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1 | /* | |
2 | * raid10.c : Multiple Devices driver for Linux | |
3 | * | |
4 | * Copyright (C) 2000-2004 Neil Brown | |
5 | * | |
6 | * RAID-10 support for md. | |
7 | * | |
8 | * Base on code in raid1.c. See raid1.c for futher copyright information. | |
9 | * | |
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 | ||
21 | #include "dm-bio-list.h" | |
22 | #include <linux/raid/raid10.h> | |
23 | #include <linux/raid/bitmap.h> | |
24 | ||
25 | /* | |
26 | * RAID10 provides a combination of RAID0 and RAID1 functionality. | |
27 | * The layout of data is defined by | |
28 | * chunk_size | |
29 | * raid_disks | |
30 | * near_copies (stored in low byte of layout) | |
31 | * far_copies (stored in second byte of layout) | |
32 | * | |
33 | * The data to be stored is divided into chunks using chunksize. | |
34 | * Each device is divided into far_copies sections. | |
35 | * In each section, chunks are laid out in a style similar to raid0, but | |
36 | * near_copies copies of each chunk is stored (each on a different drive). | |
37 | * The starting device for each section is offset near_copies from the starting | |
38 | * device of the previous section. | |
39 | * Thus there are (near_copies*far_copies) of each chunk, and each is on a different | |
40 | * drive. | |
41 | * near_copies and far_copies must be at least one, and their product is at most | |
42 | * raid_disks. | |
43 | */ | |
44 | ||
45 | /* | |
46 | * Number of guaranteed r10bios in case of extreme VM load: | |
47 | */ | |
48 | #define NR_RAID10_BIOS 256 | |
49 | ||
50 | static void unplug_slaves(mddev_t *mddev); | |
51 | ||
52 | static void allow_barrier(conf_t *conf); | |
53 | static void lower_barrier(conf_t *conf); | |
54 | ||
55 | static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data) | |
56 | { | |
57 | conf_t *conf = data; | |
58 | r10bio_t *r10_bio; | |
59 | int size = offsetof(struct r10bio_s, devs[conf->copies]); | |
60 | ||
61 | /* allocate a r10bio with room for raid_disks entries in the bios array */ | |
62 | r10_bio = kmalloc(size, gfp_flags); | |
63 | if (r10_bio) | |
64 | memset(r10_bio, 0, size); | |
65 | else | |
66 | unplug_slaves(conf->mddev); | |
67 | ||
68 | return r10_bio; | |
69 | } | |
70 | ||
71 | static void r10bio_pool_free(void *r10_bio, void *data) | |
72 | { | |
73 | kfree(r10_bio); | |
74 | } | |
75 | ||
76 | #define RESYNC_BLOCK_SIZE (64*1024) | |
77 | //#define RESYNC_BLOCK_SIZE PAGE_SIZE | |
78 | #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9) | |
79 | #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE) | |
80 | #define RESYNC_WINDOW (2048*1024) | |
81 | ||
82 | /* | |
83 | * When performing a resync, we need to read and compare, so | |
84 | * we need as many pages are there are copies. | |
85 | * When performing a recovery, we need 2 bios, one for read, | |
86 | * one for write (we recover only one drive per r10buf) | |
87 | * | |
88 | */ | |
89 | static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data) | |
90 | { | |
91 | conf_t *conf = data; | |
92 | struct page *page; | |
93 | r10bio_t *r10_bio; | |
94 | struct bio *bio; | |
95 | int i, j; | |
96 | int nalloc; | |
97 | ||
98 | r10_bio = r10bio_pool_alloc(gfp_flags, conf); | |
99 | if (!r10_bio) { | |
100 | unplug_slaves(conf->mddev); | |
101 | return NULL; | |
102 | } | |
103 | ||
104 | if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) | |
105 | nalloc = conf->copies; /* resync */ | |
106 | else | |
107 | nalloc = 2; /* recovery */ | |
108 | ||
109 | /* | |
110 | * Allocate bios. | |
111 | */ | |
112 | for (j = nalloc ; j-- ; ) { | |
113 | bio = bio_alloc(gfp_flags, RESYNC_PAGES); | |
114 | if (!bio) | |
115 | goto out_free_bio; | |
116 | r10_bio->devs[j].bio = bio; | |
117 | } | |
118 | /* | |
119 | * Allocate RESYNC_PAGES data pages and attach them | |
120 | * where needed. | |
121 | */ | |
122 | for (j = 0 ; j < nalloc; j++) { | |
123 | bio = r10_bio->devs[j].bio; | |
124 | for (i = 0; i < RESYNC_PAGES; i++) { | |
125 | page = alloc_page(gfp_flags); | |
126 | if (unlikely(!page)) | |
127 | goto out_free_pages; | |
128 | ||
129 | bio->bi_io_vec[i].bv_page = page; | |
130 | } | |
131 | } | |
132 | ||
133 | return r10_bio; | |
134 | ||
135 | out_free_pages: | |
136 | for ( ; i > 0 ; i--) | |
137 | put_page(bio->bi_io_vec[i-1].bv_page); | |
138 | while (j--) | |
139 | for (i = 0; i < RESYNC_PAGES ; i++) | |
140 | put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page); | |
141 | j = -1; | |
142 | out_free_bio: | |
143 | while ( ++j < nalloc ) | |
144 | bio_put(r10_bio->devs[j].bio); | |
145 | r10bio_pool_free(r10_bio, conf); | |
146 | return NULL; | |
147 | } | |
148 | ||
149 | static void r10buf_pool_free(void *__r10_bio, void *data) | |
150 | { | |
151 | int i; | |
152 | conf_t *conf = data; | |
153 | r10bio_t *r10bio = __r10_bio; | |
154 | int j; | |
155 | ||
156 | for (j=0; j < conf->copies; j++) { | |
157 | struct bio *bio = r10bio->devs[j].bio; | |
158 | if (bio) { | |
159 | for (i = 0; i < RESYNC_PAGES; i++) { | |
160 | put_page(bio->bi_io_vec[i].bv_page); | |
161 | bio->bi_io_vec[i].bv_page = NULL; | |
162 | } | |
163 | bio_put(bio); | |
164 | } | |
165 | } | |
166 | r10bio_pool_free(r10bio, conf); | |
167 | } | |
168 | ||
169 | static void put_all_bios(conf_t *conf, r10bio_t *r10_bio) | |
170 | { | |
171 | int i; | |
172 | ||
173 | for (i = 0; i < conf->copies; i++) { | |
174 | struct bio **bio = & r10_bio->devs[i].bio; | |
175 | if (*bio && *bio != IO_BLOCKED) | |
176 | bio_put(*bio); | |
177 | *bio = NULL; | |
178 | } | |
179 | } | |
180 | ||
181 | static inline void free_r10bio(r10bio_t *r10_bio) | |
182 | { | |
183 | conf_t *conf = mddev_to_conf(r10_bio->mddev); | |
184 | ||
185 | /* | |
186 | * Wake up any possible resync thread that waits for the device | |
187 | * to go idle. | |
188 | */ | |
189 | allow_barrier(conf); | |
190 | ||
191 | put_all_bios(conf, r10_bio); | |
192 | mempool_free(r10_bio, conf->r10bio_pool); | |
193 | } | |
194 | ||
195 | static inline void put_buf(r10bio_t *r10_bio) | |
196 | { | |
197 | conf_t *conf = mddev_to_conf(r10_bio->mddev); | |
198 | ||
199 | mempool_free(r10_bio, conf->r10buf_pool); | |
200 | ||
201 | lower_barrier(conf); | |
202 | } | |
203 | ||
204 | static void reschedule_retry(r10bio_t *r10_bio) | |
205 | { | |
206 | unsigned long flags; | |
207 | mddev_t *mddev = r10_bio->mddev; | |
208 | conf_t *conf = mddev_to_conf(mddev); | |
209 | ||
210 | spin_lock_irqsave(&conf->device_lock, flags); | |
211 | list_add(&r10_bio->retry_list, &conf->retry_list); | |
212 | conf->nr_queued ++; | |
213 | spin_unlock_irqrestore(&conf->device_lock, flags); | |
214 | ||
215 | md_wakeup_thread(mddev->thread); | |
216 | } | |
217 | ||
218 | /* | |
219 | * raid_end_bio_io() is called when we have finished servicing a mirrored | |
220 | * operation and are ready to return a success/failure code to the buffer | |
221 | * cache layer. | |
222 | */ | |
223 | static void raid_end_bio_io(r10bio_t *r10_bio) | |
224 | { | |
225 | struct bio *bio = r10_bio->master_bio; | |
226 | ||
227 | bio_endio(bio, bio->bi_size, | |
228 | test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO); | |
229 | free_r10bio(r10_bio); | |
230 | } | |
231 | ||
232 | /* | |
233 | * Update disk head position estimator based on IRQ completion info. | |
234 | */ | |
235 | static inline void update_head_pos(int slot, r10bio_t *r10_bio) | |
236 | { | |
237 | conf_t *conf = mddev_to_conf(r10_bio->mddev); | |
238 | ||
239 | conf->mirrors[r10_bio->devs[slot].devnum].head_position = | |
240 | r10_bio->devs[slot].addr + (r10_bio->sectors); | |
241 | } | |
242 | ||
243 | static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int error) | |
244 | { | |
245 | int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
246 | r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); | |
247 | int slot, dev; | |
248 | conf_t *conf = mddev_to_conf(r10_bio->mddev); | |
249 | ||
250 | if (bio->bi_size) | |
251 | return 1; | |
252 | ||
253 | slot = r10_bio->read_slot; | |
254 | dev = r10_bio->devs[slot].devnum; | |
255 | /* | |
256 | * this branch is our 'one mirror IO has finished' event handler: | |
257 | */ | |
258 | update_head_pos(slot, r10_bio); | |
259 | ||
260 | if (uptodate) { | |
261 | /* | |
262 | * Set R10BIO_Uptodate in our master bio, so that | |
263 | * we will return a good error code to the higher | |
264 | * levels even if IO on some other mirrored buffer fails. | |
265 | * | |
266 | * The 'master' represents the composite IO operation to | |
267 | * user-side. So if something waits for IO, then it will | |
268 | * wait for the 'master' bio. | |
269 | */ | |
270 | set_bit(R10BIO_Uptodate, &r10_bio->state); | |
271 | raid_end_bio_io(r10_bio); | |
272 | } else { | |
273 | /* | |
274 | * oops, read error: | |
275 | */ | |
276 | char b[BDEVNAME_SIZE]; | |
277 | if (printk_ratelimit()) | |
278 | printk(KERN_ERR "raid10: %s: rescheduling sector %llu\n", | |
279 | bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector); | |
280 | reschedule_retry(r10_bio); | |
281 | } | |
282 | ||
283 | rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); | |
284 | return 0; | |
285 | } | |
286 | ||
287 | static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, int error) | |
