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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Stephen Rothwell25570722008-10-15 09:09:21 +110021#include <linux/delay.h>
NeilBrownbff61972009-03-31 14:33:13 +110022#include <linux/blkdev.h>
NeilBrownbff61972009-03-31 14:33:13 +110023#include <linux/seq_file.h>
NeilBrown43b2e5d2009-03-31 14:33:13 +110024#include "md.h"
NeilBrownbff61972009-03-31 14:33:13 +110025#include "dm-bio-list.h"
Christoph Hellwigef740c32009-03-31 14:27:03 +110026#include "raid10.h"
27#include "bitmap.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
29/*
30 * RAID10 provides a combination of RAID0 and RAID1 functionality.
31 * The layout of data is defined by
32 * chunk_size
33 * raid_disks
34 * near_copies (stored in low byte of layout)
35 * far_copies (stored in second byte of layout)
NeilBrownc93983b2006-06-26 00:27:41 -070036 * far_offset (stored in bit 16 of layout )
Linus Torvalds1da177e2005-04-16 15:20:36 -070037 *
38 * The data to be stored is divided into chunks using chunksize.
39 * Each device is divided into far_copies sections.
40 * In each section, chunks are laid out in a style similar to raid0, but
41 * near_copies copies of each chunk is stored (each on a different drive).
42 * The starting device for each section is offset near_copies from the starting
43 * device of the previous section.
NeilBrownc93983b2006-06-26 00:27:41 -070044 * Thus they are (near_copies*far_copies) of each chunk, and each is on a different
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 * drive.
46 * near_copies and far_copies must be at least one, and their product is at most
47 * raid_disks.
NeilBrownc93983b2006-06-26 00:27:41 -070048 *
49 * If far_offset is true, then the far_copies are handled a bit differently.
50 * The copies are still in different stripes, but instead of be very far apart
51 * on disk, there are adjacent stripes.
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 */
53
54/*
55 * Number of guaranteed r10bios in case of extreme VM load:
56 */
57#define NR_RAID10_BIOS 256
58
59static void unplug_slaves(mddev_t *mddev);
60
NeilBrown0a27ec92006-01-06 00:20:13 -080061static void allow_barrier(conf_t *conf);
62static void lower_barrier(conf_t *conf);
63
Al Virodd0fc662005-10-07 07:46:04 +010064static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -070065{
66 conf_t *conf = data;
67 r10bio_t *r10_bio;
68 int size = offsetof(struct r10bio_s, devs[conf->copies]);
69
70 /* allocate a r10bio with room for raid_disks entries in the bios array */
NeilBrown9ffae0c2006-01-06 00:20:32 -080071 r10_bio = kzalloc(size, gfp_flags);
72 if (!r10_bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 unplug_slaves(conf->mddev);
74
75 return r10_bio;
76}
77
78static void r10bio_pool_free(void *r10_bio, void *data)
79{
80 kfree(r10_bio);
81}
82
NeilBrown0310fa22008-08-05 15:54:14 +100083/* Maximum size of each resync request */
Linus Torvalds1da177e2005-04-16 15:20:36 -070084#define RESYNC_BLOCK_SIZE (64*1024)
Linus Torvalds1da177e2005-04-16 15:20:36 -070085#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
NeilBrown0310fa22008-08-05 15:54:14 +100086/* amount of memory to reserve for resync requests */
87#define RESYNC_WINDOW (1024*1024)
88/* maximum number of concurrent requests, memory permitting */
89#define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
91/*
92 * When performing a resync, we need to read and compare, so
93 * we need as many pages are there are copies.
94 * When performing a recovery, we need 2 bios, one for read,
95 * one for write (we recover only one drive per r10buf)
96 *
97 */
Al Virodd0fc662005-10-07 07:46:04 +010098static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -070099{
100 conf_t *conf = data;
101 struct page *page;
102 r10bio_t *r10_bio;
103 struct bio *bio;
104 int i, j;
105 int nalloc;
106
107 r10_bio = r10bio_pool_alloc(gfp_flags, conf);
108 if (!r10_bio) {
109 unplug_slaves(conf->mddev);
110 return NULL;
111 }
112
113 if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
114 nalloc = conf->copies; /* resync */
115 else
116 nalloc = 2; /* recovery */
117
118 /*
119 * Allocate bios.
120 */
121 for (j = nalloc ; j-- ; ) {
122 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
123 if (!bio)
124 goto out_free_bio;
125 r10_bio->devs[j].bio = bio;
126 }
127 /*
128 * Allocate RESYNC_PAGES data pages and attach them
129 * where needed.
130 */
131 for (j = 0 ; j < nalloc; j++) {
132 bio = r10_bio->devs[j].bio;
133 for (i = 0; i < RESYNC_PAGES; i++) {
134 page = alloc_page(gfp_flags);
135 if (unlikely(!page))
136 goto out_free_pages;
137
138 bio->bi_io_vec[i].bv_page = page;
139 }
140 }
141
142 return r10_bio;
143
144out_free_pages:
145 for ( ; i > 0 ; i--)
NeilBrown1345b1d2006-01-06 00:20:40 -0800146 safe_put_page(bio->bi_io_vec[i-1].bv_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 while (j--)
148 for (i = 0; i < RESYNC_PAGES ; i++)
NeilBrown1345b1d2006-01-06 00:20:40 -0800149 safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 j = -1;
151out_free_bio:
152 while ( ++j < nalloc )
153 bio_put(r10_bio->devs[j].bio);
154 r10bio_pool_free(r10_bio, conf);
155 return NULL;
156}
157
158static void r10buf_pool_free(void *__r10_bio, void *data)
159{
160 int i;
161 conf_t *conf = data;
162 r10bio_t *r10bio = __r10_bio;
163 int j;
164
165 for (j=0; j < conf->copies; j++) {
166 struct bio *bio = r10bio->devs[j].bio;
167 if (bio) {
168 for (i = 0; i < RESYNC_PAGES; i++) {
NeilBrown1345b1d2006-01-06 00:20:40 -0800169 safe_put_page(bio->bi_io_vec[i].bv_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 bio->bi_io_vec[i].bv_page = NULL;
171 }
172 bio_put(bio);
173 }
174 }
175 r10bio_pool_free(r10bio, conf);
176}
177
178static void put_all_bios(conf_t *conf, r10bio_t *r10_bio)
179{
180 int i;
181
182 for (i = 0; i < conf->copies; i++) {
183 struct bio **bio = & r10_bio->devs[i].bio;
NeilBrown0eb3ff12006-01-06 00:20:29 -0800184 if (*bio && *bio != IO_BLOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 bio_put(*bio);
186 *bio = NULL;
187 }
188}
189
Arjan van de Ven858119e2006-01-14 13:20:43 -0800190static void free_r10bio(r10bio_t *r10_bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 conf_t *conf = mddev_to_conf(r10_bio->mddev);
193
194 /*
195 * Wake up any possible resync thread that waits for the device
196 * to go idle.
197 */
NeilBrown0a27ec92006-01-06 00:20:13 -0800198 allow_barrier(conf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
200 put_all_bios(conf, r10_bio);
201 mempool_free(r10_bio, conf->r10bio_pool);
202}
203
Arjan van de Ven858119e2006-01-14 13:20:43 -0800204static void put_buf(r10bio_t *r10_bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205{
206 conf_t *conf = mddev_to_conf(r10_bio->mddev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
208 mempool_free(r10_bio, conf->r10buf_pool);
209
NeilBrown0a27ec92006-01-06 00:20:13 -0800210 lower_barrier(conf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211}
212
213static void reschedule_retry(r10bio_t *r10_bio)
214{
215 unsigned long flags;
216 mddev_t *mddev = r10_bio->mddev;
217 conf_t *conf = mddev_to_conf(mddev);
218
219 spin_lock_irqsave(&conf->device_lock, flags);
220 list_add(&r10_bio->retry_list, &conf->retry_list);
NeilBrown4443ae12006-01-06 00:20:28 -0800221 conf->nr_queued ++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 spin_unlock_irqrestore(&conf->device_lock, flags);
223
Arthur Jones388667b2008-07-25 12:03:38 -0700224 /* wake up frozen array... */
225 wake_up(&conf->wait_barrier);
226
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 md_wakeup_thread(mddev->thread);
228}
229
230/*
231 * raid_end_bio_io() is called when we have finished servicing a mirrored
232 * operation and are ready to return a success/failure code to the buffer
233 * cache layer.
234 */
235static void raid_end_bio_io(r10bio_t *r10_bio)
236{
237 struct bio *bio = r10_bio->master_bio;
238
NeilBrown6712ecf2007-09-27 12:47:43 +0200239 bio_endio(bio,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO);
241 free_r10bio(r10_bio);
242}
243
244/*
245 * Update disk head position estimator based on IRQ completion info.
246 */
247static inline void update_head_pos(int slot, r10bio_t *r10_bio)
248{
249 conf_t *conf = mddev_to_conf(r10_bio->mddev);
250
251 conf->mirrors[r10_bio->devs[slot].devnum].head_position =
252 r10_bio->devs[slot].addr + (r10_bio->sectors);
253}
254
NeilBrown6712ecf2007-09-27 12:47:43 +0200255static void raid10_end_read_request(struct bio *bio, int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256{
257 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
258 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
259 int slot, dev;
260 conf_t *conf = mddev_to_conf(r10_bio->mddev);
261
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
263 slot = r10_bio->read_slot;
264 dev = r10_bio->devs[slot].devnum;
265 /*
266 * this branch is our 'one mirror IO has finished' event handler:
267 */
NeilBrown4443ae12006-01-06 00:20:28 -0800268 update_head_pos(slot, r10_bio);
269
270 if (uptodate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 /*
272 * Set R10BIO_Uptodate in our master bio, so that
273 * we will return a good error code to the higher
274 * levels even if IO on some other mirrored buffer fails.
275 *
276 * The 'master' represents the composite IO operation to
277 * user-side. So if something waits for IO, then it will
278 * wait for the 'master' bio.
279 */
280 set_bit(R10BIO_Uptodate, &r10_bio->state);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 raid_end_bio_io(r10_bio);
NeilBrown4443ae12006-01-06 00:20:28 -0800282 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 /*
284 * oops, read error:
285 */
286 char b[BDEVNAME_SIZE];
287 if (printk_ratelimit())
288 printk(KERN_ERR "raid10: %s: rescheduling sector %llu\n",
289 bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector);
290 reschedule_retry(r10_bio);
291 }
292
293 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294}
295
NeilBrown6712ecf2007-09-27 12:47:43 +0200296static void raid10_end_write_request(struct bio *bio, int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297{
298 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
299 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
300 int slot, dev;
301 conf_t *conf = mddev_to_conf(r10_bio->mddev);
302
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 for (slot = 0; slot < conf->copies; slot++)
304 if (r10_bio->devs[slot].bio == bio)
305 break;
306 dev = r10_bio->devs[slot].devnum;
307
308 /*
309 * this branch is our 'one mirror IO has finished' event handler:
310 */
NeilBrown6cce3b22006-01-06 00:20:16 -0800311 if (!uptodate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
NeilBrown6cce3b22006-01-06 00:20:16 -0800313 /* an I/O failed, we can't clear the bitmap */
314 set_bit(R10BIO_Degraded, &r10_bio->state);
315 } else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 /*
317 * Set R10BIO_Uptodate in our master bio, so that
318 * we will return a good error code for to the higher
319 * levels even if IO on some other mirrored buffer fails.
320 *
321 * The 'master' represents the composite IO operation to
322 * user-side. So if something waits for IO, then it will
323 * wait for the 'master' bio.
