Root/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 Østergaard" <jakob@ostenfeld.dk>
13 * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
14 *
15 * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
16 * bitmapped intelligence in resync:
17 *
18 * - bitmap marked during normal i/o
19 * - bitmap used to skip nondirty blocks during sync
20 *
21 * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
22 * - persistent bitmap code
23 *
24 * This program is free software; you can redistribute it and/or modify
25 * it under the terms of the GNU General Public License as published by
26 * the Free Software Foundation; either version 2, or (at your option)
27 * any later version.
28 *
29 * You should have received a copy of the GNU General Public License
30 * (for example /usr/src/linux/COPYING); if not, write to the Free
31 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
32 */
33
34#include <linux/slab.h>
35#include <linux/delay.h>
36#include <linux/blkdev.h>
37#include <linux/module.h>
38#include <linux/seq_file.h>
39#include <linux/ratelimit.h>
40#include "md.h"
41#include "raid1.h"
42#include "bitmap.h"
43
44/*
45 * Number of guaranteed r1bios in case of extreme VM load:
46 */
47#define NR_RAID1_BIOS 256
48
49/* when we get a read error on a read-only array, we redirect to another
50 * device without failing the first device, or trying to over-write to
51 * correct the read error. To keep track of bad blocks on a per-bio
52 * level, we store IO_BLOCKED in the appropriate 'bios' pointer
53 */
54#define IO_BLOCKED ((struct bio *)1)
55/* When we successfully write to a known bad-block, we need to remove the
56 * bad-block marking which must be done from process context. So we record
57 * the success by setting devs[n].bio to IO_MADE_GOOD
58 */
59#define IO_MADE_GOOD ((struct bio *)2)
60
61#define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
62
63/* When there are this many requests queue to be written by
64 * the raid1 thread, we become 'congested' to provide back-pressure
65 * for writeback.
66 */
67static int max_queued_requests = 1024;
68
69static void allow_barrier(struct r1conf *conf);
70static void lower_barrier(struct r1conf *conf);
71
72static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
73{
74    struct pool_info *pi = data;
75    int size = offsetof(struct r1bio, bios[pi->raid_disks]);
76
77    /* allocate a r1bio with room for raid_disks entries in the bios array */
78    return kzalloc(size, gfp_flags);
79}
80
81static void r1bio_pool_free(void *r1_bio, void *data)
82{
83    kfree(r1_bio);
84}
85
86#define RESYNC_BLOCK_SIZE (64*1024)
87//#define RESYNC_BLOCK_SIZE PAGE_SIZE
88#define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
89#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
90#define RESYNC_WINDOW (2048*1024)
91
92static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
93{
94    struct pool_info *pi = data;
95    struct page *page;
96    struct r1bio *r1_bio;
97    struct bio *bio;
98    int i, j;
99
100    r1_bio = r1bio_pool_alloc(gfp_flags, pi);
101    if (!r1_bio)
102        return NULL;
103
104    /*
105     * Allocate bios : 1 for reading, n-1 for writing
106     */
107    for (j = pi->raid_disks ; j-- ; ) {
108        bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
109        if (!bio)
110            goto out_free_bio;
111        r1_bio->bios[j] = bio;
112    }
113    /*
114     * Allocate RESYNC_PAGES data pages and attach them to
115     * the first bio.
116     * If this is a user-requested check/repair, allocate
117     * RESYNC_PAGES for each bio.
118     */
119    if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
120        j = pi->raid_disks;
121    else
122        j = 1;
123    while(j--) {
124        bio = r1_bio->bios[j];
125        for (i = 0; i < RESYNC_PAGES; i++) {
126            page = alloc_page(gfp_flags);
127            if (unlikely(!page))
128                goto out_free_pages;
129
130            bio->bi_io_vec[i].bv_page = page;
131            bio->bi_vcnt = i+1;
132        }
133    }
134    /* If not user-requests, copy the page pointers to all bios */
135    if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
136        for (i=0; i<RESYNC_PAGES ; i++)
137            for (j=1; j<pi->raid_disks; j++)
138                r1_bio->bios[j]->bi_io_vec[i].bv_page =
139                    r1_bio->bios[0]->bi_io_vec[i].bv_page;
140    }
141
142    r1_bio->master_bio = NULL;
143
144    return r1_bio;
145
146out_free_pages:
147    for (j=0 ; j < pi->raid_disks; j++)
148        for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
149            put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
150    j = -1;
151out_free_bio:
152    while (++j < pi->raid_disks)
153        bio_put(r1_bio->bios[j]);
154    r1bio_pool_free(r1_bio, data);
155    return NULL;
156}
157
158static void r1buf_pool_free(void *__r1_bio, void *data)
159{
160    struct pool_info *pi = data;
161    int i,j;
162    struct r1bio *r1bio = __r1_bio;
163
164    for (i = 0; i < RESYNC_PAGES; i++)
165        for (j = pi->raid_disks; j-- ;) {
166            if (j == 0 ||
167                r1bio->bios[j]->bi_io_vec[i].bv_page !=
168                r1bio->bios[0]->bi_io_vec[i].bv_page)
169                safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
170        }
171    for (i=0 ; i < pi->raid_disks; i++)
172        bio_put(r1bio->bios[i]);
173
174    r1bio_pool_free(r1bio, data);
175}
176
177static void put_all_bios(struct r1conf *conf, struct r1bio *r1_bio)
178{
179    int i;
180
181    for (i = 0; i < conf->raid_disks * 2; i++) {
182        struct bio **bio = r1_bio->bios + i;
183        if (!BIO_SPECIAL(*bio))
184            bio_put(*bio);
185        *bio = NULL;
186    }
187}
188
189static void free_r1bio(struct r1bio *r1_bio)
190{
191    struct r1conf *conf = r1_bio->mddev->private;
192
193    put_all_bios(conf, r1_bio);
194    mempool_free(r1_bio, conf->r1bio_pool);
195}
196
197static void put_buf(struct r1bio *r1_bio)
198{
199    struct r1conf *conf = r1_bio->mddev->private;
200    int i;
201
202    for (i = 0; i < conf->raid_disks * 2; 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
213static void reschedule_retry(struct r1bio *r1_bio)
214{
215    unsigned long flags;
216    struct mddev *mddev = r1_bio->mddev;
217    struct r1conf *conf = mddev->private;
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 */
233static void call_bio_endio(struct r1bio *r1_bio)
234{
235    struct bio *bio = r1_bio->master_bio;
236    int done;
237    struct r1conf *conf = r1_bio->mddev->private;
238
239    if (bio->bi_phys_segments) {
240        unsigned long flags;
241        spin_lock_irqsave(&conf->device_lock, flags);
242        bio->bi_phys_segments--;
243        done = (bio->bi_phys_segments == 0);
244        spin_unlock_irqrestore(&conf->device_lock, flags);
245    } else
246        done = 1;
247
248    if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
249        clear_bit(BIO_UPTODATE, &bio->bi_flags);
250    if (done) {
251        bio_endio(bio, 0);
252        /*
253         * Wake up any possible resync thread that waits for the device
254         * to go idle.
255         */
256        allow_barrier(conf);
257    }
258}
259
260static void raid_end_bio_io(struct r1bio *r1_bio)
261{
262    struct bio *bio = r1_bio->master_bio;
263
264    /* if nobody has done the final endio yet, do it now */
265    if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
266        pr_debug("raid1: sync end %s on sectors %llu-%llu\n",
267             (bio_data_dir(bio) == WRITE) ? "write" : "read",
268             (unsigned long long) bio->bi_sector,
269             (unsigned long long) bio->bi_sector +
270             (bio->bi_size >> 9) - 1);
271
272        call_bio_endio(r1_bio);
273    }
274    free_r1bio(r1_bio);
275}
276
277/*
278 * Update disk head position estimator based on IRQ completion info.
