0b82030c265dbf9f1789cfaf8291881f0b5e19a8
[linux-2.6.git] / drivers / md / raid1.c
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 Ć˜stergaard" <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/raid/raid1.h>
36 #include <linux/raid/bitmap.h>
37
38 #define DEBUG 0
39 #if DEBUG
40 #define PRINTK(x...) printk(x)
41 #else
42 #define PRINTK(x...)
43 #endif
44
45 /*
46  * Number of guaranteed r1bios in case of extreme VM load:
47  */
48 #define NR_RAID1_BIOS 256
49
50
51 static void unplug_slaves(mddev_t *mddev);
52
53 static void allow_barrier(conf_t *conf);
54 static void lower_barrier(conf_t *conf);
55
56 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
57 {
58         struct pool_info *pi = data;
59         r1bio_t *r1_bio;
60         int size = offsetof(r1bio_t, bios[pi->raid_disks]);
61
62         /* allocate a r1bio with room for raid_disks entries in the bios array */
63         r1_bio = kzalloc(size, gfp_flags);
64         if (!r1_bio)
65                 unplug_slaves(pi->mddev);
66
67         return r1_bio;
68 }
69
70 static void r1bio_pool_free(void *r1_bio, void *data)
71 {
72         kfree(r1_bio);
73 }
74
75 #define RESYNC_BLOCK_SIZE (64*1024)
76 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
77 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
78 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
79 #define RESYNC_WINDOW (2048*1024)
80
81 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
82 {
83         struct pool_info *pi = data;
84         struct page *page;
85         r1bio_t *r1_bio;
86         struct bio *bio;
87         int i, j;
88
89         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
90         if (!r1_bio) {
91                 unplug_slaves(pi->mddev);
92                 return NULL;
93         }
94
95         /*
96          * Allocate bios : 1 for reading, n-1 for writing
97          */
98         for (j = pi->raid_disks ; j-- ; ) {
99                 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
100                 if (!bio)
101                         goto out_free_bio;
102                 r1_bio->bios[j] = bio;
103         }
104         /*
105          * Allocate RESYNC_PAGES data pages and attach them to
106          * the first bio.
107          * If this is a user-requested check/repair, allocate
108          * RESYNC_PAGES for each bio.
109          */
110         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
111                 j = pi->raid_disks;
112         else
113                 j = 1;
114         while(j--) {
115                 bio = r1_bio->bios[j];
116                 for (i = 0; i < RESYNC_PAGES; i++) {
117                         page = alloc_page(gfp_flags);
118                         if (unlikely(!page))
119                                 goto out_free_pages;
120
121                         bio->bi_io_vec[i].bv_page = page;
122                 }
123         }
124         /* If not user-requests, copy the page pointers to all bios */
125         if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
126                 for (i=0; i<RESYNC_PAGES ; i++)
127                         for (j=1; j<pi->raid_disks; j++)
128                                 r1_bio->bios[j]->bi_io_vec[i].bv_page =
129                                         r1_bio->bios[0]->bi_io_vec[i].bv_page;
130         }
131
132         r1_bio->master_bio = NULL;
133
134         return r1_bio;
135
136 out_free_pages:
137         for (i=0; i < RESYNC_PAGES ; i++)
138                 for (j=0 ; j < pi->raid_disks; j++)
139                         safe_put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
140         j = -1;
141 out_free_bio:
142         while ( ++j < pi->raid_disks )
143                 bio_put(r1_bio->bios[j]);
144         r1bio_pool_free(r1_bio, data);
145         return NULL;
146 }
147
148 static void r1buf_pool_free(void *__r1_bio, void *data)
149 {
150         struct pool_info *pi = data;
151         int i,j;
152         r1bio_t *r1bio = __r1_bio;
153
154         for (i = 0; i < RESYNC_PAGES; i++)
155                 for (j = pi->raid_disks; j-- ;) {
156                         if (j == 0 ||
157                             r1bio->bios[j]->bi_io_vec[i].bv_page !=
158                             r1bio->bios[0]->bi_io_vec[i].bv_page)
159                                 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
160                 }
161         for (i=0 ; i < pi->raid_disks; i++)
162                 bio_put(r1bio->bios[i]);
163
164         r1bio_pool_free(r1bio, data);
165 }
166
167 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
168 {
169         int i;
170
171         for (i = 0; i < conf->raid_disks; i++) {
172                 struct bio **bio = r1_bio->bios + i;
173                 if (*bio && *bio != IO_BLOCKED)
174                         bio_put(*bio);
175                 *bio = NULL;
176         }
177 }
178
179 static void free_r1bio(r1bio_t *r1_bio)
180 {
181         conf_t *conf = mddev_to_conf(r1_bio->mddev);
182
183         /*
184          * Wake up any possible resync thread that waits for the device
185          * to go idle.
186          */
187         allow_barrier(conf);
188
189         put_all_bios(conf, r1_bio);
190         mempool_free(r1_bio, conf->r1bio_pool);
191 }
192
193 static void put_buf(r1bio_t *r1_bio)
194 {
195         conf_t *conf = mddev_to_conf(r1_bio->mddev);
196         int i;
197
198         for (i=0; i<conf->raid_disks; i++) {
199                 struct bio *bio = r1_bio->bios[i];
200                 if (bio->bi_end_io)
201                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
202         }
203
204         mempool_free(r1_bio, conf->r1buf_pool);
205
206         lower_barrier(conf);
207 }
208
209 static void reschedule_retry(r1bio_t *r1_bio)
210 {
211         unsigned long flags;
212         mddev_t *mddev = r1_bio->mddev;
213         conf_t *conf = mddev_to_conf(mddev);
214
215         spin_lock_irqsave(&conf->device_lock, flags);
216         list_add(&r1_bio->retry_list, &conf->retry_list);
217         conf->nr_queued ++;
218         spin_unlock_irqrestore(&conf->device_lock, flags);
219
220         wake_up(&conf->wait_barrier);
221         md_wakeup_thread(mddev->thread);
222 }
223
224 /*
225  * raid_end_bio_io() is called when we have finished servicing a mirrored
226  * operation and are ready to return a success/failure code to the buffer
227  * cache layer.
228  */
229 static void raid_end_bio_io(r1bio_t *r1_bio)
230 {
231         struct bio *bio = r1_bio->master_bio;
232
233         /* if nobody has done the final endio yet, do it now */
234         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
235                 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
236                         (bio_data_dir(bio) == WRITE) ? "write" : "read",
237                         (unsigned long long) bio->bi_sector,
238                         (unsigned long long) bio->bi_sector +
239                                 (bio->bi_size >> 9) - 1);
240
241                 bio_endio(bio,
242                         test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
243         }
244         free_r1bio(r1_bio);
245 }
246
247 /*
248  * Update disk head position estimator based on IRQ completion info.
249  */
250 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
251 {
252         conf_t *conf = mddev_to_conf(r1_bio->mddev);
253
254         conf->mirrors[disk].head_position =
255                 r1_bio->sector + (r1_bio->sectors);
256 }
257
258 static void raid1_end_read_request(struct bio *bio, int error)
259 {
260         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
261         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
262         int mirror;
263         conf_t *conf = mddev_to_conf(r1_bio->mddev);
264
265         mirror = r1_bio->read_disk;
266         /*
267          * this branch is our 'one mirror IO has finished' event handler:
268          */
269         update_head_pos(mirror, r1_bio);
270
271         if (uptodate)
272                 set_bit(R1BIO_Uptodate, &r1_bio->state);
273         else {
274                 /* If all other devices have failed, we want to return
275                  * the error upwards rather than fail the last device.
276                  * Here we redefine "uptodate" to mean "Don't want to retry"
277                  */
278                 unsigned long flags;
279                 spin_lock_irqsave(&conf->device_lock, flags);
280                 if (r1_bio->mddev->degraded == conf->raid_disks ||
281                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
282                      !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
283                         uptodate = 1;
284                 spin_unlock_irqrestore(&conf->device_lock, flags);
285         }
286
287         if (uptodate)
288                 raid_end_bio_io(r1_bio);
289         else {
290                 /*
291                  * oops, read error:
292                  */
293                 char b[BDEVNAME_SIZE];
294                 if (printk_ratelimit())
295                         printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
296                                bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
297                 reschedule_retry(r1_bio);
298         }
299
300         rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
301 }
302
303 static void raid1_end_write_request(struct bio *bio, int error)
304 {
305         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
306         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
307         int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
308         conf_t *conf = mddev_to_conf(r1_bio->mddev);
309         struct bio *to_put = NULL;
310
311
312         for (mirror = 0; mirror < conf->raid_disks; mirror++)
313                 if (r1_bio->bios[mirror] == bio)
314                         break;
315
316         if (error == -EOPNOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
317                 set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
318                 set_bit(R1BIO_BarrierRetry, &r1_bio->state);
319                 r1_bio->mddev->barriers_work = 0;
320                 /* Don't rdev_dec_pending in this branch - keep it for the retry */
321         } else {
322                 /*
323                  * this branch is our 'one mirror IO has finished' event handler:
324                  */
325                 r1_bio->bios[mirror] = NULL;
326                 to_put = bio;
327                 if (!uptodate) {
328                         md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
329                         /* an I/O failed, we can't clear the bitmap */
330                         set_bit(R1BIO_Degraded, &r1_bio->state);
331                 } else
332                         /*
333                          * Set R1BIO_Uptodate in our master bio, so that
334                          * we will return a good error code for to the higher
335                          * levels even if IO on some other mirrored buffer fails.
