1 /*
2 * raid1.c : Multiple Devices driver for Linux
3 *
4 * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
5 *
6 * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
7 *
8 * RAID-1 management functions.
9 *
10 * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
11 *
12 * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
13 * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
14 *
15 * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
16 * bitmapped intelligence in resync:
17 *
18 * - bitmap marked during normal i/o
19 * - bitmap used to skip nondirty blocks during sync
20 *
21 * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
22 * - persistent bitmap code
23 *
24 * This program is free software; you can redistribute it and/or modify
25 * it under the terms of the GNU General Public License as published by
26 * the Free Software Foundation; either version 2, or (at your option)
27 * any later version.
28 *
29 * You should have received a copy of the GNU General Public License
30 * (for example /usr/src/linux/COPYING); if not, write to the Free
31 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
32 */
33
34 #include "dm-bio-list.h"
35 #include <linux/delay.h>
36 #include <linux/raid/raid1.h>
37 #include <linux/raid/bitmap.h>
38
39 #define DEBUG 0
40 #if DEBUG
41 #define PRINTK(x...) printk(x)
42 #else
43 #define PRINTK(x...)
44 #endif
45
46 /*
47 * Number of guaranteed r1bios in case of extreme VM load:
48 */
49 #define NR_RAID1_BIOS 256
50
51
52 static void unplug_slaves(mddev_t *mddev);
53
54 static void allow_barrier(conf_t *conf);
55 static void lower_barrier(conf_t *conf);
56
r1bio_pool_alloc(gfp_t gfp_flags,void * data)57 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
58 {
59 struct pool_info *pi = data;
60 r1bio_t *r1_bio;
61 int size = offsetof(r1bio_t, bios[pi->raid_disks]);
62
63 /* allocate a r1bio with room for raid_disks entries in the bios array */
64 r1_bio = kzalloc(size, gfp_flags);
65 if (!r1_bio)
66 unplug_slaves(pi->mddev);
67
68 return r1_bio;
69 }
70
r1bio_pool_free(void * r1_bio,void * data)71 static void r1bio_pool_free(void *r1_bio, void *data)
72 {
73 kfree(r1_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
r1buf_pool_alloc(gfp_t gfp_flags,void * data)82 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
83 {
84 struct pool_info *pi = data;
85 struct page *page;
86 r1bio_t *r1_bio;
87 struct bio *bio;
88 int i, j;
89
90 r1_bio = r1bio_pool_alloc(gfp_flags, pi);
91 if (!r1_bio) {
92 unplug_slaves(pi->mddev);
93 return NULL;
94 }
95
96 /*
97 * Allocate bios : 1 for reading, n-1 for writing
98 */
99 for (j = pi->raid_disks ; j-- ; ) {
100 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
101 if (!bio)
102 goto out_free_bio;
103 r1_bio->bios[j] = bio;
104 }
105 /*
106 * Allocate RESYNC_PAGES data pages and attach them to
107 * the first bio.
108 * If this is a user-requested check/repair, allocate
109 * RESYNC_PAGES for each bio.
110 */
111 if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
112 j = pi->raid_disks;
113 else
114 j = 1;
115 while(j--) {
116 bio = r1_bio->bios[j];
117 for (i = 0; i < RESYNC_PAGES; i++) {
118 page = alloc_page(gfp_flags);
119 if (unlikely(!page))
120 goto out_free_pages;
121
122 bio->bi_io_vec[i].bv_page = page;
123 }
124 }
125 /* If not user-requests, copy the page pointers to all bios */
126 if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
127 for (i=0; i<RESYNC_PAGES ; i++)
128 for (j=1; j<pi->raid_disks; j++)
129 r1_bio->bios[j]->bi_io_vec[i].bv_page =
130 r1_bio->bios[0]->bi_io_vec[i].bv_page;
131 }
132
133 r1_bio->master_bio = NULL;
134
135 return r1_bio;
136
137 out_free_pages:
138 for (i=0; i < RESYNC_PAGES ; i++)
139 for (j=0 ; j < pi->raid_disks; j++)
140 safe_put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
141 j = -1;
142 out_free_bio:
143 while ( ++j < pi->raid_disks )
144 bio_put(r1_bio->bios[j]);
145 r1bio_pool_free(r1_bio, data);
146 return NULL;
147 }
148
r1buf_pool_free(void * __r1_bio,void * data)149 static void r1buf_pool_free(void *__r1_bio, void *data)
150 {
151 struct pool_info *pi = data;
152 int i,j;
153 r1bio_t *r1bio = __r1_bio;
154
155 for (i = 0; i < RESYNC_PAGES; i++)
156 for (j = pi->raid_disks; j-- ;) {
157 if (j == 0 ||
158 r1bio->bios[j]->bi_io_vec[i].bv_page !=
159 r1bio->bios[0]->bi_io_vec[i].bv_page)
160 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
161 }
162 for (i=0 ; i < pi->raid_disks; i++)
163 bio_put(r1bio->bios[i]);
164
165 r1bio_pool_free(r1bio, data);
166 }
167
put_all_bios(conf_t * conf,r1bio_t * r1_bio)168 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
169 {
170 int i;
171
172 for (i = 0; i < conf->raid_disks; i++) {
173 struct bio **bio = r1_bio->bios + i;
174 if (*bio && *bio != IO_BLOCKED)
175 bio_put(*bio);
176 *bio = NULL;
177 }
178 }
179
free_r1bio(r1bio_t * r1_bio)180 static void free_r1bio(r1bio_t *r1_bio)
181 {
182 conf_t *conf = mddev_to_conf(r1_bio->mddev);
183
184 /*
185 * Wake up any possible resync thread that waits for the device
186 * to go idle.
187 */
188 allow_barrier(conf);
189
190 put_all_bios(conf, r1_bio);
191 mempool_free(r1_bio, conf->r1bio_pool);
192 }
193
put_buf(r1bio_t * r1_bio)194 static void put_buf(r1bio_t *r1_bio)
195 {
196 conf_t *conf = mddev_to_conf(r1_bio->mddev);
197 int i;
198
199 for (i=0; i<conf->raid_disks; i++) {
200 struct bio *bio = r1_bio->bios[i];
201 if (bio->bi_end_io)
202 rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
203 }
204
205 mempool_free(r1_bio, conf->r1buf_pool);
206
207 lower_barrier(conf);
208 }
209
reschedule_retry(r1bio_t * r1_bio)210 static void reschedule_retry(r1bio_t *r1_bio)
211 {
212 unsigned long flags;
213 mddev_t *mddev = r1_bio->mddev;
214 conf_t *conf = mddev_to_conf(mddev);
215
216 spin_lock_irqsave(&conf->device_lock, flags);
217 list_add(&r1_bio->retry_list, &conf->retry_list);
218 conf->nr_queued ++;
219 spin_unlock_irqrestore(&conf->device_lock, flags);
220
221 wake_up(&conf->wait_barrier);
222 md_wakeup_thread(mddev->thread);
223 }
224
225 /*
226 * raid_end_bio_io() is called when we have finished servicing a mirrored
227 * operation and are ready to return a success/failure code to the buffer
228 * cache layer.
229 */
raid_end_bio_io(r1bio_t * r1_bio)230 static void raid_end_bio_io(r1bio_t *r1_bio)
231 {
232 struct bio *bio = r1_bio->master_bio;
233
234 /* if nobody has done the final endio yet, do it now */
235 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
236 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
237 (bio_data_dir(bio) == WRITE) ? "write" : "read",
238 (unsigned long long) bio->bi_sector,
239 (unsigned long long) bio->bi_sector +
240 (bio->bi_size >> 9) - 1);
241
242 bio_endio(bio,
243 test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
244 }
245 free_r1bio(r1_bio);
246 }
247
248 /*
249 * Update disk head position estimator based on IRQ completion info.
250 */
update_head_pos(int disk,r1bio_t * r1_bio)251 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
252 {
253 conf_t *conf = mddev_to_conf(r1_bio->mddev);
254
255 conf->mirrors[disk].head_position =
256 r1_bio->sector + (r1_bio->sectors);
257 }
258
raid1_end_read_request(struct bio * bio,int error)259 static void raid1_end_read_request(struct bio *bio, int error)
260 {
261 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
262 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
263 int mirror;
264 conf_t *conf = mddev_to_conf(r1_bio->mddev);
265
266 mirror = r1_bio->read_disk;
267 /*
268 * this branch is our 'one mirror IO has finished' event handler:
269 */
270 update_head_pos(mirror, r1_bio);
271
272 if (uptodate)
273 set_bit(R1BIO_Uptodate, &r1_bio->state);
274 else {
275 /* If all other devices have failed, we want to return
276 * the error upwards rather than fail the last device.