288 | { | |
289 | int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
290 | r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); | |
291 | int slot, dev; | |
292 | conf_t *conf = mddev_to_conf(r10_bio->mddev); | |
293 | ||
294 | if (bio->bi_size) | |
295 | return 1; | |
296 | ||
297 | for (slot = 0; slot < conf->copies; slot++) | |
298 | if (r10_bio->devs[slot].bio == bio) | |
299 | break; | |
300 | dev = r10_bio->devs[slot].devnum; | |
301 | ||
302 | /* | |
303 | * this branch is our 'one mirror IO has finished' event handler: | |
304 | */ | |
305 | if (!uptodate) { | |
306 | md_error(r10_bio->mddev, conf->mirrors[dev].rdev); | |
307 | /* an I/O failed, we can't clear the bitmap */ | |
308 | set_bit(R10BIO_Degraded, &r10_bio->state); | |
309 | } else | |
310 | /* | |
311 | * Set R10BIO_Uptodate in our master bio, so that | |
312 | * we will return a good error code for to the higher | |
313 | * levels even if IO on some other mirrored buffer fails. | |
314 | * | |
315 | * The 'master' represents the composite IO operation to | |
316 | * user-side. So if something waits for IO, then it will | |
317 | * wait for the 'master' bio. | |
318 | */ | |
319 | set_bit(R10BIO_Uptodate, &r10_bio->state); | |
320 | ||
321 | update_head_pos(slot, r10_bio); | |
322 | ||
323 | /* | |
324 | * | |
325 | * Let's see if all mirrored write operations have finished | |
326 | * already. | |
327 | */ | |
328 | if (atomic_dec_and_test(&r10_bio->remaining)) { | |
329 | /* clear the bitmap if all writes complete successfully */ | |
330 | bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector, | |
331 | r10_bio->sectors, | |
332 | !test_bit(R10BIO_Degraded, &r10_bio->state), | |
333 | 0); | |
334 | md_write_end(r10_bio->mddev); | |
335 | raid_end_bio_io(r10_bio); | |
336 | } | |
337 | ||
338 | rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); | |
339 | return 0; | |
340 | } | |
341 | ||
342 | ||
343 | /* | |
344 | * RAID10 layout manager | |
345 | * Aswell as the chunksize and raid_disks count, there are two | |
346 | * parameters: near_copies and far_copies. | |
347 | * near_copies * far_copies must be <= raid_disks. | |
348 | * Normally one of these will be 1. | |
349 | * If both are 1, we get raid0. | |
350 | * If near_copies == raid_disks, we get raid1. | |
351 | * | |
352 | * Chunks are layed out in raid0 style with near_copies copies of the | |
353 | * first chunk, followed by near_copies copies of the next chunk and | |
354 | * so on. | |
355 | * If far_copies > 1, then after 1/far_copies of the array has been assigned | |
356 | * as described above, we start again with a device offset of near_copies. | |
357 | * So we effectively have another copy of the whole array further down all | |
358 | * the drives, but with blocks on different drives. | |
359 | * With this layout, and block is never stored twice on the one device. | |
360 | * | |
361 | * raid10_find_phys finds the sector offset of a given virtual sector | |
362 | * on each device that it is on. If a block isn't on a device, | |
363 | * that entry in the array is set to MaxSector. | |
364 | * | |
365 | * raid10_find_virt does the reverse mapping, from a device and a | |
366 | * sector offset to a virtual address | |
367 | */ | |
368 | ||
369 | static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio) | |
370 | { | |
371 | int n,f; | |
372 | sector_t sector; | |
373 | sector_t chunk; | |
374 | sector_t stripe; | |
375 | int dev; | |
376 | ||
377 | int slot = 0; | |
378 | ||
379 | /* now calculate first sector/dev */ | |
380 | chunk = r10bio->sector >> conf->chunk_shift; | |
381 | sector = r10bio->sector & conf->chunk_mask; | |
382 | ||
383 | chunk *= conf->near_copies; | |
384 | stripe = chunk; | |
385 | dev = sector_div(stripe, conf->raid_disks); | |
386 | ||
387 | sector += stripe << conf->chunk_shift; | |
388 | ||
389 | /* and calculate all the others */ | |
390 | for (n=0; n < conf->near_copies; n++) { | |
391 | int d = dev; | |
392 | sector_t s = sector; | |
393 | r10bio->devs[slot].addr = sector; | |
394 | r10bio->devs[slot].devnum = d; | |
395 | slot++; | |
396 | ||
397 | for (f = 1; f < conf->far_copies; f++) { | |
398 | d += conf->near_copies; | |
399 | if (d >= conf->raid_disks) | |
400 | d -= conf->raid_disks; | |
401 | s += conf->stride; | |
402 | r10bio->devs[slot].devnum = d; | |
403 | r10bio->devs[slot].addr = s; | |
404 | slot++; | |
405 | } | |
406 | dev++; | |
407 | if (dev >= conf->raid_disks) { | |
408 | dev = 0; | |
409 | sector += (conf->chunk_mask + 1); | |
410 | } | |
411 | } | |
412 | BUG_ON(slot != conf->copies); | |
413 | } | |
414 | ||
415 | static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev) | |
416 | { | |
417 | sector_t offset, chunk, vchunk; | |
418 | ||
419 | while (sector > conf->stride) { | |
420 | sector -= conf->stride; | |
421 | if (dev < conf->near_copies) | |
422 | dev += conf->raid_disks - conf->near_copies; | |
423 | else | |
424 | dev -= conf->near_copies; | |
425 | } | |
426 | ||
427 | offset = sector & conf->chunk_mask; | |
428 | chunk = sector >> conf->chunk_shift; | |
429 | vchunk = chunk * conf->raid_disks + dev; | |
430 | sector_div(vchunk, conf->near_copies); | |
431 | return (vchunk << conf->chunk_shift) + offset; | |
432 | } | |
433 | ||
434 | /** | |
435 | * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged | |
436 | * @q: request queue | |
437 | * @bio: the buffer head that's been built up so far | |
438 | * @biovec: the request that could be merged to it. | |
439 | * | |
440 | * Return amount of bytes we can accept at this offset | |
441 | * If near_copies == raid_disk, there are no striping issues, | |
442 | * but in that case, the function isn't called at all. | |
443 | */ | |
444 | static int raid10_mergeable_bvec(request_queue_t *q, struct bio *bio, | |
445 | struct bio_vec *bio_vec) | |
446 | { | |
447 | mddev_t *mddev = q->queuedata; | |
448 | sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); | |
449 | int max; | |
450 | unsigned int chunk_sectors = mddev->chunk_size >> 9; | |
451 | unsigned int bio_sectors = bio->bi_size >> 9; | |
452 | ||
453 | max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; | |
454 | if (max < 0) max = 0; /* bio_add cannot handle a negative return */ | |
455 | if (max <= bio_vec->bv_len && bio_sectors == 0) | |
456 | return bio_vec->bv_len; | |
457 | else | |
458 | return max; | |
459 | } | |
460 | ||
461 | /* | |
462 | * This routine returns the disk from which the requested read should | |
463 | * be done. There is a per-array 'next expected sequential IO' sector | |
464 | * number - if this matches on the next IO then we use the last disk. | |
465 | * There is also a per-disk 'last know head position' sector that is | |
466 | * maintained from IRQ contexts, both the normal and the resync IO | |
467 | * completion handlers update this position correctly. If there is no | |
468 | * perfect sequential match then we pick the disk whose head is closest. | |
469 | * | |
470 | * If there are 2 mirrors in the same 2 devices, performance degrades | |
471 | * because position is mirror, not device based. | |
472 | * | |
473 | * The rdev for the device selected will have nr_pending incremented. | |
474 | */ | |
475 | ||
476 | /* | |
477 | * FIXME: possibly should rethink readbalancing and do it differently | |
478 | * depending on near_copies / far_copies geometry. | |
479 | */ | |
480 | static int read_balance(conf_t *conf, r10bio_t *r10_bio) | |
481 | { | |
482 | const unsigned long this_sector = r10_bio->sector; | |
483 | int disk, slot, nslot; | |
484 | const int sectors = r10_bio->sectors; | |
485 | sector_t new_distance, current_distance; | |
486 | mdk_rdev_t *rdev; | |
487 | ||
488 | raid10_find_phys(conf, r10_bio); | |
489 | rcu_read_lock(); | |
490 | /* | |
491 | * Check if we can balance. We can balance on the whole | |
492 | * device if no resync is going on (recovery is ok), or below | |
493 | * the resync window. We take the first readable disk when | |
494 | * above the resync window. | |
495 | */ | |
496 | if (conf->mddev->recovery_cp < MaxSector | |
497 | && (this_sector + sectors >= conf->next_resync)) { | |
498 | /* make sure that disk is operational */ | |
499 | slot = 0; | |
500 | disk = r10_bio->devs[slot].devnum; | |
501 | ||
502 | while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL || | |
503 | r10_bio->devs[slot].bio == IO_BLOCKED || | |
504 | !test_bit(In_sync, &rdev->flags)) { | |
505 | slot++; | |
506 | if (slot == conf->copies) { | |
507 | slot = 0; | |
508 | disk = -1; | |
509 | break; | |
510 | } | |
511 | disk = r10_bio->devs[slot].devnum; | |
512 | } | |
513 | goto rb_out; | |
514 | } | |
515 | ||
516 | ||
517 | /* make sure the disk is operational */ | |
518 | slot = 0; | |
519 | disk = r10_bio->devs[slot].devnum; | |
520 | while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL || | |
521 | r10_bio->devs[slot].bio == IO_BLOCKED || | |
522 | !test_bit(In_sync, &rdev->flags)) { | |
523 | slot ++; | |
524 | if (slot == conf->copies) { | |
525 | disk = -1; | |
526 | goto rb_out; | |
527 | } | |
528 | disk = r10_bio->devs[slot].devnum; | |
529 | } | |
530 | ||
531 | ||
532 | current_distance = abs(r10_bio->devs[slot].addr - | |
533 | conf->mirrors[disk].head_position); | |
534 | ||
