | |
223 | raid5_build_block(sh, i); | |
224 | } | |
225 | insert_hash(conf, sh); | |
226 | } | |
227 | ||
228 | static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector) | |
229 | { | |
230 | struct stripe_head *sh; | |
231 | ||
232 | CHECK_DEVLOCK(); | |
233 | PRINTK("__find_stripe, sector %llu\n", (unsigned long long)sector); | |
234 | for (sh = stripe_hash(conf, sector); sh; sh = sh->hash_next) | |
235 | if (sh->sector == sector) | |
236 | return sh; | |
237 | PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector); | |
238 | return NULL; | |
239 | } | |
240 | ||
241 | static void unplug_slaves(mddev_t *mddev); | |
242 | static void raid5_unplug_device(request_queue_t *q); | |
243 | ||
244 | static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector, | |
245 | int pd_idx, int noblock) | |
246 | { | |
247 | struct stripe_head *sh; | |
248 | ||
249 | PRINTK("get_stripe, sector %llu\n", (unsigned long long)sector); | |
250 | ||
251 | spin_lock_irq(&conf->device_lock); | |
252 | ||
253 | do { | |
72626685 N |
254 | wait_event_lock_irq(conf->wait_for_stripe, |
255 | conf->quiesce == 0, | |
256 | conf->device_lock, /* nothing */); | |
1da177e4 LT |
257 | sh = __find_stripe(conf, sector); |
258 | if (!sh) { | |
259 | if (!conf->inactive_blocked) | |
260 | sh = get_free_stripe(conf); | |
261 | if (noblock && sh == NULL) | |
262 | break; | |
263 | if (!sh) { | |
264 | conf->inactive_blocked = 1; | |
265 | wait_event_lock_irq(conf->wait_for_stripe, | |
266 | !list_empty(&conf->inactive_list) && | |
267 | (atomic_read(&conf->active_stripes) < (NR_STRIPES *3/4) | |
268 | || !conf->inactive_blocked), | |
269 | conf->device_lock, | |
270 | unplug_slaves(conf->mddev); | |
271 | ); | |
272 | conf->inactive_blocked = 0; | |
273 | } else | |
274 | init_stripe(sh, sector, pd_idx); | |
275 | } else { | |
276 | if (atomic_read(&sh->count)) { | |
277 | if (!list_empty(&sh->lru)) | |
278 | BUG(); | |
279 | } else { | |
280 | if (!test_bit(STRIPE_HANDLE, &sh->state)) | |
281 | atomic_inc(&conf->active_stripes); | |
282 | if (list_empty(&sh->lru)) | |
283 | BUG(); | |
284 | list_del_init(&sh->lru); | |
285 | } | |
286 | } | |
287 | } while (sh == NULL); | |
288 | ||
289 | if (sh) | |
290 | atomic_inc(&sh->count); | |
291 | ||
292 | spin_unlock_irq(&conf->device_lock); | |
293 | return sh; | |
294 | } | |
295 | ||
296 | static int grow_stripes(raid5_conf_t *conf, int num) | |
297 | { | |
298 | struct stripe_head *sh; | |
299 | kmem_cache_t *sc; | |
300 | int devs = conf->raid_disks; | |
301 | ||
302 | sprintf(conf->cache_name, "raid5/%s", mdname(conf->mddev)); | |
303 | ||
304 | sc = kmem_cache_create(conf->cache_name, | |
305 | sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev), | |
306 | 0, 0, NULL, NULL); | |
307 | if (!sc) | |
308 | return 1; | |
309 | conf->slab_cache = sc; | |
310 | while (num--) { | |
311 | sh = kmem_cache_alloc(sc, GFP_KERNEL); | |
312 | if (!sh) | |
313 | return 1; | |
314 | memset(sh, 0, sizeof(*sh) + (devs-1)*sizeof(struct r5dev)); | |
315 | sh->raid_conf = conf; | |
316 | spin_lock_init(&sh->lock); | |
317 | ||
318 | if (grow_buffers(sh, conf->raid_disks)) { | |
319 | shrink_buffers(sh, conf->raid_disks); | |
320 | kmem_cache_free(sc, sh); | |
321 | return 1; | |
322 | } | |
323 | /* we just created an active stripe so... */ | |
324 | atomic_set(&sh->count, 1); | |
325 | atomic_inc(&conf->active_stripes); | |
326 | INIT_LIST_HEAD(&sh->lru); | |
327 | release_stripe(sh); | |
328 | } | |
329 | return 0; | |
330 | } | |
331 | ||
332 | static void shrink_stripes(raid5_conf_t *conf) | |
333 | { | |
334 | struct stripe_head *sh; | |
335 | ||
336 | while (1) { | |
337 | spin_lock_irq(&conf->device_lock); | |
338 | sh = get_free_stripe(conf); | |
339 | spin_unlock_irq(&conf->device_lock); | |
340 | if (!sh) | |
341 | break; | |
342 | if (atomic_read(&sh->count)) | |
343 | BUG(); | |
344 | shrink_buffers(sh, conf->raid_disks); | |
345 | kmem_cache_free(conf->slab_cache, sh); | |
346 | atomic_dec(&conf->active_stripes); | |
347 | } | |
348 | kmem_cache_destroy(conf->slab_cache); | |
349 | conf->slab_cache = NULL; | |
350 | } | |
351 | ||
352 | static int raid5_end_read_request (struct bio * bi, unsigned int bytes_done, | |
353 | int error) | |
354 | { | |
355 | struct stripe_head *sh = bi->bi_private; | |
356 | raid5_conf_t *conf = sh->raid_conf; | |
357 | int disks = conf->raid_disks, i; | |
358 | int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); | |
359 | ||
360 | if (bi->bi_size) | |
361 | return 1; | |
362 | ||
363 | for (i=0 ; i<disks; i++) | |
364 | if (bi == &sh->dev[i].req) | |
365 | break; | |
366 | ||
367 | PRINTK("end_read_request %llu/%d, count: %d, uptodate %d.\n", | |
368 | (unsigned long long)sh->sector, i, atomic_read(&sh->count), | |
369 | uptodate); | |
370 | if (i == disks) { | |
371 | BUG(); | |
372 | return 0; | |
373 | } | |
374 | ||
375 | if (uptodate) { | |
376 | #if 0 | |
377 | struct bio *bio; | |
378 | unsigned long flags; | |
379 | spin_lock_irqsave(&conf->device_lock, flags); | |
380 | /* we can return a buffer if we bypassed the cache or | |
381 | * if the top buffer is not in highmem. If there are | |
382 | * multiple buffers, leave the extra work to | |
383 | * handle_stripe | |
384 | */ | |
385 | buffer = sh->bh_read[i]; | |
386 | if (buffer && | |
387 | (!PageHighMem(buffer->b_page) | |
388 | || buffer->b_page == bh->b_page ) | |
389 | ) { | |
390 | sh->bh_read[i] = buffer->b_reqnext; | |
391 | buffer->b_reqnext = NULL; | |
392 | } else | |
393 | buffer = NULL; | |
394 | spin_unlock_irqrestore(&conf->device_lock, flags); | |
395 | if (sh->bh_page[i]==bh->b_page) | |
396 | set_buffer_uptodate(bh); | |
397 | if (buffer) { | |
398 | if (buffer->b_page != bh->b_page) | |
399 | memcpy(buffer->b_data, bh->b_data, bh->b_size); | |
400 | buffer->b_end_io(buffer, 1); | |
401 | } | |
402 | #else | |
403 | set_bit(R5_UPTODATE, &sh->dev[i].flags); | |
404 | #endif | |
405 | } else { | |
406 | md_error(conf->mddev, conf->disks[i].rdev); | |
407 | clear_bit(R5_UPTODATE, &sh->dev[i].flags); | |
408 | } | |
409 | rdev_dec_pending(conf->disks[i].rdev, conf->mddev); | |
410 | #if 0 | |
411 | /* must restore b_page before unlocking buffer... */ | |
412 | if (sh->bh_page[i] != bh->b_page) { | |
413 | bh->b_page = sh->bh_page[i]; | |
414 | bh->b_data = page_address(bh->b_page); | |
415 | clear_buffer_uptodate(bh); | |
416 | } | |
417 | #endif | |
418 | clear_bit(R5_LOCKED, &sh->dev[i].flags); | |
419 | set_bit(STRIPE_HANDLE, &sh->state); | |
420 | release_stripe(sh); | |
421 | return 0; | |
422 | } | |
423 | ||
424 | static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done, | |
425 | int error) | |
426 | { | |
427 | struct stripe_head *sh = bi->bi_private; | |
428 | raid5_conf_t *conf = sh->raid_conf; | |
429 | int disks = conf->raid_disks, i; | |
430 | unsigned long flags; | |
431 | int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); | |
432 | ||
433 | if (bi->bi_size) | |
434 | return 1; | |
435 | ||
436 | for (i=0 ; i<disks; i++) | |
437 | if (bi == &sh->dev[i].req) | |
438 | break; | |
439 | ||
440 | PRINTK("end_write_request %llu/%d, count %d, uptodate: %d.\n", | |
441 | (unsigned long long)sh->sector, i, atomic_read(&sh->count), | |
442 | uptodate); | |
443 | if (i == disks) { | |
444 | BUG(); | |
445 | return 0; | |
446 | } | |
447 | ||
448 | spin_lock_irqsave(&conf->device_lock, flags); | |
449 | if (!uptodate) | |
450 | md_error(conf->mddev, conf->disks[i].rdev); | |
451 | ||
452 | rdev_dec_pending(conf->disks[i].rdev, conf->mddev); | |
453 | ||
454 | clear_bit(R5_LOCKED, &sh->dev[i].flags); | |
455 | set_bit(STRIPE_HANDLE, &sh->state); | |
456 | __release_stripe(conf, sh); | |
457 | spin_unlock_irqrestore(&conf->device_lock, flags); | |
458 | return 0; | |
459 | } | |
460 | ||
461 | ||
462 | static sector_t compute_blocknr(struct stripe_head *sh, int i); | |
463 | ||
464 | static void raid5_build_block (struct stripe_head *sh, int i) | |
465 | { | |
466 | struct r5dev *dev = &sh->dev[i]; | |
467 | ||
468 | bio_init(&dev->req); | |
469 | dev->req.bi_io_vec = &dev->vec; | |
470 | dev->req.bi_vcnt++; | |
471 | dev->req.bi_max_vecs++; | |
472 | dev->vec.bv_page = dev->page; | |
473 | dev->vec.bv_len = STRIPE_SIZE; | |
474 | dev->vec.bv_offset = 0; | |
475 | ||
476 | dev->req.bi_sector = sh->sector; | |