277 * Here we redefine "uptodate" to mean "Don't want to retry"
278 */
279 unsigned long flags;
280 spin_lock_irqsave(&conf->device_lock, flags);
281 if (r1_bio->mddev->degraded == conf->raid_disks ||
282 (r1_bio->mddev->degraded == conf->raid_disks-1 &&
283 !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
284 uptodate = 1;
285 spin_unlock_irqrestore(&conf->device_lock, flags);
286 }
287
288 if (uptodate)
289 raid_end_bio_io(r1_bio);
290 else {
291 /*
292 * oops, read error:
293 */
294 char b[BDEVNAME_SIZE];
295 if (printk_ratelimit())
296 printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
297 bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
298 reschedule_retry(r1_bio);
299 }
300
301 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
302 }
303
raid1_end_write_request(struct bio * bio,int error)304 static void raid1_end_write_request(struct bio *bio, int error)
305 {
306 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
307 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
308 int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
309 conf_t *conf = mddev_to_conf(r1_bio->mddev);
310 struct bio *to_put = NULL;
311
312
313 for (mirror = 0; mirror < conf->raid_disks; mirror++)
314 if (r1_bio->bios[mirror] == bio)
315 break;
316
317 if (error == -EOPNOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
318 set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
319 set_bit(R1BIO_BarrierRetry, &r1_bio->state);
320 r1_bio->mddev->barriers_work = 0;
321 /* Don't rdev_dec_pending in this branch - keep it for the retry */
322 } else {
323 /*
324 * this branch is our 'one mirror IO has finished' event handler:
325 */
326 r1_bio->bios[mirror] = NULL;
327 to_put = bio;
328 if (!uptodate) {
329 md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
330 /* an I/O failed, we can't clear the bitmap */
331 set_bit(R1BIO_Degraded, &r1_bio->state);
332 } else
333 /*
334 * Set R1BIO_Uptodate in our master bio, so that
335 * we will return a good error code for to the higher
336 * levels even if IO on some other mirrored buffer fails.
337 *
338 * The 'master' represents the composite IO operation to
339 * user-side. So if something waits for IO, then it will
340 * wait for the 'master' bio.
341 */
342 set_bit(R1BIO_Uptodate, &r1_bio->state);
343
344 update_head_pos(mirror, r1_bio);
345
346 if (behind) {
347 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
348 atomic_dec(&r1_bio->behind_remaining);
349
350 /* In behind mode, we ACK the master bio once the I/O has safely
351 * reached all non-writemostly disks. Setting the Returned bit
352 * ensures that this gets done only once -- we don't ever want to
353 * return -EIO here, instead we'll wait */
354
355 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
356 test_bit(R1BIO_Uptodate, &r1_bio->state)) {
357 /* Maybe we can return now */
358 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
359 struct bio *mbio = r1_bio->master_bio;
360 PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
361 (unsigned long long) mbio->bi_sector,
362 (unsigned long long) mbio->bi_sector +
363 (mbio->bi_size >> 9) - 1);
364 bio_endio(mbio, 0);
365 }
366 }
367 }
368 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
369 }
370 /*
371 *
372 * Let's see if all mirrored write operations have finished
373 * already.
374 */
375 if (atomic_dec_and_test(&r1_bio->remaining)) {
376 if (test_bit(R1BIO_BarrierRetry, &r1_bio->state))
377 reschedule_retry(r1_bio);
378 else {
379 /* it really is the end of this request */
380 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
381 /* free extra copy of the data pages */
382 int i = bio->bi_vcnt;
383 while (i--)
384 safe_put_page(bio->bi_io_vec[i].bv_page);
385 }
386 /* clear the bitmap if all writes complete successfully */
387 bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
388 r1_bio->sectors,
389 !test_bit(R1BIO_Degraded, &r1_bio->state),
390 behind);
391 md_write_end(r1_bio->mddev);
392 raid_end_bio_io(r1_bio);
393 }
394 }
395
396 if (to_put)
397 bio_put(to_put);
398 }
399
400
401 /*
402 * This routine returns the disk from which the requested read should
403 * be done. There is a per-array 'next expected sequential IO' sector
404 * number - if this matches on the next IO then we use the last disk.
405 * There is also a per-disk 'last know head position' sector that is
406 * maintained from IRQ contexts, both the normal and the resync IO
407 * completion handlers update this position correctly. If there is no
408 * perfect sequential match then we pick the disk whose head is closest.
409 *
410 * If there are 2 mirrors in the same 2 devices, performance degrades
411 * because position is mirror, not device based.
412 *
413 * The rdev for the device selected will have nr_pending incremented.
414 */
read_balance(conf_t * conf,r1bio_t * r1_bio)415 static int read_balance(conf_t *conf, r1bio_t *r1_bio)
416 {
417 const unsigned long this_sector = r1_bio->sector;
418 int new_disk = conf->last_used, disk = new_disk;
419 int wonly_disk = -1;
420 const int sectors = r1_bio->sectors;
421 sector_t new_distance, current_distance;
422 mdk_rdev_t *rdev;
423
424 rcu_read_lock();
425 /*
426 * Check if we can balance. We can balance on the whole
427 * device if no resync is going on, or below the resync window.
428 * We take the first readable disk when above the resync window.
429 */
430 retry:
431 if (conf->mddev->recovery_cp < MaxSector &&
432 (this_sector + sectors >= conf->next_resync)) {
433 /* Choose the first operation device, for consistancy */
434 new_disk = 0;
435
436 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
437 r1_bio->bios[new_disk] == IO_BLOCKED ||
438 !rdev || !test_bit(In_sync, &rdev->flags)
439 || test_bit(WriteMostly, &rdev->flags);
440 rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
441
442 if (rdev && test_bit(In_sync, &rdev->flags) &&
443 r1_bio->bios[new_disk] != IO_BLOCKED)
444 wonly_disk = new_disk;
445
446 if (new_disk == conf->raid_disks - 1) {
447 new_disk = wonly_disk;
448 break;
449 }
450 }
451 goto rb_out;
452 }
453
454
455 /* make sure the disk is operational */
456 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
457 r1_bio->bios[new_disk] == IO_BLOCKED ||
458 !rdev || !test_bit(In_sync, &rdev->flags) ||
459 test_bit(WriteMostly, &rdev->flags);
460 rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
461
462 if (rdev && test_bit(In_sync, &rdev->flags) &&
463 r1_bio->bios[new_disk] != IO_BLOCKED)
464 wonly_disk = new_disk;
465
466 if (new_disk <= 0)
467 new_disk = conf->raid_disks;
468 new_disk--;
469 if (new_disk == disk) {
470 new_disk = wonly_disk;
471 break;
472 }
473 }
474
475 if (new_disk < 0)
476 goto rb_out;
477
478 disk = new_disk;
479 /* now disk == new_disk == starting point for search */
480
481 /*
482 * Don't change to another disk for sequential reads:
483 */
484 if (conf->next_seq_sect == this_sector)
485 goto rb_out;
486 if (this_sector == conf->mirrors[new_disk].head_position)
487 goto rb_out;
488
489 current_distance = abs(this_sector - conf->mirrors[disk].head_position);
490
491 /* Find the disk whose head is closest */
492
493 do {
494 if (disk <= 0)
495 disk = conf->raid_disks;
496 disk--;
497
498 rdev = rcu_dereference(conf->mirrors[disk].rdev);
499
500 if (!rdev || r1_bio->bios[disk] == IO_BLOCKED ||
501 !test_bit(In_sync, &rdev->flags) ||
502 test_bit(WriteMostly, &rdev->flags))
503 continue;
504
505 if (!atomic_read(&rdev->nr_pending)) {
506 new_disk = disk;
507 break;
508 }
509 new_distance = abs(this_sector - conf->mirrors[disk].head_position);
510 if (new_distance < current_distance) {
511 current_distance = new_distance;
512 new_disk = disk;
513 }
514 } while (disk != conf->last_used);
515
516 rb_out:
517
518
519 if (new_disk >= 0) {
520 rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
521 if (!rdev)
522 goto retry;
523 atomic_inc(&rdev->nr_pending);
524 if (!test_bit(In_sync, &rdev->flags)) {
525 /* cannot risk returning a device that failed
526 * before we inc'ed nr_pending
527 */
528 rdev_dec_pending(rdev, conf->mddev);
529 goto retry;
530 }
531 conf->next_seq_sect = this_sector + sectors;
532 conf->last_used = new_disk;
533 }
534 rcu_read_unlock();
535
536 return new_disk;
537 }
538
unplug_slaves(mddev_t * mddev)539 static void unplug_slaves(mddev_t *mddev)
540 {
541 conf_t *conf = mddev_to_conf(mddev);
542 int i;
543
544 rcu_read_lock();
545 for (i=0; i<mddev->raid_disks; i++) {
546 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
547 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
548 struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
549
550 atomic_inc(&rdev->nr_pending);
551 rcu_read_unlock();
552
553 blk_unplug(r_queue);
554
555 rdev_dec_pending(rdev, mddev);
556 rcu_read_lock();
557 }
558 }
559 rcu_read_unlock();
560 }
561
raid1_unplug(struct request_queue * q)562 static void raid1_unplug(struct request_queue *q)
563 {
564 mddev_t *mddev = q->queuedata;
565
566 unplug_slaves(mddev);
567 md_wakeup_thread(mddev->thread);
568 }
569
raid1_congested(void * data,int bits)570 static int raid1_congested(void *data, int bits)
571 {
572 mddev_t *mddev = data;
573 conf_t *conf = mddev_to_conf(mddev);
574 int i, ret = 0;
575
576 rcu_read_lock();
577 for (i = 0; i < mddev->raid_disks; i++) {
578 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
579 if (rdev && !test_bit(Faulty, &rdev->flags)) {
580 struct request_queue *q = bdev_get_queue(rdev->bdev);
581
582 /* Note the '|| 1' - when read_balance prefers
583 * non-congested targets, it can be removed
584 */
585 if ((bits & (1<<BDI_write_congested)) || 1)
586 ret |= bdi_congested(&q->backing_dev_info, bits);
587 else
588 ret &= bdi_congested(&q->backing_dev_info, bits);
589 }
590 }
591 rcu_read_unlock();
592 return ret;
593 }
594
595
flush_pending_writes(conf_t * conf)596 static int flush_pending_writes(conf_t *conf)
597 {
598 /* Any writes that have been queued but are awaiting
599 * bitmap updates get flushed here.