336                          *
337                          * The 'master' represents the composite IO operation to
338                          * user-side. So if something waits for IO, then it will
339                          * wait for the 'master' bio.
340                          */
341                         set_bit(R1BIO_Uptodate, &r1_bio->state);
342
343                 update_head_pos(mirror, r1_bio);
344
345                 if (behind) {
346                         if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
347                                 atomic_dec(&r1_bio->behind_remaining);
348
349                         /* In behind mode, we ACK the master bio once the I/O has safely
350                          * reached all non-writemostly disks. Setting the Returned bit
351                          * ensures that this gets done only once -- we don't ever want to
352                          * return -EIO here, instead we'll wait */
353
354                         if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
355                             test_bit(R1BIO_Uptodate, &r1_bio->state)) {
356                                 /* Maybe we can return now */
357                                 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
358                                         struct bio *mbio = r1_bio->master_bio;
359                                         PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
360                                                (unsigned long long) mbio->bi_sector,
361                                                (unsigned long long) mbio->bi_sector +
362                                                (mbio->bi_size >> 9) - 1);
363                                         bio_endio(mbio, 0);
364                                 }
365                         }
366                 }
367                 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
368         }
369         /*
370          *
371          * Let's see if all mirrored write operations have finished
372          * already.
373          */
374         if (atomic_dec_and_test(&r1_bio->remaining)) {
375                 if (test_bit(R1BIO_BarrierRetry, &r1_bio->state))
376                         reschedule_retry(r1_bio);
377                 else {
378                         /* it really is the end of this request */
379                         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
380                                 /* free extra copy of the data pages */
381                                 int i = bio->bi_vcnt;
382                                 while (i--)
383                                         safe_put_page(bio->bi_io_vec[i].bv_page);
384                         }
385                         /* clear the bitmap if all writes complete successfully */
386                         bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
387                                         r1_bio->sectors,
388                                         !test_bit(R1BIO_Degraded, &r1_bio->state),
389                                         behind);
390                         md_write_end(r1_bio->mddev);
391                         raid_end_bio_io(r1_bio);
392                 }
393         }
394
395         if (to_put)
396                 bio_put(to_put);
397 }
398
399
400 /*
401  * This routine returns the disk from which the requested read should
402  * be done. There is a per-array 'next expected sequential IO' sector
403  * number - if this matches on the next IO then we use the last disk.
404  * There is also a per-disk 'last know head position' sector that is
405  * maintained from IRQ contexts, both the normal and the resync IO
406  * completion handlers update this position correctly. If there is no
407  * perfect sequential match then we pick the disk whose head is closest.
408  *
409  * If there are 2 mirrors in the same 2 devices, performance degrades
410  * because position is mirror, not device based.
411  *
412  * The rdev for the device selected will have nr_pending incremented.
413  */
414 static int read_balance(conf_t *conf, r1bio_t *r1_bio)
415 {
416         const unsigned long this_sector = r1_bio->sector;
417         int new_disk = conf->last_used, disk = new_disk;
418         int wonly_disk = -1;
419         const int sectors = r1_bio->sectors;
420         sector_t new_distance, current_distance;
421         mdk_rdev_t *rdev;
422
423         rcu_read_lock();
424         /*
425          * Check if we can balance. We can balance on the whole
426          * device if no resync is going on, or below the resync window.
427          * We take the first readable disk when above the resync window.
428          */
429  retry:
430         if (conf->mddev->recovery_cp < MaxSector &&
431             (this_sector + sectors >= conf->next_resync)) {
432                 /* Choose the first operation device, for consistancy */
433                 new_disk = 0;
434
435                 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
436                      r1_bio->bios[new_disk] == IO_BLOCKED ||
437                      !rdev || !test_bit(In_sync, &rdev->flags)
438                              || test_bit(WriteMostly, &rdev->flags);
439                      rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
440
441                         if (rdev && test_bit(In_sync, &rdev->flags) &&
442                                 r1_bio->bios[new_disk] != IO_BLOCKED)
443                                 wonly_disk = new_disk;
444
445                         if (new_disk == conf->raid_disks - 1) {
446                                 new_disk = wonly_disk;
447                                 break;
448                         }
449                 }
450                 goto rb_out;
451         }
452
453
454         /* make sure the disk is operational */
455         for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
456              r1_bio->bios[new_disk] == IO_BLOCKED ||
457              !rdev || !test_bit(In_sync, &rdev->flags) ||
458                      test_bit(WriteMostly, &rdev->flags);
459              rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
460
461                 if (rdev && test_bit(In_sync, &rdev->flags) &&
462                     r1_bio->bios[new_disk] != IO_BLOCKED)
463                         wonly_disk = new_disk;
464
465                 if (new_disk <= 0)
466                         new_disk = conf->raid_disks;
467                 new_disk--;
468                 if (new_disk == disk) {
469                         new_disk = wonly_disk;
470                         break;
471                 }
472         }
473
474         if (new_disk < 0)
475                 goto rb_out;
476
477         disk = new_disk;
478         /* now disk == new_disk == starting point for search */
479
480         /*
481          * Don't change to another disk for sequential reads:
482          */
483         if (conf->next_seq_sect == this_sector)
484                 goto rb_out;
485         if (this_sector == conf->mirrors[new_disk].head_position)
486                 goto rb_out;
487
488         current_distance = abs(this_sector - conf->mirrors[disk].head_position);
489
490         /* Find the disk whose head is closest */
491
492         do {
493                 if (disk <= 0)
494                         disk = conf->raid_disks;
495                 disk--;
496
497                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
498
499                 if (!rdev || r1_bio->bios[disk] == IO_BLOCKED ||
500                     !test_bit(In_sync, &rdev->flags) ||
501                     test_bit(WriteMostly, &rdev->flags))
502                         continue;
503
504                 if (!atomic_read(&rdev->nr_pending)) {
505                         new_disk = disk;
506                         break;
507                 }
508                 new_distance = abs(this_sector - conf->mirrors[disk].head_position);
509                 if (new_distance < current_distance) {
510                         current_distance = new_distance;
511                         new_disk = disk;
512                 }
513         } while (disk != conf->last_used);
514
515  rb_out:
516
517
518         if (new_disk >= 0) {
519                 rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
520                 if (!rdev)
521                         goto retry;
522                 atomic_inc(&rdev->nr_pending);
523                 if (!test_bit(In_sync, &rdev->flags)) {
524                         /* cannot risk returning a device that failed
525                          * before we inc'ed nr_pending
526                          */
527                         rdev_dec_pending(rdev, conf->mddev);
528                         goto retry;
529                 }
530                 conf->next_seq_sect = this_sector + sectors;
531                 conf->last_used = new_disk;
532         }
533         rcu_read_unlock();
534
535         return new_disk;
536 }
537
538 static void unplug_slaves(mddev_t *mddev)
539 {
540         conf_t *conf = mddev_to_conf(mddev);
541         int i;
542
543         rcu_read_lock();
544         for (i=0; i<mddev->raid_disks; i++) {
545                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
546                 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
547                         struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
548
549                         atomic_inc(&rdev->nr_pending);
550                         rcu_read_unlock();
551
552                         blk_unplug(r_queue);
553
554                         rdev_dec_pending(rdev, mddev);
555                         rcu_read_lock();
556                 }
557         }
558         rcu_read_unlock();
559 }
560
561 static void raid1_unplug(struct request_queue *q)
562 {
563         mddev_t *mddev = q->queuedata;
564
565         unplug_slaves(mddev);
566         md_wakeup_thread(mddev->thread);
567 }
568
569 static int raid1_congested(void *data, int bits)
570 {
571         mddev_t *mddev = data;
572         conf_t *conf = mddev_to_conf(mddev);
573         int i, ret = 0;
574
575         rcu_read_lock();
576         for (i = 0; i < mddev->raid_disks; i++) {
577                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
578                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
579                         struct request_queue *q = bdev_get_queue(rdev->bdev);
580
581                         /* Note the '|| 1' - when read_balance prefers
582                          * non-congested targets, it can be removed
583                          */
584                         if ((bits & (1<<BDI_write_congested)) || 1)
585                                 ret |= bdi_congested(&q->backing_dev_info, bits);
586                         else
587                                 ret &= bdi_congested(&q->backing_dev_info, bits);
588                 }
589         }
590         rcu_read_unlock();
591         return ret;
592 }
593
594
595 static int flush_pending_writes(conf_t *conf)
596 {
597         /* Any writes that have been queued but are awaiting
598          * bitmap updates get flushed here.
599          * We return 1 if any requests were actually submitted.
600          */
601         int rv = 0;
602
603         spin_lock_irq(&conf->device_lock);
604
605         if (conf->pending_bio_list.head) {
606                 struct bio *bio;
607                 bio = bio_list_get(&conf->pending_bio_list);
608                 blk_remove_plug(conf->mddev->queue);
609                 spin_unlock_irq(&conf->device_lock);
610                 /* flush any pending bitmap writes to
611                  * disk before proceeding w/ I/O */
612                 bitmap_unplug(conf->mddev->bitmap);
613
614                 while (bio) { /* submit pending writes */
615                         struct bio *next = bio->bi_next;
616                         bio->bi_next = NULL;
617                         generic_make_request(bio);
618                         bio = next;
619                 }
620                 rv = 1;
621         } else
622                 spin_unlock_irq(&conf->device_lock);
623         return rv;
624 }
625
626 /* Barriers....
627  * Sometimes we need to suspend IO while we do something else,
628  * either some resync/recovery, or reconfigure the array.