279 */
280static inline void update_head_pos(int disk, struct r1bio *r1_bio)
281{
282    struct r1conf *conf = r1_bio->mddev->private;
283
284    conf->mirrors[disk].head_position =
285        r1_bio->sector + (r1_bio->sectors);
286}
287
288/*
289 * Find the disk number which triggered given bio
290 */
291static int find_bio_disk(struct r1bio *r1_bio, struct bio *bio)
292{
293    int mirror;
294    struct r1conf *conf = r1_bio->mddev->private;
295    int raid_disks = conf->raid_disks;
296
297    for (mirror = 0; mirror < raid_disks * 2; mirror++)
298        if (r1_bio->bios[mirror] == bio)
299            break;
300
301    BUG_ON(mirror == raid_disks * 2);
302    update_head_pos(mirror, r1_bio);
303
304    return mirror;
305}
306
307static void raid1_end_read_request(struct bio *bio, int error)
308{
309    int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
310    struct r1bio *r1_bio = bio->bi_private;
311    int mirror;
312    struct r1conf *conf = r1_bio->mddev->private;
313
314    mirror = r1_bio->read_disk;
315    /*
316     * this branch is our 'one mirror IO has finished' event handler:
317     */
318    update_head_pos(mirror, r1_bio);
319
320    if (uptodate)
321        set_bit(R1BIO_Uptodate, &r1_bio->state);
322    else {
323        /* If all other devices have failed, we want to return
324         * the error upwards rather than fail the last device.
325         * Here we redefine "uptodate" to mean "Don't want to retry"
326         */
327        unsigned long flags;
328        spin_lock_irqsave(&conf->device_lock, flags);
329        if (r1_bio->mddev->degraded == conf->raid_disks ||
330            (r1_bio->mddev->degraded == conf->raid_disks-1 &&
331             !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
332            uptodate = 1;
333        spin_unlock_irqrestore(&conf->device_lock, flags);
334    }
335
336    if (uptodate)
337        raid_end_bio_io(r1_bio);
338    else {
339        /*
340         * oops, read error:
341         */
342        char b[BDEVNAME_SIZE];
343        printk_ratelimited(
344            KERN_ERR "md/raid1:%s: %s: "
345            "rescheduling sector %llu\n",
346            mdname(conf->mddev),
347            bdevname(conf->mirrors[mirror].rdev->bdev,
348                 b),
349            (unsigned long long)r1_bio->sector);
350        set_bit(R1BIO_ReadError, &r1_bio->state);
351        reschedule_retry(r1_bio);
352    }
353
354    rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
355}
356
357static void close_write(struct r1bio *r1_bio)
358{
359    /* it really is the end of this request */
360    if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
361        /* free extra copy of the data pages */
362        int i = r1_bio->behind_page_count;
363        while (i--)
364            safe_put_page(r1_bio->behind_bvecs[i].bv_page);
365        kfree(r1_bio->behind_bvecs);
366        r1_bio->behind_bvecs = NULL;
367    }
368    /* clear the bitmap if all writes complete successfully */
369    bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
370            r1_bio->sectors,
371            !test_bit(R1BIO_Degraded, &r1_bio->state),
372            test_bit(R1BIO_BehindIO, &r1_bio->state));
373    md_write_end(r1_bio->mddev);
374}
375
376static void r1_bio_write_done(struct r1bio *r1_bio)
377{
378    if (!atomic_dec_and_test(&r1_bio->remaining))
379        return;
380
381    if (test_bit(R1BIO_WriteError, &r1_bio->state))
382        reschedule_retry(r1_bio);
383    else {
384        close_write(r1_bio);
385        if (test_bit(R1BIO_MadeGood, &r1_bio->state))
386            reschedule_retry(r1_bio);
387        else
388            raid_end_bio_io(r1_bio);
389    }
390}
391
392static void raid1_end_write_request(struct bio *bio, int error)
393{
394    int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
395    struct r1bio *r1_bio = bio->bi_private;
396    int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
397    struct r1conf *conf = r1_bio->mddev->private;
398    struct bio *to_put = NULL;
399
400    mirror = find_bio_disk(r1_bio, bio);
401
402    /*
403     * 'one mirror IO has finished' event handler:
404     */
405    if (!uptodate) {
406        set_bit(WriteErrorSeen,
407            &conf->mirrors[mirror].rdev->flags);
408        if (!test_and_set_bit(WantReplacement,
409                      &conf->mirrors[mirror].rdev->flags))
410            set_bit(MD_RECOVERY_NEEDED, &
411                conf->mddev->recovery);
412
413        set_bit(R1BIO_WriteError, &r1_bio->state);
414    } else {
415        /*
416         * Set R1BIO_Uptodate in our master bio, so that we
417         * will return a good error code for to the higher
418         * levels even if IO on some other mirrored buffer
419         * fails.
420         *
421         * The 'master' represents the composite IO operation
422         * to user-side. So if something waits for IO, then it
423         * will wait for the 'master' bio.
424         */
425        sector_t first_bad;
426        int bad_sectors;
427
428        r1_bio->bios[mirror] = NULL;
429        to_put = bio;
430        set_bit(R1BIO_Uptodate, &r1_bio->state);
431
432        /* Maybe we can clear some bad blocks. */
433        if (is_badblock(conf->mirrors[mirror].rdev,
434                r1_bio->sector, r1_bio->sectors,
435                &first_bad, &bad_sectors)) {
436            r1_bio->bios[mirror] = IO_MADE_GOOD;
437            set_bit(R1BIO_MadeGood, &r1_bio->state);
438        }
439    }
440
441    if (behind) {
442        if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
443            atomic_dec(&r1_bio->behind_remaining);
444
445        /*
446         * In behind mode, we ACK the master bio once the I/O
447         * has safely reached all non-writemostly
448         * disks. Setting the Returned bit ensures that this
449         * gets done only once -- we don't ever want to return
450         * -EIO here, instead we'll wait
451         */
452        if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
453            test_bit(R1BIO_Uptodate, &r1_bio->state)) {
454            /* Maybe we can return now */
455            if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
456                struct bio *mbio = r1_bio->master_bio;
457                pr_debug("raid1: behind end write sectors"
458                     " %llu-%llu\n",
459                     (unsigned long long) mbio->bi_sector,
460                     (unsigned long long) mbio->bi_sector +
461                     (mbio->bi_size >> 9) - 1);
462                call_bio_endio(r1_bio);
463            }
464        }
465    }
466    if (r1_bio->bios[mirror] == NULL)
467        rdev_dec_pending(conf->mirrors[mirror].rdev,
468                 conf->mddev);
469
470    /*
471     * Let's see if all mirrored write operations have finished
472     * already.
473     */
474    r1_bio_write_done(r1_bio);
475
476    if (to_put)
477        bio_put(to_put);
478}
479
480
481/*
482 * This routine returns the disk from which the requested read should
483 * be done. There is a per-array 'next expected sequential IO' sector
484 * number - if this matches on the next IO then we use the last disk.
485 * There is also a per-disk 'last know head position' sector that is
486 * maintained from IRQ contexts, both the normal and the resync IO
487 * completion handlers update this position correctly. If there is no
488 * perfect sequential match then we pick the disk whose head is closest.
489 *
490 * If there are 2 mirrors in the same 2 devices, performance degrades
491 * because position is mirror, not device based.
492 *
493 * The rdev for the device selected will have nr_pending incremented.