477 | dev->req.bi_private = sh; | |
478 | ||
479 | dev->flags = 0; | |
480 | if (i != sh->pd_idx) | |
481 | dev->sector = compute_blocknr(sh, i); | |
482 | } | |
483 | ||
484 | static void error(mddev_t *mddev, mdk_rdev_t *rdev) | |
485 | { | |
486 | char b[BDEVNAME_SIZE]; | |
487 | raid5_conf_t *conf = (raid5_conf_t *) mddev->private; | |
488 | PRINTK("raid5: error called\n"); | |
489 | ||
490 | if (!rdev->faulty) { | |
491 | mddev->sb_dirty = 1; | |
492 | if (rdev->in_sync) { | |
493 | conf->working_disks--; | |
494 | mddev->degraded++; | |
495 | conf->failed_disks++; | |
496 | rdev->in_sync = 0; | |
497 | /* | |
498 | * if recovery was running, make sure it aborts. | |
499 | */ | |
500 | set_bit(MD_RECOVERY_ERR, &mddev->recovery); | |
501 | } | |
502 | rdev->faulty = 1; | |
503 | printk (KERN_ALERT | |
504 | "raid5: Disk failure on %s, disabling device." | |
505 | " Operation continuing on %d devices\n", | |
506 | bdevname(rdev->bdev,b), conf->working_disks); | |
507 | } | |
508 | } | |
509 | ||
510 | /* | |
511 | * Input: a 'big' sector number, | |
512 | * Output: index of the data and parity disk, and the sector # in them. | |
513 | */ | |
514 | static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks, | |
515 | unsigned int data_disks, unsigned int * dd_idx, | |
516 | unsigned int * pd_idx, raid5_conf_t *conf) | |
517 | { | |
518 | long stripe; | |
519 | unsigned long chunk_number; | |
520 | unsigned int chunk_offset; | |
521 | sector_t new_sector; | |
522 | int sectors_per_chunk = conf->chunk_size >> 9; | |
523 | ||
524 | /* First compute the information on this sector */ | |
525 | ||
526 | /* | |
527 | * Compute the chunk number and the sector offset inside the chunk | |
528 | */ | |
529 | chunk_offset = sector_div(r_sector, sectors_per_chunk); | |
530 | chunk_number = r_sector; | |
531 | BUG_ON(r_sector != chunk_number); | |
532 | ||
533 | /* | |
534 | * Compute the stripe number | |
535 | */ | |
536 | stripe = chunk_number / data_disks; | |
537 | ||
538 | /* | |
539 | * Compute the data disk and parity disk indexes inside the stripe | |
540 | */ | |
541 | *dd_idx = chunk_number % data_disks; | |
542 | ||
543 | /* | |
544 | * Select the parity disk based on the user selected algorithm. | |
545 | */ | |
546 | if (conf->level == 4) | |
547 | *pd_idx = data_disks; | |
548 | else switch (conf->algorithm) { | |
549 | case ALGORITHM_LEFT_ASYMMETRIC: | |
550 | *pd_idx = data_disks - stripe % raid_disks; | |
551 | if (*dd_idx >= *pd_idx) | |
552 | (*dd_idx)++; | |
553 | break; | |
554 | case ALGORITHM_RIGHT_ASYMMETRIC: | |
555 | *pd_idx = stripe % raid_disks; | |
556 | if (*dd_idx >= *pd_idx) | |
557 | (*dd_idx)++; | |
558 | break; | |
559 | case ALGORITHM_LEFT_SYMMETRIC: | |
560 | *pd_idx = data_disks - stripe % raid_disks; | |
561 | *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks; | |
562 | break; | |
563 | case ALGORITHM_RIGHT_SYMMETRIC: | |
564 | *pd_idx = stripe % raid_disks; | |
565 | *dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks; | |
566 | break; | |
567 | default: | |
568 | printk("raid5: unsupported algorithm %d\n", | |
569 | conf->algorithm); | |
570 | } | |
571 | ||
572 | /* | |
573 | * Finally, compute the new sector number | |
574 | */ | |
575 | new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset; | |
576 | return new_sector; | |
577 | } | |
578 | ||
579 | ||
580 | static sector_t compute_blocknr(struct stripe_head *sh, int i) | |
581 | { | |
582 | raid5_conf_t *conf = sh->raid_conf; | |
583 | int raid_disks = conf->raid_disks, data_disks = raid_disks - 1; | |
584 | sector_t new_sector = sh->sector, check; | |
585 | int sectors_per_chunk = conf->chunk_size >> 9; | |
586 | sector_t stripe; | |
587 | int chunk_offset; | |
588 | int chunk_number, dummy1, dummy2, dd_idx = i; | |
589 | sector_t r_sector; | |
590 | ||
591 | chunk_offset = sector_div(new_sector, sectors_per_chunk); | |
592 | stripe = new_sector; | |
593 | BUG_ON(new_sector != stripe); | |
594 | ||
595 | ||
596 | switch (conf->algorithm) { | |
597 | case ALGORITHM_LEFT_ASYMMETRIC: | |
598 | case ALGORITHM_RIGHT_ASYMMETRIC: | |
599 | if (i > sh->pd_idx) | |
600 | i--; | |
601 | break; | |
602 | case ALGORITHM_LEFT_SYMMETRIC: | |
603 | case ALGORITHM_RIGHT_SYMMETRIC: | |
604 | if (i < sh->pd_idx) | |
605 | i += raid_disks; | |
606 | i -= (sh->pd_idx + 1); | |
607 | break; | |
608 | default: | |
609 | printk("raid5: unsupported algorithm %d\n", | |
610 | conf->algorithm); | |
611 | } | |
612 | ||
613 | chunk_number = stripe * data_disks + i; | |
614 | r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset; | |
615 | ||
616 | check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf); | |
617 | if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) { | |
618 | printk("compute_blocknr: map not correct\n"); | |
619 | return 0; | |
620 | } | |
621 | return r_sector; | |
622 | } | |
623 | ||
624 | ||
625 | ||
626 | /* | |
627 | * Copy data between a page in the stripe cache, and a bio. | |
628 | * There are no alignment or size guarantees between the page or the | |
629 | * bio except that there is some overlap. | |
630 | * All iovecs in the bio must be considered. | |
631 | */ | |
632 | static void copy_data(int frombio, struct bio *bio, | |
633 | struct page *page, | |
634 | sector_t sector) | |
635 | { | |
636 | char *pa = page_address(page); | |
637 | struct bio_vec *bvl; | |
638 | int i; | |
639 | int page_offset; | |
640 | ||
641 | if (bio->bi_sector >= sector) | |
642 | page_offset = (signed)(bio->bi_sector - sector) * 512; | |
643 | else | |
644 | page_offset = (signed)(sector - bio->bi_sector) * -512; | |
645 | bio_for_each_segment(bvl, bio, i) { | |
646 | int len = bio_iovec_idx(bio,i)->bv_len; | |
647 | int clen; | |
648 | int b_offset = 0; | |
649 | ||
650 | if (page_offset < 0) { | |
651 | b_offset = -page_offset; | |
652 | page_offset += b_offset; | |
653 | len -= b_offset; | |
654 | } | |
655 | ||
656 | if (len > 0 && page_offset + len > STRIPE_SIZE) | |
657 | clen = STRIPE_SIZE - page_offset; | |
658 | else clen = len; | |
659 | ||
660 | if (clen > 0) { | |
661 | char *ba = __bio_kmap_atomic(bio, i, KM_USER0); | |
662 | if (frombio) | |
663 | memcpy(pa+page_offset, ba+b_offset, clen); | |
664 | else | |
665 | memcpy(ba+b_offset, pa+page_offset, clen); | |
666 | __bio_kunmap_atomic(ba, KM_USER0); | |
667 | } | |
668 | if (clen < len) /* hit end of page */ | |
669 | break; | |
670 | page_offset += len; | |
671 | } | |
672 | } | |
673 | ||
674 | #define check_xor() do { \ | |
675 | if (count == MAX_XOR_BLOCKS) { \ | |
676 | xor_block(count, STRIPE_SIZE, ptr); \ | |
677 | count = 1; \ | |
678 | } \ | |
679 | } while(0) | |
680 | ||
681 | ||
682 | static void compute_block(struct stripe_head *sh, int dd_idx) | |
683 | { | |
684 | raid5_conf_t *conf = sh->raid_conf; | |
685 | int i, count, disks = conf->raid_disks; | |
686 | void *ptr[MAX_XOR_BLOCKS], *p; | |
687 | ||
688 | PRINTK("compute_block, stripe %llu, idx %d\n", | |
689 | (unsigned long long)sh->sector, dd_idx); | |
690 | ||
691 | ptr[0] = page_address(sh->dev[dd_idx].page); | |
692 | memset(ptr[0], 0, STRIPE_SIZE); | |
693 | count = 1; | |
694 | for (i = disks ; i--; ) { | |
695 | if (i == dd_idx) | |
696 | continue; | |
697 | p = page_address(sh->dev[i].page); | |
698 | if (test_bit(R5_UPTODATE, &sh->dev[i].flags)) | |
699 | ptr[count++] = p; | |
700 | else | |
701 | printk("compute_block() %d, stripe %llu, %d" | |
702 | " not present\n", dd_idx, | |
703 | (unsigned long long)sh->sector, i); | |
704 | ||
705 | check_xor(); | |
706 | } | |
707 | if (count != 1) | |
708 | xor_block(count, STRIPE_SIZE, ptr); | |
709 | set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); | |
710 | } | |
711 | ||
712 | static void compute_parity(struct stripe_head *sh, int method) | |
713 | { | |
714 | raid5_conf_t *conf = sh->raid_conf; | |
715 | int i, pd_idx = sh->pd_idx, disks = conf->raid_disks, count; | |
716 | void *ptr[MAX_XOR_BLOCKS]; | |
717 | struct bio *chosen; | |
718 | ||
719 | PRINTK("compute_parity, stripe %llu, method %d\n", | |
720 | (unsigned long long)sh->sector, method); | |
721 | ||
722 | count = 1; | |
723 | ptr[0] = page_address(sh->dev[pd_idx].page); | |
724 | switch(method) { | |
725 | case READ_MODIFY_WRITE: | |