324 */
325 set_bit(R10BIO_Uptodate, &r10_bio->state);
326
327 update_head_pos(slot, r10_bio);
328
329 /*
330 *
331 * Let's see if all mirrored write operations have finished
332 * already.
333 */
334 if (atomic_dec_and_test(&r10_bio->remaining)) {
NeilBrown6cce3b22006-01-06 00:20:16 -0800335 /* clear the bitmap if all writes complete successfully */
336 bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
337 r10_bio->sectors,
338 !test_bit(R10BIO_Degraded, &r10_bio->state),
339 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 md_write_end(r10_bio->mddev);
341 raid_end_bio_io(r10_bio);
342 }
343
344 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345}
346
347
348/*
349 * RAID10 layout manager
350 * Aswell as the chunksize and raid_disks count, there are two
351 * parameters: near_copies and far_copies.
352 * near_copies * far_copies must be <= raid_disks.
353 * Normally one of these will be 1.
354 * If both are 1, we get raid0.
355 * If near_copies == raid_disks, we get raid1.
356 *
357 * Chunks are layed out in raid0 style with near_copies copies of the
358 * first chunk, followed by near_copies copies of the next chunk and
359 * so on.
360 * If far_copies > 1, then after 1/far_copies of the array has been assigned
361 * as described above, we start again with a device offset of near_copies.
362 * So we effectively have another copy of the whole array further down all
363 * the drives, but with blocks on different drives.
364 * With this layout, and block is never stored twice on the one device.
365 *
366 * raid10_find_phys finds the sector offset of a given virtual sector
NeilBrownc93983b2006-06-26 00:27:41 -0700367 * on each device that it is on.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 *
369 * raid10_find_virt does the reverse mapping, from a device and a
370 * sector offset to a virtual address
371 */
372
373static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio)
374{
375 int n,f;
376 sector_t sector;
377 sector_t chunk;
378 sector_t stripe;
379 int dev;
380
381 int slot = 0;
382
383 /* now calculate first sector/dev */
384 chunk = r10bio->sector >> conf->chunk_shift;
385 sector = r10bio->sector & conf->chunk_mask;
386
387 chunk *= conf->near_copies;
388 stripe = chunk;
389 dev = sector_div(stripe, conf->raid_disks);
NeilBrownc93983b2006-06-26 00:27:41 -0700390 if (conf->far_offset)
391 stripe *= conf->far_copies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392
393 sector += stripe << conf->chunk_shift;
394
395 /* and calculate all the others */
396 for (n=0; n < conf->near_copies; n++) {
397 int d = dev;
398 sector_t s = sector;
399 r10bio->devs[slot].addr = sector;
400 r10bio->devs[slot].devnum = d;
401 slot++;
402
403 for (f = 1; f < conf->far_copies; f++) {
404 d += conf->near_copies;
405 if (d >= conf->raid_disks)
406 d -= conf->raid_disks;
407 s += conf->stride;
408 r10bio->devs[slot].devnum = d;
409 r10bio->devs[slot].addr = s;
410 slot++;
411 }
412 dev++;
413 if (dev >= conf->raid_disks) {
414 dev = 0;
415 sector += (conf->chunk_mask + 1);
416 }
417 }
418 BUG_ON(slot != conf->copies);
419}
420
421static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev)
422{
423 sector_t offset, chunk, vchunk;
424
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 offset = sector & conf->chunk_mask;
NeilBrownc93983b2006-06-26 00:27:41 -0700426 if (conf->far_offset) {
427 int fc;
428 chunk = sector >> conf->chunk_shift;
429 fc = sector_div(chunk, conf->far_copies);
430 dev -= fc * conf->near_copies;
431 if (dev < 0)
432 dev += conf->raid_disks;
433 } else {
NeilBrown64a742b2007-02-28 20:11:18 -0800434 while (sector >= conf->stride) {
NeilBrownc93983b2006-06-26 00:27:41 -0700435 sector -= conf->stride;
436 if (dev < conf->near_copies)
437 dev += conf->raid_disks - conf->near_copies;
438 else
439 dev -= conf->near_copies;
440 }
441 chunk = sector >> conf->chunk_shift;
442 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 vchunk = chunk * conf->raid_disks + dev;
444 sector_div(vchunk, conf->near_copies);
445 return (vchunk << conf->chunk_shift) + offset;
446}
447
448/**
449 * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
450 * @q: request queue
Alasdair G Kergoncc371e62008-07-03 09:53:43 +0200451 * @bvm: properties of new bio
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 * @biovec: the request that could be merged to it.
453 *
454 * Return amount of bytes we can accept at this offset
455 * If near_copies == raid_disk, there are no striping issues,
456 * but in that case, the function isn't called at all.
457 */
Alasdair G Kergoncc371e62008-07-03 09:53:43 +0200458static int raid10_mergeable_bvec(struct request_queue *q,
459 struct bvec_merge_data *bvm,
460 struct bio_vec *biovec)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461{
462 mddev_t *mddev = q->queuedata;
Alasdair G Kergoncc371e62008-07-03 09:53:43 +0200463 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 int max;
465 unsigned int chunk_sectors = mddev->chunk_size >> 9;
Alasdair G Kergoncc371e62008-07-03 09:53:43 +0200466 unsigned int bio_sectors = bvm->bi_size >> 9;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467
468 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
469 if (max < 0) max = 0; /* bio_add cannot handle a negative return */
Alasdair G Kergoncc371e62008-07-03 09:53:43 +0200470 if (max <= biovec->bv_len && bio_sectors == 0)
471 return biovec->bv_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 else
473 return max;
474}
475
476/*
477 * This routine returns the disk from which the requested read should
478 * be done. There is a per-array 'next expected sequential IO' sector
479 * number - if this matches on the next IO then we use the last disk.
480 * There is also a per-disk 'last know head position' sector that is
481 * maintained from IRQ contexts, both the normal and the resync IO
482 * completion handlers update this position correctly. If there is no
483 * perfect sequential match then we pick the disk whose head is closest.
484 *
485 * If there are 2 mirrors in the same 2 devices, performance degrades
486 * because position is mirror, not device based.
487 *
488 * The rdev for the device selected will have nr_pending incremented.
489 */
490
491/*
492 * FIXME: possibly should rethink readbalancing and do it differently
493 * depending on near_copies / far_copies geometry.
494 */
495static int read_balance(conf_t *conf, r10bio_t *r10_bio)
496{
497 const unsigned long this_sector = r10_bio->sector;
498 int disk, slot, nslot;
499 const int sectors = r10_bio->sectors;
500 sector_t new_distance, current_distance;
Suzanne Woodd6065f72005-11-08 21:39:27 -0800501 mdk_rdev_t *rdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502
503 raid10_find_phys(conf, r10_bio);
504 rcu_read_lock();
505 /*
506 * Check if we can balance. We can balance on the whole
NeilBrown6cce3b22006-01-06 00:20:16 -0800507 * device if no resync is going on (recovery is ok), or below
508 * the resync window. We take the first readable disk when
509 * above the resync window.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 */
511 if (conf->mddev->recovery_cp < MaxSector
512 && (this_sector + sectors >= conf->next_resync)) {
513 /* make sure that disk is operational */
514 slot = 0;
515 disk = r10_bio->devs[slot].devnum;
516
Suzanne Woodd6065f72005-11-08 21:39:27 -0800517 while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
NeilBrown0eb3ff12006-01-06 00:20:29 -0800518 r10_bio->devs[slot].bio == IO_BLOCKED ||
NeilBrownb2d444d2005-11-08 21:39:31 -0800519 !test_bit(In_sync, &rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 slot++;
521 if (slot == conf->copies) {
522 slot = 0;
523 disk = -1;
524 break;
525 }
526 disk = r10_bio->devs[slot].devnum;
527 }
528 goto rb_out;
529 }
530
531
532 /* make sure the disk is operational */
533 slot = 0;
534 disk = r10_bio->devs[slot].devnum;
Suzanne Woodd6065f72005-11-08 21:39:27 -0800535 while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
NeilBrown0eb3ff12006-01-06 00:20:29 -0800536 r10_bio->devs[slot].bio == IO_BLOCKED ||
NeilBrownb2d444d2005-11-08 21:39:31 -0800537 !test_bit(In_sync, &rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 slot ++;
539 if (slot == conf->copies) {
540 disk = -1;
541 goto rb_out;
542 }
543 disk = r10_bio->devs[slot].devnum;
544 }
545
546
NeilBrown3ec67ac2005-09-09 16:23:40 -0700547 current_distance = abs(r10_bio->devs[slot].addr -
548 conf->mirrors[disk].head_position);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549
Keld Simonsen8ed3a192008-03-04 14:29:34 -0800550 /* Find the disk whose head is closest,
551 * or - for far > 1 - find the closest to partition beginning */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552
553 for (nslot = slot; nslot < conf->copies; nslot++) {
554 int ndisk = r10_bio->devs[nslot].devnum;
555
556
Suzanne Woodd6065f72005-11-08 21:39:27 -0800557 if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL ||
NeilBrown0eb3ff12006-01-06 00:20:29 -0800558 r10_bio->devs[nslot].bio == IO_BLOCKED ||
NeilBrownb2d444d2005-11-08 21:39:31 -0800559 !test_bit(In_sync, &rdev->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 continue;
561
NeilBrown22dfdf52005-11-28 13:44:09 -0800562 /* This optimisation is debatable, and completely destroys
563 * sequential read speed for 'far copies' arrays. So only
564 * keep it for 'near' arrays, and review those later.
565 */
566 if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 disk = ndisk;
568 slot = nslot;
569 break;
570 }
Keld Simonsen8ed3a192008-03-04 14:29:34 -0800571
572 /* for far > 1 always use the lowest address */
573 if (conf->far_copies > 1)
574 new_distance = r10_bio->devs[nslot].addr;
575 else
576 new_distance = abs(r10_bio->devs[nslot].addr -
577 conf->mirrors[ndisk].head_position);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 if (new_distance < current_distance) {
579 current_distance = new_distance;
580 disk = ndisk;
581 slot = nslot;
582 }
583 }
584
585rb_out:
586 r10_bio->read_slot = slot;
587/* conf->next_seq_sect = this_sector + sectors;*/
588
Suzanne Woodd6065f72005-11-08 21:39:27 -0800589 if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
NeilBrown29fc7e32006-02-03 03:03:41 -0800591 else
592 disk = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 rcu_read_unlock();
594
595 return disk;
596}
597
598static void unplug_slaves(mddev_t *mddev)
599{
600 conf_t *conf = mddev_to_conf(mddev);
601 int i;
602
603 rcu_read_lock();
604 for (i=0; i<mddev->raid_disks; i++) {
Suzanne Woodd6065f72005-11-08 21:39:27 -0800605 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
NeilBrownb2d444d2005-11-08 21:39:31 -0800606 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
Jens Axboe165125e2007-07-24 09:28:11 +0200607 struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608
609 atomic_inc(&rdev->nr_pending);
610 rcu_read_unlock();
611
Alan D. Brunelle2ad8b1e2007-11-07 14:26:56 -0500612 blk_unplug(r_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613
614 rdev_dec_pending(rdev, mddev);
615 rcu_read_lock();
616 }
617 }
618 rcu_read_unlock();
619}
620
Jens Axboe165125e2007-07-24 09:28:11 +0200621static void raid10_unplug(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622{
NeilBrown6cce3b22006-01-06 00:20:16 -0800623 mddev_t *mddev = q->queuedata;
624
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 unplug_slaves(q->queuedata);
NeilBrown6cce3b22006-01-06 00:20:16 -0800626 md_wakeup_thread(mddev->thread);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627}
628
NeilBrown0d129222006-10-03 01:15:54 -0700629static int raid10_congested(void *data, int bits)
630{
631 mddev_t *mddev = data;
632 conf_t *conf = mddev_to_conf(mddev);
633 int i, ret = 0;
634
635 rcu_read_lock();
636 for (i = 0; i < mddev->raid_disks && ret == 0; i++) {
637 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
638 if (rdev && !test_bit(Faulty, &rdev->flags)) {
Jens Axboe165125e2007-07-24 09:28:11 +0200639 struct request_queue *q = bdev_get_queue(rdev->bdev);
NeilBrown0d129222006-10-03 01:15:54 -0700640
641 ret |= bdi_congested(&q->backing_dev_info, bits);
642 }
643 }
644 rcu_read_unlock();
645 return ret;
646}
647
NeilBrowna35e63e2008-03-04 14:29:29 -0800648static int flush_pending_writes(conf_t *conf)
649{
650 /* Any writes that have been queued but are awaiting
651 * bitmap updates get flushed here.