494 */
495static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sectors)
496{
497    const sector_t this_sector = r1_bio->sector;
498    int sectors;
499    int best_good_sectors;
500    int best_disk, best_dist_disk, best_pending_disk;
501    int has_nonrot_disk;
502    int disk;
503    sector_t best_dist;
504    unsigned int min_pending;
505    struct md_rdev *rdev;
506    int choose_first;
507    int choose_next_idle;
508
509    rcu_read_lock();
510    /*
511     * Check if we can balance. We can balance on the whole
512     * device if no resync is going on, or below the resync window.
513     * We take the first readable disk when above the resync window.
514     */
515 retry:
516    sectors = r1_bio->sectors;
517    best_disk = -1;
518    best_dist_disk = -1;
519    best_dist = MaxSector;
520    best_pending_disk = -1;
521    min_pending = UINT_MAX;
522    best_good_sectors = 0;
523    has_nonrot_disk = 0;
524    choose_next_idle = 0;
525
526    if (conf->mddev->recovery_cp < MaxSector &&
527        (this_sector + sectors >= conf->next_resync))
528        choose_first = 1;
529    else
530        choose_first = 0;
531
532    for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
533        sector_t dist;
534        sector_t first_bad;
535        int bad_sectors;
536        unsigned int pending;
537        bool nonrot;
538
539        rdev = rcu_dereference(conf->mirrors[disk].rdev);
540        if (r1_bio->bios[disk] == IO_BLOCKED
541            || rdev == NULL
542            || test_bit(Unmerged, &rdev->flags)
543            || test_bit(Faulty, &rdev->flags))
544            continue;
545        if (!test_bit(In_sync, &rdev->flags) &&
546            rdev->recovery_offset < this_sector + sectors)
547            continue;
548        if (test_bit(WriteMostly, &rdev->flags)) {
549            /* Don't balance among write-mostly, just
550             * use the first as a last resort */
551            if (best_disk < 0) {
552                if (is_badblock(rdev, this_sector, sectors,
553                        &first_bad, &bad_sectors)) {
554                    if (first_bad < this_sector)
555                        /* Cannot use this */
556                        continue;
557                    best_good_sectors = first_bad - this_sector;
558                } else
559                    best_good_sectors = sectors;
560                best_disk = disk;
561            }
562            continue;
563        }
564        /* This is a reasonable device to use. It might
565         * even be best.
566         */
567        if (is_badblock(rdev, this_sector, sectors,
568                &first_bad, &bad_sectors)) {
569            if (best_dist < MaxSector)
570                /* already have a better device */
571                continue;
572            if (first_bad <= this_sector) {
573                /* cannot read here. If this is the 'primary'
574                 * device, then we must not read beyond
575                 * bad_sectors from another device..
576                 */
577                bad_sectors -= (this_sector - first_bad);
578                if (choose_first && sectors > bad_sectors)
579                    sectors = bad_sectors;
580                if (best_good_sectors > sectors)
581                    best_good_sectors = sectors;
582
583            } else {
584                sector_t good_sectors = first_bad - this_sector;
585                if (good_sectors > best_good_sectors) {
586                    best_good_sectors = good_sectors;
587                    best_disk = disk;
588                }
589                if (choose_first)
590                    break;
591            }
592            continue;
593        } else
594            best_good_sectors = sectors;
595
596        nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev));
597        has_nonrot_disk |= nonrot;
598        pending = atomic_read(&rdev->nr_pending);
599        dist = abs(this_sector - conf->mirrors[disk].head_position);
600        if (choose_first) {
601            best_disk = disk;
602            break;
603        }
604        /* Don't change to another disk for sequential reads */
605        if (conf->mirrors[disk].next_seq_sect == this_sector
606            || dist == 0) {
607            int opt_iosize = bdev_io_opt(rdev->bdev) >> 9;
608            struct raid1_info *mirror = &conf->mirrors[disk];
609
610            best_disk = disk;
611            /*
612             * If buffered sequential IO size exceeds optimal
613             * iosize, check if there is idle disk. If yes, choose
614             * the idle disk. read_balance could already choose an
615             * idle disk before noticing it's a sequential IO in
616             * this disk. This doesn't matter because this disk
617             * will idle, next time it will be utilized after the
618             * first disk has IO size exceeds optimal iosize. In
619             * this way, iosize of the first disk will be optimal
620             * iosize at least. iosize of the second disk might be
621             * small, but not a big deal since when the second disk
622             * starts IO, the first disk is likely still busy.
623             */
624            if (nonrot && opt_iosize > 0 &&
625                mirror->seq_start != MaxSector &&
626                mirror->next_seq_sect > opt_iosize &&
627                mirror->next_seq_sect - opt_iosize >=
628                mirror->seq_start) {
629                choose_next_idle = 1;
630                continue;
631            }
632            break;
633        }
634        /* If device is idle, use it */
635        if (pending == 0) {
636            best_disk = disk;
637            break;
638        }
639
640        if (choose_next_idle)
641            continue;
642
643        if (min_pending > pending) {
644            min_pending = pending;
645            best_pending_disk = disk;
646        }
647
648        if (dist < best_dist) {
649            best_dist = dist;
650            best_dist_disk = disk;
651        }
652    }
653
654    /*
655     * If all disks are rotational, choose the closest disk. If any disk is
656     * non-rotational, choose the disk with less pending request even the
657     * disk is rotational, which might/might not be optimal for raids with
658     * mixed ratation/non-rotational disks depending on workload.
659     */
660    if (best_disk == -1) {
661        if (has_nonrot_disk)
662            best_disk = best_pending_disk;
663        else
664            best_disk = best_dist_disk;
665    }
666
667    if (best_disk >= 0) {
668        rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
669        if (!rdev)
670            goto retry;
671        atomic_inc(&rdev->nr_pending);
672        if (test_bit(Faulty, &rdev->flags)) {
673            /* cannot risk returning a device that failed
674             * before we inc'ed nr_pending
675             */
676            rdev_dec_pending(rdev, conf->mddev);
677            goto retry;
678        }
679        sectors = best_good_sectors;
680
681        if (conf->mirrors[best_disk].next_seq_sect != this_sector)
682            conf->mirrors[best_disk].seq_start = this_sector;
683
684        conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
685    }
686    rcu_read_unlock();
687    *max_sectors = sectors;
688
689    return best_disk;
690}
691
692static int raid1_mergeable_bvec(struct request_queue *q,
693                struct bvec_merge_data *bvm,
694                struct bio_vec *biovec)
695{
696    struct mddev *mddev = q->queuedata;
697    struct r1conf *conf = mddev->private;
698    sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
699    int max = biovec->bv_len;
700
701    if (mddev->merge_check_needed) {
702        int disk;
703        rcu_read_lock();
704        for (disk = 0; disk < conf->raid_disks * 2; disk++) {
705            struct md_rdev *rdev = rcu_dereference(
706                conf->mirrors[disk].rdev);
707            if (rdev && !test_bit(Faulty, &rdev->flags)) {
708                struct request_queue *q =
709                    bdev_get_queue(rdev->bdev);
710                if (q->merge_bvec_fn) {
711                    bvm->bi_sector = sector +
712                        rdev->data_offset;
713                    bvm->bi_bdev = rdev->bdev;
714                    max = min(max, q->merge_bvec_fn(
715                              q, bvm, biovec));
716                }
717            }
718        }
719        rcu_read_unlock();
720    }
721    return max;
722
723}
724
725int md_raid1_congested(struct mddev *mddev, int bits)
726{
727    struct r1conf *conf = mddev->private;
728    int i, ret = 0;
729
730    if ((bits & (1 << BDI_async_congested)) &&
731        conf->pending_count >= max_queued_requests)
732        return 1;
733
734    rcu_read_lock();
735    for (i = 0; i < conf->raid_disks * 2; i++) {
736        struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
737        if (rdev && !test_bit(Faulty, &rdev->flags)) {
738            struct request_queue *q = bdev_get_queue(rdev->bdev);
739
740            BUG_ON(!q);
741
742            /* Note the '|| 1' - when read_balance prefers
743             * non-congested targets, it can be removed
744             */
745            if ((bits & (1<<BDI_async_congested)) || 1)
746                ret |= bdi_congested(&q->backing_dev_info, bits);
747            else
748                ret &= bdi_congested(&q->backing_dev_info, bits);
749        }
750    }
751    rcu_read_unlock();
752    return ret;
753}
754EXPORT_SYMBOL_GPL(md_raid1_congested);
755
756static int raid1_congested(void *data, int bits)
757{
758    struct mddev *mddev = data;
759
760    return mddev_congested(mddev, bits) ||
761        md_raid1_congested(mddev, bits);
762}
763
764static void flush_pending_writes(struct r1conf *conf)
765{
766    /* Any writes that have been queued but are awaiting
767     * bitmap updates get flushed here.