535 | /* Find the disk whose head is closest */ | |
536 | ||
537 | for (nslot = slot; nslot < conf->copies; nslot++) { | |
538 | int ndisk = r10_bio->devs[nslot].devnum; | |
539 | ||
540 | ||
541 | if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL || | |
542 | r10_bio->devs[nslot].bio == IO_BLOCKED || | |
543 | !test_bit(In_sync, &rdev->flags)) | |
544 | continue; | |
545 | ||
546 | /* This optimisation is debatable, and completely destroys | |
547 | * sequential read speed for 'far copies' arrays. So only | |
548 | * keep it for 'near' arrays, and review those later. | |
549 | */ | |
550 | if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending)) { | |
551 | disk = ndisk; | |
552 | slot = nslot; | |
553 | break; | |
554 | } | |
555 | new_distance = abs(r10_bio->devs[nslot].addr - | |
556 | conf->mirrors[ndisk].head_position); | |
557 | if (new_distance < current_distance) { | |
558 | current_distance = new_distance; | |
559 | disk = ndisk; | |
560 | slot = nslot; | |
561 | } | |
562 | } | |
563 | ||
564 | rb_out: | |
565 | r10_bio->read_slot = slot; | |
566 | /* conf->next_seq_sect = this_sector + sectors;*/ | |
567 | ||
568 | if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL) | |
569 | atomic_inc(&conf->mirrors[disk].rdev->nr_pending); | |
570 | rcu_read_unlock(); | |
571 | ||
572 | return disk; | |
573 | } | |
574 | ||
575 | static void unplug_slaves(mddev_t *mddev) | |
576 | { | |
577 | conf_t *conf = mddev_to_conf(mddev); | |
578 | int i; | |
579 | ||
580 | rcu_read_lock(); | |
581 | for (i=0; i<mddev->raid_disks; i++) { | |
582 | mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); | |
583 | if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { | |
584 | request_queue_t *r_queue = bdev_get_queue(rdev->bdev); | |
585 | ||
586 | atomic_inc(&rdev->nr_pending); | |
587 | rcu_read_unlock(); | |
588 | ||
589 | if (r_queue->unplug_fn) | |
590 | r_queue->unplug_fn(r_queue); | |
591 | ||
592 | rdev_dec_pending(rdev, mddev); | |
593 | rcu_read_lock(); | |
594 | } | |
595 | } | |
596 | rcu_read_unlock(); | |
597 | } | |
598 | ||
599 | static void raid10_unplug(request_queue_t *q) | |
600 | { | |
601 | mddev_t *mddev = q->queuedata; | |
602 | ||
603 | unplug_slaves(q->queuedata); | |
604 | md_wakeup_thread(mddev->thread); | |
605 | } | |
606 | ||
607 | static int raid10_issue_flush(request_queue_t *q, struct gendisk *disk, | |
608 | sector_t *error_sector) | |
609 | { | |
610 | mddev_t *mddev = q->queuedata; | |
611 | conf_t *conf = mddev_to_conf(mddev); | |
612 | int i, ret = 0; | |
613 | ||
614 | rcu_read_lock(); | |
615 | for (i=0; i<mddev->raid_disks && ret == 0; i++) { | |
616 | mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); | |
617 | if (rdev && !test_bit(Faulty, &rdev->flags)) { | |
618 | struct block_device *bdev = rdev->bdev; | |
619 | request_queue_t *r_queue = bdev_get_queue(bdev); | |
620 | ||
621 | if (!r_queue->issue_flush_fn) | |
622 | ret = -EOPNOTSUPP; | |
623 | else { | |
624 | atomic_inc(&rdev->nr_pending); | |
625 | rcu_read_unlock(); | |
626 | ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, | |
627 | error_sector); | |
628 | rdev_dec_pending(rdev, mddev); | |
629 | rcu_read_lock(); | |
630 | } | |
631 | } | |
632 | } | |
633 | rcu_read_unlock(); | |
634 | return ret; | |
635 | } | |
636 | ||
637 | /* Barriers.... | |
638 | * Sometimes we need to suspend IO while we do something else, | |
639 | * either some resync/recovery, or reconfigure the array. | |
640 | * To do this we raise a 'barrier'. | |
641 | * The 'barrier' is a counter that can be raised multiple times | |
642 | * to count how many activities are happening which preclude | |
643 | * normal IO. | |
644 | * We can only raise the barrier if there is no pending IO. | |
645 | * i.e. if nr_pending == 0. | |
646 | * We choose only to raise the barrier if no-one is waiting for the | |
647 | * barrier to go down. This means that as soon as an IO request | |
648 | * is ready, no other operations which require a barrier will start | |
649 | * until the IO request has had a chance. | |
650 | * | |
651 | * So: regular IO calls 'wait_barrier'. When that returns there | |
652 | * is no backgroup IO happening, It must arrange to call | |
653 | * allow_barrier when it has finished its IO. | |
654 | * backgroup IO calls must call raise_barrier. Once that returns | |
655 | * there is no normal IO happeing. It must arrange to call | |
656 | * lower_barrier when the particular background IO completes. | |
657 | */ | |
658 | #define RESYNC_DEPTH 32 | |
659 | ||
660 | static void raise_barrier(conf_t *conf, int force) | |
661 | { | |
662 | BUG_ON(force && !conf->barrier); | |
663 | spin_lock_irq(&conf->resync_lock); | |
664 | ||
665 | /* Wait until no block IO is waiting (unless 'force') */ | |
666 | wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting, | |
667 | conf->resync_lock, | |
668 | raid10_unplug(conf->mddev->queue)); | |
669 | ||
670 | /* block any new IO from starting */ | |
671 | conf->barrier++; | |
672 | ||
673 | /* No wait for all pending IO to complete */ | |
674 | wait_event_lock_irq(conf->wait_barrier, | |
675 | !conf->nr_pending && conf->barrier < RESYNC_DEPTH, | |
676 | conf->resync_lock, | |
677 | raid10_unplug(conf->mddev->queue)); | |
678 | ||
679 | spin_unlock_irq(&conf->resync_lock); | |
680 | } | |
681 | ||
682 | static void lower_barrier(conf_t *conf) | |
683 | { | |
684 | unsigned long flags; | |
685 | spin_lock_irqsave(&conf->resync_lock, flags); | |
686 | conf->barrier--; | |
687 | spin_unlock_irqrestore(&conf->resync_lock, flags); | |
688 | wake_up(&conf->wait_barrier); | |
689 | } | |
690 | ||
691 | static void wait_barrier(conf_t *conf) | |
692 | { | |
693 | spin_lock_irq(&conf->resync_lock); | |
694 | if (conf->barrier) { | |
695 | conf->nr_waiting++; | |
696 | wait_event_lock_irq(conf->wait_barrier, !conf->barrier, | |
697 | conf->resync_lock, | |
698 | raid10_unplug(conf->mddev->queue)); | |
699 | conf->nr_waiting--; | |
700 | } | |
701 | conf->nr_pending++; | |
702 | spin_unlock_irq(&conf->resync_lock); | |
703 | } | |
704 | ||
705 | static void allow_barrier(conf_t *conf) | |
706 | { | |
707 | unsigned long flags; | |
708 | spin_lock_irqsave(&conf->resync_lock, flags); | |
709 | conf->nr_pending--; | |
710 | spin_unlock_irqrestore(&conf->resync_lock, flags); | |
711 | wake_up(&conf->wait_barrier); | |
712 | } | |
713 | ||
714 | static void freeze_array(conf_t *conf) | |
715 | { | |
716 | /* stop syncio and normal IO and wait for everything to | |
717 | * go quite. | |
718 | * We increment barrier and nr_waiting, and then | |
719 | * wait until barrier+nr_pending match nr_queued+2 | |
720 | */ | |
721 | spin_lock_irq(&conf->resync_lock); | |
722 | conf->barrier++; | |
723 | conf->nr_waiting++; | |
724 | wait_event_lock_irq(conf->wait_barrier, | |
725 | conf->barrier+conf->nr_pending == conf->nr_queued+2, | |
726 | conf->resync_lock, | |
727 | raid10_unplug(conf->mddev->queue)); | |
728 | spin_unlock_irq(&conf->resync_lock); | |
729 | } | |
730 | ||
731 | static void unfreeze_array(conf_t *conf) | |
732 | { | |
733 | /* reverse the effect of the freeze */ | |
734 | spin_lock_irq(&conf->resync_lock); | |
735 | conf->barrier--; | |
736 | conf->nr_waiting--; | |
737 | wake_up(&conf->wait_barrier); | |
738 | spin_unlock_irq(&conf->resync_lock); | |
739 | } | |
740 | ||
741 | static int make_request(request_queue_t *q, struct bio * bio) | |
742 | { | |
743 | mddev_t *mddev = q->queuedata; | |
744 | conf_t *conf = mddev_to_conf(mddev); | |
745 | mirror_info_t *mirror; | |
746 | r10bio_t *r10_bio; | |
747 | struct bio *read_bio; | |
748 | int i; | |
749 | int chunk_sects = conf->chunk_mask + 1; | |
750 | const int rw = bio_data_dir(bio); | |
751 | struct bio_list bl; | |
752 | unsigned long flags; | |
753 | ||
754 | if (unlikely(bio_barrier(bio))) { | |
755 | bio_endio(bio, bio->bi_size, -EOPNOTSUPP); | |
756 | return 0; | |
757 | } | |
758 | ||
759 | /* If this request crosses a chunk boundary, we need to | |
760 | * split it. This will only happen for 1 PAGE (or less) requests. | |
761 | */ | |
762 | if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9) | |
763 | > chunk_sects && | |
764 | conf->near_copies < conf->raid_disks)) { | |
765 | struct bio_pair *bp; | |
766 | /* Sanity check -- queue functions should prevent this happening */ | |
767 | if (bio->bi_vcnt != 1 || | |
768 | bio->bi_idx != 0) | |
769 | goto bad_map; | |
770 | /* This is a one page bio that upper layers | |
771 | * refuse to split for us, so we need to split it. | |
772 | */ | |
773 | bp = bio_split(bio, bio_split_pool, | |
774 | chunk_sects - (bio->bi_sector & (chunk_sects - 1)) ); | |
775 | if (make_request(q, &bp->bio1)) | |
776 | generic_make_request(&bp->bio1); | |
777 | if (make_request(q, &bp->bio2)) | |
778 | generic_make_request(&bp->bio2); | |
779 | ||
780 | bio_pair_release(bp); | |
781 | return 0; | |
782 | bad_map: | |
783 | printk("raid10_make_request bug: can't convert block across chunks" | |
784 | " or bigger than %dk %llu %d\n", chunk_sects/2, | |
785 | (unsigned long long)bio->bi_sector, bio->bi_size >> 10); | |
786 | ||
787 | bio_io_error(bio, bio->bi_size); | |
788 | return 0; | |
789 | } | |
790 | ||
791 | md_write_start(mddev, bio); | |
792 | ||
793 | /* | |