652 * We return 1 if any requests were actually submitted.
653 */
654 int rv = 0;
NeilBrown0d129222006-10-03 01:15:54 -0700655
NeilBrowna35e63e2008-03-04 14:29:29 -0800656 spin_lock_irq(&conf->device_lock);
657
658 if (conf->pending_bio_list.head) {
659 struct bio *bio;
660 bio = bio_list_get(&conf->pending_bio_list);
661 blk_remove_plug(conf->mddev->queue);
662 spin_unlock_irq(&conf->device_lock);
663 /* flush any pending bitmap writes to disk
664 * before proceeding w/ I/O */
665 bitmap_unplug(conf->mddev->bitmap);
666
667 while (bio) { /* submit pending writes */
668 struct bio *next = bio->bi_next;
669 bio->bi_next = NULL;
670 generic_make_request(bio);
671 bio = next;
672 }
673 rv = 1;
674 } else
675 spin_unlock_irq(&conf->device_lock);
676 return rv;
677}
NeilBrown0a27ec92006-01-06 00:20:13 -0800678/* Barriers....
679 * Sometimes we need to suspend IO while we do something else,
680 * either some resync/recovery, or reconfigure the array.
681 * To do this we raise a 'barrier'.
682 * The 'barrier' is a counter that can be raised multiple times
683 * to count how many activities are happening which preclude
684 * normal IO.
685 * We can only raise the barrier if there is no pending IO.
686 * i.e. if nr_pending == 0.
687 * We choose only to raise the barrier if no-one is waiting for the
688 * barrier to go down. This means that as soon as an IO request
689 * is ready, no other operations which require a barrier will start
690 * until the IO request has had a chance.
691 *
692 * So: regular IO calls 'wait_barrier'. When that returns there
693 * is no backgroup IO happening, It must arrange to call
694 * allow_barrier when it has finished its IO.
695 * backgroup IO calls must call raise_barrier. Once that returns
696 * there is no normal IO happeing. It must arrange to call
697 * lower_barrier when the particular background IO completes.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699
NeilBrown6cce3b22006-01-06 00:20:16 -0800700static void raise_barrier(conf_t *conf, int force)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701{
NeilBrown6cce3b22006-01-06 00:20:16 -0800702 BUG_ON(force && !conf->barrier);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 spin_lock_irq(&conf->resync_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704
NeilBrown6cce3b22006-01-06 00:20:16 -0800705 /* Wait until no block IO is waiting (unless 'force') */
706 wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
NeilBrown0a27ec92006-01-06 00:20:13 -0800707 conf->resync_lock,
708 raid10_unplug(conf->mddev->queue));
709
710 /* block any new IO from starting */
711 conf->barrier++;
712
713 /* No wait for all pending IO to complete */
714 wait_event_lock_irq(conf->wait_barrier,
715 !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
716 conf->resync_lock,
717 raid10_unplug(conf->mddev->queue));
718
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 spin_unlock_irq(&conf->resync_lock);
720}
721
NeilBrown0a27ec92006-01-06 00:20:13 -0800722static void lower_barrier(conf_t *conf)
723{
724 unsigned long flags;
725 spin_lock_irqsave(&conf->resync_lock, flags);
726 conf->barrier--;
727 spin_unlock_irqrestore(&conf->resync_lock, flags);
728 wake_up(&conf->wait_barrier);
729}
730
731static void wait_barrier(conf_t *conf)
732{
733 spin_lock_irq(&conf->resync_lock);
734 if (conf->barrier) {
735 conf->nr_waiting++;
736 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
737 conf->resync_lock,
738 raid10_unplug(conf->mddev->queue));
739 conf->nr_waiting--;
740 }
741 conf->nr_pending++;
742 spin_unlock_irq(&conf->resync_lock);
743}
744
745static void allow_barrier(conf_t *conf)
746{
747 unsigned long flags;
748 spin_lock_irqsave(&conf->resync_lock, flags);
749 conf->nr_pending--;
750 spin_unlock_irqrestore(&conf->resync_lock, flags);
751 wake_up(&conf->wait_barrier);
752}
753
NeilBrown4443ae12006-01-06 00:20:28 -0800754static void freeze_array(conf_t *conf)
755{
756 /* stop syncio and normal IO and wait for everything to
NeilBrownf1885932006-01-06 00:20:42 -0800757 * go quiet.
NeilBrown4443ae12006-01-06 00:20:28 -0800758 * We increment barrier and nr_waiting, and then
NeilBrown1c830532008-03-04 14:29:35 -0800759 * wait until nr_pending match nr_queued+1
760 * This is called in the context of one normal IO request
761 * that has failed. Thus any sync request that might be pending
762 * will be blocked by nr_pending, and we need to wait for
763 * pending IO requests to complete or be queued for re-try.
764 * Thus the number queued (nr_queued) plus this request (1)
765 * must match the number of pending IOs (nr_pending) before
766 * we continue.
NeilBrown4443ae12006-01-06 00:20:28 -0800767 */
768 spin_lock_irq(&conf->resync_lock);
769 conf->barrier++;
770 conf->nr_waiting++;
771 wait_event_lock_irq(conf->wait_barrier,
NeilBrown1c830532008-03-04 14:29:35 -0800772 conf->nr_pending == conf->nr_queued+1,
NeilBrown4443ae12006-01-06 00:20:28 -0800773 conf->resync_lock,
NeilBrowna35e63e2008-03-04 14:29:29 -0800774 ({ flush_pending_writes(conf);
775 raid10_unplug(conf->mddev->queue); }));
NeilBrown4443ae12006-01-06 00:20:28 -0800776 spin_unlock_irq(&conf->resync_lock);
777}
778
779static void unfreeze_array(conf_t *conf)
780{
781 /* reverse the effect of the freeze */
782 spin_lock_irq(&conf->resync_lock);
783 conf->barrier--;
784 conf->nr_waiting--;
785 wake_up(&conf->wait_barrier);
786 spin_unlock_irq(&conf->resync_lock);
787}
788
Jens Axboe165125e2007-07-24 09:28:11 +0200789static int make_request(struct request_queue *q, struct bio * bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790{
791 mddev_t *mddev = q->queuedata;
792 conf_t *conf = mddev_to_conf(mddev);
793 mirror_info_t *mirror;
794 r10bio_t *r10_bio;
795 struct bio *read_bio;
Tejun Heoc9959052008-08-25 19:47:21 +0900796 int cpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 int i;
798 int chunk_sects = conf->chunk_mask + 1;
Jens Axboea3623572005-11-01 09:26:16 +0100799 const int rw = bio_data_dir(bio);
Lars Ellenberge3881a62007-01-10 23:15:37 -0800800 const int do_sync = bio_sync(bio);
NeilBrown6cce3b22006-01-06 00:20:16 -0800801 struct bio_list bl;
802 unsigned long flags;
Dan Williams6bfe0b42008-04-30 00:52:32 -0700803 mdk_rdev_t *blocked_rdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804
NeilBrowne5dcdd82005-09-09 16:23:41 -0700805 if (unlikely(bio_barrier(bio))) {
NeilBrown6712ecf2007-09-27 12:47:43 +0200806 bio_endio(bio, -EOPNOTSUPP);
NeilBrowne5dcdd82005-09-09 16:23:41 -0700807 return 0;
808 }
809
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 /* If this request crosses a chunk boundary, we need to
811 * split it. This will only happen for 1 PAGE (or less) requests.
812 */
813 if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9)
814 > chunk_sects &&
815 conf->near_copies < conf->raid_disks)) {
816 struct bio_pair *bp;
817 /* Sanity check -- queue functions should prevent this happening */
818 if (bio->bi_vcnt != 1 ||
819 bio->bi_idx != 0)
820 goto bad_map;
821 /* This is a one page bio that upper layers
822 * refuse to split for us, so we need to split it.
823 */
Denis ChengRq6feef532008-10-09 08:57:05 +0200824 bp = bio_split(bio,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
826 if (make_request(q, &bp->bio1))
827 generic_make_request(&bp->bio1);
828 if (make_request(q, &bp->bio2))
829 generic_make_request(&bp->bio2);
830
831 bio_pair_release(bp);
832 return 0;
833 bad_map:
834 printk("raid10_make_request bug: can't convert block across chunks"
835 " or bigger than %dk %llu %d\n", chunk_sects/2,
836 (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
837
NeilBrown6712ecf2007-09-27 12:47:43 +0200838 bio_io_error(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 return 0;
840 }
841
NeilBrown3d310eb2005-06-21 17:17:26 -0700842 md_write_start(mddev, bio);
NeilBrown06d91a52005-06-21 17:17:12 -0700843
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 /*
845 * Register the new request and wait if the reconstruction
846 * thread has put up a bar for new requests.
847 * Continue immediately if no resync is active currently.