629  * To do this we raise a 'barrier'.
630  * The 'barrier' is a counter that can be raised multiple times
631  * to count how many activities are happening which preclude
632  * normal IO.
633  * We can only raise the barrier if there is no pending IO.
634  * i.e. if nr_pending == 0.
635  * We choose only to raise the barrier if no-one is waiting for the
636  * barrier to go down.  This means that as soon as an IO request
637  * is ready, no other operations which require a barrier will start
638  * until the IO request has had a chance.
639  *
640  * So: regular IO calls 'wait_barrier'.  When that returns there
641  *    is no backgroup IO happening,  It must arrange to call
642  *    allow_barrier when it has finished its IO.
643  * backgroup IO calls must call raise_barrier.  Once that returns
644  *    there is no normal IO happeing.  It must arrange to call
645  *    lower_barrier when the particular background IO completes.
646  */
647 #define RESYNC_DEPTH 32
648
649 static void raise_barrier(conf_t *conf)
650 {
651         spin_lock_irq(&conf->resync_lock);
652
653         /* Wait until no block IO is waiting */
654         wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
655                             conf->resync_lock,
656                             raid1_unplug(conf->mddev->queue));
657
658         /* block any new IO from starting */
659         conf->barrier++;
660
661         /* No wait for all pending IO to complete */
662         wait_event_lock_irq(conf->wait_barrier,
663                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
664                             conf->resync_lock,
665                             raid1_unplug(conf->mddev->queue));
666
667         spin_unlock_irq(&conf->resync_lock);
668 }
669
670 static void lower_barrier(conf_t *conf)
671 {
672         unsigned long flags;
673         spin_lock_irqsave(&conf->resync_lock, flags);
674         conf->barrier--;
675         spin_unlock_irqrestore(&conf->resync_lock, flags);
676         wake_up(&conf->wait_barrier);
677 }
678
679 static void wait_barrier(conf_t *conf)
680 {
681         spin_lock_irq(&conf->resync_lock);
682         if (conf->barrier) {
683                 conf->nr_waiting++;
684                 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
685                                     conf->resync_lock,
686                                     raid1_unplug(conf->mddev->queue));
687                 conf->nr_waiting--;
688         }
689         conf->nr_pending++;
690         spin_unlock_irq(&conf->resync_lock);
691 }
692
693 static void allow_barrier(conf_t *conf)
694 {
695         unsigned long flags;
696         spin_lock_irqsave(&conf->resync_lock, flags);
697         conf->nr_pending--;
698         spin_unlock_irqrestore(&conf->resync_lock, flags);
699         wake_up(&conf->wait_barrier);
700 }
701
702 static void freeze_array(conf_t *conf)
703 {
704         /* stop syncio and normal IO and wait for everything to
705          * go quite.
706          * We increment barrier and nr_waiting, and then
707          * wait until nr_pending match nr_queued+1
708          * This is called in the context of one normal IO request
709          * that has failed. Thus any sync request that might be pending
710          * will be blocked by nr_pending, and we need to wait for
711          * pending IO requests to complete or be queued for re-try.
712          * Thus the number queued (nr_queued) plus this request (1)
713          * must match the number of pending IOs (nr_pending) before
714          * we continue.
715          */
716         spin_lock_irq(&conf->resync_lock);
717         conf->barrier++;
718         conf->nr_waiting++;
719         wait_event_lock_irq(conf->wait_barrier,
720                             conf->nr_pending == conf->nr_queued+1,
721                             conf->resync_lock,
722                             ({ flush_pending_writes(conf);
723                                raid1_unplug(conf->mddev->queue); }));
724         spin_unlock_irq(&conf->resync_lock);
725 }
726 static void unfreeze_array(conf_t *conf)
727 {
728         /* reverse the effect of the freeze */
729         spin_lock_irq(&conf->resync_lock);
730         conf->barrier--;
731         conf->nr_waiting--;
732         wake_up(&conf->wait_barrier);
733         spin_unlock_irq(&conf->resync_lock);
734 }
735
736
737 /* duplicate the data pages for behind I/O */
738 static struct page **alloc_behind_pages(struct bio *bio)
739 {
740         int i;
741         struct bio_vec *bvec;
742         struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
743                                         GFP_NOIO);
744         if (unlikely(!pages))
745                 goto do_sync_io;
746
747         bio_for_each_segment(bvec, bio, i) {
748                 pages[i] = alloc_page(GFP_NOIO);
749                 if (unlikely(!pages[i]))
750                         goto do_sync_io;
751                 memcpy(kmap(pages[i]) + bvec->bv_offset,
752                         kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
753                 kunmap(pages[i]);
754                 kunmap(bvec->bv_page);
755         }
756
757         return pages;
758
759 do_sync_io:
760         if (pages)
761                 for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
762                         put_page(pages[i]);
763         kfree(pages);
764         PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
765         return NULL;
766 }
767
768 static int make_request(struct request_queue *q, struct bio * bio)
769 {
770         mddev_t *mddev = q->queuedata;
771         conf_t *conf = mddev_to_conf(mddev);
772         mirror_info_t *mirror;
773         r1bio_t *r1_bio;
774         struct bio *read_bio;
775         int i, targets = 0, disks;
776         struct bitmap *bitmap;
777         unsigned long flags;
778         struct bio_list bl;
779         struct page **behind_pages = NULL;
780         const int rw = bio_data_dir(bio);
781         const int do_sync = bio_sync(bio);
782         int do_barriers;
783         mdk_rdev_t *blocked_rdev;
784
785         /*
786          * Register the new request and wait if the reconstruction
787          * thread has put up a bar for new requests.
788          * Continue immediately if no resync is active currently.
789          * We test barriers_work *after* md_write_start as md_write_start
790          * may cause the first superblock write, and that will check out
791          * if barriers work.
792          */
793
794         md_write_start(mddev, bio); /* wait on superblock update early */
795
796         if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
797                 if (rw == WRITE)
798                         md_write_end(mddev);
799                 bio_endio(bio, -EOPNOTSUPP);
800                 return 0;
801         }
802
803         wait_barrier(conf);
804
805         bitmap = mddev->bitmap;
806
807         disk_stat_inc(mddev->gendisk, ios[rw]);
808         disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
809
810         /*
811          * make_request() can abort the operation when READA is being
812          * used and no empty request is available.
813          *
814          */
815         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
816
817         r1_bio->master_bio = bio;
818         r1_bio->sectors = bio->bi_size >> 9;
819         r1_bio->state = 0;
820         r1_bio->mddev = mddev;
821         r1_bio->sector = bio->bi_sector;
822
823         if (rw == READ) {
824                 /*
825                  * read balancing logic:
826                  */
827                 int rdisk = read_balance(conf, r1_bio);
828
829                 if (rdisk < 0) {
830                         /* couldn't find anywhere to read from */
831                         raid_end_bio_io(r1_bio);
832                         return 0;
833                 }
834                 mirror = conf->mirrors + rdisk;
835
836                 r1_bio->read_disk = rdisk;
837
838                 read_bio = bio_clone(bio, GFP_NOIO);
839
840                 r1_bio->bios[rdisk] = read_bio;
841
842                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
843                 read_bio->bi_bdev = mirror->rdev->bdev;
844                 read_bio->bi_end_io = raid1_end_read_request;
845                 read_bio->bi_rw = READ | do_sync;
846                 read_bio->bi_private = r1_bio;
847
848                 generic_make_request(read_bio);
849                 return 0;
850         }
851
852         /*
853          * WRITE:
854          */
855         /* first select target devices under spinlock and
856          * inc refcount on their rdev.  Record them by setting
857          * bios[x] to bio
858          */
859         disks = conf->raid_disks;
860 #if 0
861         { static int first=1;
862         if (first) printk("First Write sector %llu disks %d\n",
863                           (unsigned long long)r1_bio->sector, disks);
864         first = 0;
865         }
866 #endif
867  retry_write:
868         blocked_rdev = NULL;
869         rcu_read_lock();
870         for (i = 0;  i < disks; i++) {
871                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
872                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
873                         atomic_inc(&rdev->nr_pending);
874                         blocked_rdev = rdev;
875                         break;
876                 }
877                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
878                         atomic_inc(&rdev->nr_pending);
879                         if (test_bit(Faulty, &rdev->flags)) {
880                                 rdev_dec_pending(rdev, mddev);
881                                 r1_bio->bios[i] = NULL;
882                         } else
883                                 r1_bio->bios[i] = bio;
884                         targets++;
885                 } else
886                         r1_bio->bios[i] = NULL;
887         }
888         rcu_read_unlock();
889
890         if (unlikely(blocked_rdev)) {
891                 /* Wait for this device to become unblocked */
892                 int j;
893
894                 for (j = 0; j < i; j++)
895                         if (r1_bio->bios[j])
896                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
897
898                 allow_barrier(conf);
899                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
900                 wait_barrier(conf);
901                 goto retry_write;
902         }
903
904         BUG_ON(targets == 0); /* we never fail the last device */
905
906         if (targets < conf->raid_disks) {
907                 /* array is degraded, we will not clear the bitmap
908                  * on I/O completion (see raid1_end_write_request) */
909                 set_bit(R1BIO_Degraded, &r1_bio->state);
910         }
911
912         /* do behind I/O ? */
