md: move lots of #include lines out of .h files and into .c
[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 <linux/delay.h>
35 #include <linux/blkdev.h>
36 #include <linux/raid/md_k.h>
37 #include <linux/seq_file.h>
38 #include "dm-bio-list.h"
39 #include "raid1.h"
40 #include "bitmap.h"
41
42 #define DEBUG 0
43 #if DEBUG
44 #define PRINTK(x...) printk(x)
45 #else
46 #define PRINTK(x...)
47 #endif
48
49 /*
50  * Number of guaranteed r1bios in case of extreme VM load:
51  */
52 #define NR_RAID1_BIOS 256
53
54
55 static void unplug_slaves(mddev_t *mddev);
56
57 static void allow_barrier(conf_t *conf);
58 static void lower_barrier(conf_t *conf);
59
60 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
61 {
62         struct pool_info *pi = data;
63         r1bio_t *r1_bio;
64         int size = offsetof(r1bio_t, bios[pi->raid_disks]);
65
66         /* allocate a r1bio with room for raid_disks entries in the bios array */
67         r1_bio = kzalloc(size, gfp_flags);
68         if (!r1_bio)
69                 unplug_slaves(pi->mddev);
70
71         return r1_bio;
72 }
73
74 static void r1bio_pool_free(void *r1_bio, void *data)
75 {
76         kfree(r1_bio);
77 }
78
79 #define RESYNC_BLOCK_SIZE (64*1024)
80 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
81 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
82 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
83 #define RESYNC_WINDOW (2048*1024)
84
85 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
86 {
87         struct pool_info *pi = data;
88         struct page *page;
89         r1bio_t *r1_bio;
90         struct bio *bio;
91         int i, j;
92
93         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
94         if (!r1_bio) {
95                 unplug_slaves(pi->mddev);
96                 return NULL;
97         }
98
99         /*
100          * Allocate bios : 1 for reading, n-1 for writing
101          */
102         for (j = pi->raid_disks ; j-- ; ) {
103                 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
104                 if (!bio)
105                         goto out_free_bio;
106                 r1_bio->bios[j] = bio;
107         }
108         /*
109          * Allocate RESYNC_PAGES data pages and attach them to
110          * the first bio.
111          * If this is a user-requested check/repair, allocate
112          * RESYNC_PAGES for each bio.
113          */
114         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
115                 j = pi->raid_disks;
116         else
117                 j = 1;
118         while(j--) {
119                 bio = r1_bio->bios[j];
120                 for (i = 0; i < RESYNC_PAGES; i++) {
121                         page = alloc_page(gfp_flags);
122                         if (unlikely(!page))
123                                 goto out_free_pages;
124
125                         bio->bi_io_vec[i].bv_page = page;
126                 }
127         }
128         /* If not user-requests, copy the page pointers to all bios */
129         if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
130                 for (i=0; i<RESYNC_PAGES ; i++)
131                         for (j=1; j<pi->raid_disks; j++)
132                                 r1_bio->bios[j]->bi_io_vec[i].bv_page =
133                                         r1_bio->bios[0]->bi_io_vec[i].bv_page;
134         }
135
136         r1_bio->master_bio = NULL;
137
138         return r1_bio;
139
140 out_free_pages:
141         for (i=0; i < RESYNC_PAGES ; i++)
142                 for (j=0 ; j < pi->raid_disks; j++)
143                         safe_put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
144         j = -1;
145 out_free_bio:
146         while ( ++j < pi->raid_disks )
147                 bio_put(r1_bio->bios[j]);
148         r1bio_pool_free(r1_bio, data);
149         return NULL;
150 }
151
152 static void r1buf_pool_free(void *__r1_bio, void *data)
153 {
154         struct pool_info *pi = data;
155         int i,j;
156         r1bio_t *r1bio = __r1_bio;
157
158         for (i = 0; i < RESYNC_PAGES; i++)
159                 for (j = pi->raid_disks; j-- ;) {
160                         if (j == 0 ||
161                             r1bio->bios[j]->bi_io_vec[i].bv_page !=
162                             r1bio->bios[0]->bi_io_vec[i].bv_page)
163                                 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
164                 }
165         for (i=0 ; i < pi->raid_disks; i++)
166                 bio_put(r1bio->bios[i]);
167
168         r1bio_pool_free(r1bio, data);
169 }
170
171 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
172 {
173         int i;
174
175         for (i = 0; i < conf->raid_disks; i++) {
176                 struct bio **bio = r1_bio->bios + i;
177                 if (*bio && *bio != IO_BLOCKED)
178                         bio_put(*bio);
179                 *bio = NULL;
180         }
181 }
182
183 static void free_r1bio(r1bio_t *r1_bio)
184 {
185         conf_t *conf = mddev_to_conf(r1_bio->mddev);
186
187         /*
188          * Wake up any possible resync thread that waits for the device
189          * to go idle.
190          */
191         allow_barrier(conf);
192
193         put_all_bios(conf, r1_bio);
194         mempool_free(r1_bio, conf->r1bio_pool);
195 }
196
197 static void put_buf(r1bio_t *r1_bio)
198 {
199         conf_t *conf = mddev_to_conf(r1_bio->mddev);
200         int i;
201
202         for (i=0; i<conf->raid_disks; i++) {
203                 struct bio *bio = r1_bio->bios[i];
204                 if (bio->bi_end_io)
205                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
206         }
207
208         mempool_free(r1_bio, conf->r1buf_pool);
209
210         lower_barrier(conf);
211 }
212
213 static void reschedule_retry(r1bio_t *r1_bio)
214 {
215         unsigned long flags;
216         mddev_t *mddev = r1_bio->mddev;
217         conf_t *conf = mddev_to_conf(mddev);
218
219         spin_lock_irqsave(&conf->device_lock, flags);
220         list_add(&r1_bio->retry_list, &conf->retry_list);
221         conf->nr_queued ++;
222         spin_unlock_irqrestore(&conf->device_lock, flags);
223
224         wake_up(&conf->wait_barrier);
225         md_wakeup_thread(mddev->thread);
226 }
227
228 /*
229  * raid_end_bio_io() is called when we have finished servicing a mirrored
230  * operation and are ready to return a success/failure code to the buffer
231  * cache layer.
232  */
233 static void raid_end_bio_io(r1bio_t *r1_bio)
234 {
235         struct bio *bio = r1_bio->master_bio;
236
237         /* if nobody has done the final endio yet, do it now */
238         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
239                 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
240                         (bio_data_dir(bio) == WRITE) ? "write" : "read",
241                         (unsigned long long) bio->bi_sector,
242                         (unsigned long long) bio->bi_sector +
243                                 (bio->bi_size >> 9) - 1);
244
245                 bio_endio(bio,
246                         test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
247         }
248         free_r1bio(r1_bio);
249 }
250
251 /*
252  * Update disk head position estimator based on IRQ completion info.
253  */
254 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
255 {
256         conf_t *conf = mddev_to_conf(r1_bio->mddev);
257
258         conf->mirrors[disk].head_position =
259                 r1_bio->sector + (r1_bio->sectors);
260 }
261
262 static void raid1_end_read_request(struct bio *bio, int error)
263 {
264         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
265         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
266         int mirror;
267         conf_t *conf = mddev_to_conf(r1_bio->mddev);
268
269         mirror = r1_bio->read_disk;
270         /*
271          * this branch is our 'one mirror IO has finished' event handler:
272          */
273         update_head_pos(mirror, r1_bio);
274
275         if (uptodate)
276                 set_bit(R1BIO_Uptodate, &r1_bio->state);
277         else {
278                 /* If all other devices have failed, we want to return
279                  * the error upwards rather than fail the last device.
280                  * Here we redefine "uptodate" to mean "Don't want to retry"
281                  */
282                 unsigned long flags;
283                 spin_lock_irqsave(&conf->device_lock, flags);
284                 if (r1_bio->mddev->degraded == conf->raid_disks ||
285                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
286                      !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
287                         uptodate = 1;
288                 spin_unlock_irqrestore(&conf->device_lock, flags);
289         }
290
291         if (uptodate)
292                 raid_end_bio_io(r1_bio);
293         else {
294                 /*
295                  * oops, read error:
296                  */
297                 char b[BDEVNAME_SIZE];
298                 if (printk_ratelimit())
299                         printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
300                                bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
301                 reschedule_retry(r1_bio);
302         }
303
304         rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
305 }
306
307 static void raid1_end_write_request(struct bio *bio, int error)
308 {
309         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
310         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
311         int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
312         conf_t *conf = mddev_to_conf(r1_bio->mddev);
313         struct bio *to_put = NULL;
314
315
316         for (mirror = 0; mirror < conf->raid_disks; mirror++)
317                 if (r1_bio->bios[mirror] == bio)
318                         break;
319
320         if (error == -EOPNOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
321                 set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
322                 set_bit(R1BIO_BarrierRetry, &r1_bio->state);
323                 r1_bio->mddev->barriers_work = 0;
324                 /* Don't rdev_dec_pending in this branch - keep it for the retry */
325         } else {
326                 /*
327                  * this branch is our 'one mirror IO has finished' event handler:
328                  */
329                 r1_bio->bios[mirror] = NULL;
330                 to_put = bio;
331                 if (!uptodate) {
332                         md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
333                         /* an I/O failed, we can't clear the bitmap */
334                         set_bit(R1BIO_Degraded, &r1_bio->state);
335                 } else
336                         /*
337                          * Set R1BIO_Uptodate in our master bio, so that
338                          * we will return a good error code for to the higher
339                          * levels even if IO on some other mirrored buffer fails.