848 */
NeilBrown0a27ec92006-01-06 00:20:13 -0800849 wait_barrier(conf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850
Tejun Heo074a7ac2008-08-25 19:56:14 +0900851 cpu = part_stat_lock();
852 part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
853 part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
854 bio_sectors(bio));
855 part_stat_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856
857 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
858
859 r10_bio->master_bio = bio;
860 r10_bio->sectors = bio->bi_size >> 9;
861
862 r10_bio->mddev = mddev;
863 r10_bio->sector = bio->bi_sector;
NeilBrown6cce3b22006-01-06 00:20:16 -0800864 r10_bio->state = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865
Jens Axboea3623572005-11-01 09:26:16 +0100866 if (rw == READ) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 /*
868 * read balancing logic:
869 */
870 int disk = read_balance(conf, r10_bio);
871 int slot = r10_bio->read_slot;
872 if (disk < 0) {
873 raid_end_bio_io(r10_bio);
874 return 0;
875 }
876 mirror = conf->mirrors + disk;
877
878 read_bio = bio_clone(bio, GFP_NOIO);
879
880 r10_bio->devs[slot].bio = read_bio;
881
882 read_bio->bi_sector = r10_bio->devs[slot].addr +
883 mirror->rdev->data_offset;
884 read_bio->bi_bdev = mirror->rdev->bdev;
885 read_bio->bi_end_io = raid10_end_read_request;
Lars Ellenberge3881a62007-01-10 23:15:37 -0800886 read_bio->bi_rw = READ | do_sync;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 read_bio->bi_private = r10_bio;
888
889 generic_make_request(read_bio);
890 return 0;
891 }
892
893 /*
894 * WRITE:
895 */
Dan Williams6bfe0b42008-04-30 00:52:32 -0700896 /* first select target devices under rcu_lock and
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 * inc refcount on their rdev. Record them by setting
898 * bios[x] to bio
899 */
900 raid10_find_phys(conf, r10_bio);
Dan Williams6bfe0b42008-04-30 00:52:32 -0700901 retry_write:
Harvey Harrisoncb6969e2008-05-06 20:42:32 -0700902 blocked_rdev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 rcu_read_lock();
904 for (i = 0; i < conf->copies; i++) {
905 int d = r10_bio->devs[i].devnum;
Suzanne Woodd6065f72005-11-08 21:39:27 -0800906 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev);
Dan Williams6bfe0b42008-04-30 00:52:32 -0700907 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
908 atomic_inc(&rdev->nr_pending);
909 blocked_rdev = rdev;
910 break;
911 }
912 if (rdev && !test_bit(Faulty, &rdev->flags)) {
Suzanne Woodd6065f72005-11-08 21:39:27 -0800913 atomic_inc(&rdev->nr_pending);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914 r10_bio->devs[i].bio = bio;
NeilBrown6cce3b22006-01-06 00:20:16 -0800915 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 r10_bio->devs[i].bio = NULL;
NeilBrown6cce3b22006-01-06 00:20:16 -0800917 set_bit(R10BIO_Degraded, &r10_bio->state);
918 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 }
920 rcu_read_unlock();
921
Dan Williams6bfe0b42008-04-30 00:52:32 -0700922 if (unlikely(blocked_rdev)) {
923 /* Have to wait for this device to get unblocked, then retry */
924 int j;
925 int d;
926
927 for (j = 0; j < i; j++)
928 if (r10_bio->devs[j].bio) {
929 d = r10_bio->devs[j].devnum;
930 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
931 }
932 allow_barrier(conf);
933 md_wait_for_blocked_rdev(blocked_rdev, mddev);
934 wait_barrier(conf);
935 goto retry_write;
936 }
937
NeilBrown6cce3b22006-01-06 00:20:16 -0800938 atomic_set(&r10_bio->remaining, 0);
NeilBrown06d91a52005-06-21 17:17:12 -0700939
NeilBrown6cce3b22006-01-06 00:20:16 -0800940 bio_list_init(&bl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 for (i = 0; i < conf->copies; i++) {
942 struct bio *mbio;
943 int d = r10_bio->devs[i].devnum;
944 if (!r10_bio->devs[i].bio)
945 continue;
946
947 mbio = bio_clone(bio, GFP_NOIO);
948 r10_bio->devs[i].bio = mbio;
949
950 mbio->bi_sector = r10_bio->devs[i].addr+
951 conf->mirrors[d].rdev->data_offset;
952 mbio->bi_bdev = conf->mirrors[d].rdev->bdev;
953 mbio->bi_end_io = raid10_end_write_request;
Lars Ellenberge3881a62007-01-10 23:15:37 -0800954 mbio->bi_rw = WRITE | do_sync;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 mbio->bi_private = r10_bio;
956
957 atomic_inc(&r10_bio->remaining);
NeilBrown6cce3b22006-01-06 00:20:16 -0800958 bio_list_add(&bl, mbio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 }
960
Arne Redlichf6f953a2007-07-31 00:37:57 -0700961 if (unlikely(!atomic_read(&r10_bio->remaining))) {
962 /* the array is dead */
963 md_write_end(mddev);
964 raid_end_bio_io(r10_bio);
965 return 0;
966 }
967
NeilBrown6cce3b22006-01-06 00:20:16 -0800968 bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0);
969 spin_lock_irqsave(&conf->device_lock, flags);
970 bio_list_merge(&conf->pending_bio_list, &bl);
971 blk_plug_device(mddev->queue);
972 spin_unlock_irqrestore(&conf->device_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973
NeilBrowna35e63e2008-03-04 14:29:29 -0800974 /* In case raid10d snuck in to freeze_array */
975 wake_up(&conf->wait_barrier);
976
Lars Ellenberge3881a62007-01-10 23:15:37 -0800977 if (do_sync)
978 md_wakeup_thread(mddev->thread);
979
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 return 0;
981}
982
983static void status(struct seq_file *seq, mddev_t *mddev)
984{
985 conf_t *conf = mddev_to_conf(mddev);
986 int i;
987
988 if (conf->near_copies < conf->raid_disks)
989 seq_printf(seq, " %dK chunks", mddev->chunk_size/1024);
990 if (conf->near_copies > 1)
991 seq_printf(seq, " %d near-copies", conf->near_copies);
NeilBrownc93983b2006-06-26 00:27:41 -0700992 if (conf->far_copies > 1) {
993 if (conf->far_offset)
994 seq_printf(seq, " %d offset-copies", conf->far_copies);
995 else
996 seq_printf(seq, " %d far-copies", conf->far_copies);
997 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
NeilBrown76186dd2006-10-03 01:15:48 -0700999 conf->raid_disks - mddev->degraded);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 for (i = 0; i < conf->raid_disks; i++)
1001 seq_printf(seq, "%s",
1002 conf->mirrors[i].rdev &&
NeilBrownb2d444d2005-11-08 21:39:31 -08001003 test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 seq_printf(seq, "]");
1005}
1006
1007static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1008{
1009 char b[BDEVNAME_SIZE];
1010 conf_t *conf = mddev_to_conf(mddev);
1011
1012 /*
1013 * If it is not operational, then we have already marked it as dead
1014 * else if it is the last working disks, ignore the error, let the
1015 * next level up know.
1016 * else mark the drive as failed
1017 */
NeilBrownb2d444d2005-11-08 21:39:31 -08001018 if (test_bit(In_sync, &rdev->flags)
NeilBrown76186dd2006-10-03 01:15:48 -07001019 && conf->raid_disks-mddev->degraded == 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020 /*
1021 * Don't fail the drive, just return an IO error.
1022 * The test should really be more sophisticated than
1023 * "working_disks == 1", but it isn't critical, and
1024 * can wait until we do more sophisticated "is the drive
1025 * really dead" tests...
1026 */
1027 return;
NeilBrownc04be0a2006-10-03 01:15:53 -07001028 if (test_and_clear_bit(In_sync, &rdev->flags)) {
1029 unsigned long flags;
1030 spin_lock_irqsave(&conf->device_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 mddev->degraded++;
NeilBrownc04be0a2006-10-03 01:15:53 -07001032 spin_unlock_irqrestore(&conf->device_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 /*
1034 * if recovery is running, make sure it aborts.
1035 */
NeilBrowndfc70642008-05-23 13:04:39 -07001036 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037 }
NeilBrownb2d444d2005-11-08 21:39:31 -08001038 set_bit(Faulty, &rdev->flags);
NeilBrown850b2b42006-10-03 01:15:46 -07001039 set_bit(MD_CHANGE_DEVS, &mddev->flags);
Nick Andrewd7a420c2008-04-28 02:15:55 -07001040 printk(KERN_ALERT "raid10: Disk failure on %s, disabling device.\n"
1041 "raid10: Operation continuing on %d devices.\n",
NeilBrown76186dd2006-10-03 01:15:48 -07001042 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043}
1044
1045static void print_conf(conf_t *conf)
1046{
1047 int i;
1048 mirror_info_t *tmp;
1049
1050 printk("RAID10 conf printout:\n");
1051 if (!conf) {
1052 printk("(!conf)\n");
1053 return;
1054 }
NeilBrown76186dd2006-10-03 01:15:48 -07001055 printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001056 conf->raid_disks);
1057
1058 for (i = 0; i < conf->raid_disks; i++) {
1059 char b[BDEVNAME_SIZE];
1060 tmp = conf->mirrors + i;
1061 if (tmp->rdev)
1062 printk(" disk %d, wo:%d, o:%d, dev:%s\n",
NeilBrownb2d444d2005-11-08 21:39:31 -08001063 i, !test_bit(In_sync, &tmp->rdev->flags),
1064 !test_bit(Faulty, &tmp->rdev->flags),
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065 bdevname(tmp->rdev->bdev,b));
1066 }
1067}
1068
1069static void close_sync(conf_t *conf)
1070{
NeilBrown0a27ec92006-01-06 00:20:13 -08001071 wait_barrier(conf);
1072 allow_barrier(conf);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073
1074 mempool_destroy(conf->r10buf_pool);
1075 conf->r10buf_pool = NULL;
1076}
1077
NeilBrown6d508242005-09-09 16:24:03 -07001078/* check if there are enough drives for
1079 * every block to appear on atleast one
1080 */
1081static int enough(conf_t *conf)
1082{
1083 int first = 0;
1084
1085 do {
1086 int n = conf->copies;
1087 int cnt = 0;
1088 while (n--) {
1089 if (conf->mirrors[first].rdev)
1090 cnt++;
1091 first = (first+1) % conf->raid_disks;
1092 }
1093 if (cnt == 0)
1094 return 0;
1095 } while (first != 0);
1096 return 1;
1097}
1098
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099static int raid10_spare_active(mddev_t *mddev)
1100{
1101 int i;
1102 conf_t *conf = mddev->private;
1103 mirror_info_t *tmp;
1104
1105 /*
1106 * Find all non-in_sync disks within the RAID10 configuration
1107 * and mark them in_sync
1108 */
1109 for (i = 0; i < conf->raid_disks; i++) {
1110 tmp = conf->mirrors + i;
1111 if (tmp->rdev
NeilBrownb2d444d2005-11-08 21:39:31 -08001112 && !test_bit(Faulty, &tmp->rdev->flags)
NeilBrownc04be0a2006-10-03 01:15:53 -07001113 && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
1114 unsigned long flags;
1115 spin_lock_irqsave(&conf->device_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 mddev->degraded--;
NeilBrownc04be0a2006-10-03 01:15:53 -07001117 spin_unlock_irqrestore(&conf->device_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118 }
1119 }
1120
1121 print_conf(conf);
1122 return 0;
1123}
1124
1125
1126static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1127{
1128 conf_t *conf = mddev->private;
Neil Brown199050e2008-06-28 08:31:33 +10001129 int err = -EEXIST;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130 int mirror;
1131 mirror_info_t *p;
Neil Brown6c2fce22008-06-28 08:31:31 +10001132 int first = 0;
1133 int last = mddev->raid_disks - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134
1135 if (mddev->recovery_cp < MaxSector)
1136 /* only hot-add to in-sync arrays, as recovery is
1137 * very different from resync
1138 */
Neil Brown199050e2008-06-28 08:31:33 +10001139 return -EBUSY;
NeilBrown6d508242005-09-09 16:24:03 -07001140 if (!enough(conf))
Neil Brown199050e2008-06-28 08:31:33 +10001141 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001142
NeilBrowna53a6c82008-11-06 17:28:20 +11001143 if (rdev->raid_disk >= 0)
Neil Brown6c2fce22008-06-28 08:31:31 +10001144 first = last = rdev->raid_disk;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145
NeilBrown6cce3b22006-01-06 00:20:16 -08001146 if (rdev->saved_raid_disk >= 0 &&
Neil Brown6c2fce22008-06-28 08:31:31 +10001147 rdev->saved_raid_disk >= first &&
NeilBrown6cce3b22006-01-06 00:20:16 -08001148 conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1149 mirror = rdev->saved_raid_disk;
1150 else
Neil Brown6c2fce22008-06-28 08:31:31 +10001151 mirror = first;
1152 for ( ; mirror <= last ; mirror++)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 if ( !(p=conf->mirrors+mirror)->rdev) {
1154
1155 blk_queue_stack_limits(mddev->queue,
1156 rdev->bdev->bd_disk->queue);
1157 /* as we don't honour merge_bvec_fn, we must never risk
1158 * violating it, so limit ->max_sector to one PAGE, as
1159 * a one page request is never in violation.