913         if (bitmap &&
914             atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind &&
915             (behind_pages = alloc_behind_pages(bio)) != NULL)
916                 set_bit(R1BIO_BehindIO, &r1_bio->state);
917
918         atomic_set(&r1_bio->remaining, 0);
919         atomic_set(&r1_bio->behind_remaining, 0);
920
921         do_barriers = bio_barrier(bio);
922         if (do_barriers)
923                 set_bit(R1BIO_Barrier, &r1_bio->state);
924
925         bio_list_init(&bl);
926         for (i = 0; i < disks; i++) {
927                 struct bio *mbio;
928                 if (!r1_bio->bios[i])
929                         continue;
930
931                 mbio = bio_clone(bio, GFP_NOIO);
932                 r1_bio->bios[i] = mbio;
933
934                 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
935                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
936                 mbio->bi_end_io = raid1_end_write_request;
937                 mbio->bi_rw = WRITE | do_barriers | do_sync;
938                 mbio->bi_private = r1_bio;
939
940                 if (behind_pages) {
941                         struct bio_vec *bvec;
942                         int j;
943
944                         /* Yes, I really want the '__' version so that
945                          * we clear any unused pointer in the io_vec, rather
946                          * than leave them unchanged.  This is important
947                          * because when we come to free the pages, we won't
948                          * know the originial bi_idx, so we just free
949                          * them all
950                          */
951                         __bio_for_each_segment(bvec, mbio, j, 0)
952                                 bvec->bv_page = behind_pages[j];
953                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
954                                 atomic_inc(&r1_bio->behind_remaining);
955                 }
956
957                 atomic_inc(&r1_bio->remaining);
958
959                 bio_list_add(&bl, mbio);
960         }
961         kfree(behind_pages); /* the behind pages are attached to the bios now */
962
963         bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
964                                 test_bit(R1BIO_BehindIO, &r1_bio->state));
965         spin_lock_irqsave(&conf->device_lock, flags);
966         bio_list_merge(&conf->pending_bio_list, &bl);
967         bio_list_init(&bl);
968
969         blk_plug_device(mddev->queue);
970         spin_unlock_irqrestore(&conf->device_lock, flags);
971
972         /* In case raid1d snuck into freeze_array */
973         wake_up(&conf->wait_barrier);
974
975         if (do_sync)
976                 md_wakeup_thread(mddev->thread);
977 #if 0
978         while ((bio = bio_list_pop(&bl)) != NULL)
979                 generic_make_request(bio);
980 #endif
981
982         return 0;
983 }
984
985 static void status(struct seq_file *seq, mddev_t *mddev)
986 {
987         conf_t *conf = mddev_to_conf(mddev);
988         int i;
989
990         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
991                    conf->raid_disks - mddev->degraded);
992         rcu_read_lock();
993         for (i = 0; i < conf->raid_disks; i++) {
994                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
995                 seq_printf(seq, "%s",
996                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
997         }
998         rcu_read_unlock();
999         seq_printf(seq, "]");
1000 }
1001
1002
1003 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1004 {
1005         char b[BDEVNAME_SIZE];
1006         conf_t *conf = mddev_to_conf(mddev);
1007
1008         /*
1009          * If it is not operational, then we have already marked it as dead
1010          * else if it is the last working disks, ignore the error, let the
1011          * next level up know.
1012          * else mark the drive as failed
1013          */
1014         if (test_bit(In_sync, &rdev->flags)
1015             && (conf->raid_disks - mddev->degraded) == 1)
1016                 /*
1017                  * Don't fail the drive, act as though we were just a
1018                  * normal single drive
1019                  */
1020                 return;
1021         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1022                 unsigned long flags;
1023                 spin_lock_irqsave(&conf->device_lock, flags);
1024                 mddev->degraded++;
1025                 set_bit(Faulty, &rdev->flags);
1026                 spin_unlock_irqrestore(&conf->device_lock, flags);
1027                 /*
1028                  * if recovery is running, make sure it aborts.
1029                  */
1030                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1031         } else
1032                 set_bit(Faulty, &rdev->flags);
1033         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1034         printk(KERN_ALERT "raid1: Disk failure on %s, disabling device.\n"
1035                 "raid1: Operation continuing on %d devices.\n",
1036                 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
1037 }
1038
1039 static void print_conf(conf_t *conf)
1040 {
1041         int i;
1042
1043         printk("RAID1 conf printout:\n");
1044         if (!conf) {
1045                 printk("(!conf)\n");
1046                 return;
1047         }
1048         printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1049                 conf->raid_disks);
1050
1051         rcu_read_lock();
1052         for (i = 0; i < conf->raid_disks; i++) {
1053                 char b[BDEVNAME_SIZE];
1054                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1055                 if (rdev)
1056                         printk(" disk %d, wo:%d, o:%d, dev:%s\n",
1057                                i, !test_bit(In_sync, &rdev->flags),
1058                                !test_bit(Faulty, &rdev->flags),
1059                                bdevname(rdev->bdev,b));
1060         }
1061         rcu_read_unlock();
1062 }
1063
1064 static void close_sync(conf_t *conf)
1065 {
1066         wait_barrier(conf);
1067         allow_barrier(conf);
1068
1069         mempool_destroy(conf->r1buf_pool);
1070         conf->r1buf_pool = NULL;
1071 }
1072
1073 static int raid1_spare_active(mddev_t *mddev)
1074 {
1075         int i;
1076         conf_t *conf = mddev->private;
1077
1078         /*
1079          * Find all failed disks within the RAID1 configuration 
1080          * and mark them readable.
1081          * Called under mddev lock, so rcu protection not needed.
1082          */
1083         for (i = 0; i < conf->raid_disks; i++) {
1084                 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1085                 if (rdev
1086                     && !test_bit(Faulty, &rdev->flags)
1087                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1088                         unsigned long flags;
1089                         spin_lock_irqsave(&conf->device_lock, flags);
1090                         mddev->degraded--;
1091                         spin_unlock_irqrestore(&conf->device_lock, flags);
1092                 }
1093         }
1094
1095         print_conf(conf);
1096         return 0;
1097 }
1098
1099
1100 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1101 {
1102         conf_t *conf = mddev->private;
1103         int err = -EEXIST;
1104         int mirror = 0;
1105         mirror_info_t *p;
1106         int first = 0;
1107         int last = mddev->raid_disks - 1;
1108
1109         if (rdev->raid_disk >= 0)
1110                 first = last = rdev->raid_disk;
1111
1112         for (mirror = first; mirror <= last; mirror++)
1113                 if ( !(p=conf->mirrors+mirror)->rdev) {
1114
1115                         blk_queue_stack_limits(mddev->queue,
1116                                                rdev->bdev->bd_disk->queue);
1117                         /* as we don't honour merge_bvec_fn, we must never risk
1118                          * violating it, so limit ->max_sector to one PAGE, as
1119                          * a one page request is never in violation.
1120                          */
1121                         if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1122                             mddev->queue->max_sectors > (PAGE_SIZE>>9))
1123                                 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1124
1125                         p->head_position = 0;
1126                         rdev->raid_disk = mirror;
1127                         err = 0;
1128                         /* As all devices are equivalent, we don't need a full recovery
1129                          * if this was recently any drive of the array
1130                          */
1131                         if (rdev->saved_raid_disk < 0)
1132                                 conf->fullsync = 1;
1133                         rcu_assign_pointer(p->rdev, rdev);
1134                         break;
1135                 }
1136
1137         print_conf(conf);
1138         return err;
1139 }
1140
1141 static int raid1_remove_disk(mddev_t *mddev, int number)
1142 {
1143         conf_t *conf = mddev->private;
1144         int err = 0;
1145         mdk_rdev_t *rdev;
1146         mirror_info_t *p = conf->mirrors+ number;
1147
1148         print_conf(conf);
1149         rdev = p->rdev;
1150         if (rdev) {
1151                 if (test_bit(In_sync, &rdev->flags) ||
1152                     atomic_read(&rdev->nr_pending)) {
1153                         err = -EBUSY;
1154                         goto abort;
1155                 }
1156                 /* Only remove non-faulty devices is recovery
1157                  * is not possible.
1158                  */
1159                 if (!test_bit(Faulty, &rdev->flags) &&
1160                     mddev->degraded < conf->raid_disks) {
1161                         err = -EBUSY;
1162                         goto abort;
1163                 }
1164                 p->rdev = NULL;
1165                 synchronize_rcu();
1166                 if (atomic_read(&rdev->nr_pending)) {
1167                         /* lost the race, try later */
1168                         err = -EBUSY;
1169                         p->rdev = rdev;
1170                 }
1171         }
1172 abort:
1173
1174         print_conf(conf);
1175         return err;
1176 }
1177
1178
1179 static void end_sync_read(struct bio *bio, int error)
1180 {
1181         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1182         int i;
1183
1184         for (i=r1_bio->mddev->raid_disks; i--; )
1185                 if (r1_bio->bios[i] == bio)
1186                         break;
1187         BUG_ON(i < 0);
1188         update_head_pos(i, r1_bio);
1189         /*
1190          * we have read a block, now it needs to be re-written,
1191          * or re-read if the read failed.