768     */
769    spin_lock_irq(&conf->device_lock);
770
771    if (conf->pending_bio_list.head) {
772        struct bio *bio;
773        bio = bio_list_get(&conf->pending_bio_list);
774        conf->pending_count = 0;
775        spin_unlock_irq(&conf->device_lock);
776        /* flush any pending bitmap writes to
777         * disk before proceeding w/ I/O */
778        bitmap_unplug(conf->mddev->bitmap);
779        wake_up(&conf->wait_barrier);
780
781        while (bio) { /* submit pending writes */
782            struct bio *next = bio->bi_next;
783            bio->bi_next = NULL;
784            generic_make_request(bio);
785            bio = next;
786        }
787    } else
788        spin_unlock_irq(&conf->device_lock);
789}
790
791/* Barriers....
792 * Sometimes we need to suspend IO while we do something else,
793 * either some resync/recovery, or reconfigure the array.
794 * To do this we raise a 'barrier'.
795 * The 'barrier' is a counter that can be raised multiple times
796 * to count how many activities are happening which preclude
797 * normal IO.
798 * We can only raise the barrier if there is no pending IO.
799 * i.e. if nr_pending == 0.
800 * We choose only to raise the barrier if no-one is waiting for the
801 * barrier to go down. This means that as soon as an IO request
802 * is ready, no other operations which require a barrier will start
803 * until the IO request has had a chance.
804 *
805 * So: regular IO calls 'wait_barrier'. When that returns there
806 * is no backgroup IO happening, It must arrange to call
807 * allow_barrier when it has finished its IO.
808 * backgroup IO calls must call raise_barrier. Once that returns
809 * there is no normal IO happeing. It must arrange to call
810 * lower_barrier when the particular background IO completes.
811 */
812#define RESYNC_DEPTH 32
813
814static void raise_barrier(struct r1conf *conf)
815{
816    spin_lock_irq(&conf->resync_lock);
817
818    /* Wait until no block IO is waiting */
819    wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
820                conf->resync_lock, );
821
822    /* block any new IO from starting */
823    conf->barrier++;
824
825    /* Now wait for all pending IO to complete */
826    wait_event_lock_irq(conf->wait_barrier,
827                !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
828                conf->resync_lock, );
829
830    spin_unlock_irq(&conf->resync_lock);
831}
832
833static void lower_barrier(struct r1conf *conf)
834{
835    unsigned long flags;
836    BUG_ON(conf->barrier <= 0);
837    spin_lock_irqsave(&conf->resync_lock, flags);
838    conf->barrier--;
839    spin_unlock_irqrestore(&conf->resync_lock, flags);
840    wake_up(&conf->wait_barrier);
841}
842
843static void wait_barrier(struct r1conf *conf)
844{
845    spin_lock_irq(&conf->resync_lock);
846    if (conf->barrier) {
847        conf->nr_waiting++;
848        /* Wait for the barrier to drop.
849         * However if there are already pending
850         * requests (preventing the barrier from
851         * rising completely), and the
852         * pre-process bio queue isn't empty,
853         * then don't wait, as we need to empty
854         * that queue to get the nr_pending
855         * count down.
856         */
857        wait_event_lock_irq(conf->wait_barrier,
858                    !conf->barrier ||
859                    (conf->nr_pending &&
860                     current->bio_list &&
861                     !bio_list_empty(current->bio_list)),
862                    conf->resync_lock,
863            );
864        conf->nr_waiting--;
865    }
866    conf->nr_pending++;
867    spin_unlock_irq(&conf->resync_lock);
868}
869
870static void allow_barrier(struct r1conf *conf)
871{
872    unsigned long flags;
873    spin_lock_irqsave(&conf->resync_lock, flags);
874    conf->nr_pending--;
875    spin_unlock_irqrestore(&conf->resync_lock, flags);
876    wake_up(&conf->wait_barrier);
877}
878
879static void freeze_array(struct r1conf *conf)
880{
881    /* stop syncio and normal IO and wait for everything to
882     * go quite.
883     * We increment barrier and nr_waiting, and then
884     * wait until nr_pending match nr_queued+1
885     * This is called in the context of one normal IO request
886     * that has failed. Thus any sync request that might be pending
887     * will be blocked by nr_pending, and we need to wait for
888     * pending IO requests to complete or be queued for re-try.
889     * Thus the number queued (nr_queued) plus this request (1)
890     * must match the number of pending IOs (nr_pending) before
891     * we continue.
892     */
893    spin_lock_irq(&conf->resync_lock);
894    conf->barrier++;
895    conf->nr_waiting++;
896    wait_event_lock_irq(conf->wait_barrier,
897                conf->nr_pending == conf->nr_queued+1,
898                conf->resync_lock,
899                flush_pending_writes(conf));
900    spin_unlock_irq(&conf->resync_lock);
901}
902static void unfreeze_array(struct r1conf *conf)
903{
904    /* reverse the effect of the freeze */
905    spin_lock_irq(&conf->resync_lock);
906    conf->barrier--;
907    conf->nr_waiting--;
908    wake_up(&conf->wait_barrier);
909    spin_unlock_irq(&conf->resync_lock);
910}
911
912
913/* duplicate the data pages for behind I/O
914 */
915static void alloc_behind_pages(struct bio *bio, struct r1bio *r1_bio)
916{
917    int i;
918    struct bio_vec *bvec;
919    struct bio_vec *bvecs = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
920                    GFP_NOIO);
921    if (unlikely(!bvecs))
922        return;
923
924    bio_for_each_segment(bvec, bio, i) {
925        bvecs[i] = *bvec;
926        bvecs[i].bv_page = alloc_page(GFP_NOIO);
927        if (unlikely(!bvecs[i].bv_page))
928            goto do_sync_io;
929        memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,
930               kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
931        kunmap(bvecs[i].bv_page);
932        kunmap(bvec->bv_page);
933    }
934    r1_bio->behind_bvecs = bvecs;
935    r1_bio->behind_page_count = bio->bi_vcnt;
936    set_bit(R1BIO_BehindIO, &r1_bio->state);
937    return;
938
939do_sync_io:
940    for (i = 0; i < bio->bi_vcnt; i++)
941        if (bvecs[i].bv_page)
942            put_page(bvecs[i].bv_page);
943    kfree(bvecs);
944    pr_debug("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
945}
946
947struct raid1_plug_cb {
948    struct blk_plug_cb cb;
949    struct bio_list pending;
950    int pending_cnt;
951};
952
953static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
954{
955    struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb,
956                          cb);
957    struct mddev *mddev = plug->cb.data;
958    struct r1conf *conf = mddev->private;
959    struct bio *bio;
960
961    if (from_schedule) {
962        spin_lock_irq(&conf->device_lock);
963        bio_list_merge(&conf->pending_bio_list, &plug->pending);
964        conf->pending_count += plug->pending_cnt;
965        spin_unlock_irq(&conf->device_lock);
966        md_wakeup_thread(mddev->thread);
967        kfree(plug);
968        return;
969    }
970
971    /* we aren't scheduling, so we can do the write-out directly. */
972    bio = bio_list_get(&plug->pending);
973    bitmap_unplug(mddev->bitmap);
974    wake_up(&conf->wait_barrier);
975
976    while (bio) { /* submit pending writes */
977        struct bio *next = bio->bi_next;
978        bio->bi_next = NULL;
979        generic_make_request(bio);
980        bio = next;
981    }
982    kfree(plug);
983}
984
985static void make_request(struct mddev *mddev, struct bio * bio)
986{
987    struct r1conf *conf = mddev->private;
988    struct raid1_info *mirror;
989    struct r1bio *r1_bio;
990    struct bio *read_bio;
991    int i, disks;
992    struct bitmap *bitmap;
993    unsigned long flags;
994    const int rw = bio_data_dir(bio);
995    const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
996    const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
997    struct md_rdev *blocked_rdev;
998    struct blk_plug_cb *cb;
999    struct raid1_plug_cb *plug = NULL;
1000    int first_clone;
1001    int sectors_handled;
1002    int max_sectors;
1003
1004    /*
1005     * Register the new request and wait if the reconstruction
1006     * thread has put up a bar for new requests.