340                          *
341                          * The 'master' represents the composite IO operation to
342                          * user-side. So if something waits for IO, then it will
343                          * wait for the 'master' bio.
344                          */
345                         set_bit(R1BIO_Uptodate, &r1_bio->state);
346
347                 update_head_pos(mirror, r1_bio);
348
349                 if (behind) {
350                         if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
351                                 atomic_dec(&r1_bio->behind_remaining);
352
353                         /* In behind mode, we ACK the master bio once the I/O has safely
354                          * reached all non-writemostly disks. Setting the Returned bit
355                          * ensures that this gets done only once -- we don't ever want to
356                          * return -EIO here, instead we'll wait */
357
358                         if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
359                             test_bit(R1BIO_Uptodate, &r1_bio->state)) {
360                                 /* Maybe we can return now */
361                                 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
362                                         struct bio *mbio = r1_bio->master_bio;
363                                         PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
364                                                (unsigned long long) mbio->bi_sector,
365                                                (unsigned long long) mbio->bi_sector +
366                                                (mbio->bi_size >> 9) - 1);
367                                         bio_endio(mbio, 0);
368                                 }
369                         }
370                 }
371                 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
372         }
373         /*
374          *
375          * Let's see if all mirrored write operations have finished
376          * already.
377          */
378         if (atomic_dec_and_test(&r1_bio->remaining)) {
379                 if (test_bit(R1BIO_BarrierRetry, &r1_bio->state))
380                         reschedule_retry(r1_bio);
381                 else {
382                         /* it really is the end of this request */
383                         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
384                                 /* free extra copy of the data pages */
385                                 int i = bio->bi_vcnt;
386                                 while (i--)
387                                         safe_put_page(bio->bi_io_vec[i].bv_page);
388                         }
389                         /* clear the bitmap if all writes complete successfully */
390                         bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
391                                         r1_bio->sectors,
392                                         !test_bit(R1BIO_Degraded, &r1_bio->state),
393                                         behind);
394                         md_write_end(r1_bio->mddev);
395                         raid_end_bio_io(r1_bio);
396                 }
397         }
398
399         if (to_put)
400                 bio_put(to_put);
401 }
402
403
404 /*
405  * This routine returns the disk from which the requested read should
406  * be done. There is a per-array 'next expected sequential IO' sector
407  * number - if this matches on the next IO then we use the last disk.
408  * There is also a per-disk 'last know head position' sector that is
409  * maintained from IRQ contexts, both the normal and the resync IO
410  * completion handlers update this position correctly. If there is no
411  * perfect sequential match then we pick the disk whose head is closest.
412  *
413  * If there are 2 mirrors in the same 2 devices, performance degrades
414  * because position is mirror, not device based.
415  *
416  * The rdev for the device selected will have nr_pending incremented.
417  */
418 static int read_balance(conf_t *conf, r1bio_t *r1_bio)
419 {
420         const unsigned long this_sector = r1_bio->sector;
421         int new_disk = conf->last_used, disk = new_disk;
422         int wonly_disk = -1;
423         const int sectors = r1_bio->sectors;
424         sector_t new_distance, current_distance;
425         mdk_rdev_t *rdev;
426
427         rcu_read_lock();
428         /*
429          * Check if we can balance. We can balance on the whole
430          * device if no resync is going on, or below the resync window.
431          * We take the first readable disk when above the resync window.
432          */
433  retry:
434         if (conf->mddev->recovery_cp < MaxSector &&
435             (this_sector + sectors >= conf->next_resync)) {
436                 /* Choose the first operation device, for consistancy */
437                 new_disk = 0;
438
439                 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
440                      r1_bio->bios[new_disk] == IO_BLOCKED ||
441                      !rdev || !test_bit(In_sync, &rdev->flags)
442                              || test_bit(WriteMostly, &rdev->flags);
443                      rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
444
445                         if (rdev && test_bit(In_sync, &rdev->flags) &&
446                                 r1_bio->bios[new_disk] != IO_BLOCKED)
447                                 wonly_disk = new_disk;
448
449                         if (new_disk == conf->raid_disks - 1) {
450                                 new_disk = wonly_disk;
451                                 break;
452                         }
453                 }
454                 goto rb_out;
455         }
456
457
458         /* make sure the disk is operational */
459         for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
460              r1_bio->bios[new_disk] == IO_BLOCKED ||
461              !rdev || !test_bit(In_sync, &rdev->flags) ||
462                      test_bit(WriteMostly, &rdev->flags);
463              rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
464
465                 if (rdev && test_bit(In_sync, &rdev->flags) &&
466                     r1_bio->bios[new_disk] != IO_BLOCKED)
467                         wonly_disk = new_disk;
468
469                 if (new_disk <= 0)
470                         new_disk = conf->raid_disks;
471                 new_disk--;
472                 if (new_disk == disk) {
473                         new_disk = wonly_disk;
474                         break;
475                 }
476         }
477
478         if (new_disk < 0)
479                 goto rb_out;
480
481         disk = new_disk;
482         /* now disk == new_disk == starting point for search */
483
484         /*
485          * Don't change to another disk for sequential reads:
486          */
487         if (conf->next_seq_sect == this_sector)
488                 goto rb_out;
489         if (this_sector == conf->mirrors[new_disk].head_position)
490                 goto rb_out;
491
492         current_distance = abs(this_sector - conf->mirrors[disk].head_position);
493
494         /* Find the disk whose head is closest */
495
496         do {
497                 if (disk <= 0)
498                         disk = conf->raid_disks;
499                 disk--;
500
501                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
502
503                 if (!rdev || r1_bio->bios[disk] == IO_BLOCKED ||
504                     !test_bit(In_sync, &rdev->flags) ||
505                     test_bit(WriteMostly, &rdev->flags))
506                         continue;
507
508                 if (!atomic_read(&rdev->nr_pending)) {
509                         new_disk = disk;
510                         break;
511                 }
512                 new_distance = abs(this_sector - conf->mirrors[disk].head_position);
513                 if (new_distance < current_distance) {
514                         current_distance = new_distance;
515                         new_disk = disk;
516                 }
517         } while (disk != conf->last_used);
518
519  rb_out:
520
521
522         if (new_disk >= 0) {
523                 rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
524                 if (!rdev)
525                         goto retry;
526                 atomic_inc(&rdev->nr_pending);
527                 if (!test_bit(In_sync, &rdev->flags)) {
528                         /* cannot risk returning a device that failed
529                          * before we inc'ed nr_pending
530                          */
531                         rdev_dec_pending(rdev, conf->mddev);
532                         goto retry;
533                 }
534                 conf->next_seq_sect = this_sector + sectors;
535                 conf->last_used = new_disk;
536         }
537         rcu_read_unlock();
538
539         return new_disk;
540 }
541
542 static void unplug_slaves(mddev_t *mddev)
543 {
544         conf_t *conf = mddev_to_conf(mddev);
545         int i;
546
547         rcu_read_lock();
548         for (i=0; i<mddev->raid_disks; i++) {
549                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
550                 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
551                         struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
552
553                         atomic_inc(&rdev->nr_pending);
554                         rcu_read_unlock();
555
556                         blk_unplug(r_queue);
557
558                         rdev_dec_pending(rdev, mddev);
559                         rcu_read_lock();
560                 }
561         }
562         rcu_read_unlock();
563 }
564
565 static void raid1_unplug(struct request_queue *q)
566 {
567         mddev_t *mddev = q->queuedata;
568
569         unplug_slaves(mddev);
570         md_wakeup_thread(mddev->thread);
571 }
572
573 static int raid1_congested(void *data, int bits)
574 {
575         mddev_t *mddev = data;
576         conf_t *conf = mddev_to_conf(mddev);
577         int i, ret = 0;
578
579         rcu_read_lock();
580         for (i = 0; i < mddev->raid_disks; i++) {
581                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
582                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
583                         struct request_queue *q = bdev_get_queue(rdev->bdev);
584
585                         /* Note the '|| 1' - when read_balance prefers
586                          * non-congested targets, it can be removed
587                          */
588                         if ((bits & (1<<BDI_write_congested)) || 1)
589                                 ret |= bdi_congested(&q->backing_dev_info, bits);
590                         else
591                                 ret &= bdi_congested(&q->backing_dev_info, bits);
592                 }
593         }
594         rcu_read_unlock();
595         return ret;
596 }
597
598
599 static int flush_pending_writes(conf_t *conf)
600 {
601         /* Any writes that have been queued but are awaiting
602          * bitmap updates get flushed here.
603          * We return 1 if any requests were actually submitted.
604          */
605         int rv = 0;
606
607         spin_lock_irq(&conf->device_lock);
608
609         if (conf->pending_bio_list.head) {
610                 struct bio *bio;
611                 bio = bio_list_get(&conf->pending_bio_list);
612                 blk_remove_plug(conf->mddev->queue);
613                 spin_unlock_irq(&conf->device_lock);
614                 /* flush any pending bitmap writes to
615                  * disk before proceeding w/ I/O */
616                 bitmap_unplug(conf->mddev->bitmap);
617
618                 while (bio) { /* submit pending writes */
619                         struct bio *next = bio->bi_next;
620                         bio->bi_next = NULL;
621                         generic_make_request(bio);
622                         bio = next;
623                 }
624                 rv = 1;
625         } else
626                 spin_unlock_irq(&conf->device_lock);
627         return rv;
628 }
629
630 /* Barriers....
631  * Sometimes we need to suspend IO while we do something else,
632  * either some resync/recovery, or reconfigure the array.
633  * To do this we raise a 'barrier'.