1160 */
1161 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1162 mddev->queue->max_sectors > (PAGE_SIZE>>9))
1163 mddev->queue->max_sectors = (PAGE_SIZE>>9);
1164
1165 p->head_position = 0;
1166 rdev->raid_disk = mirror;
Neil Brown199050e2008-06-28 08:31:33 +10001167 err = 0;
NeilBrown6cce3b22006-01-06 00:20:16 -08001168 if (rdev->saved_raid_disk != mirror)
1169 conf->fullsync = 1;
Suzanne Woodd6065f72005-11-08 21:39:27 -08001170 rcu_assign_pointer(p->rdev, rdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 break;
1172 }
1173
1174 print_conf(conf);
Neil Brown199050e2008-06-28 08:31:33 +10001175 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176}
1177
1178static int raid10_remove_disk(mddev_t *mddev, int number)
1179{
1180 conf_t *conf = mddev->private;
1181 int err = 0;
1182 mdk_rdev_t *rdev;
1183 mirror_info_t *p = conf->mirrors+ number;
1184
1185 print_conf(conf);
1186 rdev = p->rdev;
1187 if (rdev) {
NeilBrownb2d444d2005-11-08 21:39:31 -08001188 if (test_bit(In_sync, &rdev->flags) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 atomic_read(&rdev->nr_pending)) {
1190 err = -EBUSY;
1191 goto abort;
1192 }
NeilBrowndfc70642008-05-23 13:04:39 -07001193 /* Only remove faulty devices in recovery
1194 * is not possible.
1195 */
1196 if (!test_bit(Faulty, &rdev->flags) &&
1197 enough(conf)) {
1198 err = -EBUSY;
1199 goto abort;
1200 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 p->rdev = NULL;
Paul E. McKenneyfbd568a3e2005-05-01 08:59:04 -07001202 synchronize_rcu();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 if (atomic_read(&rdev->nr_pending)) {
1204 /* lost the race, try later */
1205 err = -EBUSY;
1206 p->rdev = rdev;
1207 }
1208 }
1209abort:
1210
1211 print_conf(conf);
1212 return err;
1213}
1214
1215
NeilBrown6712ecf2007-09-27 12:47:43 +02001216static void end_sync_read(struct bio *bio, int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
1219 conf_t *conf = mddev_to_conf(r10_bio->mddev);
1220 int i,d;
1221
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 for (i=0; i<conf->copies; i++)
1223 if (r10_bio->devs[i].bio == bio)
1224 break;
Eric Sesterhennb6385482006-04-02 13:34:29 +02001225 BUG_ON(i == conf->copies);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226 update_head_pos(i, r10_bio);
1227 d = r10_bio->devs[i].devnum;
NeilBrown0eb3ff12006-01-06 00:20:29 -08001228
1229 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1230 set_bit(R10BIO_Uptodate, &r10_bio->state);
NeilBrown4dbcdc72006-01-06 00:20:52 -08001231 else {
1232 atomic_add(r10_bio->sectors,
1233 &conf->mirrors[d].rdev->corrected_errors);
1234 if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
1235 md_error(r10_bio->mddev,
1236 conf->mirrors[d].rdev);
1237 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238
1239 /* for reconstruct, we always reschedule after a read.
1240 * for resync, only after all reads
1241 */
NeilBrown73d5c382009-02-25 13:18:47 +11001242 rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
1244 atomic_dec_and_test(&r10_bio->remaining)) {
1245 /* we have read all the blocks,
1246 * do the comparison in process context in raid10d
1247 */
1248 reschedule_retry(r10_bio);
1249 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250}
1251
NeilBrown6712ecf2007-09-27 12:47:43 +02001252static void end_sync_write(struct bio *bio, int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253{
1254 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1255 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
1256 mddev_t *mddev = r10_bio->mddev;
1257 conf_t *conf = mddev_to_conf(mddev);
1258 int i,d;
1259
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260 for (i = 0; i < conf->copies; i++)
1261 if (r10_bio->devs[i].bio == bio)
1262 break;
1263 d = r10_bio->devs[i].devnum;
1264
1265 if (!uptodate)
1266 md_error(mddev, conf->mirrors[d].rdev);
NeilBrowndfc70642008-05-23 13:04:39 -07001267
Linus Torvalds1da177e2005-04-16 15:20:36 -07001268 update_head_pos(i, r10_bio);
1269
NeilBrown73d5c382009-02-25 13:18:47 +11001270 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 while (atomic_dec_and_test(&r10_bio->remaining)) {
1272 if (r10_bio->master_bio == NULL) {
1273 /* the primary of several recovery bios */
NeilBrown73d5c382009-02-25 13:18:47 +11001274 sector_t s = r10_bio->sectors;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 put_buf(r10_bio);
NeilBrown73d5c382009-02-25 13:18:47 +11001276 md_done_sync(mddev, s, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 break;
1278 } else {
1279 r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio;
1280 put_buf(r10_bio);
1281 r10_bio = r10_bio2;
1282 }
1283 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284}
1285
1286/*
1287 * Note: sync and recover and handled very differently for raid10
1288 * This code is for resync.
1289 * For resync, we read through virtual addresses and read all blocks.
1290 * If there is any error, we schedule a write. The lowest numbered
1291 * drive is authoritative.
1292 * However requests come for physical address, so we need to map.
1293 * For every physical address there are raid_disks/copies virtual addresses,
1294 * which is always are least one, but is not necessarly an integer.
1295 * This means that a physical address can span multiple chunks, so we may
1296 * have to submit multiple io requests for a single sync request.
1297 */
1298/*
1299 * We check if all blocks are in-sync and only write to blocks that
1300 * aren't in sync
1301 */
1302static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio)
1303{
1304 conf_t *conf = mddev_to_conf(mddev);
1305 int i, first;
1306 struct bio *tbio, *fbio;
1307
1308 atomic_set(&r10_bio->remaining, 1);
1309
1310 /* find the first device with a block */
1311 for (i=0; i<conf->copies; i++)
1312 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
1313 break;
1314
1315 if (i == conf->copies)
1316 goto done;
1317
1318 first = i;
1319 fbio = r10_bio->devs[i].bio;
1320
1321 /* now find blocks with errors */
NeilBrown0eb3ff12006-01-06 00:20:29 -08001322 for (i=0 ; i < conf->copies ; i++) {
1323 int j, d;
1324 int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325
Linus Torvalds1da177e2005-04-16 15:20:36 -07001326 tbio = r10_bio->devs[i].bio;
NeilBrown0eb3ff12006-01-06 00:20:29 -08001327
1328 if (tbio->bi_end_io != end_sync_read)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329 continue;
NeilBrown0eb3ff12006-01-06 00:20:29 -08001330 if (i == first)
1331 continue;
1332 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) {
1333 /* We know that the bi_io_vec layout is the same for
1334 * both 'first' and 'i', so we just compare them.
1335 * All vec entries are PAGE_SIZE;
1336 */
1337 for (j = 0; j < vcnt; j++)
1338 if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
1339 page_address(tbio->bi_io_vec[j].bv_page),
1340 PAGE_SIZE))
1341 break;
1342 if (j == vcnt)
1343 continue;
1344 mddev->resync_mismatches += r10_bio->sectors;
1345 }
NeilBrown18f08812006-01-06 00:20:25 -08001346 if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
1347 /* Don't fix anything. */
1348 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349 /* Ok, we need to write this bio
1350 * First we need to fixup bv_offset, bv_len and
1351 * bi_vecs, as the read request might have corrupted these
1352 */
1353 tbio->bi_vcnt = vcnt;
1354 tbio->bi_size = r10_bio->sectors << 9;
1355 tbio->bi_idx = 0;
1356 tbio->bi_phys_segments = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001357 tbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1358 tbio->bi_flags |= 1 << BIO_UPTODATE;
1359 tbio->bi_next = NULL;
1360 tbio->bi_rw = WRITE;
1361 tbio->bi_private = r10_bio;
1362 tbio->bi_sector = r10_bio->devs[i].addr;
1363
1364 for (j=0; j < vcnt ; j++) {
1365 tbio->bi_io_vec[j].bv_offset = 0;
1366 tbio->bi_io_vec[j].bv_len = PAGE_SIZE;
1367
1368 memcpy(page_address(tbio->bi_io_vec[j].bv_page),
1369 page_address(fbio->bi_io_vec[j].bv_page),
1370 PAGE_SIZE);
1371 }
1372 tbio->bi_end_io = end_sync_write;
1373
1374 d = r10_bio->devs[i].devnum;
1375 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1376 atomic_inc(&r10_bio->remaining);
1377 md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9);
1378
1379 tbio->bi_sector += conf->mirrors[d].rdev->data_offset;
1380 tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
1381 generic_make_request(tbio);
1382 }
1383
1384done:
1385 if (atomic_dec_and_test(&r10_bio->remaining)) {
1386 md_done_sync(mddev, r10_bio->sectors, 1);
1387 put_buf(r10_bio);
1388 }
1389}
1390
1391/*
1392 * Now for the recovery code.
1393 * Recovery happens across physical sectors.
1394 * We recover all non-is_sync drives by finding the virtual address of
1395 * each, and then choose a working drive that also has that virt address.
1396 * There is a separate r10_bio for each non-in_sync drive.
1397 * Only the first two slots are in use. The first for reading,
1398 * The second for writing.
1399 *
1400 */
1401
1402static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
1403{
1404 conf_t *conf = mddev_to_conf(mddev);
1405 int i, d;
1406 struct bio *bio, *wbio;
1407
1408
1409 /* move the pages across to the second bio
1410 * and submit the write request
1411 */
1412 bio = r10_bio->devs[0].bio;
1413 wbio = r10_bio->devs[1].bio;
1414 for (i=0; i < wbio->bi_vcnt; i++) {
1415 struct page *p = bio->bi_io_vec[i].bv_page;
1416 bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page;
1417 wbio->bi_io_vec[i].bv_page = p;
1418 }
1419 d = r10_bio->devs[1].devnum;
1420
1421 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1422 md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
NeilBrown0eb3ff12006-01-06 00:20:29 -08001423 if (test_bit(R10BIO_Uptodate, &r10_bio->state))
1424 generic_make_request(wbio);
1425 else
NeilBrown6712ecf2007-09-27 12:47:43 +02001426 bio_endio(wbio, -EIO);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427}
1428
1429
1430/*
1431 * This is a kernel thread which:
1432 *
1433 * 1. Retries failed read operations on working mirrors.
1434 * 2. Updates the raid superblock when problems encounter.