1007     * Continue immediately if no resync is active currently.
1008     */
1009
1010    md_write_start(mddev, bio); /* wait on superblock update early */
1011
1012    if (bio_data_dir(bio) == WRITE &&
1013        bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
1014        bio->bi_sector < mddev->suspend_hi) {
1015        /* As the suspend_* range is controlled by
1016         * userspace, we want an interruptible
1017         * wait.
1018         */
1019        DEFINE_WAIT(w);
1020        for (;;) {
1021            flush_signals(current);
1022            prepare_to_wait(&conf->wait_barrier,
1023                    &w, TASK_INTERRUPTIBLE);
1024            if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
1025                bio->bi_sector >= mddev->suspend_hi)
1026                break;
1027            schedule();
1028        }
1029        finish_wait(&conf->wait_barrier, &w);
1030    }
1031
1032    wait_barrier(conf);
1033
1034    bitmap = mddev->bitmap;
1035
1036    /*
1037     * make_request() can abort the operation when READA is being
1038     * used and no empty request is available.
1039     *
1040     */
1041    r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1042
1043    r1_bio->master_bio = bio;
1044    r1_bio->sectors = bio->bi_size >> 9;
1045    r1_bio->state = 0;
1046    r1_bio->mddev = mddev;
1047    r1_bio->sector = bio->bi_sector;
1048
1049    /* We might need to issue multiple reads to different
1050     * devices if there are bad blocks around, so we keep
1051     * track of the number of reads in bio->bi_phys_segments.
1052     * If this is 0, there is only one r1_bio and no locking
1053     * will be needed when requests complete. If it is
1054     * non-zero, then it is the number of not-completed requests.
1055     */
1056    bio->bi_phys_segments = 0;
1057    clear_bit(BIO_SEG_VALID, &bio->bi_flags);
1058
1059    if (rw == READ) {
1060        /*
1061         * read balancing logic:
1062         */
1063        int rdisk;
1064
1065read_again:
1066        rdisk = read_balance(conf, r1_bio, &max_sectors);
1067
1068        if (rdisk < 0) {
1069            /* couldn't find anywhere to read from */
1070            raid_end_bio_io(r1_bio);
1071            return;
1072        }
1073        mirror = conf->mirrors + rdisk;
1074
1075        if (test_bit(WriteMostly, &mirror->rdev->flags) &&
1076            bitmap) {
1077            /* Reading from a write-mostly device must
1078             * take care not to over-take any writes
1079             * that are 'behind'
1080             */
1081            wait_event(bitmap->behind_wait,
1082                   atomic_read(&bitmap->behind_writes) == 0);
1083        }
1084        r1_bio->read_disk = rdisk;
1085
1086        read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1087        md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
1088                max_sectors);
1089
1090        r1_bio->bios[rdisk] = read_bio;
1091
1092        read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
1093        read_bio->bi_bdev = mirror->rdev->bdev;
1094        read_bio->bi_end_io = raid1_end_read_request;
1095        read_bio->bi_rw = READ | do_sync;
1096        read_bio->bi_private = r1_bio;
1097
1098        if (max_sectors < r1_bio->sectors) {
1099            /* could not read all from this device, so we will
1100             * need another r1_bio.
1101             */
1102
1103            sectors_handled = (r1_bio->sector + max_sectors
1104                       - bio->bi_sector);
1105            r1_bio->sectors = max_sectors;
1106            spin_lock_irq(&conf->device_lock);
1107            if (bio->bi_phys_segments == 0)
1108                bio->bi_phys_segments = 2;
1109            else
1110                bio->bi_phys_segments++;
1111            spin_unlock_irq(&conf->device_lock);
1112            /* Cannot call generic_make_request directly
1113             * as that will be queued in __make_request
1114             * and subsequent mempool_alloc might block waiting
1115             * for it. So hand bio over to raid1d.
1116             */
1117            reschedule_retry(r1_bio);
1118
1119            r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1120
1121            r1_bio->master_bio = bio;
1122            r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1123            r1_bio->state = 0;
1124            r1_bio->mddev = mddev;
1125            r1_bio->sector = bio->bi_sector + sectors_handled;
1126            goto read_again;
1127        } else
1128            generic_make_request(read_bio);
1129        return;
1130    }
1131
1132    /*
1133     * WRITE:
1134     */
1135    if (conf->pending_count >= max_queued_requests) {
1136        md_wakeup_thread(mddev->thread);
1137        wait_event(conf->wait_barrier,
1138               conf->pending_count < max_queued_requests);
1139    }
1140    /* first select target devices under rcu_lock and
1141     * inc refcount on their rdev. Record them by setting
1142     * bios[x] to bio
1143     * If there are known/acknowledged bad blocks on any device on
1144     * which we have seen a write error, we want to avoid writing those
1145     * blocks.
1146     * This potentially requires several writes to write around
1147     * the bad blocks. Each set of writes gets it's own r1bio
1148     * with a set of bios attached.
1149     */
1150
1151    disks = conf->raid_disks * 2;
1152 retry_write:
1153    blocked_rdev = NULL;
1154    rcu_read_lock();
1155    max_sectors = r1_bio->sectors;
1156    for (i = 0; i < disks; i++) {
1157        struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1158        if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1159            atomic_inc(&rdev->nr_pending);
1160            blocked_rdev = rdev;
1161            break;
1162        }
1163        r1_bio->bios[i] = NULL;
1164        if (!rdev || test_bit(Faulty, &rdev->flags)
1165            || test_bit(Unmerged, &rdev->flags)) {
1166            if (i < conf->raid_disks)
1167                set_bit(R1BIO_Degraded, &r1_bio->state);
1168            continue;
1169        }
1170
1171        atomic_inc(&rdev->nr_pending);
1172        if (test_bit(WriteErrorSeen, &rdev->flags)) {
1173            sector_t first_bad;
1174            int bad_sectors;
1175            int is_bad;
1176
1177            is_bad = is_badblock(rdev, r1_bio->sector,
1178                         max_sectors,
1179                         &first_bad, &bad_sectors);
1180            if (is_bad < 0) {
1181                /* mustn't write here until the bad block is
1182                 * acknowledged*/
1183                set_bit(BlockedBadBlocks, &rdev->flags);
1184                blocked_rdev = rdev;
1185                break;
1186            }
1187            if (is_bad && first_bad <= r1_bio->sector) {
1188                /* Cannot write here at all */
1189                bad_sectors -= (r1_bio->sector - first_bad);
1190                if (bad_sectors < max_sectors)
1191                    /* mustn't write more than bad_sectors
1192                     * to other devices yet
1193                     */
1194                    max_sectors = bad_sectors;
1195                rdev_dec_pending(rdev, mddev);
1196                /* We don't set R1BIO_Degraded as that
1197                 * only applies if the disk is
1198                 * missing, so it might be re-added,
1199                 * and we want to know to recover this
1200                 * chunk.