634  * The 'barrier' is a counter that can be raised multiple times
635  * to count how many activities are happening which preclude
636  * normal IO.
637  * We can only raise the barrier if there is no pending IO.
638  * i.e. if nr_pending == 0.
639  * We choose only to raise the barrier if no-one is waiting for the
640  * barrier to go down.  This means that as soon as an IO request
641  * is ready, no other operations which require a barrier will start
642  * until the IO request has had a chance.
643  *
644  * So: regular IO calls 'wait_barrier'.  When that returns there
645  *    is no backgroup IO happening,  It must arrange to call
646  *    allow_barrier when it has finished its IO.
647  * backgroup IO calls must call raise_barrier.  Once that returns
648  *    there is no normal IO happeing.  It must arrange to call
649  *    lower_barrier when the particular background IO completes.
650  */
651 #define RESYNC_DEPTH 32
652
653 static void raise_barrier(conf_t *conf)
654 {
655         spin_lock_irq(&conf->resync_lock);
656
657         /* Wait until no block IO is waiting */
658         wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
659                             conf->resync_lock,
660                             raid1_unplug(conf->mddev->queue));
661
662         /* block any new IO from starting */
663         conf->barrier++;
664
665         /* No wait for all pending IO to complete */
666         wait_event_lock_irq(conf->wait_barrier,
667                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
668                             conf->resync_lock,
669                             raid1_unplug(conf->mddev->queue));
670
671         spin_unlock_irq(&conf->resync_lock);
672 }
673
674 static void lower_barrier(conf_t *conf)
675 {
676         unsigned long flags;
677         spin_lock_irqsave(&conf->resync_lock, flags);
678         conf->barrier--;
679         spin_unlock_irqrestore(&conf->resync_lock, flags);
680         wake_up(&conf->wait_barrier);
681 }
682
683 static void wait_barrier(conf_t *conf)
684 {
685         spin_lock_irq(&conf->resync_lock);
686         if (conf->barrier) {
687                 conf->nr_waiting++;
688                 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
689                                     conf->resync_lock,
690                                     raid1_unplug(conf->mddev->queue));
691                 conf->nr_waiting--;
692         }
693         conf->nr_pending++;
694         spin_unlock_irq(&conf->resync_lock);
695 }
696
697 static void allow_barrier(conf_t *conf)
698 {
699         unsigned long flags;
700         spin_lock_irqsave(&conf->resync_lock, flags);
701         conf->nr_pending--;
702         spin_unlock_irqrestore(&conf->resync_lock, flags);
703         wake_up(&conf->wait_barrier);
704 }
705
706 static void freeze_array(conf_t *conf)
707 {
708         /* stop syncio and normal IO and wait for everything to
709          * go quite.
710          * We increment barrier and nr_waiting, and then
711          * wait until nr_pending match nr_queued+1
712          * This is called in the context of one normal IO request
713          * that has failed. Thus any sync request that might be pending
714          * will be blocked by nr_pending, and we need to wait for
715          * pending IO requests to complete or be queued for re-try.
716          * Thus the number queued (nr_queued) plus this request (1)
717          * must match the number of pending IOs (nr_pending) before
718          * we continue.
719          */
720         spin_lock_irq(&conf->resync_lock);
721         conf->barrier++;
722         conf->nr_waiting++;
723         wait_event_lock_irq(conf->wait_barrier,
724                             conf->nr_pending == conf->nr_queued+1,
725                             conf->resync_lock,
726                             ({ flush_pending_writes(conf);
727                                raid1_unplug(conf->mddev->queue); }));
728         spin_unlock_irq(&conf->resync_lock);
729 }
730 static void unfreeze_array(conf_t *conf)
731 {
732         /* reverse the effect of the freeze */
733         spin_lock_irq(&conf->resync_lock);
734         conf->barrier--;
735         conf->nr_waiting--;
736         wake_up(&conf->wait_barrier);
737         spin_unlock_irq(&conf->resync_lock);
738 }
739
740
741 /* duplicate the data pages for behind I/O */
742 static struct page **alloc_behind_pages(struct bio *bio)
743 {
744         int i;
745         struct bio_vec *bvec;
746         struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
747                                         GFP_NOIO);
748         if (unlikely(!pages))
749                 goto do_sync_io;
750
751         bio_for_each_segment(bvec, bio, i) {
752                 pages[i] = alloc_page(GFP_NOIO);
753                 if (unlikely(!pages[i]))
754                         goto do_sync_io;
755                 memcpy(kmap(pages[i]) + bvec->bv_offset,
756                         kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
757                 kunmap(pages[i]);
758                 kunmap(bvec->bv_page);
759         }
760
761         return pages;
762
763 do_sync_io:
764         if (pages)
765                 for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
766                         put_page(pages[i]);
767         kfree(pages);
768         PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
769         return NULL;
770 }
771
772 static int make_request(struct request_queue *q, struct bio * bio)
773 {
774         mddev_t *mddev = q->queuedata;
775         conf_t *conf = mddev_to_conf(mddev);
776         mirror_info_t *mirror;
777         r1bio_t *r1_bio;
778         struct bio *read_bio;
779         int i, targets = 0, disks;
780         struct bitmap *bitmap;
781         unsigned long flags;
782         struct bio_list bl;
783         struct page **behind_pages = NULL;
784         const int rw = bio_data_dir(bio);
785         const int do_sync = bio_sync(bio);
786         int cpu, do_barriers;
787         mdk_rdev_t *blocked_rdev;
788
789         /*
790          * Register the new request and wait if the reconstruction
791          * thread has put up a bar for new requests.
792          * Continue immediately if no resync is active currently.
793          * We test barriers_work *after* md_write_start as md_write_start
794          * may cause the first superblock write, and that will check out
795          * if barriers work.
796          */
797
798         md_write_start(mddev, bio); /* wait on superblock update early */
799
800         if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
801                 if (rw == WRITE)
802                         md_write_end(mddev);
803                 bio_endio(bio, -EOPNOTSUPP);
804                 return 0;
805         }
806
807         wait_barrier(conf);
808
809         bitmap = mddev->bitmap;
810
811         cpu = part_stat_lock();
812         part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
813         part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
814                       bio_sectors(bio));
815         part_stat_unlock();
816
817         /*
818          * make_request() can abort the operation when READA is being
819          * used and no empty request is available.
820          *
821          */
822         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
823
824         r1_bio->master_bio = bio;
825         r1_bio->sectors = bio->bi_size >> 9;
826         r1_bio->state = 0;
827         r1_bio->mddev = mddev;
828         r1_bio->sector = bio->bi_sector;
829
830         if (rw == READ) {
831                 /*
832                  * read balancing logic:
833                  */
834                 int rdisk = read_balance(conf, r1_bio);
835
836                 if (rdisk < 0) {
837                         /* couldn't find anywhere to read from */
838                         raid_end_bio_io(r1_bio);
839                         return 0;
840                 }
841                 mirror = conf->mirrors + rdisk;
842
843                 r1_bio->read_disk = rdisk;
844
845                 read_bio = bio_clone(bio, GFP_NOIO);
846
847                 r1_bio->bios[rdisk] = read_bio;
848
849                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
850                 read_bio->bi_bdev = mirror->rdev->bdev;
851                 read_bio->bi_end_io = raid1_end_read_request;
852                 read_bio->bi_rw = READ | do_sync;
853                 read_bio->bi_private = r1_bio;
854
855                 generic_make_request(read_bio);
856                 return 0;
857         }
858
859         /*
860          * WRITE:
861          */
862         /* first select target devices under spinlock and
863          * inc refcount on their rdev.  Record them by setting
864          * bios[x] to bio
865          */
866         disks = conf->raid_disks;
867 #if 0
868         { static int first=1;
869         if (first) printk("First Write sector %llu disks %d\n",
870                           (unsigned long long)r1_bio->sector, disks);
871         first = 0;
872         }
873 #endif
874  retry_write:
875         blocked_rdev = NULL;
876         rcu_read_lock();
877         for (i = 0;  i < disks; i++) {
878                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
879                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
880                         atomic_inc(&rdev->nr_pending);
881                         blocked_rdev = rdev;
882                         break;
883                 }
884                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
885                         atomic_inc(&rdev->nr_pending);
886                         if (test_bit(Faulty, &rdev->flags)) {
887                                 rdev_dec_pending(rdev, mddev);
888                                 r1_bio->bios[i] = NULL;
889                         } else
890                                 r1_bio->bios[i] = bio;
891                         targets++;
892                 } else
893                         r1_bio->bios[i] = NULL;
894         }
895         rcu_read_unlock();
896
897         if (unlikely(blocked_rdev)) {
898                 /* Wait for this device to become unblocked */
899                 int j;
900
901                 for (j = 0; j < i; j++)
902                         if (r1_bio->bios[j])
903                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
904
905                 allow_barrier(conf);
906                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
907                 wait_barrier(conf);
908                 goto retry_write;
909         }
910
911         BUG_ON(targets == 0); /* we never fail the last device */
912
913         if (targets < conf->raid_disks) {
914                 /* array is degraded, we will not clear the bitmap
915                  * on I/O completion (see raid1_end_write_request) */
916                 set_bit(R1BIO_Degraded, &r1_bio->state);
917         }
918
919         /* do behind I/O ? */
920         if (bitmap &&