726 | if (!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags)) | |
727 | BUG(); | |
728 | for (i=disks ; i-- ;) { | |
729 | if (i==pd_idx) | |
730 | continue; | |
731 | if (sh->dev[i].towrite && | |
732 | test_bit(R5_UPTODATE, &sh->dev[i].flags)) { | |
733 | ptr[count++] = page_address(sh->dev[i].page); | |
734 | chosen = sh->dev[i].towrite; | |
735 | sh->dev[i].towrite = NULL; | |
736 | ||
737 | if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) | |
738 | wake_up(&conf->wait_for_overlap); | |
739 | ||
740 | if (sh->dev[i].written) BUG(); | |
741 | sh->dev[i].written = chosen; | |
742 | check_xor(); | |
743 | } | |
744 | } | |
745 | break; | |
746 | case RECONSTRUCT_WRITE: | |
747 | memset(ptr[0], 0, STRIPE_SIZE); | |
748 | for (i= disks; i-- ;) | |
749 | if (i!=pd_idx && sh->dev[i].towrite) { | |
750 | chosen = sh->dev[i].towrite; | |
751 | sh->dev[i].towrite = NULL; | |
752 | ||
753 | if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) | |
754 | wake_up(&conf->wait_for_overlap); | |
755 | ||
756 | if (sh->dev[i].written) BUG(); | |
757 | sh->dev[i].written = chosen; | |
758 | } | |
759 | break; | |
760 | case CHECK_PARITY: | |
761 | break; | |
762 | } | |
763 | if (count>1) { | |
764 | xor_block(count, STRIPE_SIZE, ptr); | |
765 | count = 1; | |
766 | } | |
767 | ||
768 | for (i = disks; i--;) | |
769 | if (sh->dev[i].written) { | |
770 | sector_t sector = sh->dev[i].sector; | |
771 | struct bio *wbi = sh->dev[i].written; | |
772 | while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) { | |
773 | copy_data(1, wbi, sh->dev[i].page, sector); | |
774 | wbi = r5_next_bio(wbi, sector); | |
775 | } | |
776 | ||
777 | set_bit(R5_LOCKED, &sh->dev[i].flags); | |
778 | set_bit(R5_UPTODATE, &sh->dev[i].flags); | |
779 | } | |
780 | ||
781 | switch(method) { | |
782 | case RECONSTRUCT_WRITE: | |
783 | case CHECK_PARITY: | |
784 | for (i=disks; i--;) | |
785 | if (i != pd_idx) { | |
786 | ptr[count++] = page_address(sh->dev[i].page); | |
787 | check_xor(); | |
788 | } | |
789 | break; | |
790 | case READ_MODIFY_WRITE: | |
791 | for (i = disks; i--;) | |
792 | if (sh->dev[i].written) { | |
793 | ptr[count++] = page_address(sh->dev[i].page); | |
794 | check_xor(); | |
795 | } | |
796 | } | |
797 | if (count != 1) | |
798 | xor_block(count, STRIPE_SIZE, ptr); | |
799 | ||
800 | if (method != CHECK_PARITY) { | |
801 | set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); | |
802 | set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); | |
803 | } else | |
804 | clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); | |
805 | } | |
806 | ||
807 | /* | |
808 | * Each stripe/dev can have one or more bion attached. | |
809 | * toread/towrite point to the first in a chain. | |
810 | * The bi_next chain must be in order. | |
811 | */ | |
812 | static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite) | |
813 | { | |
814 | struct bio **bip; | |
815 | raid5_conf_t *conf = sh->raid_conf; | |
72626685 | 816 | int firstwrite=0; |
1da177e4 LT |
817 | |
818 | PRINTK("adding bh b#%llu to stripe s#%llu\n", | |
819 | (unsigned long long)bi->bi_sector, | |
820 | (unsigned long long)sh->sector); | |
821 | ||
822 | ||
823 | spin_lock(&sh->lock); | |
824 | spin_lock_irq(&conf->device_lock); | |
72626685 | 825 | if (forwrite) { |
1da177e4 | 826 | bip = &sh->dev[dd_idx].towrite; |
72626685 N |
827 | if (*bip == NULL && sh->dev[dd_idx].written == NULL) |
828 | firstwrite = 1; | |
829 | } else | |
1da177e4 LT |
830 | bip = &sh->dev[dd_idx].toread; |
831 | while (*bip && (*bip)->bi_sector < bi->bi_sector) { | |
832 | if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector) | |
833 | goto overlap; | |
834 | bip = & (*bip)->bi_next; | |
835 | } | |
836 | if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9)) | |
837 | goto overlap; | |
838 | ||
839 | if (*bip && bi->bi_next && (*bip) != bi->bi_next) | |
840 | BUG(); | |
841 | if (*bip) | |
842 | bi->bi_next = *bip; | |
843 | *bip = bi; | |
844 | bi->bi_phys_segments ++; | |
845 | spin_unlock_irq(&conf->device_lock); | |
846 | spin_unlock(&sh->lock); | |
847 | ||
848 | PRINTK("added bi b#%llu to stripe s#%llu, disk %d.\n", | |
849 | (unsigned long long)bi->bi_sector, | |
850 | (unsigned long long)sh->sector, dd_idx); | |
851 | ||
72626685 N |
852 | if (conf->mddev->bitmap && firstwrite) { |
853 | sh->bm_seq = conf->seq_write; | |
854 | bitmap_startwrite(conf->mddev->bitmap, sh->sector, | |
855 | STRIPE_SECTORS, 0); | |
856 | set_bit(STRIPE_BIT_DELAY, &sh->state); | |
857 | } | |
858 | ||
1da177e4 LT |
859 | if (forwrite) { |
860 | /* check if page is covered */ | |
861 | sector_t sector = sh->dev[dd_idx].sector; | |
862 | for (bi=sh->dev[dd_idx].towrite; | |
863 | sector < sh->dev[dd_idx].sector + STRIPE_SECTORS && | |
864 | bi && bi->bi_sector <= sector; | |
865 | bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) { | |
866 | if (bi->bi_sector + (bi->bi_size>>9) >= sector) | |
867 | sector = bi->bi_sector + (bi->bi_size>>9); | |
868 | } | |
869 | if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS) | |
870 | set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags); | |
871 | } | |
872 | return 1; | |
873 | ||
874 | overlap: | |
875 | set_bit(R5_Overlap, &sh->dev[dd_idx].flags); | |
876 | spin_unlock_irq(&conf->device_lock); | |
877 | spin_unlock(&sh->lock); | |
878 | return 0; | |
879 | } | |
880 | ||
881 | ||
882 | /* | |
883 | * handle_stripe - do things to a stripe. | |
884 | * | |
885 | * We lock the stripe and then examine the state of various bits | |
886 | * to see what needs to be done. | |
887 | * Possible results: | |
888 | * return some read request which now have data | |
889 | * return some write requests which are safely on disc | |
890 | * schedule a read on some buffers | |
891 | * schedule a write of some buffers | |
892 | * return confirmation of parity correctness | |
893 | * | |
894 | * Parity calculations are done inside the stripe lock | |
895 | * buffers are taken off read_list or write_list, and bh_cache buffers | |
896 | * get BH_Lock set before the stripe lock is released. | |
897 | * | |
898 | */ | |
899 | ||
900 | static void handle_stripe(struct stripe_head *sh) | |
901 | { | |
902 | raid5_conf_t *conf = sh->raid_conf; | |
903 | int disks = conf->raid_disks; | |
904 | struct bio *return_bi= NULL; | |
905 | struct bio *bi; | |
906 | int i; | |
907 | int syncing; | |
908 | int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0; | |
909 | int non_overwrite = 0; | |
910 | int failed_num=0; | |
911 | struct r5dev *dev; | |
912 | ||
913 | PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n", | |
914 | (unsigned long long)sh->sector, atomic_read(&sh->count), | |
915 | sh->pd_idx); | |
916 | ||
917 | spin_lock(&sh->lock); | |
918 | clear_bit(STRIPE_HANDLE, &sh->state); | |
919 | clear_bit(STRIPE_DELAYED, &sh->state); | |
920 | ||
921 | syncing = test_bit(STRIPE_SYNCING, &sh->state); | |
922 | /* Now to look around and see what can be done */ | |
923 | ||
924 | for (i=disks; i--; ) { | |
925 | mdk_rdev_t *rdev; | |
926 | dev = &sh->dev[i]; | |
927 | clear_bit(R5_Insync, &dev->flags); | |
928 | clear_bit(R5_Syncio, &dev->flags); | |
929 | ||
930 | PRINTK("check %d: state 0x%lx read %p write %p written %p\n", | |
931 | i, dev->flags, dev->toread, dev->towrite, dev->written); | |
932 | /* maybe we can reply to a read */ | |
933 | if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) { | |
934 | struct bio *rbi, *rbi2; | |
935 | PRINTK("Return read for disc %d\n", i); | |
936 | spin_lock_irq(&conf->device_lock); | |
937 | rbi = dev->toread; | |
938 | dev->toread = NULL; | |
939 | if (test_and_clear_bit(R5_Overlap, &dev->flags)) | |
940 | wake_up(&conf->wait_for_overlap); | |
941 | spin_unlock_irq(&conf->device_lock); | |
942 | while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) { | |
943 | copy_data(0, rbi, dev->page, dev->sector); | |
944 | rbi2 = r5_next_bio(rbi, dev->sector); | |
945 | spin_lock_irq(&conf->device_lock); | |
946 | if (--rbi->bi_phys_segments == 0) { | |
947 | rbi->bi_next = return_bi; | |
948 | return_bi = rbi; | |
949 | } | |
950 | spin_unlock_irq(&conf->device_lock); | |
951 | rbi = rbi2; | |
952 | } | |
953 | } | |
954 | ||
955 | /* now count some things */ | |
956 | if (test_bit(R5_LOCKED, &dev->flags)) locked++; | |
957 | if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++; | |