1192          * We don't do much here, just schedule handling by raid1d
1193          */
1194         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1195                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1196
1197         if (atomic_dec_and_test(&r1_bio->remaining))
1198                 reschedule_retry(r1_bio);
1199 }
1200
1201 static void end_sync_write(struct bio *bio, int error)
1202 {
1203         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1204         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1205         mddev_t *mddev = r1_bio->mddev;
1206         conf_t *conf = mddev_to_conf(mddev);
1207         int i;
1208         int mirror=0;
1209
1210         for (i = 0; i < conf->raid_disks; i++)
1211                 if (r1_bio->bios[i] == bio) {
1212                         mirror = i;
1213                         break;
1214                 }
1215         if (!uptodate) {
1216                 int sync_blocks = 0;
1217                 sector_t s = r1_bio->sector;
1218                 long sectors_to_go = r1_bio->sectors;
1219                 /* make sure these bits doesn't get cleared. */
1220                 do {
1221                         bitmap_end_sync(mddev->bitmap, s,
1222                                         &sync_blocks, 1);
1223                         s += sync_blocks;
1224                         sectors_to_go -= sync_blocks;
1225                 } while (sectors_to_go > 0);
1226                 md_error(mddev, conf->mirrors[mirror].rdev);
1227         }
1228
1229         update_head_pos(mirror, r1_bio);
1230
1231         if (atomic_dec_and_test(&r1_bio->remaining)) {
1232                 md_done_sync(mddev, r1_bio->sectors, uptodate);
1233                 put_buf(r1_bio);
1234         }
1235 }
1236
1237 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1238 {
1239         conf_t *conf = mddev_to_conf(mddev);
1240         int i;
1241         int disks = conf->raid_disks;
1242         struct bio *bio, *wbio;
1243
1244         bio = r1_bio->bios[r1_bio->read_disk];
1245
1246
1247         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1248                 /* We have read all readable devices.  If we haven't
1249                  * got the block, then there is no hope left.
1250                  * If we have, then we want to do a comparison
1251                  * and skip the write if everything is the same.
1252                  * If any blocks failed to read, then we need to
1253                  * attempt an over-write
1254                  */
1255                 int primary;
1256                 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1257                         for (i=0; i<mddev->raid_disks; i++)
1258                                 if (r1_bio->bios[i]->bi_end_io == end_sync_read)
1259                                         md_error(mddev, conf->mirrors[i].rdev);
1260
1261                         md_done_sync(mddev, r1_bio->sectors, 1);
1262                         put_buf(r1_bio);
1263                         return;
1264                 }
1265                 for (primary=0; primary<mddev->raid_disks; primary++)
1266                         if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1267                             test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1268                                 r1_bio->bios[primary]->bi_end_io = NULL;
1269                                 rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1270                                 break;
1271                         }
1272                 r1_bio->read_disk = primary;
1273                 for (i=0; i<mddev->raid_disks; i++)
1274                         if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1275                                 int j;
1276                                 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1277                                 struct bio *pbio = r1_bio->bios[primary];
1278                                 struct bio *sbio = r1_bio->bios[i];
1279
1280                                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1281                                         for (j = vcnt; j-- ; ) {
1282                                                 struct page *p, *s;
1283                                                 p = pbio->bi_io_vec[j].bv_page;
1284                                                 s = sbio->bi_io_vec[j].bv_page;
1285                                                 if (memcmp(page_address(p),
1286                                                            page_address(s),
1287                                                            PAGE_SIZE))
1288                                                         break;
1289                                         }
1290                                 } else
1291                                         j = 0;
1292                                 if (j >= 0)
1293                                         mddev->resync_mismatches += r1_bio->sectors;
1294                                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1295                                               && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1296                                         sbio->bi_end_io = NULL;
1297                                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1298                                 } else {
1299                                         /* fixup the bio for reuse */
1300                                         int size;
1301                                         sbio->bi_vcnt = vcnt;
1302                                         sbio->bi_size = r1_bio->sectors << 9;
1303                                         sbio->bi_idx = 0;
1304                                         sbio->bi_phys_segments = 0;
1305                                         sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1306                                         sbio->bi_flags |= 1 << BIO_UPTODATE;
1307                                         sbio->bi_next = NULL;
1308                                         sbio->bi_sector = r1_bio->sector +
1309                                                 conf->mirrors[i].rdev->data_offset;
1310                                         sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1311                                         size = sbio->bi_size;
1312                                         for (j = 0; j < vcnt ; j++) {
1313                                                 struct bio_vec *bi;
1314                                                 bi = &sbio->bi_io_vec[j];
1315                                                 bi->bv_offset = 0;
1316                                                 if (size > PAGE_SIZE)
1317                                                         bi->bv_len = PAGE_SIZE;
1318                                                 else
1319                                                         bi->bv_len = size;
1320                                                 size -= PAGE_SIZE;
1321                                                 memcpy(page_address(bi->bv_page),
1322                                                        page_address(pbio->bi_io_vec[j].bv_page),
1323                                                        PAGE_SIZE);
1324                                         }
1325
1326                                 }
1327                         }
1328         }
1329         if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1330                 /* ouch - failed to read all of that.
1331                  * Try some synchronous reads of other devices to get
1332                  * good data, much like with normal read errors.  Only
1333                  * read into the pages we already have so we don't
1334                  * need to re-issue the read request.
1335                  * We don't need to freeze the array, because being in an
1336                  * active sync request, there is no normal IO, and
1337                  * no overlapping syncs.
1338                  */
1339                 sector_t sect = r1_bio->sector;
1340                 int sectors = r1_bio->sectors;
1341                 int idx = 0;
1342
1343                 while(sectors) {
1344                         int s = sectors;
1345                         int d = r1_bio->read_disk;
1346                         int success = 0;
1347                         mdk_rdev_t *rdev;
1348
1349                         if (s > (PAGE_SIZE>>9))
1350                                 s = PAGE_SIZE >> 9;
1351                         do {
1352                                 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1353                                         /* No rcu protection needed here devices
1354                                          * can only be removed when no resync is
1355                                          * active, and resync is currently active
1356                                          */
1357                                         rdev = conf->mirrors[d].rdev;
1358                                         if (sync_page_io(rdev->bdev,
1359                                                          sect + rdev->data_offset,
1360                                                          s<<9,
1361                                                          bio->bi_io_vec[idx].bv_page,
1362                                                          READ)) {
1363                                                 success = 1;
1364                                                 break;
1365                                         }
1366                                 }
1367                                 d++;
1368                                 if (d == conf->raid_disks)
1369                                         d = 0;
1370                         } while (!success && d != r1_bio->read_disk);
1371
1372                         if (success) {
1373                                 int start = d;
1374                                 /* write it back and re-read */
1375                                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1376                                 while (d != r1_bio->read_disk) {
1377                                         if (d == 0)
1378                                                 d = conf->raid_disks;
1379                                         d--;
1380                                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1381                                                 continue;
1382                                         rdev = conf->mirrors[d].rdev;
1383                                         atomic_add(s, &rdev->corrected_errors);
1384                                         if (sync_page_io(rdev->bdev,
1385                                                          sect + rdev->data_offset,
1386                                                          s<<9,
1387                                                          bio->bi_io_vec[idx].bv_page,
1388                                                          WRITE) == 0)
1389                                                 md_error(mddev, rdev);
1390                                 }
1391                                 d = start;
1392                                 while (d != r1_bio->read_disk) {
1393                                         if (d == 0)
1394                                                 d = conf->raid_disks;
1395                                         d--;
1396                                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1397                                                 continue;
1398                                         rdev = conf->mirrors[d].rdev;
1399                                         if (sync_page_io(rdev->bdev,
1400                                                          sect + rdev->data_offset,
1401                                                          s<<9,
1402                                                          bio->bi_io_vec[idx].bv_page,
1403                                                          READ) == 0)
1404                                                 md_error(mddev, rdev);
1405                                 }
1406                         } else {
1407                                 char b[BDEVNAME_SIZE];
1408                                 /* Cannot read from anywhere, array is toast */
1409                                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1410                                 printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
1411                                        " for block %llu\n",
1412                                        bdevname(bio->bi_bdev,b),
1413                                        (unsigned long long)r1_bio->sector);
1414                                 md_done_sync(mddev, r1_bio->sectors, 0);
1415                                 put_buf(r1_bio);
1416                                 return;
1417                         }
1418                         sectors -= s;
1419                         sect += s;
1420                         idx ++;
1421                 }
1422         }
1423
1424         /*
1425          * schedule writes
1426          */
1427         atomic_set(&r1_bio->remaining, 1);
1428         for (i = 0; i < disks ; i++) {
1429                 wbio = r1_bio->bios[i];
1430                 if (wbio->bi_end_io == NULL ||
1431                     (wbio->bi_end_io == end_sync_read &&
1432                      (i == r1_bio->read_disk ||
1433                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1434                         continue;
1435
1436                 wbio->bi_rw = WRITE;
1437                 wbio->bi_end_io = end_sync_write;
1438                 atomic_inc(&r1_bio->remaining);
1439                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1440
1441                 generic_make_request(wbio);
1442         }
1443
1444         if (atomic_dec_and_test(&r1_bio->remaining)) {
1445                 /* if we're here, all write(s) have completed, so clean up */
1446                 md_done_sync(mddev, r1_bio->sectors, 1);
1447                 put_buf(r1_bio);
1448         }
1449 }
1450
1451 /*
1452  * This is a kernel thread which:
1453  *
1454  *      1.      Retries failed read operations on working mirrors.
1455  *      2.      Updates the raid superblock when problems encounter.
1456  *      3.      Performs writes following reads for array syncronising.
1457  */
1458
1459 static void fix_read_error(conf_t *conf, int read_disk,
1460                            sector_t sect, int sectors)
1461 {
1462         mddev_t *mddev = conf->mddev;
1463         while(sectors) {
1464                 int s = sectors;
1465                 int d = read_disk;
1466                 int success = 0;
1467                 int start;
1468                 mdk_rdev_t *rdev;
1469
1470                 if (s > (PAGE_SIZE>>9))
1471                         s = PAGE_SIZE >> 9;
1472
1473                 do {
1474                         /* Note: no rcu protection needed here
1475                          * as this is synchronous in the raid1d thread
1476                          * which is the thread that might remove
1477                          * a device.  If raid1d ever becomes multi-threaded....