921             atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind &&
922             (behind_pages = alloc_behind_pages(bio)) != NULL)
923                 set_bit(R1BIO_BehindIO, &r1_bio->state);
924
925         atomic_set(&r1_bio->remaining, 0);
926         atomic_set(&r1_bio->behind_remaining, 0);
927
928         do_barriers = bio_barrier(bio);
929         if (do_barriers)
930                 set_bit(R1BIO_Barrier, &r1_bio->state);
931
932         bio_list_init(&bl);
933         for (i = 0; i < disks; i++) {
934                 struct bio *mbio;
935                 if (!r1_bio->bios[i])
936                         continue;
937
938                 mbio = bio_clone(bio, GFP_NOIO);
939                 r1_bio->bios[i] = mbio;
940
941                 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
942                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
943                 mbio->bi_end_io = raid1_end_write_request;
944                 mbio->bi_rw = WRITE | do_barriers | do_sync;
945                 mbio->bi_private = r1_bio;
946
947                 if (behind_pages) {
948                         struct bio_vec *bvec;
949                         int j;
950
951                         /* Yes, I really want the '__' version so that
952                          * we clear any unused pointer in the io_vec, rather
953                          * than leave them unchanged.  This is important
954                          * because when we come to free the pages, we won't
955                          * know the originial bi_idx, so we just free
956                          * them all
957                          */
958                         __bio_for_each_segment(bvec, mbio, j, 0)
959                                 bvec->bv_page = behind_pages[j];
960                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
961                                 atomic_inc(&r1_bio->behind_remaining);
962                 }
963
964                 atomic_inc(&r1_bio->remaining);
965
966                 bio_list_add(&bl, mbio);
967         }
968         kfree(behind_pages); /* the behind pages are attached to the bios now */
969
970         bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
971                                 test_bit(R1BIO_BehindIO, &r1_bio->state));
972         spin_lock_irqsave(&conf->device_lock, flags);
973         bio_list_merge(&conf->pending_bio_list, &bl);
974         bio_list_init(&bl);
975
976         blk_plug_device(mddev->queue);
977         spin_unlock_irqrestore(&conf->device_lock, flags);
978
979         /* In case raid1d snuck into freeze_array */
980         wake_up(&conf->wait_barrier);
981
982         if (do_sync)
983                 md_wakeup_thread(mddev->thread);
984 #if 0
985         while ((bio = bio_list_pop(&bl)) != NULL)
986                 generic_make_request(bio);
987 #endif
988
989         return 0;
990 }
991
992 static void status(struct seq_file *seq, mddev_t *mddev)
993 {
994         conf_t *conf = mddev_to_conf(mddev);
995         int i;
996
997         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
998                    conf->raid_disks - mddev->degraded);
999         rcu_read_lock();
1000         for (i = 0; i < conf->raid_disks; i++) {
1001                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1002                 seq_printf(seq, "%s",
1003                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1004         }
1005         rcu_read_unlock();
1006         seq_printf(seq, "]");
1007 }
1008
1009
1010 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1011 {
1012         char b[BDEVNAME_SIZE];
1013         conf_t *conf = mddev_to_conf(mddev);
1014
1015         /*
1016          * If it is not operational, then we have already marked it as dead
1017          * else if it is the last working disks, ignore the error, let the
1018          * next level up know.
1019          * else mark the drive as failed
1020          */
1021         if (test_bit(In_sync, &rdev->flags)
1022             && (conf->raid_disks - mddev->degraded) == 1) {
1023                 /*
1024                  * Don't fail the drive, act as though we were just a
1025                  * normal single drive.
1026                  * However don't try a recovery from this drive as
1027                  * it is very likely to fail.
1028                  */
1029                 mddev->recovery_disabled = 1;
1030                 return;
1031         }
1032         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1033                 unsigned long flags;
1034                 spin_lock_irqsave(&conf->device_lock, flags);
1035                 mddev->degraded++;
1036                 set_bit(Faulty, &rdev->flags);
1037                 spin_unlock_irqrestore(&conf->device_lock, flags);
1038                 /*
1039                  * if recovery is running, make sure it aborts.
1040                  */
1041                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1042         } else
1043                 set_bit(Faulty, &rdev->flags);
1044         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1045         printk(KERN_ALERT "raid1: Disk failure on %s, disabling device.\n"
1046                 "raid1: Operation continuing on %d devices.\n",
1047                 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
1048 }
1049
1050 static void print_conf(conf_t *conf)
1051 {
1052         int i;
1053
1054         printk("RAID1 conf printout:\n");
1055         if (!conf) {
1056                 printk("(!conf)\n");
1057                 return;
1058         }
1059         printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1060                 conf->raid_disks);
1061
1062         rcu_read_lock();
1063         for (i = 0; i < conf->raid_disks; i++) {
1064                 char b[BDEVNAME_SIZE];
1065                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1066                 if (rdev)
1067                         printk(" disk %d, wo:%d, o:%d, dev:%s\n",
1068                                i, !test_bit(In_sync, &rdev->flags),
1069                                !test_bit(Faulty, &rdev->flags),
1070                                bdevname(rdev->bdev,b));
1071         }
1072         rcu_read_unlock();
1073 }
1074
1075 static void close_sync(conf_t *conf)
1076 {
1077         wait_barrier(conf);
1078         allow_barrier(conf);
1079
1080         mempool_destroy(conf->r1buf_pool);
1081         conf->r1buf_pool = NULL;
1082 }
1083
1084 static int raid1_spare_active(mddev_t *mddev)
1085 {
1086         int i;
1087         conf_t *conf = mddev->private;
1088
1089         /*
1090          * Find all failed disks within the RAID1 configuration 
1091          * and mark them readable.
1092          * Called under mddev lock, so rcu protection not needed.
1093          */
1094         for (i = 0; i < conf->raid_disks; i++) {
1095                 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1096                 if (rdev
1097                     && !test_bit(Faulty, &rdev->flags)
1098                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1099                         unsigned long flags;
1100                         spin_lock_irqsave(&conf->device_lock, flags);
1101                         mddev->degraded--;
1102                         spin_unlock_irqrestore(&conf->device_lock, flags);
1103                 }
1104         }
1105
1106         print_conf(conf);
1107         return 0;
1108 }
1109
1110
1111 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1112 {
1113         conf_t *conf = mddev->private;
1114         int err = -EEXIST;
1115         int mirror = 0;
1116         mirror_info_t *p;
1117         int first = 0;
1118         int last = mddev->raid_disks - 1;
1119
1120         if (rdev->raid_disk >= 0)
1121                 first = last = rdev->raid_disk;
1122
1123         for (mirror = first; mirror <= last; mirror++)
1124                 if ( !(p=conf->mirrors+mirror)->rdev) {
1125
1126                         blk_queue_stack_limits(mddev->queue,
1127                                                rdev->bdev->bd_disk->queue);
1128                         /* as we don't honour merge_bvec_fn, we must never risk
1129                          * violating it, so limit ->max_sector to one PAGE, as
1130                          * a one page request is never in violation.
1131                          */
1132                         if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1133                             mddev->queue->max_sectors > (PAGE_SIZE>>9))
1134                                 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1135
1136                         p->head_position = 0;
1137                         rdev->raid_disk = mirror;
1138                         err = 0;
1139                         /* As all devices are equivalent, we don't need a full recovery
1140                          * if this was recently any drive of the array
1141                          */
1142                         if (rdev->saved_raid_disk < 0)
1143                                 conf->fullsync = 1;
1144                         rcu_assign_pointer(p->rdev, rdev);
1145                         break;
1146                 }
1147
1148         print_conf(conf);
1149         return err;
1150 }
1151
1152 static int raid1_remove_disk(mddev_t *mddev, int number)
1153 {
1154         conf_t *conf = mddev->private;
1155         int err = 0;
1156         mdk_rdev_t *rdev;
1157         mirror_info_t *p = conf->mirrors+ number;
1158
1159         print_conf(conf);
1160         rdev = p->rdev;
1161         if (rdev) {
1162                 if (test_bit(In_sync, &rdev->flags) ||
1163                     atomic_read(&rdev->nr_pending)) {
1164                         err = -EBUSY;
1165                         goto abort;
1166                 }
1167                 /* Only remove non-faulty devices is recovery
1168                  * is not possible.
1169                  */
1170                 if (!test_bit(Faulty, &rdev->flags) &&
1171                     mddev->degraded < conf->raid_disks) {
1172                         err = -EBUSY;
1173                         goto abort;
1174                 }
1175                 p->rdev = NULL;
1176                 synchronize_rcu();
1177                 if (atomic_read(&rdev->nr_pending)) {
1178                         /* lost the race, try later */
1179                         err = -EBUSY;
1180                         p->rdev = rdev;
1181                 }
1182         }
1183 abort:
1184
1185         print_conf(conf);
1186         return err;
1187 }
1188
1189
1190 static void end_sync_read(struct bio *bio, int error)
1191 {
1192         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1193         int i;
1194
1195         for (i=r1_bio->mddev->raid_disks; i--; )
1196                 if (r1_bio->bios[i] == bio)
1197                         break;
1198         BUG_ON(i < 0);
1199         update_head_pos(i, r1_bio);
1200         /*
1201          * we have read a block, now it needs to be re-written,
1202          * or re-read if the read failed.