958 | ||
959 | ||
960 | if (dev->toread) to_read++; | |
961 | if (dev->towrite) { | |
962 | to_write++; | |
963 | if (!test_bit(R5_OVERWRITE, &dev->flags)) | |
964 | non_overwrite++; | |
965 | } | |
966 | if (dev->written) written++; | |
967 | rdev = conf->disks[i].rdev; /* FIXME, should I be looking rdev */ | |
968 | if (!rdev || !rdev->in_sync) { | |
969 | failed++; | |
970 | failed_num = i; | |
971 | } else | |
972 | set_bit(R5_Insync, &dev->flags); | |
973 | } | |
974 | PRINTK("locked=%d uptodate=%d to_read=%d" | |
975 | " to_write=%d failed=%d failed_num=%d\n", | |
976 | locked, uptodate, to_read, to_write, failed, failed_num); | |
977 | /* check if the array has lost two devices and, if so, some requests might | |
978 | * need to be failed | |
979 | */ | |
980 | if (failed > 1 && to_read+to_write+written) { | |
1da177e4 | 981 | for (i=disks; i--; ) { |
72626685 N |
982 | int bitmap_end = 0; |
983 | spin_lock_irq(&conf->device_lock); | |
1da177e4 LT |
984 | /* fail all writes first */ |
985 | bi = sh->dev[i].towrite; | |
986 | sh->dev[i].towrite = NULL; | |
72626685 | 987 | if (bi) { to_write--; bitmap_end = 1; } |
1da177e4 LT |
988 | |
989 | if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) | |
990 | wake_up(&conf->wait_for_overlap); | |
991 | ||
992 | while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){ | |
993 | struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); | |
994 | clear_bit(BIO_UPTODATE, &bi->bi_flags); | |
995 | if (--bi->bi_phys_segments == 0) { | |
996 | md_write_end(conf->mddev); | |
997 | bi->bi_next = return_bi; | |
998 | return_bi = bi; | |
999 | } | |
1000 | bi = nextbi; | |
1001 | } | |
1002 | /* and fail all 'written' */ | |
1003 | bi = sh->dev[i].written; | |
1004 | sh->dev[i].written = NULL; | |
72626685 | 1005 | if (bi) bitmap_end = 1; |
1da177e4 LT |
1006 | while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) { |
1007 | struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector); | |
1008 | clear_bit(BIO_UPTODATE, &bi->bi_flags); | |
1009 | if (--bi->bi_phys_segments == 0) { | |
1010 | md_write_end(conf->mddev); | |
1011 | bi->bi_next = return_bi; | |
1012 | return_bi = bi; | |
1013 | } | |
1014 | bi = bi2; | |
1015 | } | |
1016 | ||
1017 | /* fail any reads if this device is non-operational */ | |
1018 | if (!test_bit(R5_Insync, &sh->dev[i].flags)) { | |
1019 | bi = sh->dev[i].toread; | |
1020 | sh->dev[i].toread = NULL; | |
1021 | if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) | |
1022 | wake_up(&conf->wait_for_overlap); | |
1023 | if (bi) to_read--; | |
1024 | while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS){ | |
1025 | struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); | |
1026 | clear_bit(BIO_UPTODATE, &bi->bi_flags); | |
1027 | if (--bi->bi_phys_segments == 0) { | |
1028 | bi->bi_next = return_bi; | |
1029 | return_bi = bi; | |
1030 | } | |
1031 | bi = nextbi; | |
1032 | } | |
1033 | } | |
72626685 N |
1034 | spin_unlock_irq(&conf->device_lock); |
1035 | if (bitmap_end) | |
1036 | bitmap_endwrite(conf->mddev->bitmap, sh->sector, | |
1037 | STRIPE_SECTORS, 0, 0); | |
1da177e4 | 1038 | } |
1da177e4 LT |
1039 | } |
1040 | if (failed > 1 && syncing) { | |
1041 | md_done_sync(conf->mddev, STRIPE_SECTORS,0); | |
1042 | clear_bit(STRIPE_SYNCING, &sh->state); | |
1043 | syncing = 0; | |
1044 | } | |
1045 | ||
1046 | /* might be able to return some write requests if the parity block | |
1047 | * is safe, or on a failed drive | |
1048 | */ | |
1049 | dev = &sh->dev[sh->pd_idx]; | |
1050 | if ( written && | |
1051 | ( (test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) && | |
1052 | test_bit(R5_UPTODATE, &dev->flags)) | |
1053 | || (failed == 1 && failed_num == sh->pd_idx)) | |
1054 | ) { | |
1055 | /* any written block on an uptodate or failed drive can be returned. | |
1056 | * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but | |
1057 | * never LOCKED, so we don't need to test 'failed' directly. | |
1058 | */ | |
1059 | for (i=disks; i--; ) | |
1060 | if (sh->dev[i].written) { | |
1061 | dev = &sh->dev[i]; | |
1062 | if (!test_bit(R5_LOCKED, &dev->flags) && | |
1063 | test_bit(R5_UPTODATE, &dev->flags) ) { | |
1064 | /* We can return any write requests */ | |
1065 | struct bio *wbi, *wbi2; | |
72626685 | 1066 | int bitmap_end = 0; |
1da177e4 LT |
1067 | PRINTK("Return write for disc %d\n", i); |
1068 | spin_lock_irq(&conf->device_lock); | |
1069 | wbi = dev->written; | |
1070 | dev->written = NULL; | |
1071 | while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) { | |
1072 | wbi2 = r5_next_bio(wbi, dev->sector); | |
1073 | if (--wbi->bi_phys_segments == 0) { | |
1074 | md_write_end(conf->mddev); | |
1075 | wbi->bi_next = return_bi; | |
1076 | return_bi = wbi; | |
1077 | } | |
1078 | wbi = wbi2; | |
1079 | } | |
72626685 N |
1080 | if (dev->towrite == NULL) |
1081 | bitmap_end = 1; | |
1da177e4 | 1082 | spin_unlock_irq(&conf->device_lock); |
72626685 N |
1083 | if (bitmap_end) |
1084 | bitmap_endwrite(conf->mddev->bitmap, sh->sector, | |
1085 | STRIPE_SECTORS, | |
1086 | !test_bit(STRIPE_DEGRADED, &sh->state), 0); | |
1da177e4 LT |
1087 | } |
1088 | } | |
1089 | } | |
1090 | ||
1091 | /* Now we might consider reading some blocks, either to check/generate | |
1092 | * parity, or to satisfy requests | |
1093 | * or to load a block that is being partially written. | |
1094 | */ | |
1095 | if (to_read || non_overwrite || (syncing && (uptodate < disks))) { | |
1096 | for (i=disks; i--;) { | |
1097 | dev = &sh->dev[i]; | |
1098 | if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && | |
1099 | (dev->toread || | |
1100 | (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || | |
1101 | syncing || | |
1102 | (failed && (sh->dev[failed_num].toread || | |
1103 | (sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags)))) | |
1104 | ) | |
1105 | ) { | |
1106 | /* we would like to get this block, possibly | |
1107 | * by computing it, but we might not be able to | |
1108 | */ | |
1109 | if (uptodate == disks-1) { | |
1110 | PRINTK("Computing block %d\n", i); | |
1111 | compute_block(sh, i); | |
1112 | uptodate++; | |
1113 | } else if (test_bit(R5_Insync, &dev->flags)) { | |
1114 | set_bit(R5_LOCKED, &dev->flags); | |
1115 | set_bit(R5_Wantread, &dev->flags); | |
1116 | #if 0 | |
1117 | /* if I am just reading this block and we don't have | |
1118 | a failed drive, or any pending writes then sidestep the cache */ | |
1119 | if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext && | |
1120 | ! syncing && !failed && !to_write) { | |
1121 | sh->bh_cache[i]->b_page = sh->bh_read[i]->b_page; | |
1122 | sh->bh_cache[i]->b_data = sh->bh_read[i]->b_data; | |
1123 | } | |
1124 | #endif | |
1125 | locked++; | |
1126 | PRINTK("Reading block %d (sync=%d)\n", | |
1127 | i, syncing); | |
1128 | if (syncing) | |
1129 | md_sync_acct(conf->disks[i].rdev->bdev, | |
1130 | STRIPE_SECTORS); | |
1131 | } | |
1132 | } | |
1133 | } | |
1134 | set_bit(STRIPE_HANDLE, &sh->state); | |
1135 | } | |
1136 | ||
1137 | /* now to consider writing and what else, if anything should be read */ | |
1138 | if (to_write) { | |
1139 | int rmw=0, rcw=0; | |
1140 | for (i=disks ; i--;) { | |
1141 | /* would I have to read this buffer for read_modify_write */ | |
1142 | dev = &sh->dev[i]; | |
1143 | if ((dev->towrite || i == sh->pd_idx) && | |
1144 | (!test_bit(R5_LOCKED, &dev->flags) | |
1145 | #if 0 | |
1146 | || sh->bh_page[i]!=bh->b_page | |
1147 | #endif | |
1148 | ) && | |
1149 | !test_bit(R5_UPTODATE, &dev->flags)) { | |
1150 | if (test_bit(R5_Insync, &dev->flags) | |
1151 | /* && !(!mddev->insync && i == sh->pd_idx) */ | |
1152 | ) | |
1153 | rmw++; | |
1154 | else rmw += 2*disks; /* cannot read it */ | |
1155 | } | |
1156 | /* Would I have to read this buffer for reconstruct_write */ | |
1157 | if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && | |
1158 | (!test_bit(R5_LOCKED, &dev->flags) | |
1159 | #if 0 | |
1160 | || sh->bh_page[i] != bh->b_page | |
1161 | #endif | |
1162 | ) && | |
1163 | !test_bit(R5_UPTODATE, &dev->flags)) { | |
1164 | if (test_bit(R5_Insync, &dev->flags)) rcw++; | |
1165 | else rcw += 2*disks; | |
1166 | } | |
1167 | } | |
1168 | PRINTK("for sector %llu, rmw=%d rcw=%d\n", | |
1169 | (unsigned long long)sh->sector, rmw, rcw); | |