794 | * Register the new request and wait if the reconstruction | |
795 | * thread has put up a bar for new requests. | |
796 | * Continue immediately if no resync is active currently. | |
797 | */ | |
798 | wait_barrier(conf); | |
799 | ||
800 | disk_stat_inc(mddev->gendisk, ios[rw]); | |
801 | disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio)); | |
802 | ||
803 | r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); | |
804 | ||
805 | r10_bio->master_bio = bio; | |
806 | r10_bio->sectors = bio->bi_size >> 9; | |
807 | ||
808 | r10_bio->mddev = mddev; | |
809 | r10_bio->sector = bio->bi_sector; | |
810 | r10_bio->state = 0; | |
811 | ||
812 | if (rw == READ) { | |
813 | /* | |
814 | * read balancing logic: | |
815 | */ | |
816 | int disk = read_balance(conf, r10_bio); | |
817 | int slot = r10_bio->read_slot; | |
818 | if (disk < 0) { | |
819 | raid_end_bio_io(r10_bio); | |
820 | return 0; | |
821 | } | |
822 | mirror = conf->mirrors + disk; | |
823 | ||
824 | read_bio = bio_clone(bio, GFP_NOIO); | |
825 | ||
826 | r10_bio->devs[slot].bio = read_bio; | |
827 | ||
828 | read_bio->bi_sector = r10_bio->devs[slot].addr + | |
829 | mirror->rdev->data_offset; | |
830 | read_bio->bi_bdev = mirror->rdev->bdev; | |
831 | read_bio->bi_end_io = raid10_end_read_request; | |
832 | read_bio->bi_rw = READ; | |
833 | read_bio->bi_private = r10_bio; | |
834 | ||
835 | generic_make_request(read_bio); | |
836 | return 0; | |
837 | } | |
838 | ||
839 | /* | |
840 | * WRITE: | |
841 | */ | |
842 | /* first select target devices under spinlock and | |
843 | * inc refcount on their rdev. Record them by setting | |
844 | * bios[x] to bio | |
845 | */ | |
846 | raid10_find_phys(conf, r10_bio); | |
847 | rcu_read_lock(); | |
848 | for (i = 0; i < conf->copies; i++) { | |
849 | int d = r10_bio->devs[i].devnum; | |
850 | mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev); | |
851 | if (rdev && | |
852 | !test_bit(Faulty, &rdev->flags)) { | |
853 | atomic_inc(&rdev->nr_pending); | |
854 | r10_bio->devs[i].bio = bio; | |
855 | } else { | |
856 | r10_bio->devs[i].bio = NULL; | |
857 | set_bit(R10BIO_Degraded, &r10_bio->state); | |
858 | } | |
859 | } | |
860 | rcu_read_unlock(); | |
861 | ||
862 | atomic_set(&r10_bio->remaining, 0); | |
863 | ||
864 | bio_list_init(&bl); | |
865 | for (i = 0; i < conf->copies; i++) { | |
866 | struct bio *mbio; | |
867 | int d = r10_bio->devs[i].devnum; | |
868 | if (!r10_bio->devs[i].bio) | |
869 | continue; | |
870 | ||
871 | mbio = bio_clone(bio, GFP_NOIO); | |
872 | r10_bio->devs[i].bio = mbio; | |
873 | ||
874 | mbio->bi_sector = r10_bio->devs[i].addr+ | |
875 | conf->mirrors[d].rdev->data_offset; | |
876 | mbio->bi_bdev = conf->mirrors[d].rdev->bdev; | |
877 | mbio->bi_end_io = raid10_end_write_request; | |
878 | mbio->bi_rw = WRITE; | |
879 | mbio->bi_private = r10_bio; | |
880 | ||
881 | atomic_inc(&r10_bio->remaining); | |
882 | bio_list_add(&bl, mbio); | |
883 | } | |
884 | ||
885 | bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0); | |
886 | spin_lock_irqsave(&conf->device_lock, flags); | |
887 | bio_list_merge(&conf->pending_bio_list, &bl); | |
888 | blk_plug_device(mddev->queue); | |
889 | spin_unlock_irqrestore(&conf->device_lock, flags); | |
890 | ||
891 | return 0; | |
892 | } | |
893 | ||
894 | static void status(struct seq_file *seq, mddev_t *mddev) | |
895 | { | |
896 | conf_t *conf = mddev_to_conf(mddev); | |
897 | int i; | |
898 | ||
899 | if (conf->near_copies < conf->raid_disks) | |
900 | seq_printf(seq, " %dK chunks", mddev->chunk_size/1024); | |
901 | if (conf->near_copies > 1) | |
902 | seq_printf(seq, " %d near-copies", conf->near_copies); | |
903 | if (conf->far_copies > 1) | |
904 | seq_printf(seq, " %d far-copies", conf->far_copies); | |
905 | ||
906 | seq_printf(seq, " [%d/%d] [", conf->raid_disks, | |
907 | conf->working_disks); | |
908 | for (i = 0; i < conf->raid_disks; i++) | |
909 | seq_printf(seq, "%s", | |
910 | conf->mirrors[i].rdev && | |
911 | test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_"); | |
912 | seq_printf(seq, "]"); | |
913 | } | |
914 | ||
915 | static void error(mddev_t *mddev, mdk_rdev_t *rdev) | |
916 | { | |
917 | char b[BDEVNAME_SIZE]; | |
918 | conf_t *conf = mddev_to_conf(mddev); | |
919 | ||
920 | /* | |
921 | * If it is not operational, then we have already marked it as dead | |
922 | * else if it is the last working disks, ignore the error, let the | |
923 | * next level up know. | |
924 | * else mark the drive as failed | |
925 | */ | |
926 | if (test_bit(In_sync, &rdev->flags) | |
927 | && conf->working_disks == 1) | |
928 | /* | |
929 | * Don't fail the drive, just return an IO error. | |
930 | * The test should really be more sophisticated than | |
931 | * "working_disks == 1", but it isn't critical, and | |
932 | * can wait until we do more sophisticated "is the drive | |
933 | * really dead" tests... | |
934 | */ | |
935 | return; | |
936 | if (test_bit(In_sync, &rdev->flags)) { | |
937 | mddev->degraded++; | |
938 | conf->working_disks--; | |
939 | /* | |
940 | * if recovery is running, make sure it aborts. | |
941 | */ | |
942 | set_bit(MD_RECOVERY_ERR, &mddev->recovery); | |
943 | } | |
944 | clear_bit(In_sync, &rdev->flags); | |
945 | set_bit(Faulty, &rdev->flags); | |
946 | mddev->sb_dirty = 1; | |
947 | printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n" | |
948 | " Operation continuing on %d devices\n", | |
949 | bdevname(rdev->bdev,b), conf->working_disks); | |
950 | } | |
951 | ||
952 | static void print_conf(conf_t *conf) | |
953 | { | |
954 | int i; | |
955 | mirror_info_t *tmp; | |
956 | ||
957 | printk("RAID10 conf printout:\n"); | |
958 | if (!conf) { | |
959 | printk("(!conf)\n"); | |
960 | return; | |
961 | } | |
962 | printk(" --- wd:%d rd:%d\n", conf->working_disks, | |
963 | conf->raid_disks); | |
964 | ||
965 | for (i = 0; i < conf->raid_disks; i++) { | |
966 | char b[BDEVNAME_SIZE]; | |
967 | tmp = conf->mirrors + i; | |
968 | if (tmp->rdev) | |
969 | printk(" disk %d, wo:%d, o:%d, dev:%s\n", | |
970 | i, !test_bit(In_sync, &tmp->rdev->flags), | |
971 | !test_bit(Faulty, &tmp->rdev->flags), | |
972 | bdevname(tmp->rdev->bdev,b)); | |
973 | } | |
974 | } | |
975 | ||
976 | static void close_sync(conf_t *conf) | |
977 | { | |
978 | wait_barrier(conf); | |
979 | allow_barrier(conf); | |
980 | ||
981 | mempool_destroy(conf->r10buf_pool); | |
982 | conf->r10buf_pool = NULL; | |
983 | } | |
984 | ||
985 | /* check if there are enough drives for | |
986 | * every block to appear on atleast one | |
987 | */ | |
988 | static int enough(conf_t *conf) | |
989 | { | |
990 | int first = 0; | |
991 | ||
992 | do { | |
993 | int n = conf->copies; | |
994 | int cnt = 0; | |
995 | while (n--) { | |
996 | if (conf->mirrors[first].rdev) | |
997 | cnt++; | |
998 | first = (first+1) % conf->raid_disks; | |
999 | } | |
1000 | if (cnt == 0) | |
1001 | return 0; | |
1002 | } while (first != 0); | |
1003 | return 1; | |
1004 | } | |
1005 | ||
1006 | static int raid10_spare_active(mddev_t *mddev) | |
1007 | { | |
1008 | int i; | |
1009 | conf_t *conf = mddev->private; | |
1010 | mirror_info_t *tmp; | |
1011 | ||
1012 | /* | |
1013 | * Find all non-in_sync disks within the RAID10 configuration | |
1014 | * and mark them in_sync | |
1015 | */ | |
1016 | for (i = 0; i < conf->raid_disks; i++) { | |
1017 | tmp = conf->mirrors + i; | |
1018 | if (tmp->rdev | |
1019 | && !test_bit(Faulty, &tmp->rdev->flags) | |
1020 | && !test_bit(In_sync, &tmp->rdev->flags)) { | |
1021 | conf->working_disks++; | |
1022 | mddev->degraded--; | |
1023 | set_bit(In_sync, &tmp->rdev->flags); | |
1024 | } | |
1025 | } | |
1026 | ||
1027 | print_conf(conf); | |
1028 | return 0; | |
1029 | } | |
1030 | ||
1031 | ||
1032 | static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) | |
1033 | { | |
1034 | conf_t *conf = mddev->private; | |
1035 | int found = 0; | |
1036 | int mirror; | |
1037 | mirror_info_t *p; | |
1038 | ||
1039 | if (mddev->recovery_cp < MaxSector) | |
1040 | /* only hot-add to in-sync arrays, as recovery is | |
1041 | * very different from resync | |
1042 | */ | |
1043 | return 0; | |
1044 | if (!enough(conf)) | |
1045 | return 0; | |
1046 | ||
1047 | if (rdev->saved_raid_disk >= 0 && | |
1048 | conf->mirrors[rdev->saved_raid_disk].rdev == NULL) | |
1049 | mirror = rdev->saved_raid_disk; | |
1050 | else | |
1051 | mirror = 0; | |
1052 | for ( ; mirror < mddev->raid_disks; mirror++) | |
1053 | if ( !(p=conf->mirrors+mirror)->rdev) { | |
1054 | ||
1055 | blk_queue_stack_limits(mddev->queue, | |
1056 | rdev->bdev->bd_disk->queue); | |
1057 | /* as we don't honour merge_bvec_fn, we must never risk | |
1058 | * violating it, so limit ->max_sector to one PAGE, as | |
1059 | * a one page request is never in violation. | |
1060 | */ | |
1061 | if (rdev->bdev->bd_disk->queue->merge_bvec_fn && | |
1062 | mddev->queue->max_sectors > (PAGE_SIZE>>9)) | |
1063 | mddev->queue->max_sectors = (PAGE_SIZE>>9); | |
1064 | ||
1065 | p->head_position = 0; | |
1066 | rdev->raid_disk = mirror; | |
1067 | found = 1; | |
1068 | if (rdev->saved_raid_disk != mirror) | |
1069 | conf->fullsync = 1; | |
1070 | rcu_assign_pointer(p->rdev, rdev); | |
1071 | break; | |
1072 | } | |
1073 | ||
1074 | print_conf(conf); | |
1075 | return found; | |
1076 | } | |