600 * We return 1 if any requests were actually submitted.
601 */
602 int rv = 0;
603
604 spin_lock_irq(&conf->device_lock);
605
606 if (conf->pending_bio_list.head) {
607 struct bio *bio;
608 bio = bio_list_get(&conf->pending_bio_list);
609 blk_remove_plug(conf->mddev->queue);
610 spin_unlock_irq(&conf->device_lock);
611 /* flush any pending bitmap writes to
612 * disk before proceeding w/ I/O */
613 bitmap_unplug(conf->mddev->bitmap);
614
615 while (bio) { /* submit pending writes */
616 struct bio *next = bio->bi_next;
617 bio->bi_next = NULL;
618 generic_make_request(bio);
619 bio = next;
620 }
621 rv = 1;
622 } else
623 spin_unlock_irq(&conf->device_lock);
624 return rv;
625 }
626
627 /* Barriers....
628 * Sometimes we need to suspend IO while we do something else,
629 * either some resync/recovery, or reconfigure the array.
630 * To do this we raise a 'barrier'.
631 * The 'barrier' is a counter that can be raised multiple times
632 * to count how many activities are happening which preclude
633 * normal IO.
634 * We can only raise the barrier if there is no pending IO.
635 * i.e. if nr_pending == 0.
636 * We choose only to raise the barrier if no-one is waiting for the
637 * barrier to go down. This means that as soon as an IO request
638 * is ready, no other operations which require a barrier will start
639 * until the IO request has had a chance.
640 *
641 * So: regular IO calls 'wait_barrier'. When that returns there
642 * is no backgroup IO happening, It must arrange to call
643 * allow_barrier when it has finished its IO.
644 * backgroup IO calls must call raise_barrier. Once that returns
645 * there is no normal IO happeing. It must arrange to call
646 * lower_barrier when the particular background IO completes.
647 */
648 #define RESYNC_DEPTH 32
649
raise_barrier(conf_t * conf)650 static void raise_barrier(conf_t *conf)
651 {
652 spin_lock_irq(&conf->resync_lock);
653
654 /* Wait until no block IO is waiting */
655 wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
656 conf->resync_lock,
657 raid1_unplug(conf->mddev->queue));
658
659 /* block any new IO from starting */
660 conf->barrier++;
661
662 /* No wait for all pending IO to complete */
663 wait_event_lock_irq(conf->wait_barrier,
664 !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
665 conf->resync_lock,
666 raid1_unplug(conf->mddev->queue));
667
668 spin_unlock_irq(&conf->resync_lock);
669 }
670
lower_barrier(conf_t * conf)671 static void lower_barrier(conf_t *conf)
672 {
673 unsigned long flags;
674 spin_lock_irqsave(&conf->resync_lock, flags);
675 conf->barrier--;
676 spin_unlock_irqrestore(&conf->resync_lock, flags);
677 wake_up(&conf->wait_barrier);
678 }
679
wait_barrier(conf_t * conf)680 static void wait_barrier(conf_t *conf)
681 {
682 spin_lock_irq(&conf->resync_lock);
683 if (conf->barrier) {
684 conf->nr_waiting++;
685 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
686 conf->resync_lock,
687 raid1_unplug(conf->mddev->queue));
688 conf->nr_waiting--;
689 }
690 conf->nr_pending++;
691 spin_unlock_irq(&conf->resync_lock);
692 }
693
allow_barrier(conf_t * conf)694 static void allow_barrier(conf_t *conf)
695 {
696 unsigned long flags;
697 spin_lock_irqsave(&conf->resync_lock, flags);
698 conf->nr_pending--;
699 spin_unlock_irqrestore(&conf->resync_lock, flags);
700 wake_up(&conf->wait_barrier);
701 }
702
freeze_array(conf_t * conf)703 static void freeze_array(conf_t *conf)
704 {
705 /* stop syncio and normal IO and wait for everything to
706 * go quite.
707 * We increment barrier and nr_waiting, and then
708 * wait until nr_pending match nr_queued+1
709 * This is called in the context of one normal IO request
710 * that has failed. Thus any sync request that might be pending
711 * will be blocked by nr_pending, and we need to wait for
712 * pending IO requests to complete or be queued for re-try.
713 * Thus the number queued (nr_queued) plus this request (1)
714 * must match the number of pending IOs (nr_pending) before
715 * we continue.
716 */
717 spin_lock_irq(&conf->resync_lock);
718 conf->barrier++;
719 conf->nr_waiting++;
720 wait_event_lock_irq(conf->wait_barrier,
721 conf->nr_pending == conf->nr_queued+1,
722 conf->resync_lock,
723 ({ flush_pending_writes(conf);
724 raid1_unplug(conf->mddev->queue); }));
725 spin_unlock_irq(&conf->resync_lock);
726 }
unfreeze_array(conf_t * conf)727 static void unfreeze_array(conf_t *conf)
728 {
729 /* reverse the effect of the freeze */
730 spin_lock_irq(&conf->resync_lock);
731 conf->barrier--;
732 conf->nr_waiting--;
733 wake_up(&conf->wait_barrier);
734 spin_unlock_irq(&conf->resync_lock);
735 }
736
737
738 /* duplicate the data pages for behind I/O */
alloc_behind_pages(struct bio * bio)739 static struct page **alloc_behind_pages(struct bio *bio)
740 {
741 int i;
742 struct bio_vec *bvec;
743 struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
744 GFP_NOIO);
745 if (unlikely(!pages))
746 goto do_sync_io;
747
748 bio_for_each_segment(bvec, bio, i) {
749 pages[i] = alloc_page(GFP_NOIO);
750 if (unlikely(!pages[i]))
751 goto do_sync_io;
752 memcpy(kmap(pages[i]) + bvec->bv_offset,
753 kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
754 kunmap(pages[i]);
755 kunmap(bvec->bv_page);
756 }
757
758 return pages;
759
760 do_sync_io:
761 if (pages)
762 for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
763 put_page(pages[i]);
764 kfree(pages);
765 PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
766 return NULL;
767 }
768
make_request(struct request_queue * q,struct bio * bio)769 static int make_request(struct request_queue *q, struct bio * bio)
770 {
771 mddev_t *mddev = q->queuedata;
772 conf_t *conf = mddev_to_conf(mddev);
773 mirror_info_t *mirror;
774 r1bio_t *r1_bio;
775 struct bio *read_bio;
776 int i, targets = 0, disks;
777 struct bitmap *bitmap;
778 unsigned long flags;
779 struct bio_list bl;
780 struct page **behind_pages = NULL;
781 const int rw = bio_data_dir(bio);
782 const int do_sync = bio_sync(bio);
783 int cpu, do_barriers;
784 mdk_rdev_t *blocked_rdev;
785
786 /*
787 * Register the new request and wait if the reconstruction
788 * thread has put up a bar for new requests.
789 * Continue immediately if no resync is active currently.
790 * We test barriers_work *after* md_write_start as md_write_start
791 * may cause the first superblock write, and that will check out
792 * if barriers work.
793 */
794
795 md_write_start(mddev, bio); /* wait on superblock update early */
796
797 if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
798 if (rw == WRITE)
799 md_write_end(mddev);
800 bio_endio(bio, -EOPNOTSUPP);
801 return 0;
802 }
803
804 wait_barrier(conf);
805
806 bitmap = mddev->bitmap;
807
808 cpu = part_stat_lock();
809 part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
810 part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
811 bio_sectors(bio));
812 part_stat_unlock();
813
814 /*
815 * make_request() can abort the operation when READA is being
816 * used and no empty request is available.