NeilBrown6814d532006-10-03 01:15:45 -07001435 * 3. Performs writes following reads for array synchronising.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001436 */
1437
NeilBrown6814d532006-10-03 01:15:45 -07001438static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
1439{
1440 int sect = 0; /* Offset from r10_bio->sector */
1441 int sectors = r10_bio->sectors;
1442 mdk_rdev_t*rdev;
1443 while(sectors) {
1444 int s = sectors;
1445 int sl = r10_bio->read_slot;
1446 int success = 0;
1447 int start;
1448
1449 if (s > (PAGE_SIZE>>9))
1450 s = PAGE_SIZE >> 9;
1451
1452 rcu_read_lock();
1453 do {
1454 int d = r10_bio->devs[sl].devnum;
1455 rdev = rcu_dereference(conf->mirrors[d].rdev);
1456 if (rdev &&
1457 test_bit(In_sync, &rdev->flags)) {
1458 atomic_inc(&rdev->nr_pending);
1459 rcu_read_unlock();
1460 success = sync_page_io(rdev->bdev,
1461 r10_bio->devs[sl].addr +
1462 sect + rdev->data_offset,
1463 s<<9,
1464 conf->tmppage, READ);
1465 rdev_dec_pending(rdev, mddev);
1466 rcu_read_lock();
1467 if (success)
1468 break;
1469 }
1470 sl++;
1471 if (sl == conf->copies)
1472 sl = 0;
1473 } while (!success && sl != r10_bio->read_slot);
1474 rcu_read_unlock();
1475
1476 if (!success) {
1477 /* Cannot read from anywhere -- bye bye array */
1478 int dn = r10_bio->devs[r10_bio->read_slot].devnum;
1479 md_error(mddev, conf->mirrors[dn].rdev);
1480 break;
1481 }
1482
1483 start = sl;
1484 /* write it back and re-read */
1485 rcu_read_lock();
1486 while (sl != r10_bio->read_slot) {
1487 int d;
1488 if (sl==0)
1489 sl = conf->copies;
1490 sl--;
1491 d = r10_bio->devs[sl].devnum;
1492 rdev = rcu_dereference(conf->mirrors[d].rdev);
1493 if (rdev &&
1494 test_bit(In_sync, &rdev->flags)) {
1495 atomic_inc(&rdev->nr_pending);
1496 rcu_read_unlock();
1497 atomic_add(s, &rdev->corrected_errors);
1498 if (sync_page_io(rdev->bdev,
1499 r10_bio->devs[sl].addr +
1500 sect + rdev->data_offset,
1501 s<<9, conf->tmppage, WRITE)
1502 == 0)
1503 /* Well, this device is dead */
1504 md_error(mddev, rdev);
1505 rdev_dec_pending(rdev, mddev);
1506 rcu_read_lock();
1507 }
1508 }
1509 sl = start;
1510 while (sl != r10_bio->read_slot) {
1511 int d;
1512 if (sl==0)
1513 sl = conf->copies;
1514 sl--;
1515 d = r10_bio->devs[sl].devnum;
1516 rdev = rcu_dereference(conf->mirrors[d].rdev);
1517 if (rdev &&
1518 test_bit(In_sync, &rdev->flags)) {
1519 char b[BDEVNAME_SIZE];
1520 atomic_inc(&rdev->nr_pending);
1521 rcu_read_unlock();
1522 if (sync_page_io(rdev->bdev,
1523 r10_bio->devs[sl].addr +
1524 sect + rdev->data_offset,
1525 s<<9, conf->tmppage, READ) == 0)
1526 /* Well, this device is dead */
1527 md_error(mddev, rdev);
1528 else
1529 printk(KERN_INFO
1530 "raid10:%s: read error corrected"
1531 " (%d sectors at %llu on %s)\n",
1532 mdname(mddev), s,
Randy Dunlap969b7552006-10-28 10:38:32 -07001533 (unsigned long long)(sect+
1534 rdev->data_offset),
NeilBrown6814d532006-10-03 01:15:45 -07001535 bdevname(rdev->bdev, b));
1536
1537 rdev_dec_pending(rdev, mddev);
1538 rcu_read_lock();
1539 }
1540 }
1541 rcu_read_unlock();
1542
1543 sectors -= s;
1544 sect += s;
1545 }
1546}
1547
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548static void raid10d(mddev_t *mddev)
1549{
1550 r10bio_t *r10_bio;
1551 struct bio *bio;
1552 unsigned long flags;
1553 conf_t *conf = mddev_to_conf(mddev);
1554 struct list_head *head = &conf->retry_list;
1555 int unplug=0;
1556 mdk_rdev_t *rdev;
1557
1558 md_check_recovery(mddev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001559
1560 for (;;) {
1561 char b[BDEVNAME_SIZE];
NeilBrowna35e63e2008-03-04 14:29:29 -08001562
1563 unplug += flush_pending_writes(conf);
1564
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565 spin_lock_irqsave(&conf->device_lock, flags);
NeilBrowna35e63e2008-03-04 14:29:29 -08001566 if (list_empty(head)) {
NeilBrown6cce3b22006-01-06 00:20:16 -08001567 spin_unlock_irqrestore(&conf->device_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001568 break;
NeilBrowna35e63e2008-03-04 14:29:29 -08001569 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570 r10_bio = list_entry(head->prev, r10bio_t, retry_list);
1571 list_del(head->prev);
NeilBrown4443ae12006-01-06 00:20:28 -08001572 conf->nr_queued--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573 spin_unlock_irqrestore(&conf->device_lock, flags);
1574
1575 mddev = r10_bio->mddev;
1576 conf = mddev_to_conf(mddev);
1577 if (test_bit(R10BIO_IsSync, &r10_bio->state)) {
1578 sync_request_write(mddev, r10_bio);
1579 unplug = 1;
1580 } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) {
1581 recovery_request_write(mddev, r10_bio);
1582 unplug = 1;
1583 } else {
1584 int mirror;
NeilBrown4443ae12006-01-06 00:20:28 -08001585 /* we got a read error. Maybe the drive is bad. Maybe just
1586 * the block and we can fix it.
1587 * We freeze all other IO, and try reading the block from
1588 * other devices. When we find one, we re-write
1589 * and check it that fixes the read error.
1590 * This is all done synchronously while the array is
1591 * frozen.
1592 */
NeilBrown6814d532006-10-03 01:15:45 -07001593 if (mddev->ro == 0) {
1594 freeze_array(conf);
1595 fix_read_error(conf, mddev, r10_bio);
1596 unfreeze_array(conf);
NeilBrown4443ae12006-01-06 00:20:28 -08001597 }
1598
Linus Torvalds1da177e2005-04-16 15:20:36 -07001599 bio = r10_bio->devs[r10_bio->read_slot].bio;
NeilBrown0eb3ff12006-01-06 00:20:29 -08001600 r10_bio->devs[r10_bio->read_slot].bio =
1601 mddev->ro ? IO_BLOCKED : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001602 mirror = read_balance(conf, r10_bio);
1603 if (mirror == -1) {
1604 printk(KERN_ALERT "raid10: %s: unrecoverable I/O"
1605 " read error for block %llu\n",
1606 bdevname(bio->bi_bdev,b),
1607 (unsigned long long)r10_bio->sector);
1608 raid_end_bio_io(r10_bio);
Maik Hampel14e71342007-07-31 00:37:57 -07001609 bio_put(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001610 } else {
Lars Ellenberge3881a62007-01-10 23:15:37 -08001611 const int do_sync = bio_sync(r10_bio->master_bio);
Maik Hampel14e71342007-07-31 00:37:57 -07001612 bio_put(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001613 rdev = conf->mirrors[mirror].rdev;
1614 if (printk_ratelimit())
1615 printk(KERN_ERR "raid10: %s: redirecting sector %llu to"
1616 " another mirror\n",
1617 bdevname(rdev->bdev,b),
1618 (unsigned long long)r10_bio->sector);
1619 bio = bio_clone(r10_bio->master_bio, GFP_NOIO);
1620 r10_bio->devs[r10_bio->read_slot].bio = bio;
1621 bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr
1622 + rdev->data_offset;
1623 bio->bi_bdev = rdev->bdev;
Lars Ellenberge3881a62007-01-10 23:15:37 -08001624 bio->bi_rw = READ | do_sync;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001625 bio->bi_private = r10_bio;
1626 bio->bi_end_io = raid10_end_read_request;
1627 unplug = 1;
1628 generic_make_request(bio);
1629 }
1630 }
1631 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001632 if (unplug)
1633 unplug_slaves(mddev);
1634}
1635
1636
1637static int init_resync(conf_t *conf)
1638{
1639 int buffs;
1640
1641 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
Eric Sesterhennb6385482006-04-02 13:34:29 +02001642 BUG_ON(conf->r10buf_pool);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001643 conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
1644 if (!conf->r10buf_pool)
1645 return -ENOMEM;
1646 conf->next_resync = 0;
1647 return 0;
1648}
1649
1650/*
1651 * perform a "sync" on one "block"
1652 *
1653 * We need to make sure that no normal I/O request - particularly write
1654 * requests - conflict with active sync requests.
1655 *
1656 * This is achieved by tracking pending requests and a 'barrier' concept
1657 * that can be installed to exclude normal IO requests.
1658 *
1659 * Resync and recovery are handled very differently.
1660 * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
1661 *
1662 * For resync, we iterate over virtual addresses, read all copies,
1663 * and update if there are differences. If only one copy is live,
1664 * skip it.
1665 * For recovery, we iterate over physical addresses, read a good
1666 * value for each non-in_sync drive, and over-write.
1667 *
1668 * So, for recovery we may have several outstanding complex requests for a
1669 * given address, one for each out-of-sync device. We model this by allocating
1670 * a number of r10_bio structures, one for each out-of-sync device.
1671 * As we setup these structures, we collect all bio's together into a list
1672 * which we then process collectively to add pages, and then process again
1673 * to pass to generic_make_request.
1674 *
1675 * The r10_bio structures are linked using a borrowed master_bio pointer.
1676 * This link is counted in ->remaining. When the r10_bio that points to NULL
1677 * has its remaining count decremented to 0, the whole complex operation
1678 * is complete.
1679 *
1680 */
1681
NeilBrown57afd892005-06-21 17:17:13 -07001682static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001683{
1684 conf_t *conf = mddev_to_conf(mddev);
1685 r10bio_t *r10_bio;
1686 struct bio *biolist = NULL, *bio;
1687 sector_t max_sector, nr_sectors;
1688 int disk;
1689 int i;
NeilBrown6cce3b22006-01-06 00:20:16 -08001690 int max_sync;
1691 int sync_blocks;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001692
1693 sector_t sectors_skipped = 0;
1694 int chunks_skipped = 0;
1695
1696 if (!conf->r10buf_pool)
1697 if (init_resync(conf))
NeilBrown57afd892005-06-21 17:17:13 -07001698 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001699
1700 skipped:
1701 max_sector = mddev->size << 1;
1702 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
1703 max_sector = mddev->resync_max_sectors;
1704 if (sector_nr >= max_sector) {
NeilBrown6cce3b22006-01-06 00:20:16 -08001705 /* If we aborted, we need to abort the
1706 * sync on the 'current' bitmap chucks (there can
1707 * be several when recovering multiple devices).
1708 * as we may have started syncing it but not finished.
1709 * We can find the current address in
1710 * mddev->curr_resync, but for recovery,
1711 * we need to convert that to several
1712 * virtual addresses.
1713 */
1714 if (mddev->curr_resync < max_sector) { /* aborted */
1715 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
1716 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1717 &sync_blocks, 1);
1718 else for (i=0; i<conf->raid_disks; i++) {
1719 sector_t sect =
1720 raid10_find_virt(conf, mddev->curr_resync, i);
1721 bitmap_end_sync(mddev->bitmap, sect,
1722 &sync_blocks, 1);
1723 }
1724 } else /* completed sync */
1725 conf->fullsync = 0;
1726
1727 bitmap_close_sync(mddev->bitmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001728 close_sync(conf);
NeilBrown57afd892005-06-21 17:17:13 -07001729 *skipped = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001730 return sectors_skipped;
1731 }
1732 if (chunks_skipped >= conf->raid_disks) {
1733 /* if there has been nothing to do on any drive,
1734 * then there is nothing to do at all..
1735 */
NeilBrown57afd892005-06-21 17:17:13 -07001736 *skipped = 1;
1737 return (max_sector - sector_nr) + sectors_skipped;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001738 }
1739
NeilBrownc6207272008-02-06 01:39:52 -08001740 if (max_sector > mddev->resync_max)
1741 max_sector = mddev->resync_max; /* Don't do IO beyond here */
1742
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743 /* make sure whole request will fit in a chunk - if chunks
1744 * are meaningful
1745 */
1746 if (conf->near_copies < conf->raid_disks &&
1747 max_sector > (sector_nr | conf->chunk_mask))
1748 max_sector = (sector_nr | conf->chunk_mask) + 1;
1749 /*
1750 * If there is non-resync activity waiting for us then
1751 * put in a delay to throttle resync.