1077 | ||
1078 | static int raid10_remove_disk(mddev_t *mddev, int number) | |
1079 | { | |
1080 | conf_t *conf = mddev->private; | |
1081 | int err = 0; | |
1082 | mdk_rdev_t *rdev; | |
1083 | mirror_info_t *p = conf->mirrors+ number; | |
1084 | ||
1085 | print_conf(conf); | |
1086 | rdev = p->rdev; | |
1087 | if (rdev) { | |
1088 | if (test_bit(In_sync, &rdev->flags) || | |
1089 | atomic_read(&rdev->nr_pending)) { | |
1090 | err = -EBUSY; | |
1091 | goto abort; | |
1092 | } | |
1093 | p->rdev = NULL; | |
1094 | synchronize_rcu(); | |
1095 | if (atomic_read(&rdev->nr_pending)) { | |
1096 | /* lost the race, try later */ | |
1097 | err = -EBUSY; | |
1098 | p->rdev = rdev; | |
1099 | } | |
1100 | } | |
1101 | abort: | |
1102 | ||
1103 | print_conf(conf); | |
1104 | return err; | |
1105 | } | |
1106 | ||
1107 | ||
1108 | static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error) | |
1109 | { | |
1110 | r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); | |
1111 | conf_t *conf = mddev_to_conf(r10_bio->mddev); | |
1112 | int i,d; | |
1113 | ||
1114 | if (bio->bi_size) | |
1115 | return 1; | |
1116 | ||
1117 | for (i=0; i<conf->copies; i++) | |
1118 | if (r10_bio->devs[i].bio == bio) | |
1119 | break; | |
1120 | if (i == conf->copies) | |
1121 | BUG(); | |
1122 | update_head_pos(i, r10_bio); | |
1123 | d = r10_bio->devs[i].devnum; | |
1124 | ||
1125 | if (test_bit(BIO_UPTODATE, &bio->bi_flags)) | |
1126 | set_bit(R10BIO_Uptodate, &r10_bio->state); | |
1127 | else if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) | |
1128 | md_error(r10_bio->mddev, | |
1129 | conf->mirrors[d].rdev); | |
1130 | ||
1131 | /* for reconstruct, we always reschedule after a read. | |
1132 | * for resync, only after all reads | |
1133 | */ | |
1134 | if (test_bit(R10BIO_IsRecover, &r10_bio->state) || | |
1135 | atomic_dec_and_test(&r10_bio->remaining)) { | |
1136 | /* we have read all the blocks, | |
1137 | * do the comparison in process context in raid10d | |
1138 | */ | |
1139 | reschedule_retry(r10_bio); | |
1140 | } | |
1141 | rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev); | |
1142 | return 0; | |
1143 | } | |
1144 | ||
1145 | static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error) | |
1146 | { | |
1147 | int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
1148 | r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); | |
1149 | mddev_t *mddev = r10_bio->mddev; | |
1150 | conf_t *conf = mddev_to_conf(mddev); | |
1151 | int i,d; | |
1152 | ||
1153 | if (bio->bi_size) | |
1154 | return 1; | |
1155 | ||
1156 | for (i = 0; i < conf->copies; i++) | |
1157 | if (r10_bio->devs[i].bio == bio) | |
1158 | break; | |
1159 | d = r10_bio->devs[i].devnum; | |
1160 | ||
1161 | if (!uptodate) | |
1162 | md_error(mddev, conf->mirrors[d].rdev); | |
1163 | update_head_pos(i, r10_bio); | |
1164 | ||
1165 | while (atomic_dec_and_test(&r10_bio->remaining)) { | |
1166 | if (r10_bio->master_bio == NULL) { | |
1167 | /* the primary of several recovery bios */ | |
1168 | md_done_sync(mddev, r10_bio->sectors, 1); | |
1169 | put_buf(r10_bio); | |
1170 | break; | |
1171 | } else { | |
1172 | r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio; | |
1173 | put_buf(r10_bio); | |
1174 | r10_bio = r10_bio2; | |
1175 | } | |
1176 | } | |
1177 | rdev_dec_pending(conf->mirrors[d].rdev, mddev); | |
1178 | return 0; | |
1179 | } | |
1180 | ||
1181 | /* | |
1182 | * Note: sync and recover and handled very differently for raid10 | |
1183 | * This code is for resync. | |
1184 | * For resync, we read through virtual addresses and read all blocks. | |
1185 | * If there is any error, we schedule a write. The lowest numbered | |
1186 | * drive is authoritative. | |
1187 | * However requests come for physical address, so we need to map. | |
1188 | * For every physical address there are raid_disks/copies virtual addresses, | |
1189 | * which is always are least one, but is not necessarly an integer. | |
1190 | * This means that a physical address can span multiple chunks, so we may | |
1191 | * have to submit multiple io requests for a single sync request. | |
1192 | */ | |
1193 | /* | |
1194 | * We check if all blocks are in-sync and only write to blocks that | |
1195 | * aren't in sync | |
1196 | */ | |
1197 | static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio) | |
1198 | { | |
1199 | conf_t *conf = mddev_to_conf(mddev); | |
1200 | int i, first; | |
1201 | struct bio *tbio, *fbio; | |
1202 | ||
1203 | atomic_set(&r10_bio->remaining, 1); | |
1204 | ||
1205 | /* find the first device with a block */ | |
1206 | for (i=0; i<conf->copies; i++) | |
1207 | if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) | |
1208 | break; | |
1209 | ||
1210 | if (i == conf->copies) | |
1211 | goto done; | |
1212 | ||
1213 | first = i; | |
1214 | fbio = r10_bio->devs[i].bio; | |
1215 | ||
1216 | /* now find blocks with errors */ | |
1217 | for (i=0 ; i < conf->copies ; i++) { | |
1218 | int j, d; | |
1219 | int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9); | |
1220 | ||
1221 | tbio = r10_bio->devs[i].bio; | |
1222 | ||
1223 | if (tbio->bi_end_io != end_sync_read) | |
1224 | continue; | |
1225 | if (i == first) | |
1226 | continue; | |
1227 | if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) { | |
1228 | /* We know that the bi_io_vec layout is the same for | |
1229 | * both 'first' and 'i', so we just compare them. | |
1230 | * All vec entries are PAGE_SIZE; | |
1231 | */ | |
1232 | for (j = 0; j < vcnt; j++) | |
1233 | if (memcmp(page_address(fbio->bi_io_vec[j].bv_page), | |
1234 | page_address(tbio->bi_io_vec[j].bv_page), | |
1235 | PAGE_SIZE)) | |
1236 | break; | |
1237 | if (j == vcnt) | |
1238 | continue; | |
1239 | mddev->resync_mismatches += r10_bio->sectors; | |
1240 | } | |
1241 | if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) | |
1242 | /* Don't fix anything. */ | |
1243 | continue; | |
1244 | /* Ok, we need to write this bio | |
1245 | * First we need to fixup bv_offset, bv_len and | |
1246 | * bi_vecs, as the read request might have corrupted these | |
1247 | */ | |
1248 | tbio->bi_vcnt = vcnt; | |
1249 | tbio->bi_size = r10_bio->sectors << 9; | |
1250 | tbio->bi_idx = 0; | |
1251 | tbio->bi_phys_segments = 0; | |
1252 | tbio->bi_hw_segments = 0; | |
1253 | tbio->bi_hw_front_size = 0; | |
1254 | tbio->bi_hw_back_size = 0; | |
1255 | tbio->bi_flags &= ~(BIO_POOL_MASK - 1); | |
1256 | tbio->bi_flags |= 1 << BIO_UPTODATE; | |
1257 | tbio->bi_next = NULL; | |
1258 | tbio->bi_rw = WRITE; | |
1259 | tbio->bi_private = r10_bio; | |
1260 | tbio->bi_sector = r10_bio->devs[i].addr; | |
1261 | ||
1262 | for (j=0; j < vcnt ; j++) { | |
1263 | tbio->bi_io_vec[j].bv_offset = 0; | |
1264 | tbio->bi_io_vec[j].bv_len = PAGE_SIZE; | |
1265 | ||
1266 | memcpy(page_address(tbio->bi_io_vec[j].bv_page), | |
1267 | page_address(fbio->bi_io_vec[j].bv_page), | |
1268 | PAGE_SIZE); | |
1269 | } | |
1270 | tbio->bi_end_io = end_sync_write; | |
1271 | ||
1272 | d = r10_bio->devs[i].devnum; | |
1273 | atomic_inc(&conf->mirrors[d].rdev->nr_pending); | |
1274 | atomic_inc(&r10_bio->remaining); | |
1275 | md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9); | |
1276 | ||
1277 | tbio->bi_sector += conf->mirrors[d].rdev->data_offset; | |
1278 | tbio->bi_bdev = conf->mirrors[d].rdev->bdev; | |
1279 | generic_make_request(tbio); | |
1280 | } | |
1281 | ||
1282 | done: | |
1283 | if (atomic_dec_and_test(&r10_bio->remaining)) { | |
1284 | md_done_sync(mddev, r10_bio->sectors, 1); | |
1285 | put_buf(r10_bio); | |
1286 | } | |
1287 | } | |
1288 | ||
1289 | /* | |
1290 | * Now for the recovery code. | |
1291 | * Recovery happens across physical sectors. | |
1292 | * We recover all non-is_sync drives by finding the virtual address of | |
1293 | * each, and then choose a working drive that also has that virt address. | |
1294 | * There is a separate r10_bio for each non-in_sync drive. | |
1295 | * Only the first two slots are in use. The first for reading, | |
1296 | * The second for writing. | |
1297 | * | |
1298 | */ | |
1299 | ||
1300 | static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio) | |
1301 | { | |
1302 | conf_t *conf = mddev_to_conf(mddev); | |
1303 | int i, d; | |
1304 | struct bio *bio, *wbio; | |
1305 | ||
1306 | ||
1307 | /* move the pages across to the second bio | |
1308 | * and submit the write request | |
1309 | */ | |
1310 | bio = r10_bio->devs[0].bio; | |
1311 | wbio = r10_bio->devs[1].bio; | |
1312 | for (i=0; i < wbio->bi_vcnt; i++) { | |
1313 | struct page *p = bio->bi_io_vec[i].bv_page; | |
1314 | bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page; | |
1315 | wbio->bi_io_vec[i].bv_page = p; | |
1316 | } | |
1317 | d = r10_bio->devs[1].devnum; | |
1318 | ||
1319 | atomic_inc(&conf->mirrors[d].rdev->nr_pending); | |
1320 | md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9); | |
1321 | if (test_bit(R10BIO_Uptodate, &r10_bio->state)) | |
1322 | generic_make_request(wbio); | |
1323 | else | |
1324 | bio_endio(wbio, wbio->bi_size, -EIO); | |
1325 | } | |
1326 | ||
1327 | ||
1328 | /* | |
1329 | * This is a kernel thread which: | |
1330 | * | |
1331 | * 1. Retries failed read operations on working mirrors. | |
1332 | * 2. Updates the raid superblock when problems encounter. | |