1201                 * In this case the device is here,
1202                 * and the fact that this chunk is not
1203                 * in-sync is recorded in the bad
1204                 * block log
1205                 */
1206                continue;
1207            }
1208            if (is_bad) {
1209                int good_sectors = first_bad - r1_bio->sector;
1210                if (good_sectors < max_sectors)
1211                    max_sectors = good_sectors;
1212            }
1213        }
1214        r1_bio->bios[i] = bio;
1215    }
1216    rcu_read_unlock();
1217
1218    if (unlikely(blocked_rdev)) {
1219        /* Wait for this device to become unblocked */
1220        int j;
1221
1222        for (j = 0; j < i; j++)
1223            if (r1_bio->bios[j])
1224                rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1225        r1_bio->state = 0;
1226        allow_barrier(conf);
1227        md_wait_for_blocked_rdev(blocked_rdev, mddev);
1228        wait_barrier(conf);
1229        goto retry_write;
1230    }
1231
1232    if (max_sectors < r1_bio->sectors) {
1233        /* We are splitting this write into multiple parts, so
1234         * we need to prepare for allocating another r1_bio.
1235         */
1236        r1_bio->sectors = max_sectors;
1237        spin_lock_irq(&conf->device_lock);
1238        if (bio->bi_phys_segments == 0)
1239            bio->bi_phys_segments = 2;
1240        else
1241            bio->bi_phys_segments++;
1242        spin_unlock_irq(&conf->device_lock);
1243    }
1244    sectors_handled = r1_bio->sector + max_sectors - bio->bi_sector;
1245
1246    atomic_set(&r1_bio->remaining, 1);
1247    atomic_set(&r1_bio->behind_remaining, 0);
1248
1249    first_clone = 1;
1250    for (i = 0; i < disks; i++) {
1251        struct bio *mbio;
1252        if (!r1_bio->bios[i])
1253            continue;
1254
1255        mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1256        md_trim_bio(mbio, r1_bio->sector - bio->bi_sector, max_sectors);
1257
1258        if (first_clone) {
1259            /* do behind I/O ?
1260             * Not if there are too many, or cannot
1261             * allocate memory, or a reader on WriteMostly
1262             * is waiting for behind writes to flush */
1263            if (bitmap &&
1264                (atomic_read(&bitmap->behind_writes)
1265                 < mddev->bitmap_info.max_write_behind) &&
1266                !waitqueue_active(&bitmap->behind_wait))
1267                alloc_behind_pages(mbio, r1_bio);
1268
1269            bitmap_startwrite(bitmap, r1_bio->sector,
1270                      r1_bio->sectors,
1271                      test_bit(R1BIO_BehindIO,
1272                           &r1_bio->state));
1273            first_clone = 0;
1274        }
1275        if (r1_bio->behind_bvecs) {
1276            struct bio_vec *bvec;
1277            int j;
1278
1279            /* Yes, I really want the '__' version so that
1280             * we clear any unused pointer in the io_vec, rather
1281             * than leave them unchanged. This is important
1282             * because when we come to free the pages, we won't
1283             * know the original bi_idx, so we just free
1284             * them all
1285             */
1286            __bio_for_each_segment(bvec, mbio, j, 0)
1287                bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
1288            if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
1289                atomic_inc(&r1_bio->behind_remaining);
1290        }
1291
1292        r1_bio->bios[i] = mbio;
1293
1294        mbio->bi_sector = (r1_bio->sector +
1295                   conf->mirrors[i].rdev->data_offset);
1296        mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1297        mbio->bi_end_io = raid1_end_write_request;
1298        mbio->bi_rw = WRITE | do_flush_fua | do_sync;
1299        mbio->bi_private = r1_bio;
1300
1301        atomic_inc(&r1_bio->remaining);
1302
1303        cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
1304        if (cb)
1305            plug = container_of(cb, struct raid1_plug_cb, cb);
1306        else
1307            plug = NULL;
1308        spin_lock_irqsave(&conf->device_lock, flags);
1309        if (plug) {
1310            bio_list_add(&plug->pending, mbio);
1311            plug->pending_cnt++;
1312        } else {
1313            bio_list_add(&conf->pending_bio_list, mbio);
1314            conf->pending_count++;
1315        }
1316        spin_unlock_irqrestore(&conf->device_lock, flags);
1317        if (!plug)
1318            md_wakeup_thread(mddev->thread);
1319    }
1320    /* Mustn't call r1_bio_write_done before this next test,
1321     * as it could result in the bio being freed.
1322     */
1323    if (sectors_handled < (bio->bi_size >> 9)) {
1324        r1_bio_write_done(r1_bio);
1325        /* We need another r1_bio. It has already been counted
1326         * in bio->bi_phys_segments
1327         */
1328        r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1329        r1_bio->master_bio = bio;
1330        r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1331        r1_bio->state = 0;
1332        r1_bio->mddev = mddev;
1333        r1_bio->sector = bio->bi_sector + sectors_handled;
1334        goto retry_write;
1335    }
1336
1337    r1_bio_write_done(r1_bio);
1338
1339    /* In case raid1d snuck in to freeze_array */
1340    wake_up(&conf->wait_barrier);
1341}
1342
1343static void status(struct seq_file *seq, struct mddev *mddev)
1344{
1345    struct r1conf *conf = mddev->private;
1346    int i;
1347
1348    seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1349           conf->raid_disks - mddev->degraded);
1350    rcu_read_lock();
1351    for (i = 0; i < conf->raid_disks; i++) {
1352        struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1353        seq_printf(seq, "%s",
1354               rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1355    }
1356    rcu_read_unlock();
1357    seq_printf(seq, "]");
1358}
1359
1360
1361static void error(struct mddev *mddev, struct md_rdev *rdev)
1362{
1363    char b[BDEVNAME_SIZE];
1364    struct r1conf *conf = mddev->private;
1365
1366    /*
1367     * If it is not operational, then we have already marked it as dead
1368     * else if it is the last working disks, ignore the error, let the
1369     * next level up know.
1370     * else mark the drive as failed
1371     */
1372    if (test_bit(In_sync, &rdev->flags)
1373        && (conf->raid_disks - mddev->degraded) == 1) {
1374        /*
1375         * Don't fail the drive, act as though we were just a
1376         * normal single drive.
1377         * However don't try a recovery from this drive as
1378         * it is very likely to fail.
1379         */
1380        conf->recovery_disabled = mddev->recovery_disabled;
1381        return;
1382    }
1383    set_bit(Blocked, &rdev->flags);
1384    if (test_and_clear_bit(In_sync, &rdev->flags)) {
1385        unsigned long flags;
1386        spin_lock_irqsave(&conf->device_lock, flags);
1387        mddev->degraded++;
1388        set_bit(Faulty, &rdev->flags);
1389        spin_unlock_irqrestore(&conf->device_lock, flags);
1390        /*
1391         * if recovery is running, make sure it aborts.