1203          * We don't do much here, just schedule handling by raid1d
1204          */
1205         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1206                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1207
1208         if (atomic_dec_and_test(&r1_bio->remaining))
1209                 reschedule_retry(r1_bio);
1210 }
1211
1212 static void end_sync_write(struct bio *bio, int error)
1213 {
1214         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1215         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1216         mddev_t *mddev = r1_bio->mddev;
1217         conf_t *conf = mddev_to_conf(mddev);
1218         int i;
1219         int mirror=0;
1220
1221         for (i = 0; i < conf->raid_disks; i++)
1222                 if (r1_bio->bios[i] == bio) {
1223                         mirror = i;
1224                         break;
1225                 }
1226         if (!uptodate) {
1227                 int sync_blocks = 0;
1228                 sector_t s = r1_bio->sector;
1229                 long sectors_to_go = r1_bio->sectors;
1230                 /* make sure these bits doesn't get cleared. */
1231                 do {
1232                         bitmap_end_sync(mddev->bitmap, s,
1233                                         &sync_blocks, 1);
1234                         s += sync_blocks;
1235                         sectors_to_go -= sync_blocks;
1236                 } while (sectors_to_go > 0);
1237                 md_error(mddev, conf->mirrors[mirror].rdev);
1238         }
1239
1240         update_head_pos(mirror, r1_bio);
1241
1242         if (atomic_dec_and_test(&r1_bio->remaining)) {
1243                 sector_t s = r1_bio->sectors;
1244                 put_buf(r1_bio);
1245                 md_done_sync(mddev, s, uptodate);
1246         }
1247 }
1248
1249 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1250 {
1251         conf_t *conf = mddev_to_conf(mddev);
1252         int i;
1253         int disks = conf->raid_disks;
1254         struct bio *bio, *wbio;
1255
1256         bio = r1_bio->bios[r1_bio->read_disk];
1257
1258
1259         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1260                 /* We have read all readable devices.  If we haven't
1261                  * got the block, then there is no hope left.
1262                  * If we have, then we want to do a comparison
1263                  * and skip the write if everything is the same.
1264                  * If any blocks failed to read, then we need to
1265                  * attempt an over-write
1266                  */
1267                 int primary;
1268                 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1269                         for (i=0; i<mddev->raid_disks; i++)
1270                                 if (r1_bio->bios[i]->bi_end_io == end_sync_read)
1271                                         md_error(mddev, conf->mirrors[i].rdev);
1272
1273                         md_done_sync(mddev, r1_bio->sectors, 1);
1274                         put_buf(r1_bio);
1275                         return;
1276                 }
1277                 for (primary=0; primary<mddev->raid_disks; primary++)
1278                         if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1279                             test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1280                                 r1_bio->bios[primary]->bi_end_io = NULL;
1281                                 rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1282                                 break;
1283                         }
1284                 r1_bio->read_disk = primary;
1285                 for (i=0; i<mddev->raid_disks; i++)
1286                         if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1287                                 int j;
1288                                 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1289                                 struct bio *pbio = r1_bio->bios[primary];
1290                                 struct bio *sbio = r1_bio->bios[i];
1291
1292                                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1293                                         for (j = vcnt; j-- ; ) {
1294                                                 struct page *p, *s;
1295                                                 p = pbio->bi_io_vec[j].bv_page;
1296                                                 s = sbio->bi_io_vec[j].bv_page;
1297                                                 if (memcmp(page_address(p),
1298                                                            page_address(s),
1299                                                            PAGE_SIZE))
1300                                                         break;
1301                                         }
1302                                 } else
1303                                         j = 0;
1304                                 if (j >= 0)
1305                                         mddev->resync_mismatches += r1_bio->sectors;
1306                                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1307                                               && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1308                                         sbio->bi_end_io = NULL;
1309                                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1310                                 } else {
1311                                         /* fixup the bio for reuse */
1312                                         int size;
1313                                         sbio->bi_vcnt = vcnt;
1314                                         sbio->bi_size = r1_bio->sectors << 9;
1315                                         sbio->bi_idx = 0;
1316                                         sbio->bi_phys_segments = 0;
1317                                         sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1318                                         sbio->bi_flags |= 1 << BIO_UPTODATE;
1319                                         sbio->bi_next = NULL;
1320                                         sbio->bi_sector = r1_bio->sector +
1321                                                 conf->mirrors[i].rdev->data_offset;
1322                                         sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1323                                         size = sbio->bi_size;
1324                                         for (j = 0; j < vcnt ; j++) {
1325                                                 struct bio_vec *bi;
1326                                                 bi = &sbio->bi_io_vec[j];
1327                                                 bi->bv_offset = 0;
1328                                                 if (size > PAGE_SIZE)
1329                                                         bi->bv_len = PAGE_SIZE;
1330                                                 else
1331                                                         bi->bv_len = size;
1332                                                 size -= PAGE_SIZE;
1333                                                 memcpy(page_address(bi->bv_page),
1334                                                        page_address(pbio->bi_io_vec[j].bv_page),
1335                                                        PAGE_SIZE);
1336                                         }
1337
1338                                 }
1339                         }
1340         }
1341         if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1342                 /* ouch - failed to read all of that.
1343                  * Try some synchronous reads of other devices to get
1344                  * good data, much like with normal read errors.  Only
1345                  * read into the pages we already have so we don't
1346                  * need to re-issue the read request.
1347                  * We don't need to freeze the array, because being in an
1348                  * active sync request, there is no normal IO, and
1349                  * no overlapping syncs.
1350                  */
1351                 sector_t sect = r1_bio->sector;
1352                 int sectors = r1_bio->sectors;
1353                 int idx = 0;
1354
1355                 while(sectors) {
1356                         int s = sectors;
1357                         int d = r1_bio->read_disk;
1358                         int success = 0;
1359                         mdk_rdev_t *rdev;
1360
1361                         if (s > (PAGE_SIZE>>9))
1362                                 s = PAGE_SIZE >> 9;
1363                         do {
1364                                 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1365                                         /* No rcu protection needed here devices
1366                                          * can only be removed when no resync is
1367                                          * active, and resync is currently active
1368                                          */
1369                                         rdev = conf->mirrors[d].rdev;
1370                                         if (sync_page_io(rdev->bdev,
1371                                                          sect + rdev->data_offset,
1372                                                          s<<9,
1373                                                          bio->bi_io_vec[idx].bv_page,
1374                                                          READ)) {
1375                                                 success = 1;
1376                                                 break;
1377                                         }
1378                                 }
1379                                 d++;
1380                                 if (d == conf->raid_disks)
1381                                         d = 0;
1382                         } while (!success && d != r1_bio->read_disk);
1383
1384                         if (success) {
1385                                 int start = d;
1386                                 /* write it back and re-read */
1387                                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1388                                 while (d != r1_bio->read_disk) {
1389                                         if (d == 0)
1390                                                 d = conf->raid_disks;
1391                                         d--;
1392                                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1393                                                 continue;
1394                                         rdev = conf->mirrors[d].rdev;
1395                                         atomic_add(s, &rdev->corrected_errors);
1396                                         if (sync_page_io(rdev->bdev,
1397                                                          sect + rdev->data_offset,
1398                                                          s<<9,
1399                                                          bio->bi_io_vec[idx].bv_page,
1400                                                          WRITE) == 0)
1401                                                 md_error(mddev, rdev);
1402                                 }
1403                                 d = start;
1404                                 while (d != r1_bio->read_disk) {
1405                                         if (d == 0)
1406                                                 d = conf->raid_disks;
1407                                         d--;
1408                                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1409                                                 continue;
1410                                         rdev = conf->mirrors[d].rdev;
1411                                         if (sync_page_io(rdev->bdev,
1412                                                          sect + rdev->data_offset,
1413                                                          s<<9,
1414                                                          bio->bi_io_vec[idx].bv_page,
1415                                                          READ) == 0)
1416                                                 md_error(mddev, rdev);
1417                                 }
1418                         } else {
1419                                 char b[BDEVNAME_SIZE];
1420                                 /* Cannot read from anywhere, array is toast */
1421                                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1422                                 printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
1423                                        " for block %llu\n",
1424                                        bdevname(bio->bi_bdev,b),
1425                                        (unsigned long long)r1_bio->sector);
1426                                 md_done_sync(mddev, r1_bio->sectors, 0);
1427                                 put_buf(r1_bio);
1428                                 return;
1429                         }
1430                         sectors -= s;
1431                         sect += s;
1432                         idx ++;
1433                 }
1434         }
1435
1436         /*
1437          * schedule writes
1438          */
1439         atomic_set(&r1_bio->remaining, 1);
1440         for (i = 0; i < disks ; i++) {
1441                 wbio = r1_bio->bios[i];
1442                 if (wbio->bi_end_io == NULL ||
1443                     (wbio->bi_end_io == end_sync_read &&
1444                      (i == r1_bio->read_disk ||
1445                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1446                         continue;
1447
1448                 wbio->bi_rw = WRITE;
1449                 wbio->bi_end_io = end_sync_write;
1450                 atomic_inc(&r1_bio->remaining);
1451                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1452
1453                 generic_make_request(wbio);
1454         }
1455
1456         if (atomic_dec_and_test(&r1_bio->remaining)) {
1457                 /* if we're here, all write(s) have completed, so clean up */
1458                 md_done_sync(mddev, r1_bio->sectors, 1);
1459                 put_buf(r1_bio);
1460         }
1461 }
1462
1463 /*
1464  * This is a kernel thread which:
1465  *
1466  *      1.      Retries failed read operations on working mirrors.
1467  *      2.      Updates the raid superblock when problems encounter.
1468  *      3.      Performs writes following reads for array syncronising.
1469  */
1470
1471 static void fix_read_error(conf_t *conf, int read_disk,
1472                            sector_t sect, int sectors)
1473 {
1474         mddev_t *mddev = conf->mddev;
1475         while(sectors) {
1476                 int s = sectors;
1477                 int d = read_disk;
1478                 int success = 0;
1479                 int start;
1480                 mdk_rdev_t *rdev;
1481
1482                 if (s > (PAGE_SIZE>>9))
1483                         s = PAGE_SIZE >> 9;
1484
1485                 do {
1486                         /* Note: no rcu protection needed here
1487                          * as this is synchronous in the raid1d thread
1488                          * which is the thread that might remove
1489                          * a device.  If raid1d ever becomes multi-threaded....