1333 | * 3. Performs writes following reads for array syncronising. | |
1334 | */ | |
1335 | ||
1336 | static void raid10d(mddev_t *mddev) | |
1337 | { | |
1338 | r10bio_t *r10_bio; | |
1339 | struct bio *bio; | |
1340 | unsigned long flags; | |
1341 | conf_t *conf = mddev_to_conf(mddev); | |
1342 | struct list_head *head = &conf->retry_list; | |
1343 | int unplug=0; | |
1344 | mdk_rdev_t *rdev; | |
1345 | ||
1346 | md_check_recovery(mddev); | |
1347 | ||
1348 | for (;;) { | |
1349 | char b[BDEVNAME_SIZE]; | |
1350 | spin_lock_irqsave(&conf->device_lock, flags); | |
1351 | ||
1352 | if (conf->pending_bio_list.head) { | |
1353 | bio = bio_list_get(&conf->pending_bio_list); | |
1354 | blk_remove_plug(mddev->queue); | |
1355 | spin_unlock_irqrestore(&conf->device_lock, flags); | |
1356 | /* flush any pending bitmap writes to disk before proceeding w/ I/O */ | |
1357 | if (bitmap_unplug(mddev->bitmap) != 0) | |
1358 | printk("%s: bitmap file write failed!\n", mdname(mddev)); | |
1359 | ||
1360 | while (bio) { /* submit pending writes */ | |
1361 | struct bio *next = bio->bi_next; | |
1362 | bio->bi_next = NULL; | |
1363 | generic_make_request(bio); | |
1364 | bio = next; | |
1365 | } | |
1366 | unplug = 1; | |
1367 | ||
1368 | continue; | |
1369 | } | |
1370 | ||
1371 | if (list_empty(head)) | |
1372 | break; | |
1373 | r10_bio = list_entry(head->prev, r10bio_t, retry_list); | |
1374 | list_del(head->prev); | |
1375 | conf->nr_queued--; | |
1376 | spin_unlock_irqrestore(&conf->device_lock, flags); | |
1377 | ||
1378 | mddev = r10_bio->mddev; | |
1379 | conf = mddev_to_conf(mddev); | |
1380 | if (test_bit(R10BIO_IsSync, &r10_bio->state)) { | |
1381 | sync_request_write(mddev, r10_bio); | |
1382 | unplug = 1; | |
1383 | } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) { | |
1384 | recovery_request_write(mddev, r10_bio); | |
1385 | unplug = 1; | |
1386 | } else { | |
1387 | int mirror; | |
1388 | /* we got a read error. Maybe the drive is bad. Maybe just | |
1389 | * the block and we can fix it. | |
1390 | * We freeze all other IO, and try reading the block from | |
1391 | * other devices. When we find one, we re-write | |
1392 | * and check it that fixes the read error. | |
1393 | * This is all done synchronously while the array is | |
1394 | * frozen. | |
1395 | */ | |
1396 | int sect = 0; /* Offset from r10_bio->sector */ | |
1397 | int sectors = r10_bio->sectors; | |
1398 | freeze_array(conf); | |
1399 | if (mddev->ro == 0) while(sectors) { | |
1400 | int s = sectors; | |
1401 | int sl = r10_bio->read_slot; | |
1402 | int success = 0; | |
1403 | ||
1404 | if (s > (PAGE_SIZE>>9)) | |
1405 | s = PAGE_SIZE >> 9; | |
1406 | ||
1407 | do { | |
1408 | int d = r10_bio->devs[sl].devnum; | |
1409 | rdev = conf->mirrors[d].rdev; | |
1410 | if (rdev && | |
1411 | test_bit(In_sync, &rdev->flags) && | |
1412 | sync_page_io(rdev->bdev, | |
1413 | r10_bio->devs[sl].addr + | |
1414 | sect + rdev->data_offset, | |
1415 | s<<9, | |
1416 | conf->tmppage, READ)) | |
1417 | success = 1; | |
1418 | else { | |
1419 | sl++; | |
1420 | if (sl == conf->copies) | |
1421 | sl = 0; | |
1422 | } | |
1423 | } while (!success && sl != r10_bio->read_slot); | |
1424 | ||
1425 | if (success) { | |
1426 | /* write it back and re-read */ | |
1427 | while (sl != r10_bio->read_slot) { | |
1428 | int d; | |
1429 | if (sl==0) | |
1430 | sl = conf->copies; | |
1431 | sl--; | |
1432 | d = r10_bio->devs[sl].devnum; | |
1433 | rdev = conf->mirrors[d].rdev; | |
1434 | if (rdev && | |
1435 | test_bit(In_sync, &rdev->flags)) { | |
1436 | if (sync_page_io(rdev->bdev, | |
1437 | r10_bio->devs[sl].addr + | |
1438 | sect + rdev->data_offset, | |
1439 | s<<9, conf->tmppage, WRITE) == 0 || | |
1440 | sync_page_io(rdev->bdev, | |
1441 | r10_bio->devs[sl].addr + | |
1442 | sect + rdev->data_offset, | |
1443 | s<<9, conf->tmppage, READ) == 0) { | |
1444 | /* Well, this device is dead */ | |
1445 | md_error(mddev, rdev); | |
1446 | } | |
1447 | } | |
1448 | } | |
1449 | } else { | |
1450 | /* Cannot read from anywhere -- bye bye array */ | |
1451 | md_error(mddev, conf->mirrors[r10_bio->devs[r10_bio->read_slot].devnum].rdev); | |
1452 | break; | |
1453 | } | |
1454 | sectors -= s; | |
1455 | sect += s; | |
1456 | } | |
1457 | ||
1458 | unfreeze_array(conf); | |
1459 | ||
1460 | bio = r10_bio->devs[r10_bio->read_slot].bio; | |
1461 | r10_bio->devs[r10_bio->read_slot].bio = | |
1462 | mddev->ro ? IO_BLOCKED : NULL; | |
1463 | bio_put(bio); | |
1464 | mirror = read_balance(conf, r10_bio); | |
1465 | if (mirror == -1) { | |
1466 | printk(KERN_ALERT "raid10: %s: unrecoverable I/O" | |
1467 | " read error for block %llu\n", | |
1468 | bdevname(bio->bi_bdev,b), | |
1469 | (unsigned long long)r10_bio->sector); | |
1470 | raid_end_bio_io(r10_bio); | |
1471 | } else { | |
1472 | rdev = conf->mirrors[mirror].rdev; | |
1473 | if (printk_ratelimit()) | |
1474 | printk(KERN_ERR "raid10: %s: redirecting sector %llu to" | |
1475 | " another mirror\n", | |
1476 | bdevname(rdev->bdev,b), | |
1477 | (unsigned long long)r10_bio->sector); | |
1478 | bio = bio_clone(r10_bio->master_bio, GFP_NOIO); | |
1479 | r10_bio->devs[r10_bio->read_slot].bio = bio; | |
1480 | bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr | |
1481 | + rdev->data_offset; | |
1482 | bio->bi_bdev = rdev->bdev; | |
1483 | bio->bi_rw = READ; | |
1484 | bio->bi_private = r10_bio; | |
1485 | bio->bi_end_io = raid10_end_read_request; | |
1486 | unplug = 1; | |
1487 | generic_make_request(bio); | |
1488 | } | |
1489 | } | |
1490 | } | |
1491 | spin_unlock_irqrestore(&conf->device_lock, flags); | |
1492 | if (unplug) | |
1493 | unplug_slaves(mddev); | |
1494 | } | |
1495 | ||
1496 | ||
1497 | static int init_resync(conf_t *conf) | |
1498 | { | |
1499 | int buffs; | |
1500 | ||
1501 | buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE; | |
1502 | if (conf->r10buf_pool) | |
1503 | BUG(); | |
1504 | conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf); | |
1505 | if (!conf->r10buf_pool) | |
1506 | return -ENOMEM; | |
1507 | conf->next_resync = 0; | |
1508 | return 0; | |
1509 | } | |
1510 | ||
1511 | /* | |
1512 | * perform a "sync" on one "block" | |
1513 | * | |
1514 | * We need to make sure that no normal I/O request - particularly write | |
1515 | * requests - conflict with active sync requests. | |
1516 | * | |
1517 | * This is achieved by tracking pending requests and a 'barrier' concept | |
1518 | * that can be installed to exclude normal IO requests. | |
1519 | * | |
1520 | * Resync and recovery are handled very differently. | |
1521 | * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery. | |
1522 | * | |
1523 | * For resync, we iterate over virtual addresses, read all copies, | |
1524 | * and update if there are differences. If only one copy is live, | |
1525 | * skip it. | |
1526 | * For recovery, we iterate over physical addresses, read a good | |
1527 | * value for each non-in_sync drive, and over-write. | |
1528 | * | |
1529 | * So, for recovery we may have several outstanding complex requests for a | |
1530 | * given address, one for each out-of-sync device. We model this by allocating | |
1531 | * a number of r10_bio structures, one for each out-of-sync device. | |
1532 | * As we setup these structures, we collect all bio's together into a list | |
1533 | * which we then process collectively to add pages, and then process again | |
1534 | * to pass to generic_make_request. | |
1535 | * | |
1536 | * The r10_bio structures are linked using a borrowed master_bio pointer. | |
1537 | * This link is counted in ->remaining. When the r10_bio that points to NULL | |
1538 | * has its remaining count decremented to 0, the whole complex operation | |
1539 | * is complete. | |
1540 | * | |
1541 | */ | |
1542 | ||
1543 | static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) | |
1544 | { | |
1545 | conf_t *conf = mddev_to_conf(mddev); | |
1546 | r10bio_t *r10_bio; | |
1547 | struct bio *biolist = NULL, *bio; | |
1548 | sector_t max_sector, nr_sectors; | |
1549 | int disk; | |
1550 | int i; | |
1551 | int max_sync; | |
1552 | int sync_blocks; | |
1553 | ||
1554 | sector_t sectors_skipped = 0; | |
1555 | int chunks_skipped = 0; | |
1556 | ||
1557 | if (!conf->r10buf_pool) | |
1558 | if (init_resync(conf)) | |
1559 | return 0; | |
1560 | ||
1561 | skipped: | |
1562 | max_sector = mddev->size << 1; | |
1563 | if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) | |
1564 | max_sector = mddev->resync_max_sectors; | |
1565 | if (sector_nr >= max_sector) { | |
1566 | /* If we aborted, we need to abort the | |
1567 | * sync on the 'current' bitmap chucks (there can | |
1568 | * be several when recovering multiple devices). | |
1569 | * as we may have started syncing it but not finished. | |
1570 | * We can find the current address in | |
1571 | * mddev->curr_resync, but for recovery, | |
1572 | * we need to convert that to several | |
1573 | * virtual addresses. | |
1574 | */ | |
1575 | if (mddev->curr_resync < max_sector) { /* aborted */ | |
1576 | if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) | |
1577 | bitmap_end_sync(mddev->bitmap, mddev->curr_resync, | |
1578 | &sync_blocks, 1); | |
1579 | else for (i=0; i<conf->raid_disks; i++) { | |
1580 | sector_t sect = | |