1478                          */
1479                         rdev = conf->mirrors[d].rdev;
1480                         if (rdev &&
1481                             test_bit(In_sync, &rdev->flags) &&
1482                             sync_page_io(rdev->bdev,
1483                                          sect + rdev->data_offset,
1484                                          s<<9,
1485                                          conf->tmppage, READ))
1486                                 success = 1;
1487                         else {
1488                                 d++;
1489                                 if (d == conf->raid_disks)
1490                                         d = 0;
1491                         }
1492                 } while (!success && d != read_disk);
1493
1494                 if (!success) {
1495                         /* Cannot read from anywhere -- bye bye array */
1496                         md_error(mddev, conf->mirrors[read_disk].rdev);
1497                         break;
1498                 }
1499                 /* write it back and re-read */
1500                 start = d;
1501                 while (d != read_disk) {
1502                         if (d==0)
1503                                 d = conf->raid_disks;
1504                         d--;
1505                         rdev = conf->mirrors[d].rdev;
1506                         if (rdev &&
1507                             test_bit(In_sync, &rdev->flags)) {
1508                                 if (sync_page_io(rdev->bdev,
1509                                                  sect + rdev->data_offset,
1510                                                  s<<9, conf->tmppage, WRITE)
1511                                     == 0)
1512                                         /* Well, this device is dead */
1513                                         md_error(mddev, rdev);
1514                         }
1515                 }
1516                 d = start;
1517                 while (d != read_disk) {
1518                         char b[BDEVNAME_SIZE];
1519                         if (d==0)
1520                                 d = conf->raid_disks;
1521                         d--;
1522                         rdev = conf->mirrors[d].rdev;
1523                         if (rdev &&
1524                             test_bit(In_sync, &rdev->flags)) {
1525                                 if (sync_page_io(rdev->bdev,
1526                                                  sect + rdev->data_offset,
1527                                                  s<<9, conf->tmppage, READ)
1528                                     == 0)
1529                                         /* Well, this device is dead */
1530                                         md_error(mddev, rdev);
1531                                 else {
1532                                         atomic_add(s, &rdev->corrected_errors);
1533                                         printk(KERN_INFO
1534                                                "raid1:%s: read error corrected "
1535                                                "(%d sectors at %llu on %s)\n",
1536                                                mdname(mddev), s,
1537                                                (unsigned long long)(sect +
1538                                                    rdev->data_offset),
1539                                                bdevname(rdev->bdev, b));
1540                                 }
1541                         }
1542                 }
1543                 sectors -= s;
1544                 sect += s;
1545         }
1546 }
1547
1548 static void raid1d(mddev_t *mddev)
1549 {
1550         r1bio_t *r1_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);
1559         
1560         for (;;) {
1561                 char b[BDEVNAME_SIZE];
1562
1563                 unplug += flush_pending_writes(conf);
1564
1565                 spin_lock_irqsave(&conf->device_lock, flags);
1566                 if (list_empty(head)) {
1567                         spin_unlock_irqrestore(&conf->device_lock, flags);
1568                         break;
1569                 }
1570                 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1571                 list_del(head->prev);
1572                 conf->nr_queued--;
1573                 spin_unlock_irqrestore(&conf->device_lock, flags);
1574
1575                 mddev = r1_bio->mddev;
1576                 conf = mddev_to_conf(mddev);
1577                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
1578                         sync_request_write(mddev, r1_bio);
1579                         unplug = 1;
1580                 } else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
1581                         /* some requests in the r1bio were BIO_RW_BARRIER
1582                          * requests which failed with -EOPNOTSUPP.  Hohumm..
1583                          * Better resubmit without the barrier.
1584                          * We know which devices to resubmit for, because
1585                          * all others have had their bios[] entry cleared.
1586                          * We already have a nr_pending reference on these rdevs.
1587                          */
1588                         int i;
1589                         const int do_sync = bio_sync(r1_bio->master_bio);
1590                         clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
1591                         clear_bit(R1BIO_Barrier, &r1_bio->state);
1592                         for (i=0; i < conf->raid_disks; i++)
1593                                 if (r1_bio->bios[i])
1594                                         atomic_inc(&r1_bio->remaining);
1595                         for (i=0; i < conf->raid_disks; i++)
1596                                 if (r1_bio->bios[i]) {
1597                                         struct bio_vec *bvec;
1598                                         int j;
1599
1600                                         bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1601                                         /* copy pages from the failed bio, as
1602                                          * this might be a write-behind device */
1603                                         __bio_for_each_segment(bvec, bio, j, 0)
1604                                                 bvec->bv_page = bio_iovec_idx(r1_bio->bios[i], j)->bv_page;
1605                                         bio_put(r1_bio->bios[i]);
1606                                         bio->bi_sector = r1_bio->sector +
1607                                                 conf->mirrors[i].rdev->data_offset;
1608                                         bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1609                                         bio->bi_end_io = raid1_end_write_request;
1610                                         bio->bi_rw = WRITE | do_sync;
1611                                         bio->bi_private = r1_bio;
1612                                         r1_bio->bios[i] = bio;
1613                                         generic_make_request(bio);
1614                                 }
1615                 } else {
1616                         int disk;
1617
1618                         /* we got a read error. Maybe the drive is bad.  Maybe just
1619                          * the block and we can fix it.
1620                          * We freeze all other IO, and try reading the block from
1621                          * other devices.  When we find one, we re-write
1622                          * and check it that fixes the read error.
1623                          * This is all done synchronously while the array is
1624                          * frozen
1625                          */
1626                         if (mddev->ro == 0) {
1627                                 freeze_array(conf);
1628                                 fix_read_error(conf, r1_bio->read_disk,
1629                                                r1_bio->sector,
1630                                                r1_bio->sectors);
1631                                 unfreeze_array(conf);
1632                         }
1633
1634                         bio = r1_bio->bios[r1_bio->read_disk];
1635                         if ((disk=read_balance(conf, r1_bio)) == -1) {
1636                                 printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
1637                                        " read error for block %llu\n",
1638                                        bdevname(bio->bi_bdev,b),
1639                                        (unsigned long long)r1_bio->sector);
1640                                 raid_end_bio_io(r1_bio);
1641                         } else {
1642                                 const int do_sync = bio_sync(r1_bio->master_bio);
1643                                 r1_bio->bios[r1_bio->read_disk] =
1644                                         mddev->ro ? IO_BLOCKED : NULL;
1645                                 r1_bio->read_disk = disk;
1646                                 bio_put(bio);
1647                                 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1648                                 r1_bio->bios[r1_bio->read_disk] = bio;
1649                                 rdev = conf->mirrors[disk].rdev;
1650                                 if (printk_ratelimit())
1651                                         printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
1652                                                " another mirror\n",
1653                                                bdevname(rdev->bdev,b),
1654                                                (unsigned long long)r1_bio->sector);
1655                                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1656                                 bio->bi_bdev = rdev->bdev;
1657                                 bio->bi_end_io = raid1_end_read_request;
1658                                 bio->bi_rw = READ | do_sync;
1659                                 bio->bi_private = r1_bio;
1660                                 unplug = 1;
1661                                 generic_make_request(bio);
1662                         }
1663                 }
1664         }
1665         if (unplug)
1666                 unplug_slaves(mddev);
1667 }
1668
1669
1670 static int init_resync(conf_t *conf)
1671 {
1672         int buffs;
1673
1674         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1675         BUG_ON(conf->r1buf_pool);
1676         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1677                                           conf->poolinfo);
1678         if (!conf->r1buf_pool)
1679                 return -ENOMEM;
1680         conf->next_resync = 0;
1681         return 0;
1682 }
1683
1684 /*
1685  * perform a "sync" on one "block"
1686  *
1687  * We need to make sure that no normal I/O request - particularly write
1688  * requests - conflict with active sync requests.
1689  *
1690  * This is achieved by tracking pending requests and a 'barrier' concept
1691  * that can be installed to exclude normal IO requests.
1692  */
1693
1694 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1695 {
1696         conf_t *conf = mddev_to_conf(mddev);
1697         r1bio_t *r1_bio;
1698         struct bio *bio;
1699         sector_t max_sector, nr_sectors;
1700         int disk = -1;
1701         int i;
1702         int wonly = -1;
1703         int write_targets = 0, read_targets = 0;
1704         int sync_blocks;
1705         int still_degraded = 0;
1706
1707         if (!conf->r1buf_pool)
1708         {
1709 /*
1710                 printk("sync start - bitmap %p\n", mddev->bitmap);
1711 */
1712                 if (init_resync(conf))
1713                         return 0;
1714         }
1715
1716         max_sector = mddev->size << 1;
1717         if (sector_nr >= max_sector) {
1718                 /* If we aborted, we need to abort the
1719                  * sync on the 'current' bitmap chunk (there will
1720                  * only be one in raid1 resync.
1721                  * We can find the current addess in mddev->curr_resync
1722                  */
1723                 if (mddev->curr_resync < max_sector) /* aborted */
1724                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1725                                                 &sync_blocks, 1);
1726                 else /* completed sync */
1727                         conf->fullsync = 0;
1728
1729                 bitmap_close_sync(mddev->bitmap);
1730                 close_sync(conf);
1731                 return 0;
1732         }
1733
1734         if (mddev->bitmap == NULL &&
1735             mddev->recovery_cp == MaxSector &&
1736             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1737             conf->fullsync == 0) {
1738                 *skipped = 1;
1739                 return max_sector - sector_nr;
1740         }
1741         /* before building a request, check if we can skip these blocks..