817 *
818 */
819 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
820
821 r1_bio->master_bio = bio;
822 r1_bio->sectors = bio->bi_size >> 9;
823 r1_bio->state = 0;
824 r1_bio->mddev = mddev;
825 r1_bio->sector = bio->bi_sector;
826
827 if (rw == READ) {
828 /*
829 * read balancing logic:
830 */
831 int rdisk = read_balance(conf, r1_bio);
832
833 if (rdisk < 0) {
834 /* couldn't find anywhere to read from */
835 raid_end_bio_io(r1_bio);
836 return 0;
837 }
838 mirror = conf->mirrors + rdisk;
839
840 r1_bio->read_disk = rdisk;
841
842 read_bio = bio_clone(bio, GFP_NOIO);
843
844 r1_bio->bios[rdisk] = read_bio;
845
846 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
847 read_bio->bi_bdev = mirror->rdev->bdev;
848 read_bio->bi_end_io = raid1_end_read_request;
849 read_bio->bi_rw = READ | do_sync;
850 read_bio->bi_private = r1_bio;
851
852 generic_make_request(read_bio);
853 return 0;
854 }
855
856 /*
857 * WRITE:
858 */
859 /* first select target devices under spinlock and
860 * inc refcount on their rdev. Record them by setting
861 * bios[x] to bio
862 */
863 disks = conf->raid_disks;
864 #if 0
865 { static int first=1;
866 if (first) printk("First Write sector %llu disks %d\n",
867 (unsigned long long)r1_bio->sector, disks);
868 first = 0;
869 }
870 #endif
871 retry_write:
872 blocked_rdev = NULL;
873 rcu_read_lock();
874 for (i = 0; i < disks; i++) {
875 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
876 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
877 atomic_inc(&rdev->nr_pending);
878 blocked_rdev = rdev;
879 break;
880 }
881 if (rdev && !test_bit(Faulty, &rdev->flags)) {
882 atomic_inc(&rdev->nr_pending);
883 if (test_bit(Faulty, &rdev->flags)) {
884 rdev_dec_pending(rdev, mddev);
885 r1_bio->bios[i] = NULL;
886 } else
887 r1_bio->bios[i] = bio;
888 targets++;
889 } else
890 r1_bio->bios[i] = NULL;
891 }
892 rcu_read_unlock();
893
894 if (unlikely(blocked_rdev)) {
895 /* Wait for this device to become unblocked */
896 int j;
897
898 for (j = 0; j < i; j++)
899 if (r1_bio->bios[j])
900 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
901
902 allow_barrier(conf);
903 md_wait_for_blocked_rdev(blocked_rdev, mddev);
904 wait_barrier(conf);
905 goto retry_write;
906 }
907
908 BUG_ON(targets == 0); /* we never fail the last device */
909
910 if (targets < conf->raid_disks) {
911 /* array is degraded, we will not clear the bitmap
912 * on I/O completion (see raid1_end_write_request) */
913 set_bit(R1BIO_Degraded, &r1_bio->state);
914 }
915
916 /* do behind I/O ? */
917 if (bitmap &&
918 atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind &&
919 (behind_pages = alloc_behind_pages(bio)) != NULL)
920 set_bit(R1BIO_BehindIO, &r1_bio->state);
921
922 atomic_set(&r1_bio->remaining, 0);
923 atomic_set(&r1_bio->behind_remaining, 0);
924
925 do_barriers = bio_barrier(bio);
926 if (do_barriers)
927 set_bit(R1BIO_Barrier, &r1_bio->state);
928
929 bio_list_init(&bl);
930 for (i = 0; i < disks; i++) {
931 struct bio *mbio;
932 if (!r1_bio->bios[i])
933 continue;
934
935 mbio = bio_clone(bio, GFP_NOIO);
936 r1_bio->bios[i] = mbio;
937
938 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
939 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
940 mbio->bi_end_io = raid1_end_write_request;
941 mbio->bi_rw = WRITE | do_barriers | do_sync;
942 mbio->bi_private = r1_bio;
943
944 if (behind_pages) {
945 struct bio_vec *bvec;
946 int j;
947
948 /* Yes, I really want the '__' version so that
949 * we clear any unused pointer in the io_vec, rather
950 * than leave them unchanged. This is important
951 * because when we come to free the pages, we won't
952 * know the originial bi_idx, so we just free
953 * them all
954 */
955 __bio_for_each_segment(bvec, mbio, j, 0)
956 bvec->bv_page = behind_pages[j];
957 if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
958 atomic_inc(&r1_bio->behind_remaining);
959 }
960
961 atomic_inc(&r1_bio->remaining);
962
963 bio_list_add(&bl, mbio);
964 }
965 kfree(behind_pages); /* the behind pages are attached to the bios now */
966
967 bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
968 test_bit(R1BIO_BehindIO, &r1_bio->state));
969 spin_lock_irqsave(&conf->device_lock, flags);
970 bio_list_merge(&conf->pending_bio_list, &bl);
971 bio_list_init(&bl);
972
973 blk_plug_device(mddev->queue);
974 spin_unlock_irqrestore(&conf->device_lock, flags);
975
976 /* In case raid1d snuck into freeze_array */
977 wake_up(&conf->wait_barrier);
978
979 if (do_sync)
980 md_wakeup_thread(mddev->thread);
981 #if 0
982 while ((bio = bio_list_pop(&bl)) != NULL)
983 generic_make_request(bio);
984 #endif
985
986 return 0;
987 }
988
status(struct seq_file * seq,mddev_t * mddev)989 static void status(struct seq_file *seq, mddev_t *mddev)
990 {
991 conf_t *conf = mddev_to_conf(mddev);
992 int i;
993
994 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
995 conf->raid_disks - mddev->degraded);
996 rcu_read_lock();
997 for (i = 0; i < conf->raid_disks; i++) {
998 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
999 seq_printf(seq, "%s",
1000 rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1001 }
1002 rcu_read_unlock();
1003 seq_printf(seq, "]");
1004 }
1005
1006
error(mddev_t * mddev,mdk_rdev_t * rdev)1007 static 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 */
1018 if (test_bit(In_sync, &rdev->flags)
1019 && (conf->raid_disks - mddev->degraded) == 1) {
1020 /*
1021 * Don't fail the drive, act as though we were just a
1022 * normal single drive.
1023 * However don't try a recovery from this drive as
1024 * it is very likely to fail.
1025 */
1026 mddev->recovery_disabled = 1;
1027 return;
1028 }
1029 if (test_and_clear_bit(In_sync, &rdev->flags)) {
1030 unsigned long flags;
1031 spin_lock_irqsave(&conf->device_lock, flags);
1032 mddev->degraded++;
1033 set_bit(Faulty, &rdev->flags);
1034 spin_unlock_irqrestore(&conf->device_lock, flags);
1035 /*
1036 * if recovery is running, make sure it aborts.
1037 */
1038 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1039 } else
1040 set_bit(Faulty, &rdev->flags);
1041 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1042 printk(KERN_ALERT "raid1: Disk failure on %s, disabling device.\n"
1043 "raid1: Operation continuing on %d devices.\n",
1044 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
1045 }
1046
print_conf(conf_t * conf)1047 static void print_conf(conf_t *conf)
1048 {
1049 int i;
1050
1051 printk("RAID1 conf printout:\n");
1052 if (!conf) {
1053 printk("(!conf)\n");
1054 return;
1055 }
1056 printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1057 conf->raid_disks);
1058
1059 rcu_read_lock();
1060 for (i = 0; i < conf->raid_disks; i++) {
1061 char b[BDEVNAME_SIZE];
1062 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1063 if (rdev)
1064 printk(" disk %d, wo:%d, o:%d, dev:%s\n",
1065 i, !test_bit(In_sync, &rdev->flags),
1066 !test_bit(Faulty, &rdev->flags),
1067 bdevname(rdev->bdev,b));
1068 }
1069 rcu_read_unlock();
1070 }
1071
close_sync(conf_t * conf)1072 static void close_sync(conf_t *conf)
1073 {
1074 wait_barrier(conf);
1075 allow_barrier(conf);
1076
1077 mempool_destroy(conf->r1buf_pool);
1078 conf->r1buf_pool = NULL;
1079 }
1080
raid1_spare_active(mddev_t * mddev)1081 static int raid1_spare_active(mddev_t *mddev)
1082 {
1083 int i;
1084 conf_t *conf = mddev->private;
1085
1086 /*
1087 * Find all failed disks within the RAID1 configuration
1088 * and mark them readable.
1089 * Called under mddev lock, so rcu protection not needed.
1090 */
1091 for (i = 0; i < conf->raid_disks; i++) {
1092 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1093 if (rdev
1094 && !test_bit(Faulty, &rdev->flags)
1095 && !test_and_set_bit(In_sync, &rdev->flags)) {
1096 unsigned long flags;
1097 spin_lock_irqsave(&conf->device_lock, flags);
1098 mddev->degraded--;
1099 spin_unlock_irqrestore(&conf->device_lock, flags);
1100 }
1101 }
1102
1103 print_conf(conf);
1104 return 0;
1105 }
1106
1107
raid1_add_disk(mddev_t * mddev,mdk_rdev_t * rdev)1108 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1109 {
1110 conf_t *conf = mddev->private;
1111 int err = -EEXIST;
1112 int mirror = 0;
1113 mirror_info_t *p;
1114 int first = 0;
1115 int last = mddev->raid_disks - 1;
1116
1117 if (rdev->raid_disk >= 0)
1118 first = last = rdev->raid_disk;
1119
1120 for (mirror = first; mirror <= last; mirror++)
1121 if ( !(p=conf->mirrors+mirror)->rdev) {
1122
1123 blk_queue_stack_limits(mddev->queue,
1124 rdev->bdev->bd_disk->queue);
1125 /* as we don't honour merge_bvec_fn, we must never risk
1126 * violating it, so limit ->max_sector to one PAGE, as
1127 * a one page request is never in violation.
1128 */
1129 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1130 mddev->queue->max_sectors > (PAGE_SIZE>>9))
1131 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1132
1133 p->head_position = 0;
1134 rdev->raid_disk = mirror;
1135 err = 0;
1136 /* As all devices are equivalent, we don't need a full recovery
1137 * if this was recently any drive of the array
1138 */
1139 if (rdev->saved_raid_disk < 0)
1140 conf->fullsync = 1;
1141 rcu_assign_pointer(p->rdev, rdev);
1142 break;
1143 }
1144
1145 print_conf(conf);
1146 return err;
1147 }
1148
raid1_remove_disk(mddev_t * mddev,int number)1149 static int raid1_remove_disk(mddev_t *mddev, int number)
1150 {
1151 conf_t *conf = mddev->private;
1152 int err = 0;
1153 mdk_rdev_t *rdev;
1154 mirror_info_t *p = conf->mirrors+ number;
1155
1156 print_conf(conf);
1157 rdev = p->rdev;
1158 if (rdev) {
1159 if (test_bit(In_sync, &rdev->flags) ||
1160 atomic_read(&rdev->nr_pending)) {
1161 err = -EBUSY;
1162 goto abort;
1163 }
1164 /* Only remove non-faulty devices is recovery
1165 * is not possible.