1392         */
1393        set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1394    } else
1395        set_bit(Faulty, &rdev->flags);
1396    set_bit(MD_CHANGE_DEVS, &mddev->flags);
1397    printk(KERN_ALERT
1398           "md/raid1:%s: Disk failure on %s, disabling device.\n"
1399           "md/raid1:%s: Operation continuing on %d devices.\n",
1400           mdname(mddev), bdevname(rdev->bdev, b),
1401           mdname(mddev), conf->raid_disks - mddev->degraded);
1402}
1403
1404static void print_conf(struct r1conf *conf)
1405{
1406    int i;
1407
1408    printk(KERN_DEBUG "RAID1 conf printout:\n");
1409    if (!conf) {
1410        printk(KERN_DEBUG "(!conf)\n");
1411        return;
1412    }
1413    printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1414        conf->raid_disks);
1415
1416    rcu_read_lock();
1417    for (i = 0; i < conf->raid_disks; i++) {
1418        char b[BDEVNAME_SIZE];
1419        struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1420        if (rdev)
1421            printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1422                   i, !test_bit(In_sync, &rdev->flags),
1423                   !test_bit(Faulty, &rdev->flags),
1424                   bdevname(rdev->bdev,b));
1425    }
1426    rcu_read_unlock();
1427}
1428
1429static void close_sync(struct r1conf *conf)
1430{
1431    wait_barrier(conf);
1432    allow_barrier(conf);
1433
1434    mempool_destroy(conf->r1buf_pool);
1435    conf->r1buf_pool = NULL;
1436}
1437
1438static int raid1_spare_active(struct mddev *mddev)
1439{
1440    int i;
1441    struct r1conf *conf = mddev->private;
1442    int count = 0;
1443    unsigned long flags;
1444
1445    /*
1446     * Find all failed disks within the RAID1 configuration
1447     * and mark them readable.
1448     * Called under mddev lock, so rcu protection not needed.
1449     */
1450    for (i = 0; i < conf->raid_disks; i++) {
1451        struct md_rdev *rdev = conf->mirrors[i].rdev;
1452        struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1453        if (repl
1454            && repl->recovery_offset == MaxSector
1455            && !test_bit(Faulty, &repl->flags)
1456            && !test_and_set_bit(In_sync, &repl->flags)) {
1457            /* replacement has just become active */
1458            if (!rdev ||
1459                !test_and_clear_bit(In_sync, &rdev->flags))
1460                count++;
1461            if (rdev) {
1462                /* Replaced device not technically
1463                 * faulty, but we need to be sure
1464                 * it gets removed and never re-added
1465                 */
1466                set_bit(Faulty, &rdev->flags);
1467                sysfs_notify_dirent_safe(
1468                    rdev->sysfs_state);
1469            }
1470        }
1471        if (rdev
1472            && !test_bit(Faulty, &rdev->flags)
1473            && !test_and_set_bit(In_sync, &rdev->flags)) {
1474            count++;
1475            sysfs_notify_dirent_safe(rdev->sysfs_state);
1476        }
1477    }
1478    spin_lock_irqsave(&conf->device_lock, flags);
1479    mddev->degraded -= count;
1480    spin_unlock_irqrestore(&conf->device_lock, flags);
1481
1482    print_conf(conf);
1483    return count;
1484}
1485
1486
1487static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1488{
1489    struct r1conf *conf = mddev->private;
1490    int err = -EEXIST;
1491    int mirror = 0;
1492    struct raid1_info *p;
1493    int first = 0;
1494    int last = conf->raid_disks - 1;
1495    struct request_queue *q = bdev_get_queue(rdev->bdev);
1496
1497    if (mddev->recovery_disabled == conf->recovery_disabled)
1498        return -EBUSY;
1499
1500    if (rdev->raid_disk >= 0)
1501        first = last = rdev->raid_disk;
1502
1503    if (q->merge_bvec_fn) {
1504        set_bit(Unmerged, &rdev->flags);
1505        mddev->merge_check_needed = 1;
1506    }
1507
1508    for (mirror = first; mirror <= last; mirror++) {
1509        p = conf->mirrors+mirror;
1510        if (!p->rdev) {
1511
1512            disk_stack_limits(mddev->gendisk, rdev->bdev,
1513                      rdev->data_offset << 9);
1514
1515            p->head_position = 0;
1516            rdev->raid_disk = mirror;
1517            err = 0;
1518            /* As all devices are equivalent, we don't need a full recovery
1519             * if this was recently any drive of the array
1520             */
1521            if (rdev->saved_raid_disk < 0)
1522                conf->fullsync = 1;
1523            rcu_assign_pointer(p->rdev, rdev);
1524            break;
1525        }
1526        if (test_bit(WantReplacement, &p->rdev->flags) &&
1527            p[conf->raid_disks].rdev == NULL) {
1528            /* Add this device as a replacement */
1529            clear_bit(In_sync, &rdev->flags);
1530            set_bit(Replacement, &rdev->flags);
1531            rdev->raid_disk = mirror;
1532            err = 0;
1533            conf->fullsync = 1;
1534            rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
1535            break;
1536        }
1537    }
1538    if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
1539        /* Some requests might not have seen this new
1540         * merge_bvec_fn. We must wait for them to complete
1541         * before merging the device fully.
1542         * First we make sure any code which has tested
1543         * our function has submitted the request, then
1544         * we wait for all outstanding requests to complete.
1545         */
1546        synchronize_sched();
1547        raise_barrier(conf);
1548        lower_barrier(conf);
1549        clear_bit(Unmerged, &rdev->flags);
1550    }
1551    md_integrity_add_rdev(rdev, mddev);
1552    print_conf(conf);
1553    return err;
1554}
1555
1556static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1557{
1558    struct r1conf *conf = mddev->private;
1559    int err = 0;
1560    int number = rdev->raid_disk;
1561    struct raid1_info *p = conf->mirrors + number;
1562
1563    if (rdev != p->rdev)
1564        p = conf->mirrors + conf->raid_disks + number;
1565
1566    print_conf(conf);
1567    if (rdev == p->rdev) {
1568        if (test_bit(In_sync, &rdev->flags) ||
1569            atomic_read(&rdev->nr_pending)) {
1570            err = -EBUSY;
1571            goto abort;
1572        }
1573        /* Only remove non-faulty devices if recovery
1574         * is not possible.
1575         */
1576        if (!test_bit(Faulty, &rdev->flags) &&
1577            mddev->recovery_disabled != conf->recovery_disabled &&
1578            mddev->degraded < conf->raid_disks) {
1579            err = -EBUSY;
1580            goto abort;
1581        }
1582        p->rdev = NULL;
1583        synchronize_rcu();
1584        if (atomic_read(&rdev->nr_pending)) {
1585            /* lost the race, try later */
1586            err = -EBUSY;
1587            p->rdev = rdev;
1588            goto abort;
1589        } else if (conf->mirrors[conf->raid_disks + number].rdev) {
1590            /* We just removed a device that is being replaced.
1591             * Move down the replacement. We drain all IO before
1592             * doing this to avoid confusion.
1593             */
1594            struct md_rdev *repl =
1595                conf->mirrors[conf->raid_disks + number].rdev;
1596            raise_barrier(conf);
1597            clear_bit(Replacement, &repl->flags);
1598            p->rdev = repl;
1599            conf->mirrors[conf->raid_disks + number].rdev = NULL;
1600            lower_barrier(conf);
1601            clear_bit(WantReplacement, &rdev->flags);
1602        } else
1603            clear_bit(WantReplacement, &rdev->flags);
1604        err = md_integrity_register(mddev);
1605    }
1606abort:
1607
1608    print_conf(conf);
1609    return err;
1610}
1611
1612
1613static void end_sync_read(struct bio *bio, int error)
1614{
1615    struct r1bio *r1_bio = bio->bi_private;
1616
1617    update_head_pos(r1_bio->read_disk, r1_bio);
1618
1619    /*
1620     * we have read a block, now it needs to be re-written,
1621     * or re-read if the read failed.