1742          * This call the bitmap_start_sync doesn't actually record anything
1743          */
1744         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1745             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1746                 /* We can skip this block, and probably several more */
1747                 *skipped = 1;
1748                 return sync_blocks;
1749         }
1750         /*
1751          * If there is non-resync activity waiting for a turn,
1752          * and resync is going fast enough,
1753          * then let it though before starting on this new sync request.
1754          */
1755         if (!go_faster && conf->nr_waiting)
1756                 msleep_interruptible(1000);
1757
1758         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1759         raise_barrier(conf);
1760
1761         conf->next_resync = sector_nr;
1762
1763         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1764         rcu_read_lock();
1765         /*
1766          * If we get a correctably read error during resync or recovery,
1767          * we might want to read from a different device.  So we
1768          * flag all drives that could conceivably be read from for READ,
1769          * and any others (which will be non-In_sync devices) for WRITE.
1770          * If a read fails, we try reading from something else for which READ
1771          * is OK.
1772          */
1773
1774         r1_bio->mddev = mddev;
1775         r1_bio->sector = sector_nr;
1776         r1_bio->state = 0;
1777         set_bit(R1BIO_IsSync, &r1_bio->state);
1778
1779         for (i=0; i < conf->raid_disks; i++) {
1780                 mdk_rdev_t *rdev;
1781                 bio = r1_bio->bios[i];
1782
1783                 /* take from bio_init */
1784                 bio->bi_next = NULL;
1785                 bio->bi_flags |= 1 << BIO_UPTODATE;
1786                 bio->bi_rw = READ;
1787                 bio->bi_vcnt = 0;
1788                 bio->bi_idx = 0;
1789                 bio->bi_phys_segments = 0;
1790                 bio->bi_size = 0;
1791                 bio->bi_end_io = NULL;
1792                 bio->bi_private = NULL;
1793
1794                 rdev = rcu_dereference(conf->mirrors[i].rdev);
1795                 if (rdev == NULL ||
1796                            test_bit(Faulty, &rdev->flags)) {
1797                         still_degraded = 1;
1798                         continue;
1799                 } else if (!test_bit(In_sync, &rdev->flags)) {
1800                         bio->bi_rw = WRITE;
1801                         bio->bi_end_io = end_sync_write;
1802                         write_targets ++;
1803                 } else {
1804                         /* may need to read from here */
1805                         bio->bi_rw = READ;
1806                         bio->bi_end_io = end_sync_read;
1807                         if (test_bit(WriteMostly, &rdev->flags)) {
1808                                 if (wonly < 0)
1809                                         wonly = i;
1810                         } else {
1811                                 if (disk < 0)
1812                                         disk = i;
1813                         }
1814                         read_targets++;
1815                 }
1816                 atomic_inc(&rdev->nr_pending);
1817                 bio->bi_sector = sector_nr + rdev->data_offset;
1818                 bio->bi_bdev = rdev->bdev;
1819                 bio->bi_private = r1_bio;
1820         }
1821         rcu_read_unlock();
1822         if (disk < 0)
1823                 disk = wonly;
1824         r1_bio->read_disk = disk;
1825
1826         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1827                 /* extra read targets are also write targets */
1828                 write_targets += read_targets-1;
1829
1830         if (write_targets == 0 || read_targets == 0) {
1831                 /* There is nowhere to write, so all non-sync
1832                  * drives must be failed - so we are finished
1833                  */
1834                 sector_t rv = max_sector - sector_nr;
1835                 *skipped = 1;
1836                 put_buf(r1_bio);
1837                 return rv;
1838         }
1839
1840         if (max_sector > mddev->resync_max)
1841                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
1842         nr_sectors = 0;
1843         sync_blocks = 0;
1844         do {
1845                 struct page *page;
1846                 int len = PAGE_SIZE;
1847                 if (sector_nr + (len>>9) > max_sector)
1848                         len = (max_sector - sector_nr) << 9;
1849                 if (len == 0)
1850                         break;
1851                 if (sync_blocks == 0) {
1852                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1853                                                &sync_blocks, still_degraded) &&
1854                             !conf->fullsync &&
1855                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1856                                 break;
1857                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1858                         if (len > (sync_blocks<<9))
1859                                 len = sync_blocks<<9;
1860                 }
1861
1862                 for (i=0 ; i < conf->raid_disks; i++) {
1863                         bio = r1_bio->bios[i];
1864                         if (bio->bi_end_io) {
1865                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1866                                 if (bio_add_page(bio, page, len, 0) == 0) {
1867                                         /* stop here */
1868                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1869                                         while (i > 0) {
1870                                                 i--;
1871                                                 bio = r1_bio->bios[i];
1872                                                 if (bio->bi_end_io==NULL)
1873                                                         continue;
1874                                                 /* remove last page from this bio */
1875                                                 bio->bi_vcnt--;
1876                                                 bio->bi_size -= len;
1877                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1878                                         }
1879                                         goto bio_full;
1880                                 }
1881                         }
1882                 }
1883                 nr_sectors += len>>9;
1884                 sector_nr += len>>9;
1885                 sync_blocks -= (len>>9);
1886         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1887  bio_full:
1888         r1_bio->sectors = nr_sectors;
1889
1890         /* For a user-requested sync, we read all readable devices and do a
1891          * compare
1892          */
1893         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1894                 atomic_set(&r1_bio->remaining, read_targets);
1895                 for (i=0; i<conf->raid_disks; i++) {
1896                         bio = r1_bio->bios[i];
1897                         if (bio->bi_end_io == end_sync_read) {
1898                                 md_sync_acct(bio->bi_bdev, nr_sectors);
1899                                 generic_make_request(bio);
1900                         }
1901                 }
1902         } else {
1903                 atomic_set(&r1_bio->remaining, 1);
1904                 bio = r1_bio->bios[r1_bio->read_disk];
1905                 md_sync_acct(bio->bi_bdev, nr_sectors);
1906                 generic_make_request(bio);
1907
1908         }
1909         return nr_sectors;
1910 }
1911
1912 static int run(mddev_t *mddev)
1913 {
1914         conf_t *conf;
1915         int i, j, disk_idx;
1916         mirror_info_t *disk;
1917         mdk_rdev_t *rdev;
1918         struct list_head *tmp;
1919
1920         if (mddev->level != 1) {
1921                 printk("raid1: %s: raid level not set to mirroring (%d)\n",
1922                        mdname(mddev), mddev->level);
1923                 goto out;
1924         }
1925         if (mddev->reshape_position != MaxSector) {
1926                 printk("raid1: %s: reshape_position set but not supported\n",
1927                        mdname(mddev));
1928                 goto out;
1929         }
1930         /*
1931          * copy the already verified devices into our private RAID1
1932          * bookkeeping area. [whatever we allocate in run(),
1933          * should be freed in stop()]
1934          */
1935         conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
1936         mddev->private = conf;
1937         if (!conf)
1938                 goto out_no_mem;
1939
1940         conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1941                                  GFP_KERNEL);
1942         if (!conf->mirrors)
1943                 goto out_no_mem;
1944
1945         conf->tmppage = alloc_page(GFP_KERNEL);
1946         if (!conf->tmppage)
1947                 goto out_no_mem;
1948
1949         conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
1950         if (!conf->poolinfo)
1951                 goto out_no_mem;
1952         conf->poolinfo->mddev = mddev;
1953         conf->poolinfo->raid_disks = mddev->raid_disks;
1954         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1955                                           r1bio_pool_free,
1956                                           conf->poolinfo);
1957         if (!conf->r1bio_pool)
1958                 goto out_no_mem;
1959
1960         spin_lock_init(&conf->device_lock);
1961         mddev->queue->queue_lock = &conf->device_lock;
1962
1963         rdev_for_each(rdev, tmp, mddev) {
1964                 disk_idx = rdev->raid_disk;
1965                 if (disk_idx >= mddev->raid_disks
1966                     || disk_idx < 0)
1967                         continue;
1968                 disk = conf->mirrors + disk_idx;
1969
1970                 disk->rdev = rdev;
1971
1972                 blk_queue_stack_limits(mddev->queue,
1973                                        rdev->bdev->bd_disk->queue);
1974                 /* as we don't honour merge_bvec_fn, we must never risk
1975                  * violating it, so limit ->max_sector to one PAGE, as
1976                  * a one page request is never in violation.
1977                  */
1978                 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1979                     mddev->queue->max_sectors > (PAGE_SIZE>>9))
1980                         blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1981
1982                 disk->head_position = 0;
1983         }
1984         conf->raid_disks = mddev->raid_disks;
1985         conf->mddev = mddev;
1986         INIT_LIST_HEAD(&conf->retry_list);
1987
1988         spin_lock_init(&conf->resync_lock);
1989         init_waitqueue_head(&conf->wait_barrier);
1990
1991         bio_list_init(&conf->pending_bio_list);
1992         bio_list_init(&conf->flushing_bio_list);
1993
1994
1995         mddev->degraded = 0;
1996         for (i = 0; i < conf->raid_disks; i++) {
1997
1998                 disk = conf->mirrors + i;
1999
2000                 if (!disk->rdev ||
2001                     !test_bit(In_sync, &disk->rdev->flags)) {
2002                         disk->head_position = 0;
2003                         mddev->degraded++;
2004                         if (disk->rdev)
2005                                 conf->fullsync = 1;
2006                 }
2007         }
2008         if (mddev->degraded == conf->raid_disks) {
2009                 printk(KERN_ERR "raid1: no operational mirrors for %s\n",
2010                         mdname(mddev));
2011                 goto out_free_conf;
2012         }
2013         if (conf->raid_disks - mddev->degraded == 1)
2014                 mddev->recovery_cp = MaxSector;
2015
2016         /*
2017          * find the first working one and use it as a starting point
2018          * to read balancing.