1166 */
1167 if (!test_bit(Faulty, &rdev->flags) &&
1168 mddev->degraded < conf->raid_disks) {
1169 err = -EBUSY;
1170 goto abort;
1171 }
1172 p->rdev = NULL;
1173 synchronize_rcu();
1174 if (atomic_read(&rdev->nr_pending)) {
1175 /* lost the race, try later */
1176 err = -EBUSY;
1177 p->rdev = rdev;
1178 }
1179 }
1180 abort:
1181
1182 print_conf(conf);
1183 return err;
1184 }
1185
1186
end_sync_read(struct bio * bio,int error)1187 static void end_sync_read(struct bio *bio, int error)
1188 {
1189 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1190 int i;
1191
1192 for (i=r1_bio->mddev->raid_disks; i--; )
1193 if (r1_bio->bios[i] == bio)
1194 break;
1195 BUG_ON(i < 0);
1196 update_head_pos(i, r1_bio);
1197 /*
1198 * we have read a block, now it needs to be re-written,
1199 * or re-read if the read failed.
1200 * We don't do much here, just schedule handling by raid1d
1201 */
1202 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1203 set_bit(R1BIO_Uptodate, &r1_bio->state);
1204
1205 if (atomic_dec_and_test(&r1_bio->remaining))
1206 reschedule_retry(r1_bio);
1207 }
1208
end_sync_write(struct bio * bio,int error)1209 static void end_sync_write(struct bio *bio, int error)
1210 {
1211 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1212 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1213 mddev_t *mddev = r1_bio->mddev;
1214 conf_t *conf = mddev_to_conf(mddev);
1215 int i;
1216 int mirror=0;
1217
1218 for (i = 0; i < conf->raid_disks; i++)
1219 if (r1_bio->bios[i] == bio) {
1220 mirror = i;
1221 break;
1222 }
1223 if (!uptodate) {
1224 int sync_blocks = 0;
1225 sector_t s = r1_bio->sector;
1226 long sectors_to_go = r1_bio->sectors;
1227 /* make sure these bits doesn't get cleared. */
1228 do {
1229 bitmap_end_sync(mddev->bitmap, s,
1230 &sync_blocks, 1);
1231 s += sync_blocks;
1232 sectors_to_go -= sync_blocks;
1233 } while (sectors_to_go > 0);
1234 md_error(mddev, conf->mirrors[mirror].rdev);
1235 }
1236
1237 update_head_pos(mirror, r1_bio);
1238
1239 if (atomic_dec_and_test(&r1_bio->remaining)) {
1240 sector_t s = r1_bio->sectors;
1241 put_buf(r1_bio);
1242 md_done_sync(mddev, s, uptodate);
1243 }
1244 }
1245
sync_request_write(mddev_t * mddev,r1bio_t * r1_bio)1246 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1247 {
1248 conf_t *conf = mddev_to_conf(mddev);
1249 int i;
1250 int disks = conf->raid_disks;
1251 struct bio *bio, *wbio;
1252
1253 bio = r1_bio->bios[r1_bio->read_disk];
1254
1255
1256 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1257 /* We have read all readable devices. If we haven't
1258 * got the block, then there is no hope left.
1259 * If we have, then we want to do a comparison
1260 * and skip the write if everything is the same.
1261 * If any blocks failed to read, then we need to
1262 * attempt an over-write
1263 */
1264 int primary;
1265 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1266 for (i=0; i<mddev->raid_disks; i++)
1267 if (r1_bio->bios[i]->bi_end_io == end_sync_read)
1268 md_error(mddev, conf->mirrors[i].rdev);
1269
1270 md_done_sync(mddev, r1_bio->sectors, 1);
1271 put_buf(r1_bio);
1272 return;
1273 }
1274 for (primary=0; primary<mddev->raid_disks; primary++)
1275 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1276 test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1277 r1_bio->bios[primary]->bi_end_io = NULL;
1278 rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1279 break;
1280 }
1281 r1_bio->read_disk = primary;
1282 for (i=0; i<mddev->raid_disks; i++)
1283 if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1284 int j;
1285 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1286 struct bio *pbio = r1_bio->bios[primary];
1287 struct bio *sbio = r1_bio->bios[i];
1288
1289 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1290 for (j = vcnt; j-- ; ) {
1291 struct page *p, *s;
1292 p = pbio->bi_io_vec[j].bv_page;
1293 s = sbio->bi_io_vec[j].bv_page;
1294 if (memcmp(page_address(p),
1295 page_address(s),
1296 PAGE_SIZE))
1297 break;
1298 }
1299 } else
1300 j = 0;
1301 if (j >= 0)
1302 mddev->resync_mismatches += r1_bio->sectors;
1303 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1304 && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1305 sbio->bi_end_io = NULL;
1306 rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1307 } else {
1308 /* fixup the bio for reuse */
1309 int size;
1310 sbio->bi_vcnt = vcnt;
1311 sbio->bi_size = r1_bio->sectors << 9;
1312 sbio->bi_idx = 0;
1313 sbio->bi_phys_segments = 0;
1314 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1315 sbio->bi_flags |= 1 << BIO_UPTODATE;
1316 sbio->bi_next = NULL;
1317 sbio->bi_sector = r1_bio->sector +
1318 conf->mirrors[i].rdev->data_offset;
1319 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1320 size = sbio->bi_size;
1321 for (j = 0; j < vcnt ; j++) {
1322 struct bio_vec *bi;
1323 bi = &sbio->bi_io_vec[j];
1324 bi->bv_offset = 0;
1325 if (size > PAGE_SIZE)
1326 bi->bv_len = PAGE_SIZE;
1327 else
1328 bi->bv_len = size;
1329 size -= PAGE_SIZE;
1330 memcpy(page_address(bi->bv_page),
1331 page_address(pbio->bi_io_vec[j].bv_page),
1332 PAGE_SIZE);
1333 }
1334
1335 }
1336 }
1337 }
1338 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1339 /* ouch - failed to read all of that.
1340 * Try some synchronous reads of other devices to get
1341 * good data, much like with normal read errors. Only
1342 * read into the pages we already have so we don't
1343 * need to re-issue the read request.
1344 * We don't need to freeze the array, because being in an
1345 * active sync request, there is no normal IO, and
1346 * no overlapping syncs.
1347 */
1348 sector_t sect = r1_bio->sector;
1349 int sectors = r1_bio->sectors;
1350 int idx = 0;
1351
1352 while(sectors) {
1353 int s = sectors;
1354 int d = r1_bio->read_disk;
1355 int success = 0;
1356 mdk_rdev_t *rdev;
1357
1358 if (s > (PAGE_SIZE>>9))
1359 s = PAGE_SIZE >> 9;
1360 do {
1361 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1362 /* No rcu protection needed here devices
1363 * can only be removed when no resync is
1364 * active, and resync is currently active
1365 */
1366 rdev = conf->mirrors[d].rdev;
1367 if (sync_page_io(rdev->bdev,
1368 sect + rdev->data_offset,
1369 s<<9,
1370 bio->bi_io_vec[idx].bv_page,
1371 READ)) {
1372 success = 1;
1373 break;
1374 }
1375 }
1376 d++;
1377 if (d == conf->raid_disks)
1378 d = 0;
1379 } while (!success && d != r1_bio->read_disk);
1380
1381 if (success) {
1382 int start = d;
1383 /* write it back and re-read */
1384 set_bit(R1BIO_Uptodate, &r1_bio->state);
1385 while (d != r1_bio->read_disk) {
1386 if (d == 0)
1387 d = conf->raid_disks;
1388 d--;
1389 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1390 continue;
1391 rdev = conf->mirrors[d].rdev;
1392 atomic_add(s, &rdev->corrected_errors);
1393 if (sync_page_io(rdev->bdev,
1394 sect + rdev->data_offset,
1395 s<<9,
1396 bio->bi_io_vec[idx].bv_page,
1397 WRITE) == 0)
1398 md_error(mddev, rdev);
1399 }
1400 d = start;
1401 while (d != r1_bio->read_disk) {
1402 if (d == 0)
1403 d = conf->raid_disks;
1404 d--;
1405 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1406 continue;
1407 rdev = conf->mirrors[d].rdev;
1408 if (sync_page_io(rdev->bdev,
1409 sect + rdev->data_offset,
1410 s<<9,
1411 bio->bi_io_vec[idx].bv_page,
1412 READ) == 0)
1413 md_error(mddev, rdev);
1414 }
1415 } else {
1416 char b[BDEVNAME_SIZE];
1417 /* Cannot read from anywhere, array is toast */
1418 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1419 printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
1420 " for block %llu\n",
1421 bdevname(bio->bi_bdev,b),
1422 (unsigned long long)r1_bio->sector);
1423 md_done_sync(mddev, r1_bio->sectors, 0);
1424 put_buf(r1_bio);
1425 return;
1426 }
1427 sectors -= s;
1428 sect += s;
1429 idx ++;
1430 }
1431 }
1432
1433 /*
1434 * schedule writes
1435 */
1436 atomic_set(&r1_bio->remaining, 1);
1437 for (i = 0; i < disks ; i++) {
1438 wbio = r1_bio->bios[i];
1439 if (wbio->bi_end_io == NULL ||
1440 (wbio->bi_end_io == end_sync_read &&
1441 (i == r1_bio->read_disk ||
1442 !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1443 continue;
1444
1445 wbio->bi_rw = WRITE;
1446 wbio->bi_end_io = end_sync_write;
1447 atomic_inc(&r1_bio->remaining);
1448 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1449
1450 generic_make_request(wbio);
1451 }
1452
1453 if (atomic_dec_and_test(&r1_bio->remaining)) {
1454 /* if we're here, all write(s) have completed, so clean up */
1455 md_done_sync(mddev, r1_bio->sectors, 1);
1456 put_buf(r1_bio);
1457 }
1458 }
1459
1460 /*
1461 * This is a kernel thread which:
1462 *
1463 * 1. Retries failed read operations on working mirrors.