1490                          */
1491                         rdev = conf->mirrors[d].rdev;
1492                         if (rdev &&
1493                             test_bit(In_sync, &rdev->flags) &&
1494                             sync_page_io(rdev->bdev,
1495                                          sect + rdev->data_offset,
1496                                          s<<9,
1497                                          conf->tmppage, READ))
1498                                 success = 1;
1499                         else {
1500                                 d++;
1501                                 if (d == conf->raid_disks)
1502                                         d = 0;
1503                         }
1504                 } while (!success && d != read_disk);
1505
1506                 if (!success) {
1507                         /* Cannot read from anywhere -- bye bye array */
1508                         md_error(mddev, conf->mirrors[read_disk].rdev);
1509                         break;
1510                 }
1511                 /* write it back and re-read */
1512                 start = d;
1513                 while (d != read_disk) {
1514                         if (d==0)
1515                                 d = conf->raid_disks;
1516                         d--;
1517                         rdev = conf->mirrors[d].rdev;
1518                         if (rdev &&
1519                             test_bit(In_sync, &rdev->flags)) {
1520                                 if (sync_page_io(rdev->bdev,
1521                                                  sect + rdev->data_offset,
1522                                                  s<<9, conf->tmppage, WRITE)
1523                                     == 0)
1524                                         /* Well, this device is dead */
1525                                         md_error(mddev, rdev);
1526                         }
1527                 }
1528                 d = start;
1529                 while (d != read_disk) {
1530                         char b[BDEVNAME_SIZE];
1531                         if (d==0)
1532                                 d = conf->raid_disks;
1533                         d--;
1534                         rdev = conf->mirrors[d].rdev;
1535                         if (rdev &&
1536                             test_bit(In_sync, &rdev->flags)) {
1537                                 if (sync_page_io(rdev->bdev,
1538                                                  sect + rdev->data_offset,
1539                                                  s<<9, conf->tmppage, READ)
1540                                     == 0)
1541                                         /* Well, this device is dead */
1542                                         md_error(mddev, rdev);
1543                                 else {
1544                                         atomic_add(s, &rdev->corrected_errors);
1545                                         printk(KERN_INFO
1546                                                "raid1:%s: read error corrected "
1547                                                "(%d sectors at %llu on %s)\n",
1548                                                mdname(mddev), s,
1549                                                (unsigned long long)(sect +
1550                                                    rdev->data_offset),
1551                                                bdevname(rdev->bdev, b));
1552                                 }
1553                         }
1554                 }
1555                 sectors -= s;
1556                 sect += s;
1557         }
1558 }
1559
1560 static void raid1d(mddev_t *mddev)
1561 {
1562         r1bio_t *r1_bio;
1563         struct bio *bio;
1564         unsigned long flags;
1565         conf_t *conf = mddev_to_conf(mddev);
1566         struct list_head *head = &conf->retry_list;
1567         int unplug=0;
1568         mdk_rdev_t *rdev;
1569
1570         md_check_recovery(mddev);
1571         
1572         for (;;) {
1573                 char b[BDEVNAME_SIZE];
1574
1575                 unplug += flush_pending_writes(conf);
1576
1577                 spin_lock_irqsave(&conf->device_lock, flags);
1578                 if (list_empty(head)) {
1579                         spin_unlock_irqrestore(&conf->device_lock, flags);
1580                         break;
1581                 }
1582                 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1583                 list_del(head->prev);
1584                 conf->nr_queued--;
1585                 spin_unlock_irqrestore(&conf->device_lock, flags);
1586
1587                 mddev = r1_bio->mddev;
1588                 conf = mddev_to_conf(mddev);
1589                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
1590                         sync_request_write(mddev, r1_bio);
1591                         unplug = 1;
1592                 } else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
1593                         /* some requests in the r1bio were BIO_RW_BARRIER
1594                          * requests which failed with -EOPNOTSUPP.  Hohumm..
1595                          * Better resubmit without the barrier.
1596                          * We know which devices to resubmit for, because
1597                          * all others have had their bios[] entry cleared.
1598                          * We already have a nr_pending reference on these rdevs.
1599                          */
1600                         int i;
1601                         const int do_sync = bio_sync(r1_bio->master_bio);
1602                         clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
1603                         clear_bit(R1BIO_Barrier, &r1_bio->state);
1604                         for (i=0; i < conf->raid_disks; i++)
1605                                 if (r1_bio->bios[i])
1606                                         atomic_inc(&r1_bio->remaining);
1607                         for (i=0; i < conf->raid_disks; i++)
1608                                 if (r1_bio->bios[i]) {
1609                                         struct bio_vec *bvec;
1610                                         int j;
1611
1612                                         bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1613                                         /* copy pages from the failed bio, as
1614                                          * this might be a write-behind device */
1615                                         __bio_for_each_segment(bvec, bio, j, 0)
1616                                                 bvec->bv_page = bio_iovec_idx(r1_bio->bios[i], j)->bv_page;
1617                                         bio_put(r1_bio->bios[i]);
1618                                         bio->bi_sector = r1_bio->sector +
1619                                                 conf->mirrors[i].rdev->data_offset;
1620                                         bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1621                                         bio->bi_end_io = raid1_end_write_request;
1622                                         bio->bi_rw = WRITE | do_sync;
1623                                         bio->bi_private = r1_bio;
1624                                         r1_bio->bios[i] = bio;
1625                                         generic_make_request(bio);
1626                                 }
1627                 } else {
1628                         int disk;
1629
1630                         /* we got a read error. Maybe the drive is bad.  Maybe just
1631                          * the block and we can fix it.
1632                          * We freeze all other IO, and try reading the block from
1633                          * other devices.  When we find one, we re-write
1634                          * and check it that fixes the read error.
1635                          * This is all done synchronously while the array is
1636                          * frozen
1637                          */
1638                         if (mddev->ro == 0) {
1639                                 freeze_array(conf);
1640                                 fix_read_error(conf, r1_bio->read_disk,
1641                                                r1_bio->sector,
1642                                                r1_bio->sectors);
1643                                 unfreeze_array(conf);
1644                         }
1645
1646                         bio = r1_bio->bios[r1_bio->read_disk];
1647                         if ((disk=read_balance(conf, r1_bio)) == -1 ||
1648                             disk == r1_bio->read_disk) {
1649                                 printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
1650                                        " read error for block %llu\n",
1651                                        bdevname(bio->bi_bdev,b),
1652                                        (unsigned long long)r1_bio->sector);
1653                                 raid_end_bio_io(r1_bio);
1654                         } else {
1655                                 const int do_sync = bio_sync(r1_bio->master_bio);
1656                                 r1_bio->bios[r1_bio->read_disk] =
1657                                         mddev->ro ? IO_BLOCKED : NULL;
1658                                 r1_bio->read_disk = disk;
1659                                 bio_put(bio);
1660                                 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1661                                 r1_bio->bios[r1_bio->read_disk] = bio;
1662                                 rdev = conf->mirrors[disk].rdev;
1663                                 if (printk_ratelimit())
1664                                         printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
1665                                                " another mirror\n",
1666                                                bdevname(rdev->bdev,b),
1667                                                (unsigned long long)r1_bio->sector);
1668                                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1669                                 bio->bi_bdev = rdev->bdev;
1670                                 bio->bi_end_io = raid1_end_read_request;
1671                                 bio->bi_rw = READ | do_sync;
1672                                 bio->bi_private = r1_bio;
1673                                 unplug = 1;
1674                                 generic_make_request(bio);
1675                         }
1676                 }
1677         }
1678         if (unplug)
1679                 unplug_slaves(mddev);
1680 }
1681
1682
1683 static int init_resync(conf_t *conf)
1684 {
1685         int buffs;
1686
1687         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1688         BUG_ON(conf->r1buf_pool);
1689         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1690                                           conf->poolinfo);
1691         if (!conf->r1buf_pool)
1692                 return -ENOMEM;
1693         conf->next_resync = 0;
1694         return 0;
1695 }
1696
1697 /*
1698  * perform a "sync" on one "block"
1699  *
1700  * We need to make sure that no normal I/O request - particularly write
1701  * requests - conflict with active sync requests.
1702  *
1703  * This is achieved by tracking pending requests and a 'barrier' concept
1704  * that can be installed to exclude normal IO requests.
1705  */
1706
1707 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1708 {
1709         conf_t *conf = mddev_to_conf(mddev);
1710         r1bio_t *r1_bio;
1711         struct bio *bio;
1712         sector_t max_sector, nr_sectors;
1713         int disk = -1;
1714         int i;
1715         int wonly = -1;
1716         int write_targets = 0, read_targets = 0;
1717         int sync_blocks;
1718         int still_degraded = 0;
1719
1720         if (!conf->r1buf_pool)
1721         {
1722 /*
1723                 printk("sync start - bitmap %p\n", mddev->bitmap);
1724 */
1725                 if (init_resync(conf))
1726                         return 0;
1727         }
1728
1729         max_sector = mddev->size << 1;
1730         if (sector_nr >= max_sector) {
1731                 /* If we aborted, we need to abort the
1732                  * sync on the 'current' bitmap chunk (there will
1733                  * only be one in raid1 resync.