1170 | set_bit(STRIPE_HANDLE, &sh->state); | |
1171 | if (rmw < rcw && rmw > 0) | |
1172 | /* prefer read-modify-write, but need to get some data */ | |
1173 | for (i=disks; i--;) { | |
1174 | dev = &sh->dev[i]; | |
1175 | if ((dev->towrite || i == sh->pd_idx) && | |
1176 | !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && | |
1177 | test_bit(R5_Insync, &dev->flags)) { | |
1178 | if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) | |
1179 | { | |
1180 | PRINTK("Read_old block %d for r-m-w\n", i); | |
1181 | set_bit(R5_LOCKED, &dev->flags); | |
1182 | set_bit(R5_Wantread, &dev->flags); | |
1183 | locked++; | |
1184 | } else { | |
1185 | set_bit(STRIPE_DELAYED, &sh->state); | |
1186 | set_bit(STRIPE_HANDLE, &sh->state); | |
1187 | } | |
1188 | } | |
1189 | } | |
1190 | if (rcw <= rmw && rcw > 0) | |
1191 | /* want reconstruct write, but need to get some data */ | |
1192 | for (i=disks; i--;) { | |
1193 | dev = &sh->dev[i]; | |
1194 | if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && | |
1195 | !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && | |
1196 | test_bit(R5_Insync, &dev->flags)) { | |
1197 | if (test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) | |
1198 | { | |
1199 | PRINTK("Read_old block %d for Reconstruct\n", i); | |
1200 | set_bit(R5_LOCKED, &dev->flags); | |
1201 | set_bit(R5_Wantread, &dev->flags); | |
1202 | locked++; | |
1203 | } else { | |
1204 | set_bit(STRIPE_DELAYED, &sh->state); | |
1205 | set_bit(STRIPE_HANDLE, &sh->state); | |
1206 | } | |
1207 | } | |
1208 | } | |
1209 | /* now if nothing is locked, and if we have enough data, we can start a write request */ | |
72626685 N |
1210 | if (locked == 0 && (rcw == 0 ||rmw == 0) && |
1211 | !test_bit(STRIPE_BIT_DELAY, &sh->state)) { | |
1da177e4 LT |
1212 | PRINTK("Computing parity...\n"); |
1213 | compute_parity(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE); | |
1214 | /* now every locked buffer is ready to be written */ | |
1215 | for (i=disks; i--;) | |
1216 | if (test_bit(R5_LOCKED, &sh->dev[i].flags)) { | |
1217 | PRINTK("Writing block %d\n", i); | |
1218 | locked++; | |
1219 | set_bit(R5_Wantwrite, &sh->dev[i].flags); | |
1220 | if (!test_bit(R5_Insync, &sh->dev[i].flags) | |
1221 | || (i==sh->pd_idx && failed == 0)) | |
1222 | set_bit(STRIPE_INSYNC, &sh->state); | |
1223 | } | |
1224 | if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { | |
1225 | atomic_dec(&conf->preread_active_stripes); | |
1226 | if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) | |
1227 | md_wakeup_thread(conf->mddev->thread); | |
1228 | } | |
1229 | } | |
1230 | } | |
1231 | ||
1232 | /* maybe we need to check and possibly fix the parity for this stripe | |
1233 | * Any reads will already have been scheduled, so we just see if enough data | |
1234 | * is available | |
1235 | */ | |
1236 | if (syncing && locked == 0 && | |
1237 | !test_bit(STRIPE_INSYNC, &sh->state) && failed <= 1) { | |
1238 | set_bit(STRIPE_HANDLE, &sh->state); | |
1239 | if (failed == 0) { | |
1240 | char *pagea; | |
1241 | if (uptodate != disks) | |
1242 | BUG(); | |
1243 | compute_parity(sh, CHECK_PARITY); | |
1244 | uptodate--; | |
1245 | pagea = page_address(sh->dev[sh->pd_idx].page); | |
1246 | if ((*(u32*)pagea) == 0 && | |
1247 | !memcmp(pagea, pagea+4, STRIPE_SIZE-4)) { | |
1248 | /* parity is correct (on disc, not in buffer any more) */ | |
1249 | set_bit(STRIPE_INSYNC, &sh->state); | |
1250 | } | |
1251 | } | |
1252 | if (!test_bit(STRIPE_INSYNC, &sh->state)) { | |
1253 | if (failed==0) | |
1254 | failed_num = sh->pd_idx; | |
1255 | /* should be able to compute the missing block and write it to spare */ | |
1256 | if (!test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)) { | |
1257 | if (uptodate+1 != disks) | |
1258 | BUG(); | |
1259 | compute_block(sh, failed_num); | |
1260 | uptodate++; | |
1261 | } | |
1262 | if (uptodate != disks) | |
1263 | BUG(); | |
1264 | dev = &sh->dev[failed_num]; | |
1265 | set_bit(R5_LOCKED, &dev->flags); | |
1266 | set_bit(R5_Wantwrite, &dev->flags); | |
72626685 | 1267 | clear_bit(STRIPE_DEGRADED, &sh->state); |
1da177e4 LT |
1268 | locked++; |
1269 | set_bit(STRIPE_INSYNC, &sh->state); | |
1270 | set_bit(R5_Syncio, &dev->flags); | |
1271 | } | |
1272 | } | |
1273 | if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { | |
1274 | md_done_sync(conf->mddev, STRIPE_SECTORS,1); | |
1275 | clear_bit(STRIPE_SYNCING, &sh->state); | |
1276 | } | |
1277 | ||
1278 | spin_unlock(&sh->lock); | |
1279 | ||
1280 | while ((bi=return_bi)) { | |
1281 | int bytes = bi->bi_size; | |
1282 | ||
1283 | return_bi = bi->bi_next; | |
1284 | bi->bi_next = NULL; | |
1285 | bi->bi_size = 0; | |
1286 | bi->bi_end_io(bi, bytes, 0); | |
1287 | } | |
1288 | for (i=disks; i-- ;) { | |
1289 | int rw; | |
1290 | struct bio *bi; | |
1291 | mdk_rdev_t *rdev; | |
1292 | if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) | |
1293 | rw = 1; | |
1294 | else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags)) | |
1295 | rw = 0; | |
1296 | else | |
1297 | continue; | |
1298 | ||
1299 | bi = &sh->dev[i].req; | |
1300 | ||
1301 | bi->bi_rw = rw; | |
1302 | if (rw) | |
1303 | bi->bi_end_io = raid5_end_write_request; | |
1304 | else | |
1305 | bi->bi_end_io = raid5_end_read_request; | |
1306 | ||
1307 | rcu_read_lock(); | |
1308 | rdev = conf->disks[i].rdev; | |
1309 | if (rdev && rdev->faulty) | |
1310 | rdev = NULL; | |
1311 | if (rdev) | |
1312 | atomic_inc(&rdev->nr_pending); | |
1313 | rcu_read_unlock(); | |
1314 | ||
1315 | if (rdev) { | |
1316 | if (test_bit(R5_Syncio, &sh->dev[i].flags)) | |
1317 | md_sync_acct(rdev->bdev, STRIPE_SECTORS); | |
1318 | ||
1319 | bi->bi_bdev = rdev->bdev; | |
1320 | PRINTK("for %llu schedule op %ld on disc %d\n", | |
1321 | (unsigned long long)sh->sector, bi->bi_rw, i); | |
1322 | atomic_inc(&sh->count); | |
1323 | bi->bi_sector = sh->sector + rdev->data_offset; | |
1324 | bi->bi_flags = 1 << BIO_UPTODATE; | |
1325 | bi->bi_vcnt = 1; | |
1326 | bi->bi_max_vecs = 1; | |
1327 | bi->bi_idx = 0; | |
1328 | bi->bi_io_vec = &sh->dev[i].vec; | |
1329 | bi->bi_io_vec[0].bv_len = STRIPE_SIZE; | |
1330 | bi->bi_io_vec[0].bv_offset = 0; | |
1331 | bi->bi_size = STRIPE_SIZE; | |
1332 | bi->bi_next = NULL; | |
1333 | generic_make_request(bi); | |
1334 | } else { | |
72626685 N |
1335 | if (rw == 1) |
1336 | set_bit(STRIPE_DEGRADED, &sh->state); | |
1da177e4 LT |
1337 | PRINTK("skip op %ld on disc %d for sector %llu\n", |
1338 | bi->bi_rw, i, (unsigned long long)sh->sector); | |
1339 | clear_bit(R5_LOCKED, &sh->dev[i].flags); | |
1340 | set_bit(STRIPE_HANDLE, &sh->state); | |
1341 | } | |
1342 | } | |
1343 | } | |
1344 | ||
1345 | static inline void raid5_activate_delayed(raid5_conf_t *conf) | |
1346 | { | |
1347 | if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) { | |
1348 | while (!list_empty(&conf->delayed_list)) { | |
1349 | struct list_head *l = conf->delayed_list.next; | |
1350 | struct stripe_head *sh; | |
1351 | sh = list_entry(l, struct stripe_head, lru); | |
1352 | list_del_init(l); | |
1353 | clear_bit(STRIPE_DELAYED, &sh->state); | |
1354 | if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) | |
1355 | atomic_inc(&conf->preread_active_stripes); | |
1356 | list_add_tail(&sh->lru, &conf->handle_list); | |
1357 | } | |
1358 | } | |
1359 | } | |
1360 | ||
72626685 N |
1361 | static inline void activate_bit_delay(raid5_conf_t *conf) |
1362 | { | |
1363 | /* device_lock is held */ | |
1364 | struct list_head head; | |
1365 | list_add(&head, &conf->bitmap_list); | |
1366 | list_del_init(&conf->bitmap_list); | |
1367 | while (!list_empty(&head)) { | |
1368 | struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru); | |
1369 | list_del_init(&sh->lru); | |
1370 | atomic_inc(&sh->count); | |
1371 | __release_stripe(conf, sh); | |
1372 | } | |
1373 | } | |
1374 | ||
1da177e4 LT |
1375 | static void unplug_slaves(mddev_t *mddev) |
1376 | { | |
1377 | raid5_conf_t *conf = mddev_to_conf(mddev); | |
1378 | int i; | |
1379 | ||
1380 | rcu_read_lock(); | |
1381 | for (i=0; i<mddev->raid_disks; i++) { | |
1382 | mdk_rdev_t *rdev = conf->disks[i].rdev; | |
1383 | if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) { | |
1384 | request_queue_t *r_queue = bdev_get_queue(rdev->bdev); | |
1385 | ||