1464 * 2. Updates the raid superblock when problems encounter.
1465 * 3. Performs writes following reads for array syncronising.
1466 */
1467
fix_read_error(conf_t * conf,int read_disk,sector_t sect,int sectors)1468 static void fix_read_error(conf_t *conf, int read_disk,
1469 sector_t sect, int sectors)
1470 {
1471 mddev_t *mddev = conf->mddev;
1472 while(sectors) {
1473 int s = sectors;
1474 int d = read_disk;
1475 int success = 0;
1476 int start;
1477 mdk_rdev_t *rdev;
1478
1479 if (s > (PAGE_SIZE>>9))
1480 s = PAGE_SIZE >> 9;
1481
1482 do {
1483 /* Note: no rcu protection needed here
1484 * as this is synchronous in the raid1d thread
1485 * which is the thread that might remove
1486 * a device. If raid1d ever becomes multi-threaded....
1487 */
1488 rdev = conf->mirrors[d].rdev;
1489 if (rdev &&
1490 test_bit(In_sync, &rdev->flags) &&
1491 sync_page_io(rdev->bdev,
1492 sect + rdev->data_offset,
1493 s<<9,
1494 conf->tmppage, READ))
1495 success = 1;
1496 else {
1497 d++;
1498 if (d == conf->raid_disks)
1499 d = 0;
1500 }
1501 } while (!success && d != read_disk);
1502
1503 if (!success) {
1504 /* Cannot read from anywhere -- bye bye array */
1505 md_error(mddev, conf->mirrors[read_disk].rdev);
1506 break;
1507 }
1508 /* write it back and re-read */
1509 start = d;
1510 while (d != read_disk) {
1511 if (d==0)
1512 d = conf->raid_disks;
1513 d--;
1514 rdev = conf->mirrors[d].rdev;
1515 if (rdev &&
1516 test_bit(In_sync, &rdev->flags)) {
1517 if (sync_page_io(rdev->bdev,
1518 sect + rdev->data_offset,
1519 s<<9, conf->tmppage, WRITE)
1520 == 0)
1521 /* Well, this device is dead */
1522 md_error(mddev, rdev);
1523 }
1524 }
1525 d = start;
1526 while (d != read_disk) {
1527 char b[BDEVNAME_SIZE];
1528 if (d==0)
1529 d = conf->raid_disks;
1530 d--;
1531 rdev = conf->mirrors[d].rdev;
1532 if (rdev &&
1533 test_bit(In_sync, &rdev->flags)) {
1534 if (sync_page_io(rdev->bdev,
1535 sect + rdev->data_offset,
1536 s<<9, conf->tmppage, READ)
1537 == 0)
1538 /* Well, this device is dead */
1539 md_error(mddev, rdev);
1540 else {
1541 atomic_add(s, &rdev->corrected_errors);
1542 printk(KERN_INFO
1543 "raid1:%s: read error corrected "
1544 "(%d sectors at %llu on %s)\n",
1545 mdname(mddev), s,
1546 (unsigned long long)(sect +
1547 rdev->data_offset),
1548 bdevname(rdev->bdev, b));
1549 }
1550 }
1551 }
1552 sectors -= s;
1553 sect += s;
1554 }
1555 }
1556
raid1d(mddev_t * mddev)1557 static void raid1d(mddev_t *mddev)
1558 {
1559 r1bio_t *r1_bio;
1560 struct bio *bio;
1561 unsigned long flags;
1562 conf_t *conf = mddev_to_conf(mddev);
1563 struct list_head *head = &conf->retry_list;
1564 int unplug=0;
1565 mdk_rdev_t *rdev;
1566
1567 md_check_recovery(mddev);
1568
1569 for (;;) {
1570 char b[BDEVNAME_SIZE];
1571
1572 unplug += flush_pending_writes(conf);
1573
1574 spin_lock_irqsave(&conf->device_lock, flags);
1575 if (list_empty(head)) {
1576 spin_unlock_irqrestore(&conf->device_lock, flags);
1577 break;
1578 }
1579 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1580 list_del(head->prev);
1581 conf->nr_queued--;
1582 spin_unlock_irqrestore(&conf->device_lock, flags);
1583
1584 mddev = r1_bio->mddev;
1585 conf = mddev_to_conf(mddev);
1586 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
1587 sync_request_write(mddev, r1_bio);
1588 unplug = 1;
1589 } else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
1590 /* some requests in the r1bio were BIO_RW_BARRIER
1591 * requests which failed with -EOPNOTSUPP. Hohumm..
1592 * Better resubmit without the barrier.
1593 * We know which devices to resubmit for, because
1594 * all others have had their bios[] entry cleared.
1595 * We already have a nr_pending reference on these rdevs.
1596 */
1597 int i;
1598 const int do_sync = bio_sync(r1_bio->master_bio);
1599 clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
1600 clear_bit(R1BIO_Barrier, &r1_bio->state);
1601 for (i=0; i < conf->raid_disks; i++)
1602 if (r1_bio->bios[i])
1603 atomic_inc(&r1_bio->remaining);
1604 for (i=0; i < conf->raid_disks; i++)
1605 if (r1_bio->bios[i]) {
1606 struct bio_vec *bvec;
1607 int j;
1608
1609 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1610 /* copy pages from the failed bio, as
1611 * this might be a write-behind device */
1612 __bio_for_each_segment(bvec, bio, j, 0)
1613 bvec->bv_page = bio_iovec_idx(r1_bio->bios[i], j)->bv_page;
1614 bio_put(r1_bio->bios[i]);
1615 bio->bi_sector = r1_bio->sector +
1616 conf->mirrors[i].rdev->data_offset;
1617 bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1618 bio->bi_end_io = raid1_end_write_request;
1619 bio->bi_rw = WRITE | do_sync;
1620 bio->bi_private = r1_bio;
1621 r1_bio->bios[i] = bio;
1622 generic_make_request(bio);
1623 }
1624 } else {
1625 int disk;
1626
1627 /* we got a read error. Maybe the drive is bad. Maybe just
1628 * the block and we can fix it.
1629 * We freeze all other IO, and try reading the block from
1630 * other devices. When we find one, we re-write
1631 * and check it that fixes the read error.
1632 * This is all done synchronously while the array is
1633 * frozen
1634 */
1635 if (mddev->ro == 0) {
1636 freeze_array(conf);
1637 fix_read_error(conf, r1_bio->read_disk,
1638 r1_bio->sector,
1639 r1_bio->sectors);
1640 unfreeze_array(conf);
1641 }
1642
1643 bio = r1_bio->bios[r1_bio->read_disk];
1644 if ((disk=read_balance(conf, r1_bio)) == -1 ||
1645 disk == r1_bio->read_disk) {
1646 printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
1647 " read error for block %llu\n",
1648 bdevname(bio->bi_bdev,b),
1649 (unsigned long long)r1_bio->sector);
1650 raid_end_bio_io(r1_bio);
1651 } else {
1652 const int do_sync = bio_sync(r1_bio->master_bio);
1653 r1_bio->bios[r1_bio->read_disk] =
1654 mddev->ro ? IO_BLOCKED : NULL;
1655 r1_bio->read_disk = disk;
1656 bio_put(bio);
1657 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1658 r1_bio->bios[r1_bio->read_disk] = bio;
1659 rdev = conf->mirrors[disk].rdev;
1660 if (printk_ratelimit())
1661 printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
1662 " another mirror\n",
1663 bdevname(rdev->bdev,b),
1664 (unsigned long long)r1_bio->sector);
1665 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1666 bio->bi_bdev = rdev->bdev;
1667 bio->bi_end_io = raid1_end_read_request;
1668 bio->bi_rw = READ | do_sync;
1669 bio->bi_private = r1_bio;
1670 unplug = 1;
1671 generic_make_request(bio);
1672 }
1673 }
1674 }
1675 if (unplug)
1676 unplug_slaves(mddev);
1677 }
1678
1679
init_resync(conf_t * conf)1680 static int init_resync(conf_t *conf)
1681 {
1682 int buffs;
1683
1684 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1685 BUG_ON(conf->r1buf_pool);
1686 conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1687 conf->poolinfo);
1688 if (!conf->r1buf_pool)
1689 return -ENOMEM;
1690 conf->next_resync = 0;
1691 return 0;
1692 }
1693
1694 /*
1695 * perform a "sync" on one "block"
1696 *
1697 * We need to make sure that no normal I/O request - particularly write
1698 * requests - conflict with active sync requests.
1699 *
1700 * This is achieved by tracking pending requests and a 'barrier' concept
1701 * that can be installed to exclude normal IO requests.
1702 */
1703
sync_request(mddev_t * mddev,sector_t sector_nr,int * skipped,int go_faster)1704 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1705 {
1706 conf_t *conf = mddev_to_conf(mddev);
1707 r1bio_t *r1_bio;
1708 struct bio *bio;
1709 sector_t max_sector, nr_sectors;
1710 int disk = -1;
1711 int i;
1712 int wonly = -1;
1713 int write_targets = 0, read_targets = 0;
1714 int sync_blocks;
1715 int still_degraded = 0;
1716
1717 if (!conf->r1buf_pool)
1718 {
1719 /*
1720 printk("sync start - bitmap %p\n", mddev->bitmap);
1721 */
1722 if (init_resync(conf))
1723 return 0;
1724 }
1725
1726 max_sector = mddev->size << 1;
1727 if (sector_nr >= max_sector) {
1728 /* If we aborted, we need to abort the
1729 * sync on the 'current' bitmap chunk (there will
1730 * only be one in raid1 resync.