1581 | raid10_find_virt(conf, mddev->curr_resync, i); | |
1582 | bitmap_end_sync(mddev->bitmap, sect, | |
1583 | &sync_blocks, 1); | |
1584 | } | |
1585 | } else /* completed sync */ | |
1586 | conf->fullsync = 0; | |
1587 | ||
1588 | bitmap_close_sync(mddev->bitmap); | |
1589 | close_sync(conf); | |
1590 | *skipped = 1; | |
1591 | return sectors_skipped; | |
1592 | } | |
1593 | if (chunks_skipped >= conf->raid_disks) { | |
1594 | /* if there has been nothing to do on any drive, | |
1595 | * then there is nothing to do at all.. | |
1596 | */ | |
1597 | *skipped = 1; | |
1598 | return (max_sector - sector_nr) + sectors_skipped; | |
1599 | } | |
1600 | ||
1601 | /* make sure whole request will fit in a chunk - if chunks | |
1602 | * are meaningful | |
1603 | */ | |
1604 | if (conf->near_copies < conf->raid_disks && | |
1605 | max_sector > (sector_nr | conf->chunk_mask)) | |
1606 | max_sector = (sector_nr | conf->chunk_mask) + 1; | |
1607 | /* | |
1608 | * If there is non-resync activity waiting for us then | |
1609 | * put in a delay to throttle resync. | |
1610 | */ | |
1611 | if (!go_faster && conf->nr_waiting) | |
1612 | msleep_interruptible(1000); | |
1613 | ||
1614 | /* Again, very different code for resync and recovery. | |
1615 | * Both must result in an r10bio with a list of bios that | |
1616 | * have bi_end_io, bi_sector, bi_bdev set, | |
1617 | * and bi_private set to the r10bio. | |
1618 | * For recovery, we may actually create several r10bios | |
1619 | * with 2 bios in each, that correspond to the bios in the main one. | |
1620 | * In this case, the subordinate r10bios link back through a | |
1621 | * borrowed master_bio pointer, and the counter in the master | |
1622 | * includes a ref from each subordinate. | |
1623 | */ | |
1624 | /* First, we decide what to do and set ->bi_end_io | |
1625 | * To end_sync_read if we want to read, and | |
1626 | * end_sync_write if we will want to write. | |
1627 | */ | |
1628 | ||
1629 | max_sync = RESYNC_PAGES << (PAGE_SHIFT-9); | |
1630 | if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { | |
1631 | /* recovery... the complicated one */ | |
1632 | int i, j, k; | |
1633 | r10_bio = NULL; | |
1634 | ||
1635 | for (i=0 ; i<conf->raid_disks; i++) | |
1636 | if (conf->mirrors[i].rdev && | |
1637 | !test_bit(In_sync, &conf->mirrors[i].rdev->flags)) { | |
1638 | int still_degraded = 0; | |
1639 | /* want to reconstruct this device */ | |
1640 | r10bio_t *rb2 = r10_bio; | |
1641 | sector_t sect = raid10_find_virt(conf, sector_nr, i); | |
1642 | int must_sync; | |
1643 | /* Unless we are doing a full sync, we only need | |
1644 | * to recover the block if it is set in the bitmap | |
1645 | */ | |
1646 | must_sync = bitmap_start_sync(mddev->bitmap, sect, | |
1647 | &sync_blocks, 1); | |
1648 | if (sync_blocks < max_sync) | |
1649 | max_sync = sync_blocks; | |
1650 | if (!must_sync && | |
1651 | !conf->fullsync) { | |
1652 | /* yep, skip the sync_blocks here, but don't assume | |
1653 | * that there will never be anything to do here | |
1654 | */ | |
1655 | chunks_skipped = -1; | |
1656 | continue; | |
1657 | } | |
1658 | ||
1659 | r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); | |
1660 | raise_barrier(conf, rb2 != NULL); | |
1661 | atomic_set(&r10_bio->remaining, 0); | |
1662 | ||
1663 | r10_bio->master_bio = (struct bio*)rb2; | |
1664 | if (rb2) | |
1665 | atomic_inc(&rb2->remaining); | |
1666 | r10_bio->mddev = mddev; | |
1667 | set_bit(R10BIO_IsRecover, &r10_bio->state); | |
1668 | r10_bio->sector = sect; | |
1669 | ||
1670 | raid10_find_phys(conf, r10_bio); | |
1671 | /* Need to check if this section will still be | |
1672 | * degraded | |
1673 | */ | |
1674 | for (j=0; j<conf->copies;j++) { | |
1675 | int d = r10_bio->devs[j].devnum; | |
1676 | if (conf->mirrors[d].rdev == NULL || | |
1677 | test_bit(Faulty, &conf->mirrors[d].rdev->flags)) | |
1678 | still_degraded = 1; | |
1679 | } | |
1680 | must_sync = bitmap_start_sync(mddev->bitmap, sect, | |
1681 | &sync_blocks, still_degraded); | |
1682 | ||
1683 | for (j=0; j<conf->copies;j++) { | |
1684 | int d = r10_bio->devs[j].devnum; | |
1685 | if (conf->mirrors[d].rdev && | |
1686 | test_bit(In_sync, &conf->mirrors[d].rdev->flags)) { | |
1687 | /* This is where we read from */ | |
1688 | bio = r10_bio->devs[0].bio; | |
1689 | bio->bi_next = biolist; | |
1690 | biolist = bio; | |
1691 | bio->bi_private = r10_bio; | |
1692 | bio->bi_end_io = end_sync_read; | |
1693 | bio->bi_rw = 0; | |
1694 | bio->bi_sector = r10_bio->devs[j].addr + | |
1695 | conf->mirrors[d].rdev->data_offset; | |
1696 | bio->bi_bdev = conf->mirrors[d].rdev->bdev; | |
1697 | atomic_inc(&conf->mirrors[d].rdev->nr_pending); | |
1698 | atomic_inc(&r10_bio->remaining); | |
1699 | /* and we write to 'i' */ | |
1700 | ||
1701 | for (k=0; k<conf->copies; k++) | |
1702 | if (r10_bio->devs[k].devnum == i) | |
1703 | break; | |
1704 | bio = r10_bio->devs[1].bio; | |
1705 | bio->bi_next = biolist; | |
1706 | biolist = bio; | |
1707 | bio->bi_private = r10_bio; | |
1708 | bio->bi_end_io = end_sync_write; | |
1709 | bio->bi_rw = 1; | |
1710 | bio->bi_sector = r10_bio->devs[k].addr + | |
1711 | conf->mirrors[i].rdev->data_offset; | |
1712 | bio->bi_bdev = conf->mirrors[i].rdev->bdev; | |
1713 | ||
1714 | r10_bio->devs[0].devnum = d; | |
1715 | r10_bio->devs[1].devnum = i; | |
1716 | ||
1717 | break; | |
1718 | } | |
1719 | } | |
1720 | if (j == conf->copies) { | |
1721 | /* Cannot recover, so abort the recovery */ | |
1722 | put_buf(r10_bio); | |
1723 | r10_bio = rb2; | |
1724 | if (!test_and_set_bit(MD_RECOVERY_ERR, &mddev->recovery)) | |
1725 | printk(KERN_INFO "raid10: %s: insufficient working devices for recovery.\n", | |
1726 | mdname(mddev)); | |
1727 | break; | |
1728 | } | |
1729 | } | |
1730 | if (biolist == NULL) { | |
1731 | while (r10_bio) { | |
1732 | r10bio_t *rb2 = r10_bio; | |
1733 | r10_bio = (r10bio_t*) rb2->master_bio; | |
1734 | rb2->master_bio = NULL; | |
1735 | put_buf(rb2); | |
1736 | } | |
1737 | goto giveup; | |
1738 | } | |
1739 | } else { | |
1740 | /* resync. Schedule a read for every block at this virt offset */ | |
1741 | int count = 0; | |
1742 | ||
1743 | if (!bitmap_start_sync(mddev->bitmap, sector_nr, | |
1744 | &sync_blocks, mddev->degraded) && | |
1745 | !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { | |
1746 | /* We can skip this block */ | |
1747 | *skipped = 1; | |
1748 | return sync_blocks + sectors_skipped; | |
1749 | } | |
1750 | if (sync_blocks < max_sync) | |
1751 | max_sync = sync_blocks; | |
1752 | r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); | |
1753 | ||
1754 | r10_bio->mddev = mddev; | |
1755 | atomic_set(&r10_bio->remaining, 0); | |
1756 | raise_barrier(conf, 0); | |
1757 | conf->next_resync = sector_nr; | |
1758 | ||
1759 | r10_bio->master_bio = NULL; | |
1760 | r10_bio->sector = sector_nr; | |
1761 | set_bit(R10BIO_IsSync, &r10_bio->state); | |
1762 | raid10_find_phys(conf, r10_bio); | |
1763 | r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1; | |
1764 | ||
1765 | for (i=0; i<conf->copies; i++) { | |
1766 | int d = r10_bio->devs[i].devnum; | |
1767 | bio = r10_bio->devs[i].bio; | |
1768 | bio->bi_end_io = NULL; | |
1769 | if (conf->mirrors[d].rdev == NULL || | |
1770 | test_bit(Faulty, &conf->mirrors[d].rdev->flags)) | |
1771 | continue; | |
1772 | atomic_inc(&conf->mirrors[d].rdev->nr_pending); | |
1773 | atomic_inc(&r10_bio->remaining); | |
1774 | bio->bi_next = biolist; | |
1775 | biolist = bio; | |
1776 | bio->bi_private = r10_bio; | |
1777 | bio->bi_end_io = end_sync_read; | |
1778 | bio->bi_rw = 0; | |
1779 | bio->bi_sector = r10_bio->devs[i].addr + | |
1780 | conf->mirrors[d].rdev->data_offset; | |
1781 | bio->bi_bdev = conf->mirrors[d].rdev->bdev; | |
1782 | count++; | |
1783 | } | |
1784 | ||
1785 | if (count < 2) { | |
1786 | for (i=0; i<conf->copies; i++) { | |
1787 | int d = r10_bio->devs[i].devnum; | |
1788 | if (r10_bio->devs[i].bio->bi_end_io) | |
1789 | rdev_dec_pending(conf->mirrors[d].rdev, mddev); | |
1790 | } | |
1791 | put_buf(r10_bio); | |
1792 | biolist = NULL; | |
1793 | goto giveup; | |
1794 | } | |
1795 | } | |
1796 | ||
1797 | for (bio = biolist; bio ; bio=bio->bi_next) { | |
1798 | ||
1799 | bio->bi_flags &= ~(BIO_POOL_MASK - 1); | |
1800 | if (bio->bi_end_io) | |
1801 | bio->bi_flags |= 1 << BIO_UPTODATE; | |
1802 | bio->bi_vcnt = 0; | |
1803 | bio->bi_idx = 0; | |
1804 | bio->bi_phys_segments = 0; | |
1805 | bio->bi_hw_segments = 0; | |
1806 | bio->bi_size = 0; | |
1807 | } | |
1808 | ||
1809 | nr_sectors = 0; | |
1810 | if (sector_nr + max_sync < max_sector) | |
1811 | max_sector = sector_nr + max_sync; | |
1812 | do { | |
1813 | struct page *page; | |
1814 | int len = PAGE_SIZE; | |
1815 | disk = 0; | |
1816 | if (sector_nr + (len>>9) > max_sector) | |
1817 | len = (max_sector - sector_nr) << 9; | |
1818 | if (len == 0) | |
1819 | break; | |
1820 | for (bio= biolist ; bio ; bio=bio->bi_next) { | |
1821 | page = bio->bi_io_vec[bio->bi_vcnt].bv_page; | |
1822 | if (bio_add_page(bio, page, len, 0) == 0) { | |
1823 | /* stop here */ | |
1824 | struct bio *bio2; | |
1825 | bio->bi_io_vec[bio->bi_vcnt].bv_page = page; | |
1826 | for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) { | |
1827 | /* remove last page from this bio */ | |
1828 | bio2->bi_vcnt--; | |