1386 | atomic_inc(&rdev->nr_pending); | |
1387 | rcu_read_unlock(); | |
1388 | ||
1389 | if (r_queue->unplug_fn) | |
1390 | r_queue->unplug_fn(r_queue); | |
1391 | ||
1392 | rdev_dec_pending(rdev, mddev); | |
1393 | rcu_read_lock(); | |
1394 | } | |
1395 | } | |
1396 | rcu_read_unlock(); | |
1397 | } | |
1398 | ||
1399 | static void raid5_unplug_device(request_queue_t *q) | |
1400 | { | |
1401 | mddev_t *mddev = q->queuedata; | |
1402 | raid5_conf_t *conf = mddev_to_conf(mddev); | |
1403 | unsigned long flags; | |
1404 | ||
1405 | spin_lock_irqsave(&conf->device_lock, flags); | |
1406 | ||
72626685 N |
1407 | if (blk_remove_plug(q)) { |
1408 | conf->seq_flush++; | |
1da177e4 | 1409 | raid5_activate_delayed(conf); |
72626685 | 1410 | } |
1da177e4 LT |
1411 | md_wakeup_thread(mddev->thread); |
1412 | ||
1413 | spin_unlock_irqrestore(&conf->device_lock, flags); | |
1414 | ||
1415 | unplug_slaves(mddev); | |
1416 | } | |
1417 | ||
1418 | static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk, | |
1419 | sector_t *error_sector) | |
1420 | { | |
1421 | mddev_t *mddev = q->queuedata; | |
1422 | raid5_conf_t *conf = mddev_to_conf(mddev); | |
1423 | int i, ret = 0; | |
1424 | ||
1425 | rcu_read_lock(); | |
1426 | for (i=0; i<mddev->raid_disks && ret == 0; i++) { | |
1427 | mdk_rdev_t *rdev = conf->disks[i].rdev; | |
1428 | if (rdev && !rdev->faulty) { | |
1429 | struct block_device *bdev = rdev->bdev; | |
1430 | request_queue_t *r_queue = bdev_get_queue(bdev); | |
1431 | ||
1432 | if (!r_queue->issue_flush_fn) | |
1433 | ret = -EOPNOTSUPP; | |
1434 | else { | |
1435 | atomic_inc(&rdev->nr_pending); | |
1436 | rcu_read_unlock(); | |
1437 | ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, | |
1438 | error_sector); | |
1439 | rdev_dec_pending(rdev, mddev); | |
1440 | rcu_read_lock(); | |
1441 | } | |
1442 | } | |
1443 | } | |
1444 | rcu_read_unlock(); | |
1445 | return ret; | |
1446 | } | |
1447 | ||
1448 | static inline void raid5_plug_device(raid5_conf_t *conf) | |
1449 | { | |
1450 | spin_lock_irq(&conf->device_lock); | |
1451 | blk_plug_device(conf->mddev->queue); | |
1452 | spin_unlock_irq(&conf->device_lock); | |
1453 | } | |
1454 | ||
1455 | static int make_request (request_queue_t *q, struct bio * bi) | |
1456 | { | |
1457 | mddev_t *mddev = q->queuedata; | |
1458 | raid5_conf_t *conf = mddev_to_conf(mddev); | |
1459 | const unsigned int raid_disks = conf->raid_disks; | |
1460 | const unsigned int data_disks = raid_disks - 1; | |
1461 | unsigned int dd_idx, pd_idx; | |
1462 | sector_t new_sector; | |
1463 | sector_t logical_sector, last_sector; | |
1464 | struct stripe_head *sh; | |
a362357b | 1465 | const int rw = bio_data_dir(bi); |
1da177e4 | 1466 | |
e5dcdd80 N |
1467 | if (unlikely(bio_barrier(bi))) { |
1468 | bio_endio(bi, bi->bi_size, -EOPNOTSUPP); | |
1469 | return 0; | |
1470 | } | |
1471 | ||
3d310eb7 | 1472 | md_write_start(mddev, bi); |
06d91a5f | 1473 | |
a362357b JA |
1474 | disk_stat_inc(mddev->gendisk, ios[rw]); |
1475 | disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi)); | |
1da177e4 LT |
1476 | |
1477 | logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1); | |
1478 | last_sector = bi->bi_sector + (bi->bi_size>>9); | |
1479 | bi->bi_next = NULL; | |
1480 | bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ | |
06d91a5f | 1481 | |
1da177e4 LT |
1482 | for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { |
1483 | DEFINE_WAIT(w); | |
1484 | ||
1485 | new_sector = raid5_compute_sector(logical_sector, | |
1486 | raid_disks, data_disks, &dd_idx, &pd_idx, conf); | |
1487 | ||
1488 | PRINTK("raid5: make_request, sector %llu logical %llu\n", | |
1489 | (unsigned long long)new_sector, | |
1490 | (unsigned long long)logical_sector); | |
1491 | ||
1492 | retry: | |
1493 | prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); | |
1494 | sh = get_active_stripe(conf, new_sector, pd_idx, (bi->bi_rw&RWA_MASK)); | |
1495 | if (sh) { | |
1496 | if (!add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) { | |
1497 | /* Add failed due to overlap. Flush everything | |
1498 | * and wait a while | |
1499 | */ | |
1500 | raid5_unplug_device(mddev->queue); | |
1501 | release_stripe(sh); | |
1502 | schedule(); | |
1503 | goto retry; | |
1504 | } | |
1505 | finish_wait(&conf->wait_for_overlap, &w); | |
1506 | raid5_plug_device(conf); | |
1507 | handle_stripe(sh); | |
1508 | release_stripe(sh); | |
1509 | ||
1510 | } else { | |
1511 | /* cannot get stripe for read-ahead, just give-up */ | |
1512 | clear_bit(BIO_UPTODATE, &bi->bi_flags); | |
1513 | finish_wait(&conf->wait_for_overlap, &w); | |
1514 | break; | |
1515 | } | |
1516 | ||
1517 | } | |
1518 | spin_lock_irq(&conf->device_lock); | |
1519 | if (--bi->bi_phys_segments == 0) { | |
1520 | int bytes = bi->bi_size; | |
1521 | ||
1522 | if ( bio_data_dir(bi) == WRITE ) | |
1523 | md_write_end(mddev); | |
1524 | bi->bi_size = 0; | |
1525 | bi->bi_end_io(bi, bytes, 0); | |
1526 | } | |
1527 | spin_unlock_irq(&conf->device_lock); | |
1528 | return 0; | |
1529 | } | |
1530 | ||
1531 | /* FIXME go_faster isn't used */ | |
57afd89f | 1532 | static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) |
1da177e4 LT |
1533 | { |
1534 | raid5_conf_t *conf = (raid5_conf_t *) mddev->private; | |
1535 | struct stripe_head *sh; | |
1536 | int sectors_per_chunk = conf->chunk_size >> 9; | |
1537 | sector_t x; | |
1538 | unsigned long stripe; | |
1539 | int chunk_offset; | |
1540 | int dd_idx, pd_idx; | |
1541 | sector_t first_sector; | |
1542 | int raid_disks = conf->raid_disks; | |
1543 | int data_disks = raid_disks-1; | |
72626685 N |
1544 | sector_t max_sector = mddev->size << 1; |
1545 | int sync_blocks; | |
1da177e4 | 1546 | |
72626685 | 1547 | if (sector_nr >= max_sector) { |
1da177e4 LT |
1548 | /* just being told to finish up .. nothing much to do */ |
1549 | unplug_slaves(mddev); | |
72626685 N |
1550 | |
1551 | if (mddev->curr_resync < max_sector) /* aborted */ | |
1552 | bitmap_end_sync(mddev->bitmap, mddev->curr_resync, | |
1553 | &sync_blocks, 1); | |
1554 | else /* compelted sync */ | |
1555 | conf->fullsync = 0; | |
1556 | bitmap_close_sync(mddev->bitmap); | |
1557 | ||
1da177e4 LT |
1558 | return 0; |
1559 | } | |
1560 | /* if there is 1 or more failed drives and we are trying | |
1561 | * to resync, then assert that we are finished, because there is | |
1562 | * nothing we can do. | |
1563 | */ | |
1564 | if (mddev->degraded >= 1 && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { | |
57afd89f N |
1565 | sector_t rv = (mddev->size << 1) - sector_nr; |
1566 | *skipped = 1; | |
1da177e4 LT |
1567 | return rv; |
1568 | } | |
72626685 N |
1569 | if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && |
1570 | !conf->fullsync && sync_blocks >= STRIPE_SECTORS) { | |
1571 | /* we can skip this block, and probably more */ | |
1572 | sync_blocks /= STRIPE_SECTORS; | |
1573 | *skipped = 1; | |
1574 | return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */ | |
1575 | } | |
1da177e4 LT |
1576 | |
1577 | x = sector_nr; | |
1578 | chunk_offset = sector_div(x, sectors_per_chunk); | |
1579 | stripe = x; | |
1580 | BUG_ON(x != stripe); | |
1581 | ||
1582 | first_sector = raid5_compute_sector((sector_t)stripe*data_disks*sectors_per_chunk | |
1583 | + chunk_offset, raid_disks, data_disks, &dd_idx, &pd_idx, conf); | |
1584 | sh = get_active_stripe(conf, sector_nr, pd_idx, 1); | |
1585 | if (sh == NULL) { | |
1586 | sh = get_active_stripe(conf, sector_nr, pd_idx, 0); | |
1587 | /* make sure we don't swamp the stripe cache if someone else | |
1588 | * is trying to get access | |
1589 | */ | |
1590 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1591 | schedule_timeout(1); | |
1592 | } | |
72626685 | 1593 | bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 0); |
1da177e4 LT |
1594 | spin_lock(&sh->lock); |
1595 | set_bit(STRIPE_SYNCING, &sh->state); | |
1596 | clear_bit(STRIPE_INSYNC, &sh->state); | |
1597 | spin_unlock(&sh->lock); | |
1598 | ||
1599 | handle_stripe(sh); | |
1600 | release_stripe(sh); | |
1601 | ||
1602 | return STRIPE_SECTORS; | |
1603 | } | |
1604 | ||
1605 | /* | |
1606 | * This is our raid5 kernel thread. | |
1607 | * | |
1608 | * We scan the hash table for stripes which can be handled now. | |
1609 | * During the scan, completed stripes are saved for us by the interrupt | |