1731 * We can find the current addess in mddev->curr_resync
1732 */
1733 if (mddev->curr_resync < max_sector) /* aborted */
1734 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1735 &sync_blocks, 1);
1736 else /* completed sync */
1737 conf->fullsync = 0;
1738
1739 bitmap_close_sync(mddev->bitmap);
1740 close_sync(conf);
1741 return 0;
1742 }
1743
1744 if (mddev->bitmap == NULL &&
1745 mddev->recovery_cp == MaxSector &&
1746 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1747 conf->fullsync == 0) {
1748 *skipped = 1;
1749 return max_sector - sector_nr;
1750 }
1751 /* before building a request, check if we can skip these blocks..
1752 * This call the bitmap_start_sync doesn't actually record anything
1753 */
1754 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1755 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1756 /* We can skip this block, and probably several more */
1757 *skipped = 1;
1758 return sync_blocks;
1759 }
1760 /*
1761 * If there is non-resync activity waiting for a turn,
1762 * and resync is going fast enough,
1763 * then let it though before starting on this new sync request.
1764 */
1765 if (!go_faster && conf->nr_waiting)
1766 msleep_interruptible(1000);
1767
1768 bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1769 raise_barrier(conf);
1770
1771 conf->next_resync = sector_nr;
1772
1773 r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1774 rcu_read_lock();
1775 /*
1776 * If we get a correctably read error during resync or recovery,
1777 * we might want to read from a different device. So we
1778 * flag all drives that could conceivably be read from for READ,
1779 * and any others (which will be non-In_sync devices) for WRITE.
1780 * If a read fails, we try reading from something else for which READ
1781 * is OK.
1782 */
1783
1784 r1_bio->mddev = mddev;
1785 r1_bio->sector = sector_nr;
1786 r1_bio->state = 0;
1787 set_bit(R1BIO_IsSync, &r1_bio->state);
1788
1789 for (i=0; i < conf->raid_disks; i++) {
1790 mdk_rdev_t *rdev;
1791 bio = r1_bio->bios[i];
1792
1793 /* take from bio_init */
1794 bio->bi_next = NULL;
1795 bio->bi_flags |= 1 << BIO_UPTODATE;
1796 bio->bi_rw = READ;
1797 bio->bi_vcnt = 0;
1798 bio->bi_idx = 0;
1799 bio->bi_phys_segments = 0;
1800 bio->bi_size = 0;
1801 bio->bi_end_io = NULL;
1802 bio->bi_private = NULL;
1803
1804 rdev = rcu_dereference(conf->mirrors[i].rdev);
1805 if (rdev == NULL ||
1806 test_bit(Faulty, &rdev->flags)) {
1807 still_degraded = 1;
1808 continue;
1809 } else if (!test_bit(In_sync, &rdev->flags)) {
1810 bio->bi_rw = WRITE;
1811 bio->bi_end_io = end_sync_write;
1812 write_targets ++;
1813 } else {
1814 /* may need to read from here */
1815 bio->bi_rw = READ;
1816 bio->bi_end_io = end_sync_read;
1817 if (test_bit(WriteMostly, &rdev->flags)) {
1818 if (wonly < 0)
1819 wonly = i;
1820 } else {
1821 if (disk < 0)
1822 disk = i;
1823 }
1824 read_targets++;
1825 }
1826 atomic_inc(&rdev->nr_pending);
1827 bio->bi_sector = sector_nr + rdev->data_offset;
1828 bio->bi_bdev = rdev->bdev;
1829 bio->bi_private = r1_bio;
1830 }
1831 rcu_read_unlock();
1832 if (disk < 0)
1833 disk = wonly;
1834 r1_bio->read_disk = disk;
1835
1836 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1837 /* extra read targets are also write targets */
1838 write_targets += read_targets-1;
1839
1840 if (write_targets == 0 || read_targets == 0) {
1841 /* There is nowhere to write, so all non-sync
1842 * drives must be failed - so we are finished
1843 */
1844 sector_t rv = max_sector - sector_nr;
1845 *skipped = 1;
1846 put_buf(r1_bio);
1847 return rv;
1848 }
1849
1850 if (max_sector > mddev->resync_max)
1851 max_sector = mddev->resync_max; /* Don't do IO beyond here */
1852 nr_sectors = 0;
1853 sync_blocks = 0;
1854 do {
1855 struct page *page;
1856 int len = PAGE_SIZE;
1857 if (sector_nr + (len>>9) > max_sector)
1858 len = (max_sector - sector_nr) << 9;
1859 if (len == 0)
1860 break;
1861 if (sync_blocks == 0) {
1862 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1863 &sync_blocks, still_degraded) &&
1864 !conf->fullsync &&
1865 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1866 break;
1867 BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1868 if (len > (sync_blocks<<9))
1869 len = sync_blocks<<9;
1870 }
1871
1872 for (i=0 ; i < conf->raid_disks; i++) {
1873 bio = r1_bio->bios[i];
1874 if (bio->bi_end_io) {
1875 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1876 if (bio_add_page(bio, page, len, 0) == 0) {
1877 /* stop here */
1878 bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1879 while (i > 0) {
1880 i--;
1881 bio = r1_bio->bios[i];
1882 if (bio->bi_end_io==NULL)
1883 continue;
1884 /* remove last page from this bio */
1885 bio->bi_vcnt--;
1886 bio->bi_size -= len;
1887 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1888 }
1889 goto bio_full;
1890 }
1891 }
1892 }
1893 nr_sectors += len>>9;
1894 sector_nr += len>>9;
1895 sync_blocks -= (len>>9);
1896 } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1897 bio_full:
1898 r1_bio->sectors = nr_sectors;
1899
1900 /* For a user-requested sync, we read all readable devices and do a
1901 * compare
1902 */
1903 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1904 atomic_set(&r1_bio->remaining, read_targets);
1905 for (i=0; i<conf->raid_disks; i++) {
1906 bio = r1_bio->bios[i];
1907 if (bio->bi_end_io == end_sync_read) {
1908 md_sync_acct(bio->bi_bdev, nr_sectors);
1909 generic_make_request(bio);
1910 }
1911 }
1912 } else {
1913 atomic_set(&r1_bio->remaining, 1);
1914 bio = r1_bio->bios[r1_bio->read_disk];
1915 md_sync_acct(bio->bi_bdev, nr_sectors);
1916 generic_make_request(bio);
1917
1918 }
1919 return nr_sectors;
1920 }
1921
run(mddev_t * mddev)1922 static int run(mddev_t *mddev)
1923 {
1924 conf_t *conf;
1925 int i, j, disk_idx;
1926 mirror_info_t *disk;
1927 mdk_rdev_t *rdev;
1928
1929 if (mddev->level != 1) {
1930 printk("raid1: %s: raid level not set to mirroring (%d)\n",
1931 mdname(mddev), mddev->level);
1932 goto out;
1933 }
1934 if (mddev->reshape_position != MaxSector) {
1935 printk("raid1: %s: reshape_position set but not supported\n",
1936 mdname(mddev));
1937 goto out;
1938 }
1939 /*
1940 * copy the already verified devices into our private RAID1
1941 * bookkeeping area. [whatever we allocate in run(),
1942 * should be freed in stop()]
1943 */
1944 conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
1945 mddev->private = conf;
1946 if (!conf)
1947 goto out_no_mem;
1948
1949 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1950 GFP_KERNEL);
1951 if (!conf->mirrors)
1952 goto out_no_mem;
1953
1954 conf->tmppage = alloc_page(GFP_KERNEL);
1955 if (!conf->tmppage)
1956 goto out_no_mem;
1957
1958 conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
1959 if (!conf->poolinfo)
1960 goto out_no_mem;
1961 conf->poolinfo->mddev = mddev;
1962 conf->poolinfo->raid_disks = mddev->raid_disks;
1963 conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1964 r1bio_pool_free,
1965 conf->poolinfo);
1966 if (!conf->r1bio_pool)
1967 goto out_no_mem;
1968
1969 spin_lock_init(&conf->device_lock);
1970 mddev->queue->queue_lock = &conf->device_lock;
1971
1972 list_for_each_entry(rdev, &mddev->disks, same_set) {
1973 disk_idx = rdev->raid_disk;
1974 if (disk_idx >= mddev->raid_disks
1975 || disk_idx < 0)
1976 continue;
1977 disk = conf->mirrors + disk_idx;
1978
1979 disk->rdev = rdev;
1980
1981 blk_queue_stack_limits(mddev->queue,
1982 rdev->bdev->bd_disk->queue);
1983 /* as we don't honour merge_bvec_fn, we must never risk
1984 * violating it, so limit ->max_sector to one PAGE, as
1985 * a one page request is never in violation.
1986 */
1987 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1988 mddev->queue->max_sectors > (PAGE_SIZE>>9))
1989 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1990
1991 disk->head_position = 0;
1992 }
1993 conf->raid_disks = mddev->raid_disks;
1994 conf->mddev = mddev;
1995 INIT_LIST_HEAD(&conf->retry_list);
1996
1997 spin_lock_init(&conf->resync_lock);
1998 init_waitqueue_head(&conf->wait_barrier);
1999
2000 bio_list_init(&conf->pending_bio_list);
2001 bio_list_init(&conf->flushing_bio_list);
2002
2003
2004 mddev->degraded = 0;
2005 for (i = 0; i < conf->raid_disks; i++) {
2006
2007 disk = conf->mirrors + i;
2008
2009 if (!disk->rdev ||
2010 !test_bit(In_sync, &disk->rdev->flags)) {
2011 disk->head_position = 0;
2012 mddev->degraded++;
2013 if (disk->rdev)
2014 conf->fullsync = 1;
2015 }
2016 }
2017 if (mddev->degraded == conf->raid_disks) {
2018 printk(KERN_ERR "raid1: no operational mirrors for %s\n",
2019 mdname(mddev));
2020 goto out_free_conf;
2021 }
2022 if (conf->raid_disks - mddev->degraded == 1)
2023 mddev->recovery_cp = MaxSector;
2024
2025 /*
2026 * find the first working one and use it as a starting point
2027 * to read balancing.