1829 | bio2->bi_size -= len; | |
1830 | bio2->bi_flags &= ~(1<< BIO_SEG_VALID); | |
1831 | } | |
1832 | goto bio_full; | |
1833 | } | |
1834 | disk = i; | |
1835 | } | |
1836 | nr_sectors += len>>9; | |
1837 | sector_nr += len>>9; | |
1838 | } while (biolist->bi_vcnt < RESYNC_PAGES); | |
1839 | bio_full: | |
1840 | r10_bio->sectors = nr_sectors; | |
1841 | ||
1842 | while (biolist) { | |
1843 | bio = biolist; | |
1844 | biolist = biolist->bi_next; | |
1845 | ||
1846 | bio->bi_next = NULL; | |
1847 | r10_bio = bio->bi_private; | |
1848 | r10_bio->sectors = nr_sectors; | |
1849 | ||
1850 | if (bio->bi_end_io == end_sync_read) { | |
1851 | md_sync_acct(bio->bi_bdev, nr_sectors); | |
1852 | generic_make_request(bio); | |
1853 | } | |
1854 | } | |
1855 | ||
1856 | if (sectors_skipped) | |
1857 | /* pretend they weren't skipped, it makes | |
1858 | * no important difference in this case | |
1859 | */ | |
1860 | md_done_sync(mddev, sectors_skipped, 1); | |
1861 | ||
1862 | return sectors_skipped + nr_sectors; | |
1863 | giveup: | |
1864 | /* There is nowhere to write, so all non-sync | |
1865 | * drives must be failed, so try the next chunk... | |
1866 | */ | |
1867 | { | |
1868 | sector_t sec = max_sector - sector_nr; | |
1869 | sectors_skipped += sec; | |
1870 | chunks_skipped ++; | |
1871 | sector_nr = max_sector; | |
1872 | goto skipped; | |
1873 | } | |
1874 | } | |
1875 | ||
1876 | static int run(mddev_t *mddev) | |
1877 | { | |
1878 | conf_t *conf; | |
1879 | int i, disk_idx; | |
1880 | mirror_info_t *disk; | |
1881 | mdk_rdev_t *rdev; | |
1882 | struct list_head *tmp; | |
1883 | int nc, fc; | |
1884 | sector_t stride, size; | |
1885 | ||
1886 | if (mddev->level != 10) { | |
1887 | printk(KERN_ERR "raid10: %s: raid level not set correctly... (%d)\n", | |
1888 | mdname(mddev), mddev->level); | |
1889 | goto out; | |
1890 | } | |
1891 | nc = mddev->layout & 255; | |
1892 | fc = (mddev->layout >> 8) & 255; | |
1893 | if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks || | |
1894 | (mddev->layout >> 16)) { | |
1895 | printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n", | |
1896 | mdname(mddev), mddev->layout); | |
1897 | goto out; | |
1898 | } | |
1899 | /* | |
1900 | * copy the already verified devices into our private RAID10 | |
1901 | * bookkeeping area. [whatever we allocate in run(), | |
1902 | * should be freed in stop()] | |
1903 | */ | |
1904 | conf = kzalloc(sizeof(conf_t), GFP_KERNEL); | |
1905 | mddev->private = conf; | |
1906 | if (!conf) { | |
1907 | printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", | |
1908 | mdname(mddev)); | |
1909 | goto out; | |
1910 | } | |
1911 | conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks, | |
1912 | GFP_KERNEL); | |
1913 | if (!conf->mirrors) { | |
1914 | printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", | |
1915 | mdname(mddev)); | |
1916 | goto out_free_conf; | |
1917 | } | |
1918 | ||
1919 | conf->tmppage = alloc_page(GFP_KERNEL); | |
1920 | if (!conf->tmppage) | |
1921 | goto out_free_conf; | |
1922 | ||
1923 | conf->near_copies = nc; | |
1924 | conf->far_copies = fc; | |
1925 | conf->copies = nc*fc; | |
1926 | conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1; | |
1927 | conf->chunk_shift = ffz(~mddev->chunk_size) - 9; | |
1928 | stride = mddev->size >> (conf->chunk_shift-1); | |
1929 | sector_div(stride, fc); | |
1930 | conf->stride = stride << conf->chunk_shift; | |
1931 | ||
1932 | conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc, | |
1933 | r10bio_pool_free, conf); | |
1934 | if (!conf->r10bio_pool) { | |
1935 | printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", | |
1936 | mdname(mddev)); | |
1937 | goto out_free_conf; | |
1938 | } | |
1939 | ||
1940 | ITERATE_RDEV(mddev, rdev, tmp) { | |
1941 | disk_idx = rdev->raid_disk; | |
1942 | if (disk_idx >= mddev->raid_disks | |
1943 | || disk_idx < 0) | |
1944 | continue; | |
1945 | disk = conf->mirrors + disk_idx; | |
1946 | ||
1947 | disk->rdev = rdev; | |
1948 | ||
1949 | blk_queue_stack_limits(mddev->queue, | |
1950 | rdev->bdev->bd_disk->queue); | |
1951 | /* as we don't honour merge_bvec_fn, we must never risk | |
1952 | * violating it, so limit ->max_sector to one PAGE, as | |
1953 | * a one page request is never in violation. | |
1954 | */ | |
1955 | if (rdev->bdev->bd_disk->queue->merge_bvec_fn && | |
1956 | mddev->queue->max_sectors > (PAGE_SIZE>>9)) | |
1957 | mddev->queue->max_sectors = (PAGE_SIZE>>9); | |
1958 | ||
1959 | disk->head_position = 0; | |
1960 | if (!test_bit(Faulty, &rdev->flags) && test_bit(In_sync, &rdev->flags)) | |
1961 | conf->working_disks++; | |
1962 | } | |
1963 | conf->raid_disks = mddev->raid_disks; | |
1964 | conf->mddev = mddev; | |
1965 | spin_lock_init(&conf->device_lock); | |
1966 | INIT_LIST_HEAD(&conf->retry_list); | |
1967 | ||
1968 | spin_lock_init(&conf->resync_lock); | |
1969 | init_waitqueue_head(&conf->wait_barrier); | |
1970 | ||
1971 | /* need to check that every block has at least one working mirror */ | |
1972 | if (!enough(conf)) { | |
1973 | printk(KERN_ERR "raid10: not enough operational mirrors for %s\n", | |
1974 | mdname(mddev)); | |
1975 | goto out_free_conf; | |
1976 | } | |
1977 | ||
1978 | mddev->degraded = 0; | |
1979 | for (i = 0; i < conf->raid_disks; i++) { | |
1980 | ||
1981 | disk = conf->mirrors + i; | |
1982 | ||
1983 | if (!disk->rdev) { | |
1984 | disk->head_position = 0; | |
1985 | mddev->degraded++; | |
1986 | } | |
1987 | } | |
1988 | ||
1989 | ||
1990 | mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10"); | |
1991 | if (!mddev->thread) { | |
1992 | printk(KERN_ERR | |
1993 | "raid10: couldn't allocate thread for %s\n", | |
1994 | mdname(mddev)); | |
1995 | goto out_free_conf; | |
1996 | } | |
1997 | ||
1998 | printk(KERN_INFO | |
1999 | "raid10: raid set %s active with %d out of %d devices\n", | |
2000 | mdname(mddev), mddev->raid_disks - mddev->degraded, | |
2001 | mddev->raid_disks); | |
2002 | /* | |
2003 | * Ok, everything is just fine now | |
2004 | */ | |
2005 | size = conf->stride * conf->raid_disks; | |
2006 | sector_div(size, conf->near_copies); | |
2007 | mddev->array_size = size/2; | |
2008 | mddev->resync_max_sectors = size; | |
2009 | ||
2010 | mddev->queue->unplug_fn = raid10_unplug; | |
2011 | mddev->queue->issue_flush_fn = raid10_issue_flush; | |
2012 | ||
2013 | /* Calculate max read-ahead size. | |
2014 | * We need to readahead at least twice a whole stripe.... | |
2015 | * maybe... | |
2016 | */ | |
2017 | { | |
2018 | int stripe = conf->raid_disks * mddev->chunk_size / PAGE_SIZE; | |
2019 | stripe /= conf->near_copies; | |
2020 | if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) | |
2021 | mddev->queue->backing_dev_info.ra_pages = 2* stripe; | |
2022 | } | |
2023 | ||
2024 | if (conf->near_copies < mddev->raid_disks) | |
2025 | blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec); | |
2026 | return 0; | |
2027 | ||
2028 | out_free_conf: | |
2029 | if (conf->r10bio_pool) | |
2030 | mempool_destroy(conf->r10bio_pool); | |
2031 | put_page(conf->tmppage); | |
2032 | kfree(conf->mirrors); | |
2033 | kfree(conf); | |
2034 | mddev->private = NULL; | |
2035 | out: | |
2036 | return -EIO; | |
2037 | } | |
2038 | ||
2039 | static int stop(mddev_t *mddev) | |
2040 | { | |
2041 | conf_t *conf = mddev_to_conf(mddev); | |
2042 | ||
2043 | md_unregister_thread(mddev->thread); | |
2044 | mddev->thread = NULL; | |
2045 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ | |
2046 | if (conf->r10bio_pool) | |
2047 | mempool_destroy(conf->r10bio_pool); | |
2048 | kfree(conf->mirrors); | |
2049 | kfree(conf); | |
2050 | mddev->private = NULL; | |
2051 | return 0; | |
2052 | } | |
2053 | ||
2054 | static void raid10_quiesce(mddev_t *mddev, int state) | |
2055 | { | |
2056 | conf_t *conf = mddev_to_conf(mddev); | |
2057 | ||
2058 | switch(state) { | |
2059 | case 1: | |
2060 | raise_barrier(conf, 0); | |
2061 | break; | |
2062 | case 0: | |
2063 | lower_barrier(conf); | |
2064 | break; | |
2065 | } | |
2066 | if (mddev->thread) { | |
2067 | if (mddev->bitmap) | |
2068 | mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ; | |
2069 | else | |
2070 | mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT; | |
2071 | md_wakeup_thread(mddev->thread); | |
2072 | } | |
2073 | } | |
2074 | ||
2075 | static mdk_personality_t raid10_personality = | |
2076 | { | |
2077 | .name = "raid10", | |
2078 | .owner = THIS_MODULE, | |
2079 | .make_request = make_request, | |
2080 | .run = run, | |
2081 | .stop = stop, | |
2082 | .status = status, | |
2083 | .error_handler = error, | |
2084 | .hot_add_disk = raid10_add_disk, | |
2085 | .hot_remove_disk= raid10_remove_disk, | |
2086 | .spare_active = raid10_spare_active, | |
2087 | .sync_request = sync_request, | |
2088 | .quiesce = raid10_quiesce, | |
2089 | }; | |
2090 | ||
2091 | static int __init raid_init(void) | |
2092 | { | |
2093 | return register_md_personality(RAID10, &raid10_personality); | |
2094 | } | |
2095 | ||
2096 | static void raid_exit(void) | |
2097 | { | |
2098 | unregister_md_personality(RAID10); | |
2099 | } | |
2100 | ||
2101 | module_init(raid_init); | |
2102 | module_exit(raid_exit); | |
2103 | MODULE_LICENSE("GPL"); | |
2104 | MODULE_ALIAS("md-personality-9"); /* RAID10 */ |