1734                  * We can find the current addess in mddev->curr_resync
1735                  */
1736                 if (mddev->curr_resync < max_sector) /* aborted */
1737                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1738                                                 &sync_blocks, 1);
1739                 else /* completed sync */
1740                         conf->fullsync = 0;
1741
1742                 bitmap_close_sync(mddev->bitmap);
1743                 close_sync(conf);
1744                 return 0;
1745         }
1746
1747         if (mddev->bitmap == NULL &&
1748             mddev->recovery_cp == MaxSector &&
1749             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1750             conf->fullsync == 0) {
1751                 *skipped = 1;
1752                 return max_sector - sector_nr;
1753         }
1754         /* before building a request, check if we can skip these blocks..
1755          * This call the bitmap_start_sync doesn't actually record anything
1756          */
1757         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1758             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1759                 /* We can skip this block, and probably several more */
1760                 *skipped = 1;
1761                 return sync_blocks;
1762         }
1763         /*
1764          * If there is non-resync activity waiting for a turn,
1765          * and resync is going fast enough,
1766          * then let it though before starting on this new sync request.
1767          */
1768         if (!go_faster && conf->nr_waiting)
1769                 msleep_interruptible(1000);
1770
1771         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1772         raise_barrier(conf);
1773
1774         conf->next_resync = sector_nr;
1775
1776         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1777         rcu_read_lock();
1778         /*
1779          * If we get a correctably read error during resync or recovery,
1780          * we might want to read from a different device.  So we
1781          * flag all drives that could conceivably be read from for READ,
1782          * and any others (which will be non-In_sync devices) for WRITE.
1783          * If a read fails, we try reading from something else for which READ
1784          * is OK.
1785          */
1786
1787         r1_bio->mddev = mddev;
1788         r1_bio->sector = sector_nr;
1789         r1_bio->state = 0;
1790         set_bit(R1BIO_IsSync, &r1_bio->state);
1791
1792         for (i=0; i < conf->raid_disks; i++) {
1793                 mdk_rdev_t *rdev;
1794                 bio = r1_bio->bios[i];
1795
1796                 /* take from bio_init */
1797                 bio->bi_next = NULL;
1798                 bio->bi_flags |= 1 << BIO_UPTODATE;
1799                 bio->bi_rw = READ;
1800                 bio->bi_vcnt = 0;
1801                 bio->bi_idx = 0;
1802                 bio->bi_phys_segments = 0;
1803                 bio->bi_size = 0;
1804                 bio->bi_end_io = NULL;
1805                 bio->bi_private = NULL;
1806
1807                 rdev = rcu_dereference(conf->mirrors[i].rdev);
1808                 if (rdev == NULL ||
1809                            test_bit(Faulty, &rdev->flags)) {
1810                         still_degraded = 1;
1811                         continue;
1812                 } else if (!test_bit(In_sync, &rdev->flags)) {
1813                         bio->bi_rw = WRITE;
1814                         bio->bi_end_io = end_sync_write;
1815                         write_targets ++;
1816                 } else {
1817                         /* may need to read from here */
1818                         bio->bi_rw = READ;
1819                         bio->bi_end_io = end_sync_read;
1820                         if (test_bit(WriteMostly, &rdev->flags)) {
1821                                 if (wonly < 0)
1822                                         wonly = i;
1823                         } else {
1824                                 if (disk < 0)
1825                                         disk = i;
1826                         }
1827                         read_targets++;
1828                 }
1829                 atomic_inc(&rdev->nr_pending);
1830                 bio->bi_sector = sector_nr + rdev->data_offset;
1831                 bio->bi_bdev = rdev->bdev;
1832                 bio->bi_private = r1_bio;
1833         }
1834         rcu_read_unlock();
1835         if (disk < 0)
1836                 disk = wonly;
1837         r1_bio->read_disk = disk;
1838
1839         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1840                 /* extra read targets are also write targets */
1841                 write_targets += read_targets-1;
1842
1843         if (write_targets == 0 || read_targets == 0) {
1844                 /* There is nowhere to write, so all non-sync
1845                  * drives must be failed - so we are finished
1846                  */
1847                 sector_t rv = max_sector - sector_nr;
1848                 *skipped = 1;
1849                 put_buf(r1_bio);
1850                 return rv;
1851         }
1852
1853         if (max_sector > mddev->resync_max)
1854                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
1855         nr_sectors = 0;
1856         sync_blocks = 0;
1857         do {
1858                 struct page *page;
1859                 int len = PAGE_SIZE;
1860                 if (sector_nr + (len>>9) > max_sector)
1861                         len = (max_sector - sector_nr) << 9;
1862                 if (len == 0)
1863                         break;
1864                 if (sync_blocks == 0) {
1865                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1866                                                &sync_blocks, still_degraded) &&
1867                             !conf->fullsync &&
1868                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1869                                 break;
1870                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1871                         if (len > (sync_blocks<<9))
1872                                 len = sync_blocks<<9;
1873                 }
1874
1875                 for (i=0 ; i < conf->raid_disks; i++) {
1876                         bio = r1_bio->bios[i];
1877                         if (bio->bi_end_io) {
1878                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1879                                 if (bio_add_page(bio, page, len, 0) == 0) {
1880                                         /* stop here */
1881                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1882                                         while (i > 0) {
1883                                                 i--;
1884                                                 bio = r1_bio->bios[i];
1885                                                 if (bio->bi_end_io==NULL)
1886                                                         continue;
1887                                                 /* remove last page from this bio */
1888                                                 bio->bi_vcnt--;
1889                                                 bio->bi_size -= len;
1890                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1891                                         }
1892                                         goto bio_full;
1893                                 }
1894                         }
1895                 }
1896                 nr_sectors += len>>9;
1897                 sector_nr += len>>9;
1898                 sync_blocks -= (len>>9);
1899         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1900  bio_full:
1901         r1_bio->sectors = nr_sectors;
1902
1903         /* For a user-requested sync, we read all readable devices and do a
1904          * compare
1905          */
1906         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1907                 atomic_set(&r1_bio->remaining, read_targets);
1908                 for (i=0; i<conf->raid_disks; i++) {
1909                         bio = r1_bio->bios[i];
1910                         if (bio->bi_end_io == end_sync_read) {
1911                                 md_sync_acct(bio->bi_bdev, nr_sectors);
1912                                 generic_make_request(bio);
1913                         }
1914                 }
1915         } else {
1916                 atomic_set(&r1_bio->remaining, 1);
1917                 bio = r1_bio->bios[r1_bio->read_disk];
1918                 md_sync_acct(bio->bi_bdev, nr_sectors);
1919                 generic_make_request(bio);
1920
1921         }
1922         return nr_sectors;
1923 }
1924
1925 static int run(mddev_t *mddev)
1926 {
1927         conf_t *conf;
1928         int i, j, disk_idx;
1929         mirror_info_t *disk;
1930         mdk_rdev_t *rdev;
1931
1932         if (mddev->level != 1) {
1933                 printk("raid1: %s: raid level not set to mirroring (%d)\n",
1934                        mdname(mddev), mddev->level);
1935                 goto out;
1936         }
1937         if (mddev->reshape_position != MaxSector) {
1938                 printk("raid1: %s: reshape_position set but not supported\n",
1939                        mdname(mddev));
1940                 goto out;
1941         }
1942         /*
1943          * copy the already verified devices into our private RAID1
1944          * bookkeeping area. [whatever we allocate in run(),
1945          * should be freed in stop()]
1946          */
1947         conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
1948         mddev->private = conf;
1949         if (!conf)
1950                 goto out_no_mem;
1951
1952         conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1953                                  GFP_KERNEL);
1954         if (!conf->mirrors)
1955                 goto out_no_mem;
1956
1957         conf->tmppage = alloc_page(GFP_KERNEL);
1958         if (!conf->tmppage)
1959                 goto out_no_mem;
1960
1961         conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
1962         if (!conf->poolinfo)
1963                 goto out_no_mem;
1964         conf->poolinfo->mddev = mddev;
1965         conf->poolinfo->raid_disks = mddev->raid_disks;
1966         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1967                                           r1bio_pool_free,
1968                                           conf->poolinfo);
1969         if (!conf->r1bio_pool)
1970                 goto out_no_mem;
1971
1972         spin_lock_init(&conf->device_lock);
1973         mddev->queue->queue_lock = &conf->device_lock;
1974
1975         list_for_each_entry(rdev, &mddev->disks, same_set) {
1976                 disk_idx = rdev->raid_disk;
1977                 if (disk_idx >= mddev->raid_disks
1978                     || disk_idx < 0)
1979                         continue;
1980                 disk = conf->mirrors + disk_idx;
1981
1982                 disk->rdev = rdev;
1983
1984                 blk_queue_stack_limits(mddev->queue,
1985                                        rdev->bdev->bd_disk->queue);
1986                 /* as we don't honour merge_bvec_fn, we must never risk
1987                  * violating it, so limit ->max_sector to one PAGE, as
1988                  * a one page request is never in violation.
1989                  */
1990                 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1991                     mddev->queue->max_sectors > (PAGE_SIZE>>9))
1992                         blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1993
1994                 disk->head_position = 0;
1995         }
1996         conf->raid_disks = mddev->raid_disks;
1997         conf->mddev = mddev;
1998         INIT_LIST_HEAD(&conf->retry_list);
1999
2000         spin_lock_init(&conf->resync_lock);
2001         init_waitqueue_head(&conf->wait_barrier);
2002
2003         bio_list_init(&conf->pending_bio_list);
2004         bio_list_init(&conf->flushing_bio_list);
2005
2006
2007         mddev->degraded = 0;
2008         for (i = 0; i < conf->raid_disks; i++) {
2009
2010                 disk = conf->mirrors + i;
2011
2012                 if (!disk->rdev ||
2013                     !test_bit(In_sync, &disk->rdev->flags)) {
2014                         disk->head_position = 0;
2015                         mddev->degraded++;
2016                         if (disk->rdev)
2017                                 conf->fullsync = 1;
2018                 }
2019         }
2020         if (mddev->degraded == conf->raid_disks) {
2021                 printk(KERN_ERR "raid1: no operational mirrors for %s\n",
2022                         mdname(mddev));
2023                 goto out_free_conf;
2024         }
2025         if (conf->raid_disks - mddev->degraded == 1)
2026                 mddev->recovery_cp = MaxSector;
2027
2028         /*
2029          * find the first working one and use it as a starting point
2030          * to read balancing.