1752 */
NeilBrown0a27ec92006-01-06 00:20:13 -08001753 if (!go_faster && conf->nr_waiting)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754 msleep_interruptible(1000);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001755
1756 /* Again, very different code for resync and recovery.
1757 * Both must result in an r10bio with a list of bios that
1758 * have bi_end_io, bi_sector, bi_bdev set,
1759 * and bi_private set to the r10bio.
1760 * For recovery, we may actually create several r10bios
1761 * with 2 bios in each, that correspond to the bios in the main one.
1762 * In this case, the subordinate r10bios link back through a
1763 * borrowed master_bio pointer, and the counter in the master
1764 * includes a ref from each subordinate.
1765 */
1766 /* First, we decide what to do and set ->bi_end_io
1767 * To end_sync_read if we want to read, and
1768 * end_sync_write if we will want to write.
1769 */
1770
NeilBrown6cce3b22006-01-06 00:20:16 -08001771 max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001772 if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
1773 /* recovery... the complicated one */
1774 int i, j, k;
1775 r10_bio = NULL;
1776
1777 for (i=0 ; i<conf->raid_disks; i++)
1778 if (conf->mirrors[i].rdev &&
NeilBrownb2d444d2005-11-08 21:39:31 -08001779 !test_bit(In_sync, &conf->mirrors[i].rdev->flags)) {
NeilBrown6cce3b22006-01-06 00:20:16 -08001780 int still_degraded = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781 /* want to reconstruct this device */
1782 r10bio_t *rb2 = r10_bio;
NeilBrown6cce3b22006-01-06 00:20:16 -08001783 sector_t sect = raid10_find_virt(conf, sector_nr, i);
1784 int must_sync;
1785 /* Unless we are doing a full sync, we only need
1786 * to recover the block if it is set in the bitmap
1787 */
1788 must_sync = bitmap_start_sync(mddev->bitmap, sect,
1789 &sync_blocks, 1);
1790 if (sync_blocks < max_sync)
1791 max_sync = sync_blocks;
1792 if (!must_sync &&
1793 !conf->fullsync) {
1794 /* yep, skip the sync_blocks here, but don't assume
1795 * that there will never be anything to do here
1796 */
1797 chunks_skipped = -1;
1798 continue;
1799 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800
1801 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
NeilBrown6cce3b22006-01-06 00:20:16 -08001802 raise_barrier(conf, rb2 != NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001803 atomic_set(&r10_bio->remaining, 0);
1804
1805 r10_bio->master_bio = (struct bio*)rb2;
1806 if (rb2)
1807 atomic_inc(&rb2->remaining);
1808 r10_bio->mddev = mddev;
1809 set_bit(R10BIO_IsRecover, &r10_bio->state);
NeilBrown6cce3b22006-01-06 00:20:16 -08001810 r10_bio->sector = sect;
1811
Linus Torvalds1da177e2005-04-16 15:20:36 -07001812 raid10_find_phys(conf, r10_bio);
NeilBrown6cce3b22006-01-06 00:20:16 -08001813 /* Need to check if this section will still be
1814 * degraded
1815 */
1816 for (j=0; j<conf->copies;j++) {
1817 int d = r10_bio->devs[j].devnum;
1818 if (conf->mirrors[d].rdev == NULL ||
NeilBrowna24a8dd2006-01-06 00:20:35 -08001819 test_bit(Faulty, &conf->mirrors[d].rdev->flags)) {
NeilBrown6cce3b22006-01-06 00:20:16 -08001820 still_degraded = 1;
NeilBrowna24a8dd2006-01-06 00:20:35 -08001821 break;
1822 }
NeilBrown6cce3b22006-01-06 00:20:16 -08001823 }
1824 must_sync = bitmap_start_sync(mddev->bitmap, sect,
1825 &sync_blocks, still_degraded);
1826
Linus Torvalds1da177e2005-04-16 15:20:36 -07001827 for (j=0; j<conf->copies;j++) {
1828 int d = r10_bio->devs[j].devnum;
1829 if (conf->mirrors[d].rdev &&
NeilBrownb2d444d2005-11-08 21:39:31 -08001830 test_bit(In_sync, &conf->mirrors[d].rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 /* This is where we read from */
1832 bio = r10_bio->devs[0].bio;
1833 bio->bi_next = biolist;
1834 biolist = bio;
1835 bio->bi_private = r10_bio;
1836 bio->bi_end_io = end_sync_read;
NeilBrown802ba062006-12-13 00:34:13 -08001837 bio->bi_rw = READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838 bio->bi_sector = r10_bio->devs[j].addr +
1839 conf->mirrors[d].rdev->data_offset;
1840 bio->bi_bdev = conf->mirrors[d].rdev->bdev;
1841 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1842 atomic_inc(&r10_bio->remaining);
1843 /* and we write to 'i' */
1844
1845 for (k=0; k<conf->copies; k++)
1846 if (r10_bio->devs[k].devnum == i)
1847 break;
NeilBrown64a742b2007-02-28 20:11:18 -08001848 BUG_ON(k == conf->copies);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849 bio = r10_bio->devs[1].bio;
1850 bio->bi_next = biolist;
1851 biolist = bio;
1852 bio->bi_private = r10_bio;
1853 bio->bi_end_io = end_sync_write;
NeilBrown802ba062006-12-13 00:34:13 -08001854 bio->bi_rw = WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001855 bio->bi_sector = r10_bio->devs[k].addr +
1856 conf->mirrors[i].rdev->data_offset;
1857 bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1858
1859 r10_bio->devs[0].devnum = d;
1860 r10_bio->devs[1].devnum = i;
1861
1862 break;
1863 }
1864 }
1865 if (j == conf->copies) {
NeilBrown87fc7672005-09-09 16:24:04 -07001866 /* Cannot recover, so abort the recovery */
1867 put_buf(r10_bio);
K.Tanakaa07e6ab2008-03-04 14:29:37 -08001868 if (rb2)
1869 atomic_dec(&rb2->remaining);
NeilBrown87fc7672005-09-09 16:24:04 -07001870 r10_bio = rb2;
NeilBrowndfc70642008-05-23 13:04:39 -07001871 if (!test_and_set_bit(MD_RECOVERY_INTR,
1872 &mddev->recovery))
NeilBrown87fc7672005-09-09 16:24:04 -07001873 printk(KERN_INFO "raid10: %s: insufficient working devices for recovery.\n",
1874 mdname(mddev));
1875 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001876 }
1877 }
1878 if (biolist == NULL) {
1879 while (r10_bio) {
1880 r10bio_t *rb2 = r10_bio;
1881 r10_bio = (r10bio_t*) rb2->master_bio;
1882 rb2->master_bio = NULL;
1883 put_buf(rb2);
1884 }
1885 goto giveup;
1886 }
1887 } else {
1888 /* resync. Schedule a read for every block at this virt offset */
1889 int count = 0;
NeilBrown6cce3b22006-01-06 00:20:16 -08001890
NeilBrown78200d42009-02-25 13:18:47 +11001891 bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1892
NeilBrown6cce3b22006-01-06 00:20:16 -08001893 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1894 &sync_blocks, mddev->degraded) &&
1895 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1896 /* We can skip this block */
1897 *skipped = 1;
1898 return sync_blocks + sectors_skipped;
1899 }
1900 if (sync_blocks < max_sync)
1901 max_sync = sync_blocks;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
1903
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904 r10_bio->mddev = mddev;
1905 atomic_set(&r10_bio->remaining, 0);
NeilBrown6cce3b22006-01-06 00:20:16 -08001906 raise_barrier(conf, 0);
1907 conf->next_resync = sector_nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908
1909 r10_bio->master_bio = NULL;
1910 r10_bio->sector = sector_nr;
1911 set_bit(R10BIO_IsSync, &r10_bio->state);
1912 raid10_find_phys(conf, r10_bio);
1913 r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1;
1914
1915 for (i=0; i<conf->copies; i++) {
1916 int d = r10_bio->devs[i].devnum;
1917 bio = r10_bio->devs[i].bio;
1918 bio->bi_end_io = NULL;
NeilBrownaf03b8e2007-06-16 10:16:06 -07001919 clear_bit(BIO_UPTODATE, &bio->bi_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920 if (conf->mirrors[d].rdev == NULL ||
NeilBrownb2d444d2005-11-08 21:39:31 -08001921 test_bit(Faulty, &conf->mirrors[d].rdev->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922 continue;
1923 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1924 atomic_inc(&r10_bio->remaining);
1925 bio->bi_next = biolist;
1926 biolist = bio;
1927 bio->bi_private = r10_bio;
1928 bio->bi_end_io = end_sync_read;
NeilBrown802ba062006-12-13 00:34:13 -08001929 bio->bi_rw = READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930 bio->bi_sector = r10_bio->devs[i].addr +
1931 conf->mirrors[d].rdev->data_offset;
1932 bio->bi_bdev = conf->mirrors[d].rdev->bdev;
1933 count++;
1934 }
1935
1936 if (count < 2) {
1937 for (i=0; i<conf->copies; i++) {
1938 int d = r10_bio->devs[i].devnum;
1939 if (r10_bio->devs[i].bio->bi_end_io)
1940 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1941 }
1942 put_buf(r10_bio);
1943 biolist = NULL;
1944 goto giveup;
1945 }
1946 }
1947
1948 for (bio = biolist; bio ; bio=bio->bi_next) {
1949
1950 bio->bi_flags &= ~(BIO_POOL_MASK - 1);
1951 if (bio->bi_end_io)
1952 bio->bi_flags |= 1 << BIO_UPTODATE;
1953 bio->bi_vcnt = 0;
1954 bio->bi_idx = 0;
1955 bio->bi_phys_segments = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956 bio->bi_size = 0;
1957 }
1958
1959 nr_sectors = 0;
NeilBrown6cce3b22006-01-06 00:20:16 -08001960 if (sector_nr + max_sync < max_sector)
1961 max_sector = sector_nr + max_sync;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962 do {
1963 struct page *page;
1964 int len = PAGE_SIZE;
1965 disk = 0;
1966 if (sector_nr + (len>>9) > max_sector)
1967 len = (max_sector - sector_nr) << 9;
1968 if (len == 0)
1969 break;
1970 for (bio= biolist ; bio ; bio=bio->bi_next) {
1971 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1972 if (bio_add_page(bio, page, len, 0) == 0) {
1973 /* stop here */
1974 struct bio *bio2;
1975 bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1976 for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) {
1977 /* remove last page from this bio */
1978 bio2->bi_vcnt--;
1979 bio2->bi_size -= len;
1980 bio2->bi_flags &= ~(1<< BIO_SEG_VALID);
1981 }
1982 goto bio_full;
1983 }
1984 disk = i;
1985 }
1986 nr_sectors += len>>9;
1987 sector_nr += len>>9;
1988 } while (biolist->bi_vcnt < RESYNC_PAGES);
1989 bio_full:
1990 r10_bio->sectors = nr_sectors;
1991
1992 while (biolist) {
1993 bio = biolist;
1994 biolist = biolist->bi_next;
1995
1996 bio->bi_next = NULL;
1997 r10_bio = bio->bi_private;
1998 r10_bio->sectors = nr_sectors;
1999
2000 if (bio->bi_end_io == end_sync_read) {
2001 md_sync_acct(bio->bi_bdev, nr_sectors);
2002 generic_make_request(bio);
2003 }
2004 }
2005
NeilBrown57afd892005-06-21 17:17:13 -07002006 if (sectors_skipped)
2007 /* pretend they weren't skipped, it makes
2008 * no important difference in this case
2009 */
2010 md_done_sync(mddev, sectors_skipped, 1);
2011
Linus Torvalds1da177e2005-04-16 15:20:36 -07002012 return sectors_skipped + nr_sectors;
2013 giveup:
2014 /* There is nowhere to write, so all non-sync
2015 * drives must be failed, so try the next chunk...