1610 | * handler, so that they will not have to wait for our next wakeup. | |
1611 | */ | |
1612 | static void raid5d (mddev_t *mddev) | |
1613 | { | |
1614 | struct stripe_head *sh; | |
1615 | raid5_conf_t *conf = mddev_to_conf(mddev); | |
1616 | int handled; | |
1617 | ||
1618 | PRINTK("+++ raid5d active\n"); | |
1619 | ||
1620 | md_check_recovery(mddev); | |
1da177e4 LT |
1621 | |
1622 | handled = 0; | |
1623 | spin_lock_irq(&conf->device_lock); | |
1624 | while (1) { | |
1625 | struct list_head *first; | |
1626 | ||
72626685 N |
1627 | if (conf->seq_flush - conf->seq_write > 0) { |
1628 | int seq = conf->seq_flush; | |
1629 | bitmap_unplug(mddev->bitmap); | |
1630 | conf->seq_write = seq; | |
1631 | activate_bit_delay(conf); | |
1632 | } | |
1633 | ||
1da177e4 LT |
1634 | if (list_empty(&conf->handle_list) && |
1635 | atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD && | |
1636 | !blk_queue_plugged(mddev->queue) && | |
1637 | !list_empty(&conf->delayed_list)) | |
1638 | raid5_activate_delayed(conf); | |
1639 | ||
1640 | if (list_empty(&conf->handle_list)) | |
1641 | break; | |
1642 | ||
1643 | first = conf->handle_list.next; | |
1644 | sh = list_entry(first, struct stripe_head, lru); | |
1645 | ||
1646 | list_del_init(first); | |
1647 | atomic_inc(&sh->count); | |
1648 | if (atomic_read(&sh->count)!= 1) | |
1649 | BUG(); | |
1650 | spin_unlock_irq(&conf->device_lock); | |
1651 | ||
1652 | handled++; | |
1653 | handle_stripe(sh); | |
1654 | release_stripe(sh); | |
1655 | ||
1656 | spin_lock_irq(&conf->device_lock); | |
1657 | } | |
1658 | PRINTK("%d stripes handled\n", handled); | |
1659 | ||
1660 | spin_unlock_irq(&conf->device_lock); | |
1661 | ||
1662 | unplug_slaves(mddev); | |
1663 | ||
1664 | PRINTK("--- raid5d inactive\n"); | |
1665 | } | |
1666 | ||
72626685 | 1667 | static int run(mddev_t *mddev) |
1da177e4 LT |
1668 | { |
1669 | raid5_conf_t *conf; | |
1670 | int raid_disk, memory; | |
1671 | mdk_rdev_t *rdev; | |
1672 | struct disk_info *disk; | |
1673 | struct list_head *tmp; | |
1674 | ||
1675 | if (mddev->level != 5 && mddev->level != 4) { | |
1676 | printk("raid5: %s: raid level not set to 4/5 (%d)\n", mdname(mddev), mddev->level); | |
1677 | return -EIO; | |
1678 | } | |
1679 | ||
1680 | mddev->private = kmalloc (sizeof (raid5_conf_t) | |
1681 | + mddev->raid_disks * sizeof(struct disk_info), | |
1682 | GFP_KERNEL); | |
1683 | if ((conf = mddev->private) == NULL) | |
1684 | goto abort; | |
1685 | memset (conf, 0, sizeof (*conf) + mddev->raid_disks * sizeof(struct disk_info) ); | |
1686 | conf->mddev = mddev; | |
1687 | ||
1688 | if ((conf->stripe_hashtbl = (struct stripe_head **) __get_free_pages(GFP_ATOMIC, HASH_PAGES_ORDER)) == NULL) | |
1689 | goto abort; | |
1690 | memset(conf->stripe_hashtbl, 0, HASH_PAGES * PAGE_SIZE); | |
1691 | ||
1692 | spin_lock_init(&conf->device_lock); | |
1693 | init_waitqueue_head(&conf->wait_for_stripe); | |
1694 | init_waitqueue_head(&conf->wait_for_overlap); | |
1695 | INIT_LIST_HEAD(&conf->handle_list); | |
1696 | INIT_LIST_HEAD(&conf->delayed_list); | |
72626685 | 1697 | INIT_LIST_HEAD(&conf->bitmap_list); |
1da177e4 LT |
1698 | INIT_LIST_HEAD(&conf->inactive_list); |
1699 | atomic_set(&conf->active_stripes, 0); | |
1700 | atomic_set(&conf->preread_active_stripes, 0); | |
1701 | ||
1da177e4 LT |
1702 | PRINTK("raid5: run(%s) called.\n", mdname(mddev)); |
1703 | ||
1704 | ITERATE_RDEV(mddev,rdev,tmp) { | |
1705 | raid_disk = rdev->raid_disk; | |
1706 | if (raid_disk >= mddev->raid_disks | |
1707 | || raid_disk < 0) | |
1708 | continue; | |
1709 | disk = conf->disks + raid_disk; | |
1710 | ||
1711 | disk->rdev = rdev; | |
1712 | ||
1713 | if (rdev->in_sync) { | |
1714 | char b[BDEVNAME_SIZE]; | |
1715 | printk(KERN_INFO "raid5: device %s operational as raid" | |
1716 | " disk %d\n", bdevname(rdev->bdev,b), | |
1717 | raid_disk); | |
1718 | conf->working_disks++; | |
1719 | } | |
1720 | } | |
1721 | ||
1722 | conf->raid_disks = mddev->raid_disks; | |
1723 | /* | |
1724 | * 0 for a fully functional array, 1 for a degraded array. | |
1725 | */ | |
1726 | mddev->degraded = conf->failed_disks = conf->raid_disks - conf->working_disks; | |
1727 | conf->mddev = mddev; | |
1728 | conf->chunk_size = mddev->chunk_size; | |
1729 | conf->level = mddev->level; | |
1730 | conf->algorithm = mddev->layout; | |
1731 | conf->max_nr_stripes = NR_STRIPES; | |
1732 | ||
1733 | /* device size must be a multiple of chunk size */ | |
1734 | mddev->size &= ~(mddev->chunk_size/1024 -1); | |
b1581566 | 1735 | mddev->resync_max_sectors = mddev->size << 1; |
1da177e4 LT |
1736 | |
1737 | if (!conf->chunk_size || conf->chunk_size % 4) { | |
1738 | printk(KERN_ERR "raid5: invalid chunk size %d for %s\n", | |
1739 | conf->chunk_size, mdname(mddev)); | |
1740 | goto abort; | |
1741 | } | |
1742 | if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) { | |
1743 | printk(KERN_ERR | |
1744 | "raid5: unsupported parity algorithm %d for %s\n", | |
1745 | conf->algorithm, mdname(mddev)); | |
1746 | goto abort; | |
1747 | } | |
1748 | if (mddev->degraded > 1) { | |
1749 | printk(KERN_ERR "raid5: not enough operational devices for %s" | |
1750 | " (%d/%d failed)\n", | |
1751 | mdname(mddev), conf->failed_disks, conf->raid_disks); | |
1752 | goto abort; | |
1753 | } | |
1754 | ||
1755 | if (mddev->degraded == 1 && | |
1756 | mddev->recovery_cp != MaxSector) { | |
1757 | printk(KERN_ERR | |
1758 | "raid5: cannot start dirty degraded array for %s\n", | |
1759 | mdname(mddev)); | |
1760 | goto abort; | |
1761 | } | |
1762 | ||
1763 | { | |
1764 | mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5"); | |
1765 | if (!mddev->thread) { | |
1766 | printk(KERN_ERR | |
1767 | "raid5: couldn't allocate thread for %s\n", | |
1768 | mdname(mddev)); | |
1769 | goto abort; | |
1770 | } | |
1771 | } | |
1772 | memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + | |
1773 | conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; | |
1774 | if (grow_stripes(conf, conf->max_nr_stripes)) { | |
1775 | printk(KERN_ERR | |
1776 | "raid5: couldn't allocate %dkB for buffers\n", memory); | |
1777 | shrink_stripes(conf); | |
1778 | md_unregister_thread(mddev->thread); | |
1779 | goto abort; | |
1780 | } else | |
1781 | printk(KERN_INFO "raid5: allocated %dkB for %s\n", | |
1782 | memory, mdname(mddev)); | |
1783 | ||
1784 | if (mddev->degraded == 0) | |
1785 | printk("raid5: raid level %d set %s active with %d out of %d" | |
1786 | " devices, algorithm %d\n", conf->level, mdname(mddev), | |
1787 | mddev->raid_disks-mddev->degraded, mddev->raid_disks, | |
1788 | conf->algorithm); | |
1789 | else | |
1790 | printk(KERN_ALERT "raid5: raid level %d set %s active with %d" | |
1791 | " out of %d devices, algorithm %d\n", conf->level, | |
1792 | mdname(mddev), mddev->raid_disks - mddev->degraded, | |
1793 | mddev->raid_disks, conf->algorithm); | |
1794 | ||
1795 | print_raid5_conf(conf); | |
1796 | ||
1797 | /* read-ahead size must cover two whole stripes, which is | |
1798 | * 2 * (n-1) * chunksize where 'n' is the number of raid devices | |
1799 | */ | |
1800 | { | |
1801 | int stripe = (mddev->raid_disks-1) * mddev->chunk_size | |
1802 | / PAGE_CACHE_SIZE; | |
1803 | if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe) | |
1804 | mddev->queue->backing_dev_info.ra_pages = 2 * stripe; | |
1805 | } | |
1806 | ||
1807 | /* Ok, everything is just fine now */ | |
7a5febe9 | 1808 | |
72626685 N |
1809 | if (mddev->bitmap) |
1810 | mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ; | |
1811 | ||
7a5febe9 N |
1812 | mddev->queue->unplug_fn = raid5_unplug_device; |
1813 | mddev->queue->issue_flush_fn = raid5_issue_flush; | |
1814 | ||
1da177e4 LT |
1815 | mddev->array_size = mddev->size * (mddev->raid_disks - 1); |
1816 | return 0; | |
1817 | abort: | |
1818 | if (conf) { | |
1819 | print_raid5_conf(conf); | |
1820 | if (conf->stripe_hashtbl) | |
1821 | free_pages((unsigned long) conf->stripe_hashtbl, | |
1822 | HASH_PAGES_ORDER); | |
1823 | kfree(conf); | |
1824 | } | |
1825 | mddev->private = NULL; | |
1826 | printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev)); | |
1827 | return -EIO; | |
1828 | } | |
1829 | ||
1830 | ||
1831 | ||
1832 | static int stop (mddev_t *mddev) | |
1833 | { | |