2028 */
2029 for (j = 0; j < conf->raid_disks &&
2030 (!conf->mirrors[j].rdev ||
2031 !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++)
2032 /* nothing */;
2033 conf->last_used = j;
2034
2035
2036 mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
2037 if (!mddev->thread) {
2038 printk(KERN_ERR
2039 "raid1: couldn't allocate thread for %s\n",
2040 mdname(mddev));
2041 goto out_free_conf;
2042 }
2043
2044 printk(KERN_INFO
2045 "raid1: raid set %s active with %d out of %d mirrors\n",
2046 mdname(mddev), mddev->raid_disks - mddev->degraded,
2047 mddev->raid_disks);
2048 /*
2049 * Ok, everything is just fine now
2050 */
2051 mddev->array_sectors = mddev->size * 2;
2052
2053 mddev->queue->unplug_fn = raid1_unplug;
2054 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2055 mddev->queue->backing_dev_info.congested_data = mddev;
2056
2057 return 0;
2058
2059 out_no_mem:
2060 printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
2061 mdname(mddev));
2062
2063 out_free_conf:
2064 if (conf) {
2065 if (conf->r1bio_pool)
2066 mempool_destroy(conf->r1bio_pool);
2067 kfree(conf->mirrors);
2068 safe_put_page(conf->tmppage);
2069 kfree(conf->poolinfo);
2070 kfree(conf);
2071 mddev->private = NULL;
2072 }
2073 out:
2074 return -EIO;
2075 }
2076
stop(mddev_t * mddev)2077 static int stop(mddev_t *mddev)
2078 {
2079 conf_t *conf = mddev_to_conf(mddev);
2080 struct bitmap *bitmap = mddev->bitmap;
2081 int behind_wait = 0;
2082
2083 /* wait for behind writes to complete */
2084 while (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2085 behind_wait++;
2086 printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), behind_wait);
2087 set_current_state(TASK_UNINTERRUPTIBLE);
2088 schedule_timeout(HZ); /* wait a second */
2089 /* need to kick something here to make sure I/O goes? */
2090 }
2091
2092 md_unregister_thread(mddev->thread);
2093 mddev->thread = NULL;
2094 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2095 if (conf->r1bio_pool)
2096 mempool_destroy(conf->r1bio_pool);
2097 kfree(conf->mirrors);
2098 kfree(conf->poolinfo);
2099 kfree(conf);
2100 mddev->private = NULL;
2101 return 0;
2102 }
2103
raid1_resize(mddev_t * mddev,sector_t sectors)2104 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2105 {
2106 /* no resync is happening, and there is enough space
2107 * on all devices, so we can resize.
2108 * We need to make sure resync covers any new space.
2109 * If the array is shrinking we should possibly wait until
2110 * any io in the removed space completes, but it hardly seems
2111 * worth it.
2112 */
2113 mddev->array_sectors = sectors;
2114 set_capacity(mddev->gendisk, mddev->array_sectors);
2115 mddev->changed = 1;
2116 if (mddev->array_sectors / 2 > mddev->size &&
2117 mddev->recovery_cp == MaxSector) {
2118 mddev->recovery_cp = mddev->size << 1;
2119 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2120 }
2121 mddev->size = mddev->array_sectors / 2;
2122 mddev->resync_max_sectors = sectors;
2123 return 0;
2124 }
2125
raid1_reshape(mddev_t * mddev)2126 static int raid1_reshape(mddev_t *mddev)
2127 {
2128 /* We need to:
2129 * 1/ resize the r1bio_pool
2130 * 2/ resize conf->mirrors
2131 *
2132 * We allocate a new r1bio_pool if we can.
2133 * Then raise a device barrier and wait until all IO stops.
2134 * Then resize conf->mirrors and swap in the new r1bio pool.
2135 *
2136 * At the same time, we "pack" the devices so that all the missing
2137 * devices have the higher raid_disk numbers.
2138 */
2139 mempool_t *newpool, *oldpool;
2140 struct pool_info *newpoolinfo;
2141 mirror_info_t *newmirrors;
2142 conf_t *conf = mddev_to_conf(mddev);
2143 int cnt, raid_disks;
2144 unsigned long flags;
2145 int d, d2, err;
2146
2147 /* Cannot change chunk_size, layout, or level */
2148 if (mddev->chunk_size != mddev->new_chunk ||
2149 mddev->layout != mddev->new_layout ||
2150 mddev->level != mddev->new_level) {
2151 mddev->new_chunk = mddev->chunk_size;
2152 mddev->new_layout = mddev->layout;
2153 mddev->new_level = mddev->level;
2154 return -EINVAL;
2155 }
2156
2157 err = md_allow_write(mddev);
2158 if (err)
2159 return err;
2160
2161 raid_disks = mddev->raid_disks + mddev->delta_disks;
2162
2163 if (raid_disks < conf->raid_disks) {
2164 cnt=0;
2165 for (d= 0; d < conf->raid_disks; d++)
2166 if (conf->mirrors[d].rdev)
2167 cnt++;
2168 if (cnt > raid_disks)
2169 return -EBUSY;
2170 }
2171
2172 newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2173 if (!newpoolinfo)
2174 return -ENOMEM;
2175 newpoolinfo->mddev = mddev;
2176 newpoolinfo->raid_disks = raid_disks;
2177
2178 newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2179 r1bio_pool_free, newpoolinfo);
2180 if (!newpool) {
2181 kfree(newpoolinfo);
2182 return -ENOMEM;
2183 }
2184 newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2185 if (!newmirrors) {
2186 kfree(newpoolinfo);
2187 mempool_destroy(newpool);
2188 return -ENOMEM;
2189 }
2190
2191 raise_barrier(conf);
2192
2193 /* ok, everything is stopped */
2194 oldpool = conf->r1bio_pool;
2195 conf->r1bio_pool = newpool;
2196
2197 for (d = d2 = 0; d < conf->raid_disks; d++) {
2198 mdk_rdev_t *rdev = conf->mirrors[d].rdev;
2199 if (rdev && rdev->raid_disk != d2) {
2200 char nm[20];
2201 sprintf(nm, "rd%d", rdev->raid_disk);
2202 sysfs_remove_link(&mddev->kobj, nm);
2203 rdev->raid_disk = d2;
2204 sprintf(nm, "rd%d", rdev->raid_disk);
2205 sysfs_remove_link(&mddev->kobj, nm);
2206 if (sysfs_create_link(&mddev->kobj,
2207 &rdev->kobj, nm))
2208 printk(KERN_WARNING
2209 "md/raid1: cannot register "
2210 "%s for %s\n",
2211 nm, mdname(mddev));
2212 }
2213 if (rdev)
2214 newmirrors[d2++].rdev = rdev;
2215 }
2216 kfree(conf->mirrors);
2217 conf->mirrors = newmirrors;
2218 kfree(conf->poolinfo);
2219 conf->poolinfo = newpoolinfo;
2220
2221 spin_lock_irqsave(&conf->device_lock, flags);
2222 mddev->degraded += (raid_disks - conf->raid_disks);
2223 spin_unlock_irqrestore(&conf->device_lock, flags);
2224 conf->raid_disks = mddev->raid_disks = raid_disks;
2225 mddev->delta_disks = 0;
2226
2227 conf->last_used = 0; /* just make sure it is in-range */
2228 lower_barrier(conf);
2229
2230 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2231 md_wakeup_thread(mddev->thread);
2232
2233 mempool_destroy(oldpool);
2234 return 0;
2235 }
2236
raid1_quiesce(mddev_t * mddev,int state)2237 static void raid1_quiesce(mddev_t *mddev, int state)
2238 {
2239 conf_t *conf = mddev_to_conf(mddev);
2240
2241 switch(state) {
2242 case 1:
2243 raise_barrier(conf);
2244 break;
2245 case 0:
2246 lower_barrier(conf);
2247 break;
2248 }
2249 }
2250
2251
2252 static struct mdk_personality raid1_personality =
2253 {
2254 .name = "raid1",
2255 .level = 1,
2256 .owner = THIS_MODULE,
2257 .make_request = make_request,
2258 .run = run,
2259 .stop = stop,
2260 .status = status,
2261 .error_handler = error,
2262 .hot_add_disk = raid1_add_disk,
2263 .hot_remove_disk= raid1_remove_disk,
2264 .spare_active = raid1_spare_active,
2265 .sync_request = sync_request,
2266 .resize = raid1_resize,
2267 .check_reshape = raid1_reshape,
2268 .quiesce = raid1_quiesce,
2269 };
2270
raid_init(void)2271 static int __init raid_init(void)
2272 {
2273 return register_md_personality(&raid1_personality);
2274 }
2275
raid_exit(void)2276 static void raid_exit(void)
2277 {
2278 unregister_md_personality(&raid1_personality);
2279 }
2280
2281 module_init(raid_init);
2282 module_exit(raid_exit);
2283 MODULE_LICENSE("GPL");
2284 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2285 MODULE_ALIAS("md-raid1");
2286 MODULE_ALIAS("md-level-1");
2287