2016 */
NeilBrown09b40682009-02-25 13:18:47 +11002017 if (sector_nr + max_sync < max_sector)
2018 max_sector = sector_nr + max_sync;
2019
2020 sectors_skipped += (max_sector - sector_nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002021 chunks_skipped ++;
2022 sector_nr = max_sector;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002023 goto skipped;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002024}
2025
2026static int run(mddev_t *mddev)
2027{
2028 conf_t *conf;
2029 int i, disk_idx;
2030 mirror_info_t *disk;
2031 mdk_rdev_t *rdev;
NeilBrownc93983b2006-06-26 00:27:41 -07002032 int nc, fc, fo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002033 sector_t stride, size;
2034
NeilBrown4bbf3772008-10-13 11:55:12 +11002035 if (mddev->chunk_size < PAGE_SIZE) {
2036 printk(KERN_ERR "md/raid10: chunk size must be "
2037 "at least PAGE_SIZE(%ld).\n", PAGE_SIZE);
NeilBrown2604b702006-01-06 00:20:36 -08002038 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002039 }
NeilBrown2604b702006-01-06 00:20:36 -08002040
Linus Torvalds1da177e2005-04-16 15:20:36 -07002041 nc = mddev->layout & 255;
2042 fc = (mddev->layout >> 8) & 255;
NeilBrownc93983b2006-06-26 00:27:41 -07002043 fo = mddev->layout & (1<<16);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002044 if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks ||
NeilBrownc93983b2006-06-26 00:27:41 -07002045 (mddev->layout >> 17)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046 printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n",
2047 mdname(mddev), mddev->layout);
2048 goto out;
2049 }
2050 /*
2051 * copy the already verified devices into our private RAID10
2052 * bookkeeping area. [whatever we allocate in run(),
2053 * should be freed in stop()]
2054 */
NeilBrown4443ae12006-01-06 00:20:28 -08002055 conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002056 mddev->private = conf;
2057 if (!conf) {
2058 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
2059 mdname(mddev));
2060 goto out;
2061 }
NeilBrown4443ae12006-01-06 00:20:28 -08002062 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002063 GFP_KERNEL);
2064 if (!conf->mirrors) {
2065 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
2066 mdname(mddev));
2067 goto out_free_conf;
2068 }
NeilBrown4443ae12006-01-06 00:20:28 -08002069
2070 conf->tmppage = alloc_page(GFP_KERNEL);
2071 if (!conf->tmppage)
2072 goto out_free_conf;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002073
NeilBrown64a742b2007-02-28 20:11:18 -08002074 conf->mddev = mddev;
2075 conf->raid_disks = mddev->raid_disks;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002076 conf->near_copies = nc;
2077 conf->far_copies = fc;
2078 conf->copies = nc*fc;
NeilBrownc93983b2006-06-26 00:27:41 -07002079 conf->far_offset = fo;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080 conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1;
2081 conf->chunk_shift = ffz(~mddev->chunk_size) - 9;
NeilBrown64a742b2007-02-28 20:11:18 -08002082 size = mddev->size >> (conf->chunk_shift-1);
2083 sector_div(size, fc);
2084 size = size * conf->raid_disks;
2085 sector_div(size, nc);
2086 /* 'size' is now the number of chunks in the array */
2087 /* calculate "used chunks per device" in 'stride' */
2088 stride = size * conf->copies;
NeilBrownaf03b8e2007-06-16 10:16:06 -07002089
2090 /* We need to round up when dividing by raid_disks to
2091 * get the stride size.
2092 */
2093 stride += conf->raid_disks - 1;
NeilBrown64a742b2007-02-28 20:11:18 -08002094 sector_div(stride, conf->raid_disks);
2095 mddev->size = stride << (conf->chunk_shift-1);
2096
NeilBrownc93983b2006-06-26 00:27:41 -07002097 if (fo)
NeilBrown64a742b2007-02-28 20:11:18 -08002098 stride = 1;
2099 else
NeilBrownc93983b2006-06-26 00:27:41 -07002100 sector_div(stride, fc);
NeilBrown64a742b2007-02-28 20:11:18 -08002101 conf->stride = stride << conf->chunk_shift;
2102
Linus Torvalds1da177e2005-04-16 15:20:36 -07002103 conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
2104 r10bio_pool_free, conf);
2105 if (!conf->r10bio_pool) {
2106 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
2107 mdname(mddev));
2108 goto out_free_conf;
2109 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002110
Neil Browne7e72bf2008-05-14 16:05:54 -07002111 spin_lock_init(&conf->device_lock);
2112 mddev->queue->queue_lock = &conf->device_lock;
2113
Cheng Renquan159ec1f2009-01-09 08:31:08 +11002114 list_for_each_entry(rdev, &mddev->disks, same_set) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002115 disk_idx = rdev->raid_disk;
2116 if (disk_idx >= mddev->raid_disks
2117 || disk_idx < 0)
2118 continue;
2119 disk = conf->mirrors + disk_idx;
2120
2121 disk->rdev = rdev;
2122
2123 blk_queue_stack_limits(mddev->queue,
2124 rdev->bdev->bd_disk->queue);
2125 /* as we don't honour merge_bvec_fn, we must never risk
2126 * violating it, so limit ->max_sector to one PAGE, as
2127 * a one page request is never in violation.
2128 */
2129 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
2130 mddev->queue->max_sectors > (PAGE_SIZE>>9))
2131 mddev->queue->max_sectors = (PAGE_SIZE>>9);
2132
2133 disk->head_position = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002134 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002135 INIT_LIST_HEAD(&conf->retry_list);
2136
2137 spin_lock_init(&conf->resync_lock);
NeilBrown0a27ec92006-01-06 00:20:13 -08002138 init_waitqueue_head(&conf->wait_barrier);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002139
NeilBrown6d508242005-09-09 16:24:03 -07002140 /* need to check that every block has at least one working mirror */
2141 if (!enough(conf)) {
2142 printk(KERN_ERR "raid10: not enough operational mirrors for %s\n",
2143 mdname(mddev));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002144 goto out_free_conf;
2145 }
2146
2147 mddev->degraded = 0;
2148 for (i = 0; i < conf->raid_disks; i++) {
2149
2150 disk = conf->mirrors + i;
2151
NeilBrown5fd6c1d2006-06-26 00:27:40 -07002152 if (!disk->rdev ||
NeilBrown2e333e82006-10-21 10:24:07 -07002153 !test_bit(In_sync, &disk->rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002154 disk->head_position = 0;
2155 mddev->degraded++;
Neil Brown8c2e8702008-06-28 08:30:52 +10002156 if (disk->rdev)
2157 conf->fullsync = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002158 }
2159 }
2160
2161
2162 mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10");
2163 if (!mddev->thread) {
2164 printk(KERN_ERR
2165 "raid10: couldn't allocate thread for %s\n",
2166 mdname(mddev));
2167 goto out_free_conf;
2168 }
2169
2170 printk(KERN_INFO
2171 "raid10: raid set %s active with %d out of %d devices\n",
2172 mdname(mddev), mddev->raid_disks - mddev->degraded,
2173 mddev->raid_disks);
2174 /*
2175 * Ok, everything is just fine now
2176 */
Andre Nollf233ea52008-07-21 17:05:22 +10002177 mddev->array_sectors = size << conf->chunk_shift;
NeilBrown64a742b2007-02-28 20:11:18 -08002178 mddev->resync_max_sectors = size << conf->chunk_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179
NeilBrown7a5febe2005-05-16 21:53:16 -07002180 mddev->queue->unplug_fn = raid10_unplug;
NeilBrown0d129222006-10-03 01:15:54 -07002181 mddev->queue->backing_dev_info.congested_fn = raid10_congested;
2182 mddev->queue->backing_dev_info.congested_data = mddev;
NeilBrown7a5febe2005-05-16 21:53:16 -07002183
Linus Torvalds1da177e2005-04-16 15:20:36 -07002184 /* Calculate max read-ahead size.
2185 * We need to readahead at least twice a whole stripe....
2186 * maybe...
2187 */
2188 {
NeilBrown8932c2e2006-06-26 00:27:36 -07002189 int stripe = conf->raid_disks * (mddev->chunk_size / PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002190 stripe /= conf->near_copies;
2191 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
2192 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
2193 }
2194
2195 if (conf->near_copies < mddev->raid_disks)
2196 blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
2197 return 0;
2198
2199out_free_conf:
2200 if (conf->r10bio_pool)
2201 mempool_destroy(conf->r10bio_pool);
NeilBrown1345b1d2006-01-06 00:20:40 -08002202 safe_put_page(conf->tmppage);
Jesper Juhl990a8ba2005-06-21 17:17:30 -07002203 kfree(conf->mirrors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002204 kfree(conf);
2205 mddev->private = NULL;
2206out:
2207 return -EIO;
2208}
2209
2210static int stop(mddev_t *mddev)
2211{
2212 conf_t *conf = mddev_to_conf(mddev);
2213
2214 md_unregister_thread(mddev->thread);
2215 mddev->thread = NULL;
2216 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2217 if (conf->r10bio_pool)
2218 mempool_destroy(conf->r10bio_pool);
Jesper Juhl990a8ba2005-06-21 17:17:30 -07002219 kfree(conf->mirrors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002220 kfree(conf);
2221 mddev->private = NULL;
2222 return 0;
2223}
2224
NeilBrown6cce3b22006-01-06 00:20:16 -08002225static void raid10_quiesce(mddev_t *mddev, int state)
2226{
2227 conf_t *conf = mddev_to_conf(mddev);
2228
2229 switch(state) {
2230 case 1:
2231 raise_barrier(conf, 0);
2232 break;
2233 case 0:
2234 lower_barrier(conf);
2235 break;
2236 }
2237 if (mddev->thread) {
2238 if (mddev->bitmap)
2239 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
2240 else
2241 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
2242 md_wakeup_thread(mddev->thread);
2243 }
2244}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002245
NeilBrown2604b702006-01-06 00:20:36 -08002246static struct mdk_personality raid10_personality =
Linus Torvalds1da177e2005-04-16 15:20:36 -07002247{
2248 .name = "raid10",
NeilBrown2604b702006-01-06 00:20:36 -08002249 .level = 10,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002250 .owner = THIS_MODULE,
2251 .make_request = make_request,
2252 .run = run,
2253 .stop = stop,
2254 .status = status,
2255 .error_handler = error,
2256 .hot_add_disk = raid10_add_disk,
2257 .hot_remove_disk= raid10_remove_disk,
2258 .spare_active = raid10_spare_active,
2259 .sync_request = sync_request,
NeilBrown6cce3b22006-01-06 00:20:16 -08002260 .quiesce = raid10_quiesce,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002261};
2262
2263static int __init raid_init(void)
2264{
NeilBrown2604b702006-01-06 00:20:36 -08002265 return register_md_personality(&raid10_personality);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002266}
2267
2268static void raid_exit(void)
2269{
NeilBrown2604b702006-01-06 00:20:36 -08002270 unregister_md_personality(&raid10_personality);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002271}
2272
2273module_init(raid_init);
2274module_exit(raid_exit);
2275MODULE_LICENSE("GPL");
2276MODULE_ALIAS("md-personality-9"); /* RAID10 */
NeilBrownd9d166c2006-01-06 00:20:51 -08002277MODULE_ALIAS("md-raid10");
NeilBrown2604b702006-01-06 00:20:36 -08002278MODULE_ALIAS("md-level-10");