2019          */
2020         for (j = 0; j < conf->raid_disks &&
2021                      (!conf->mirrors[j].rdev ||
2022                       !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++)
2023                 /* nothing */;
2024         conf->last_used = j;
2025
2026
2027         mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
2028         if (!mddev->thread) {
2029                 printk(KERN_ERR
2030                        "raid1: couldn't allocate thread for %s\n",
2031                        mdname(mddev));
2032                 goto out_free_conf;
2033         }
2034
2035         printk(KERN_INFO 
2036                 "raid1: raid set %s active with %d out of %d mirrors\n",
2037                 mdname(mddev), mddev->raid_disks - mddev->degraded, 
2038                 mddev->raid_disks);
2039         /*
2040          * Ok, everything is just fine now
2041          */
2042         mddev->array_sectors = mddev->size * 2;
2043
2044         mddev->queue->unplug_fn = raid1_unplug;
2045         mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2046         mddev->queue->backing_dev_info.congested_data = mddev;
2047
2048         return 0;
2049
2050 out_no_mem:
2051         printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
2052                mdname(mddev));
2053
2054 out_free_conf:
2055         if (conf) {
2056                 if (conf->r1bio_pool)
2057                         mempool_destroy(conf->r1bio_pool);
2058                 kfree(conf->mirrors);
2059                 safe_put_page(conf->tmppage);
2060                 kfree(conf->poolinfo);
2061                 kfree(conf);
2062                 mddev->private = NULL;
2063         }
2064 out:
2065         return -EIO;
2066 }
2067
2068 static int stop(mddev_t *mddev)
2069 {
2070         conf_t *conf = mddev_to_conf(mddev);
2071         struct bitmap *bitmap = mddev->bitmap;
2072         int behind_wait = 0;
2073
2074         /* wait for behind writes to complete */
2075         while (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2076                 behind_wait++;
2077                 printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), behind_wait);
2078                 set_current_state(TASK_UNINTERRUPTIBLE);
2079                 schedule_timeout(HZ); /* wait a second */
2080                 /* need to kick something here to make sure I/O goes? */
2081         }
2082
2083         md_unregister_thread(mddev->thread);
2084         mddev->thread = NULL;
2085         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2086         if (conf->r1bio_pool)
2087                 mempool_destroy(conf->r1bio_pool);
2088         kfree(conf->mirrors);
2089         kfree(conf->poolinfo);
2090         kfree(conf);
2091         mddev->private = NULL;
2092         return 0;
2093 }
2094
2095 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2096 {
2097         /* no resync is happening, and there is enough space
2098          * on all devices, so we can resize.
2099          * We need to make sure resync covers any new space.
2100          * If the array is shrinking we should possibly wait until
2101          * any io in the removed space completes, but it hardly seems
2102          * worth it.
2103          */
2104         mddev->array_sectors = sectors;
2105         set_capacity(mddev->gendisk, mddev->array_sectors);
2106         mddev->changed = 1;
2107         if (mddev->array_sectors / 2 > mddev->size &&
2108             mddev->recovery_cp == MaxSector) {
2109                 mddev->recovery_cp = mddev->size << 1;
2110                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2111         }
2112         mddev->size = mddev->array_sectors / 2;
2113         mddev->resync_max_sectors = sectors;
2114         return 0;
2115 }
2116
2117 static int raid1_reshape(mddev_t *mddev)
2118 {
2119         /* We need to:
2120          * 1/ resize the r1bio_pool
2121          * 2/ resize conf->mirrors
2122          *
2123          * We allocate a new r1bio_pool if we can.
2124          * Then raise a device barrier and wait until all IO stops.
2125          * Then resize conf->mirrors and swap in the new r1bio pool.
2126          *
2127          * At the same time, we "pack" the devices so that all the missing
2128          * devices have the higher raid_disk numbers.
2129          */
2130         mempool_t *newpool, *oldpool;
2131         struct pool_info *newpoolinfo;
2132         mirror_info_t *newmirrors;
2133         conf_t *conf = mddev_to_conf(mddev);
2134         int cnt, raid_disks;
2135         unsigned long flags;
2136         int d, d2, err;
2137
2138         /* Cannot change chunk_size, layout, or level */
2139         if (mddev->chunk_size != mddev->new_chunk ||
2140             mddev->layout != mddev->new_layout ||
2141             mddev->level != mddev->new_level) {
2142                 mddev->new_chunk = mddev->chunk_size;
2143                 mddev->new_layout = mddev->layout;
2144                 mddev->new_level = mddev->level;
2145                 return -EINVAL;
2146         }
2147
2148         err = md_allow_write(mddev);
2149         if (err)
2150                 return err;
2151
2152         raid_disks = mddev->raid_disks + mddev->delta_disks;
2153
2154         if (raid_disks < conf->raid_disks) {
2155                 cnt=0;
2156                 for (d= 0; d < conf->raid_disks; d++)
2157                         if (conf->mirrors[d].rdev)
2158                                 cnt++;
2159                 if (cnt > raid_disks)
2160                         return -EBUSY;
2161         }
2162
2163         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2164         if (!newpoolinfo)
2165                 return -ENOMEM;
2166         newpoolinfo->mddev = mddev;
2167         newpoolinfo->raid_disks = raid_disks;
2168
2169         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2170                                  r1bio_pool_free, newpoolinfo);
2171         if (!newpool) {
2172                 kfree(newpoolinfo);
2173                 return -ENOMEM;
2174         }
2175         newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2176         if (!newmirrors) {
2177                 kfree(newpoolinfo);
2178                 mempool_destroy(newpool);
2179                 return -ENOMEM;
2180         }
2181
2182         raise_barrier(conf);
2183
2184         /* ok, everything is stopped */
2185         oldpool = conf->r1bio_pool;
2186         conf->r1bio_pool = newpool;
2187
2188         for (d = d2 = 0; d < conf->raid_disks; d++) {
2189                 mdk_rdev_t *rdev = conf->mirrors[d].rdev;
2190                 if (rdev && rdev->raid_disk != d2) {
2191                         char nm[20];
2192                         sprintf(nm, "rd%d", rdev->raid_disk);
2193                         sysfs_remove_link(&mddev->kobj, nm);
2194                         rdev->raid_disk = d2;
2195                         sprintf(nm, "rd%d", rdev->raid_disk);
2196                         sysfs_remove_link(&mddev->kobj, nm);
2197                         if (sysfs_create_link(&mddev->kobj,
2198                                               &rdev->kobj, nm))
2199                                 printk(KERN_WARNING
2200                                        "md/raid1: cannot register "
2201                                        "%s for %s\n",
2202                                        nm, mdname(mddev));
2203                 }
2204                 if (rdev)
2205                         newmirrors[d2++].rdev = rdev;
2206         }
2207         kfree(conf->mirrors);
2208         conf->mirrors = newmirrors;
2209         kfree(conf->poolinfo);
2210         conf->poolinfo = newpoolinfo;
2211
2212         spin_lock_irqsave(&conf->device_lock, flags);
2213         mddev->degraded += (raid_disks - conf->raid_disks);
2214         spin_unlock_irqrestore(&conf->device_lock, flags);
2215         conf->raid_disks = mddev->raid_disks = raid_disks;
2216         mddev->delta_disks = 0;
2217
2218         conf->last_used = 0; /* just make sure it is in-range */
2219         lower_barrier(conf);
2220
2221         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2222         md_wakeup_thread(mddev->thread);
2223
2224         mempool_destroy(oldpool);
2225         return 0;
2226 }
2227
2228 static void raid1_quiesce(mddev_t *mddev, int state)
2229 {
2230         conf_t *conf = mddev_to_conf(mddev);
2231
2232         switch(state) {
2233         case 1:
2234                 raise_barrier(conf);
2235                 break;
2236         case 0:
2237                 lower_barrier(conf);
2238                 break;
2239         }
2240 }
2241
2242
2243 static struct mdk_personality raid1_personality =
2244 {
2245         .name           = "raid1",
2246         .level          = 1,
2247         .owner          = THIS_MODULE,
2248         .make_request   = make_request,
2249         .run            = run,
2250         .stop           = stop,
2251         .status         = status,
2252         .error_handler  = error,
2253         .hot_add_disk   = raid1_add_disk,
2254         .hot_remove_disk= raid1_remove_disk,
2255         .spare_active   = raid1_spare_active,
2256         .sync_request   = sync_request,
2257         .resize         = raid1_resize,
2258         .check_reshape  = raid1_reshape,
2259         .quiesce        = raid1_quiesce,
2260 };
2261
2262 static int __init raid_init(void)
2263 {
2264         return register_md_personality(&raid1_personality);
2265 }
2266
2267 static void raid_exit(void)
2268 {
2269         unregister_md_personality(&raid1_personality);
2270 }
2271
2272 module_init(raid_init);
2273 module_exit(raid_exit);
2274 MODULE_LICENSE("GPL");
2275 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2276 MODULE_ALIAS("md-raid1");
2277 MODULE_ALIAS("md-level-1");