2031          */
2032         for (j = 0; j < conf->raid_disks &&
2033                      (!conf->mirrors[j].rdev ||
2034                       !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++)
2035                 /* nothing */;
2036         conf->last_used = j;
2037
2038
2039         mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
2040         if (!mddev->thread) {
2041                 printk(KERN_ERR
2042                        "raid1: couldn't allocate thread for %s\n",
2043                        mdname(mddev));
2044                 goto out_free_conf;
2045         }
2046
2047         printk(KERN_INFO 
2048                 "raid1: raid set %s active with %d out of %d mirrors\n",
2049                 mdname(mddev), mddev->raid_disks - mddev->degraded, 
2050                 mddev->raid_disks);
2051         /*
2052          * Ok, everything is just fine now
2053          */
2054         mddev->array_sectors = mddev->size * 2;
2055
2056         mddev->queue->unplug_fn = raid1_unplug;
2057         mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2058         mddev->queue->backing_dev_info.congested_data = mddev;
2059
2060         return 0;
2061
2062 out_no_mem:
2063         printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
2064                mdname(mddev));
2065
2066 out_free_conf:
2067         if (conf) {
2068                 if (conf->r1bio_pool)
2069                         mempool_destroy(conf->r1bio_pool);
2070                 kfree(conf->mirrors);
2071                 safe_put_page(conf->tmppage);
2072                 kfree(conf->poolinfo);
2073                 kfree(conf);
2074                 mddev->private = NULL;
2075         }
2076 out:
2077         return -EIO;
2078 }
2079
2080 static int stop(mddev_t *mddev)
2081 {
2082         conf_t *conf = mddev_to_conf(mddev);
2083         struct bitmap *bitmap = mddev->bitmap;
2084         int behind_wait = 0;
2085
2086         /* wait for behind writes to complete */
2087         while (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2088                 behind_wait++;
2089                 printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), behind_wait);
2090                 set_current_state(TASK_UNINTERRUPTIBLE);
2091                 schedule_timeout(HZ); /* wait a second */
2092                 /* need to kick something here to make sure I/O goes? */
2093         }
2094
2095         md_unregister_thread(mddev->thread);
2096         mddev->thread = NULL;
2097         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2098         if (conf->r1bio_pool)
2099                 mempool_destroy(conf->r1bio_pool);
2100         kfree(conf->mirrors);
2101         kfree(conf->poolinfo);
2102         kfree(conf);
2103         mddev->private = NULL;
2104         return 0;
2105 }
2106
2107 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2108 {
2109         /* no resync is happening, and there is enough space
2110          * on all devices, so we can resize.
2111          * We need to make sure resync covers any new space.
2112          * If the array is shrinking we should possibly wait until
2113          * any io in the removed space completes, but it hardly seems
2114          * worth it.
2115          */
2116         mddev->array_sectors = sectors;
2117         set_capacity(mddev->gendisk, mddev->array_sectors);
2118         mddev->changed = 1;
2119         if (mddev->array_sectors / 2 > mddev->size &&
2120             mddev->recovery_cp == MaxSector) {
2121                 mddev->recovery_cp = mddev->size << 1;
2122                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2123         }
2124         mddev->size = mddev->array_sectors / 2;
2125         mddev->resync_max_sectors = sectors;
2126         return 0;
2127 }
2128
2129 static int raid1_reshape(mddev_t *mddev)
2130 {
2131         /* We need to:
2132          * 1/ resize the r1bio_pool
2133          * 2/ resize conf->mirrors
2134          *
2135          * We allocate a new r1bio_pool if we can.
2136          * Then raise a device barrier and wait until all IO stops.
2137          * Then resize conf->mirrors and swap in the new r1bio pool.
2138          *
2139          * At the same time, we "pack" the devices so that all the missing
2140          * devices have the higher raid_disk numbers.
2141          */
2142         mempool_t *newpool, *oldpool;
2143         struct pool_info *newpoolinfo;
2144         mirror_info_t *newmirrors;
2145         conf_t *conf = mddev_to_conf(mddev);
2146         int cnt, raid_disks;
2147         unsigned long flags;
2148         int d, d2, err;
2149
2150         /* Cannot change chunk_size, layout, or level */
2151         if (mddev->chunk_size != mddev->new_chunk ||
2152             mddev->layout != mddev->new_layout ||
2153             mddev->level != mddev->new_level) {
2154                 mddev->new_chunk = mddev->chunk_size;
2155                 mddev->new_layout = mddev->layout;
2156                 mddev->new_level = mddev->level;
2157                 return -EINVAL;
2158         }
2159
2160         err = md_allow_write(mddev);
2161         if (err)
2162                 return err;
2163
2164         raid_disks = mddev->raid_disks + mddev->delta_disks;
2165
2166         if (raid_disks < conf->raid_disks) {
2167                 cnt=0;
2168                 for (d= 0; d < conf->raid_disks; d++)
2169                         if (conf->mirrors[d].rdev)
2170                                 cnt++;
2171                 if (cnt > raid_disks)
2172                         return -EBUSY;
2173         }
2174
2175         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2176         if (!newpoolinfo)
2177                 return -ENOMEM;
2178         newpoolinfo->mddev = mddev;
2179         newpoolinfo->raid_disks = raid_disks;
2180
2181         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2182                                  r1bio_pool_free, newpoolinfo);
2183         if (!newpool) {
2184                 kfree(newpoolinfo);
2185                 return -ENOMEM;
2186         }
2187         newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2188         if (!newmirrors) {
2189                 kfree(newpoolinfo);
2190                 mempool_destroy(newpool);
2191                 return -ENOMEM;
2192         }
2193
2194         raise_barrier(conf);
2195
2196         /* ok, everything is stopped */
2197         oldpool = conf->r1bio_pool;
2198         conf->r1bio_pool = newpool;
2199
2200         for (d = d2 = 0; d < conf->raid_disks; d++) {
2201                 mdk_rdev_t *rdev = conf->mirrors[d].rdev;
2202                 if (rdev && rdev->raid_disk != d2) {
2203                         char nm[20];
2204                         sprintf(nm, "rd%d", rdev->raid_disk);
2205                         sysfs_remove_link(&mddev->kobj, nm);
2206                         rdev->raid_disk = d2;
2207                         sprintf(nm, "rd%d", rdev->raid_disk);
2208                         sysfs_remove_link(&mddev->kobj, nm);
2209                         if (sysfs_create_link(&mddev->kobj,
2210                                               &rdev->kobj, nm))
2211                                 printk(KERN_WARNING
2212                                        "md/raid1: cannot register "
2213                                        "%s for %s\n",
2214                                        nm, mdname(mddev));
2215                 }
2216                 if (rdev)
2217                         newmirrors[d2++].rdev = rdev;
2218         }
2219         kfree(conf->mirrors);
2220         conf->mirrors = newmirrors;
2221         kfree(conf->poolinfo);
2222         conf->poolinfo = newpoolinfo;
2223
2224         spin_lock_irqsave(&conf->device_lock, flags);
2225         mddev->degraded += (raid_disks - conf->raid_disks);
2226         spin_unlock_irqrestore(&conf->device_lock, flags);
2227         conf->raid_disks = mddev->raid_disks = raid_disks;
2228         mddev->delta_disks = 0;
2229
2230         conf->last_used = 0; /* just make sure it is in-range */
2231         lower_barrier(conf);
2232
2233         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2234         md_wakeup_thread(mddev->thread);
2235
2236         mempool_destroy(oldpool);
2237         return 0;
2238 }
2239
2240 static void raid1_quiesce(mddev_t *mddev, int state)
2241 {
2242         conf_t *conf = mddev_to_conf(mddev);
2243
2244         switch(state) {
2245         case 1:
2246                 raise_barrier(conf);
2247                 break;
2248         case 0:
2249                 lower_barrier(conf);
2250                 break;
2251         }
2252 }
2253
2254
2255 static struct mdk_personality raid1_personality =
2256 {
2257         .name           = "raid1",
2258         .level          = 1,
2259         .owner          = THIS_MODULE,
2260         .make_request   = make_request,
2261         .run            = run,
2262         .stop           = stop,
2263         .status         = status,
2264         .error_handler  = error,
2265         .hot_add_disk   = raid1_add_disk,
2266         .hot_remove_disk= raid1_remove_disk,
2267         .spare_active   = raid1_spare_active,
2268         .sync_request   = sync_request,
2269         .resize         = raid1_resize,
2270         .check_reshape  = raid1_reshape,
2271         .quiesce        = raid1_quiesce,
2272 };
2273
2274 static int __init raid_init(void)
2275 {
2276         return register_md_personality(&raid1_personality);
2277 }
2278
2279 static void raid_exit(void)
2280 {
2281         unregister_md_personality(&raid1_personality);
2282 }
2283
2284 module_init(raid_init);
2285 module_exit(raid_exit);
2286 MODULE_LICENSE("GPL");
2287 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2288 MODULE_ALIAS("md-raid1");
2289 MODULE_ALIAS("md-level-1");