1834 | raid5_conf_t *conf = (raid5_conf_t *) mddev->private; | |
1835 | ||
1836 | md_unregister_thread(mddev->thread); | |
1837 | mddev->thread = NULL; | |
1838 | shrink_stripes(conf); | |
1839 | free_pages((unsigned long) conf->stripe_hashtbl, HASH_PAGES_ORDER); | |
1840 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ | |
1841 | kfree(conf); | |
1842 | mddev->private = NULL; | |
1843 | return 0; | |
1844 | } | |
1845 | ||
1846 | #if RAID5_DEBUG | |
1847 | static void print_sh (struct stripe_head *sh) | |
1848 | { | |
1849 | int i; | |
1850 | ||
1851 | printk("sh %llu, pd_idx %d, state %ld.\n", | |
1852 | (unsigned long long)sh->sector, sh->pd_idx, sh->state); | |
1853 | printk("sh %llu, count %d.\n", | |
1854 | (unsigned long long)sh->sector, atomic_read(&sh->count)); | |
1855 | printk("sh %llu, ", (unsigned long long)sh->sector); | |
1856 | for (i = 0; i < sh->raid_conf->raid_disks; i++) { | |
1857 | printk("(cache%d: %p %ld) ", | |
1858 | i, sh->dev[i].page, sh->dev[i].flags); | |
1859 | } | |
1860 | printk("\n"); | |
1861 | } | |
1862 | ||
1863 | static void printall (raid5_conf_t *conf) | |
1864 | { | |
1865 | struct stripe_head *sh; | |
1866 | int i; | |
1867 | ||
1868 | spin_lock_irq(&conf->device_lock); | |
1869 | for (i = 0; i < NR_HASH; i++) { | |
1870 | sh = conf->stripe_hashtbl[i]; | |
1871 | for (; sh; sh = sh->hash_next) { | |
1872 | if (sh->raid_conf != conf) | |
1873 | continue; | |
1874 | print_sh(sh); | |
1875 | } | |
1876 | } | |
1877 | spin_unlock_irq(&conf->device_lock); | |
1878 | } | |
1879 | #endif | |
1880 | ||
1881 | static void status (struct seq_file *seq, mddev_t *mddev) | |
1882 | { | |
1883 | raid5_conf_t *conf = (raid5_conf_t *) mddev->private; | |
1884 | int i; | |
1885 | ||
1886 | seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout); | |
1887 | seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks); | |
1888 | for (i = 0; i < conf->raid_disks; i++) | |
1889 | seq_printf (seq, "%s", | |
1890 | conf->disks[i].rdev && | |
1891 | conf->disks[i].rdev->in_sync ? "U" : "_"); | |
1892 | seq_printf (seq, "]"); | |
1893 | #if RAID5_DEBUG | |
1894 | #define D(x) \ | |
1895 | seq_printf (seq, "<"#x":%d>", atomic_read(&conf->x)) | |
1896 | printall(conf); | |
1897 | #endif | |
1898 | } | |
1899 | ||
1900 | static void print_raid5_conf (raid5_conf_t *conf) | |
1901 | { | |
1902 | int i; | |
1903 | struct disk_info *tmp; | |
1904 | ||
1905 | printk("RAID5 conf printout:\n"); | |
1906 | if (!conf) { | |
1907 | printk("(conf==NULL)\n"); | |
1908 | return; | |
1909 | } | |
1910 | printk(" --- rd:%d wd:%d fd:%d\n", conf->raid_disks, | |
1911 | conf->working_disks, conf->failed_disks); | |
1912 | ||
1913 | for (i = 0; i < conf->raid_disks; i++) { | |
1914 | char b[BDEVNAME_SIZE]; | |
1915 | tmp = conf->disks + i; | |
1916 | if (tmp->rdev) | |
1917 | printk(" disk %d, o:%d, dev:%s\n", | |
1918 | i, !tmp->rdev->faulty, | |
1919 | bdevname(tmp->rdev->bdev,b)); | |
1920 | } | |
1921 | } | |
1922 | ||
1923 | static int raid5_spare_active(mddev_t *mddev) | |
1924 | { | |
1925 | int i; | |
1926 | raid5_conf_t *conf = mddev->private; | |
1927 | struct disk_info *tmp; | |
1928 | ||
1929 | for (i = 0; i < conf->raid_disks; i++) { | |
1930 | tmp = conf->disks + i; | |
1931 | if (tmp->rdev | |
1932 | && !tmp->rdev->faulty | |
1933 | && !tmp->rdev->in_sync) { | |
1934 | mddev->degraded--; | |
1935 | conf->failed_disks--; | |
1936 | conf->working_disks++; | |
1937 | tmp->rdev->in_sync = 1; | |
1938 | } | |
1939 | } | |
1940 | print_raid5_conf(conf); | |
1941 | return 0; | |
1942 | } | |
1943 | ||
1944 | static int raid5_remove_disk(mddev_t *mddev, int number) | |
1945 | { | |
1946 | raid5_conf_t *conf = mddev->private; | |
1947 | int err = 0; | |
1948 | mdk_rdev_t *rdev; | |
1949 | struct disk_info *p = conf->disks + number; | |
1950 | ||
1951 | print_raid5_conf(conf); | |
1952 | rdev = p->rdev; | |
1953 | if (rdev) { | |
1954 | if (rdev->in_sync || | |
1955 | atomic_read(&rdev->nr_pending)) { | |
1956 | err = -EBUSY; | |
1957 | goto abort; | |
1958 | } | |
1959 | p->rdev = NULL; | |
fbd568a3 | 1960 | synchronize_rcu(); |
1da177e4 LT |
1961 | if (atomic_read(&rdev->nr_pending)) { |
1962 | /* lost the race, try later */ | |
1963 | err = -EBUSY; | |
1964 | p->rdev = rdev; | |
1965 | } | |
1966 | } | |
1967 | abort: | |
1968 | ||
1969 | print_raid5_conf(conf); | |
1970 | return err; | |
1971 | } | |
1972 | ||
1973 | static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) | |
1974 | { | |
1975 | raid5_conf_t *conf = mddev->private; | |
1976 | int found = 0; | |
1977 | int disk; | |
1978 | struct disk_info *p; | |
1979 | ||
1980 | if (mddev->degraded > 1) | |
1981 | /* no point adding a device */ | |
1982 | return 0; | |
1983 | ||
1984 | /* | |
1985 | * find the disk ... | |
1986 | */ | |
1987 | for (disk=0; disk < mddev->raid_disks; disk++) | |
1988 | if ((p=conf->disks + disk)->rdev == NULL) { | |
1989 | rdev->in_sync = 0; | |
1990 | rdev->raid_disk = disk; | |
1991 | found = 1; | |
72626685 N |
1992 | if (rdev->saved_raid_disk != disk) |
1993 | conf->fullsync = 1; | |
1da177e4 LT |
1994 | p->rdev = rdev; |
1995 | break; | |
1996 | } | |
1997 | print_raid5_conf(conf); | |
1998 | return found; | |
1999 | } | |
2000 | ||
2001 | static int raid5_resize(mddev_t *mddev, sector_t sectors) | |
2002 | { | |
2003 | /* no resync is happening, and there is enough space | |
2004 | * on all devices, so we can resize. | |
2005 | * We need to make sure resync covers any new space. | |
2006 | * If the array is shrinking we should possibly wait until | |
2007 | * any io in the removed space completes, but it hardly seems | |
2008 | * worth it. | |
2009 | */ | |
2010 | sectors &= ~((sector_t)mddev->chunk_size/512 - 1); | |
2011 | mddev->array_size = (sectors * (mddev->raid_disks-1))>>1; | |
2012 | set_capacity(mddev->gendisk, mddev->array_size << 1); | |
2013 | mddev->changed = 1; | |
2014 | if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) { | |
2015 | mddev->recovery_cp = mddev->size << 1; | |
2016 | set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); | |
2017 | } | |
2018 | mddev->size = sectors /2; | |
4b5c7ae8 | 2019 | mddev->resync_max_sectors = sectors; |
1da177e4 LT |
2020 | return 0; |
2021 | } | |
2022 | ||
72626685 N |
2023 | static void raid5_quiesce(mddev_t *mddev, int state) |
2024 | { | |
2025 | raid5_conf_t *conf = mddev_to_conf(mddev); | |
2026 | ||
2027 | switch(state) { | |
2028 | case 1: /* stop all writes */ | |
2029 | spin_lock_irq(&conf->device_lock); | |
2030 | conf->quiesce = 1; | |
2031 | wait_event_lock_irq(conf->wait_for_stripe, | |
2032 | atomic_read(&conf->active_stripes) == 0, | |
2033 | conf->device_lock, /* nothing */); | |
2034 | spin_unlock_irq(&conf->device_lock); | |
2035 | break; | |
2036 | ||
2037 | case 0: /* re-enable writes */ | |
2038 | spin_lock_irq(&conf->device_lock); | |
2039 | conf->quiesce = 0; | |
2040 | wake_up(&conf->wait_for_stripe); | |
2041 | spin_unlock_irq(&conf->device_lock); | |
2042 | break; | |
2043 | } | |
2044 | if (mddev->thread) { | |
2045 | if (mddev->bitmap) | |
2046 | mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ; | |
2047 | else | |
2048 | mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT; | |
2049 | md_wakeup_thread(mddev->thread); | |
2050 | } | |
2051 | } | |
1da177e4 LT |
2052 | static mdk_personality_t raid5_personality= |
2053 | { | |
2054 | .name = "raid5", | |
2055 | .owner = THIS_MODULE, | |
2056 | .make_request = make_request, | |
2057 | .run = run, | |
2058 | .stop = stop, | |
2059 | .status = status, | |
2060 | .error_handler = error, | |
2061 | .hot_add_disk = raid5_add_disk, | |
2062 | .hot_remove_disk= raid5_remove_disk, | |
2063 | .spare_active = raid5_spare_active, | |
2064 | .sync_request = sync_request, | |
2065 | .resize = raid5_resize, | |
72626685 | 2066 | .quiesce = raid5_quiesce, |
1da177e4 LT |
2067 | }; |
2068 | ||
2069 | static int __init raid5_init (void) | |
2070 | { | |
2071 | return register_md_personality (RAID5, &raid5_personality); | |
2072 | } | |
2073 | ||
2074 | static void raid5_exit (void) | |
2075 | { | |
2076 | unregister_md_personality (RAID5); | |
2077 | } | |
2078 | ||
2079 | module_init(raid5_init); | |
2080 | module_exit(raid5_exit); | |
2081 | MODULE_LICENSE("GPL"); | |
2082 | MODULE_ALIAS("md-personality-4"); /* RAID5 */ |