1622     * We don't do much here, just schedule handling by raid1d
1623     */
1624    if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1625        set_bit(R1BIO_Uptodate, &r1_bio->state);
1626
1627    if (atomic_dec_and_test(&r1_bio->remaining))
1628        reschedule_retry(r1_bio);
1629}
1630
1631static void end_sync_write(struct bio *bio, int error)
1632{
1633    int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1634    struct r1bio *r1_bio = bio->bi_private;
1635    struct mddev *mddev = r1_bio->mddev;
1636    struct r1conf *conf = mddev->private;
1637    int mirror=0;
1638    sector_t first_bad;
1639    int bad_sectors;
1640
1641    mirror = find_bio_disk(r1_bio, bio);
1642
1643    if (!uptodate) {
1644        sector_t sync_blocks = 0;
1645        sector_t s = r1_bio->sector;
1646        long sectors_to_go = r1_bio->sectors;
1647        /* make sure these bits doesn't get cleared. */
1648        do {
1649            bitmap_end_sync(mddev->bitmap, s,
1650                    &sync_blocks, 1);
1651            s += sync_blocks;
1652            sectors_to_go -= sync_blocks;
1653        } while (sectors_to_go > 0);
1654        set_bit(WriteErrorSeen,
1655            &conf->mirrors[mirror].rdev->flags);
1656        if (!test_and_set_bit(WantReplacement,
1657                      &conf->mirrors[mirror].rdev->flags))
1658            set_bit(MD_RECOVERY_NEEDED, &
1659                mddev->recovery);
1660        set_bit(R1BIO_WriteError, &r1_bio->state);
1661    } else if (is_badblock(conf->mirrors[mirror].rdev,
1662                   r1_bio->sector,
1663                   r1_bio->sectors,
1664                   &first_bad, &bad_sectors) &&
1665           !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1666                r1_bio->sector,
1667                r1_bio->sectors,
1668                &first_bad, &bad_sectors)
1669        )
1670        set_bit(R1BIO_MadeGood, &r1_bio->state);
1671
1672    if (atomic_dec_and_test(&r1_bio->remaining)) {
1673        int s = r1_bio->sectors;
1674        if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1675            test_bit(R1BIO_WriteError, &r1_bio->state))
1676            reschedule_retry(r1_bio);
1677        else {
1678            put_buf(r1_bio);
1679            md_done_sync(mddev, s, uptodate);
1680        }
1681    }
1682}
1683
1684static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
1685                int sectors, struct page *page, int rw)
1686{
1687    if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
1688        /* success */
1689        return 1;
1690    if (rw == WRITE) {
1691        set_bit(WriteErrorSeen, &rdev->flags);
1692        if (!test_and_set_bit(WantReplacement,
1693                      &rdev->flags))
1694            set_bit(MD_RECOVERY_NEEDED, &
1695                rdev->mddev->recovery);
1696    }
1697    /* need to record an error - either for the block or the device */
1698    if (!rdev_set_badblocks(rdev, sector, sectors, 0))
1699        md_error(rdev->mddev, rdev);
1700    return 0;
1701}
1702
1703static int fix_sync_read_error(struct r1bio *r1_bio)
1704{
1705    /* Try some synchronous reads of other devices to get
1706     * good data, much like with normal read errors. Only
1707     * read into the pages we already have so we don't
1708     * need to re-issue the read request.
1709     * We don't need to freeze the array, because being in an
1710     * active sync request, there is no normal IO, and
1711     * no overlapping syncs.
1712     * We don't need to check is_badblock() again as we
1713     * made sure that anything with a bad block in range
1714     * will have bi_end_io clear.
1715     */
1716    struct mddev *mddev = r1_bio->mddev;
1717    struct r1conf *conf = mddev->private;
1718    struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1719    sector_t sect = r1_bio->sector;
1720    int sectors = r1_bio->sectors;
1721    int idx = 0;
1722
1723    while(sectors) {
1724        int s = sectors;
1725        int d = r1_bio->read_disk;
1726        int success = 0;
1727        struct md_rdev *rdev;
1728        int start;
1729
1730        if (s > (PAGE_SIZE>>9))
1731            s = PAGE_SIZE >> 9;
1732        do {
1733            if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1734                /* No rcu protection needed here devices
1735                 * can only be removed when no resync is
1736                 * active, and resync is currently active
1737                 */
1738                rdev = conf->mirrors[d].rdev;
1739                if (sync_page_io(rdev, sect, s<<9,
1740                         bio->bi_io_vec[idx].bv_page,
1741                         READ, false)) {
1742                    success = 1;
1743                    break;
1744                }
1745            }
1746            d++;
1747            if (d == conf->raid_disks * 2)
1748                d = 0;
1749        } while (!success && d != r1_bio->read_disk);
1750
1751        if (!success) {
1752            char b[BDEVNAME_SIZE];
1753            int abort = 0;
1754            /* Cannot read from anywhere, this block is lost.
1755             * Record a bad block on each device. If that doesn't
1756             * work just disable and interrupt the recovery.
1757             * Don't fail devices as that won't really help.
1758             */
1759            printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1760                   " for block %llu\n",
1761                   mdname(mddev),
1762                   bdevname(bio->bi_bdev, b),
1763                   (unsigned long long)r1_bio->sector);
1764            for (d = 0; d < conf->raid_disks * 2; d++) {
1765                rdev = conf->mirrors[d].rdev;
1766                if (!rdev || test_bit(Faulty, &rdev->flags))
1767                    continue;
1768                if (!rdev_set_badblocks(rdev, sect, s, 0))
1769                    abort = 1;
1770            }
1771            if (abort) {
1772                conf->recovery_disabled =
1773                    mddev->recovery_disabled;
1774                set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1775                md_done_sync(mddev, r1_bio->sectors, 0);
1776                put_buf(r1_bio);
1777                return 0;
1778            }
1779            /* Try next page */
1780            sectors -= s;
1781            sect += s;
1782            idx++;
1783            continue;
1784        }
1785
1786        start = d;
1787        /* write it back and re-read */
1788        while (d != r1_bio->read_disk) {
1789            if (d == 0)
1790                d = conf->raid_disks * 2;
1791            d--;
1792            if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1793                continue;
1794            rdev = conf->mirrors[d].rdev;
1795            if (r1_sync_page_io(rdev, sect, s,
1796                        bio->bi_io_vec[idx].bv_page,
1797                        WRITE) == 0) {
1798                r1_bio->bios[d]->bi_end_io = NULL;
1799                rdev_dec_pending(rdev, mddev);
1800            }
1801        }
1802        d = start;
1803        while (d != r1_bio->read_disk) {
1804            if (d == 0)
1805                d = conf->raid_disks * 2;
1806            d--;
1807            if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1808                continue;
1809            rdev = conf->mirrors[d].rdev;
1810            if (r1_sync_page_io(rdev, sect, s,
1811                        bio->bi_io_vec[idx].bv_page,
1812                        READ) != 0)
1813                atomic_add(s, &rdev->corrected_errors);
1814        }
1815        sectors -= s;
1816        sect += s;
1817        idx ++;
1818    }
1819    set_bit(R1BIO_Uptodate, &r1_bio->state);
1820    set_bit(BIO_UPTODATE, &bio->bi_flags);
1821    return 1;
1822}
1823
1824static int process_checks(struct r1bio *r1_bio)
1825{
1826    /* We have read all readable devices. If we haven't
1827     * got the block, then there is no hope left.
1828     * If we have, then we want to do a comparison
1829     * and skip the write if everything is the same.
1830     * If any blocks failed to read, then we need to
1831     * attempt an over-write
1832     */
1833    struct mddev *mddev = r1_bio->mddev;
1834    struct r1conf *conf = mddev->private;
1835    int primary;
1836    int i;
1837    int vcnt;
1838
1839    for (primary = 0; primary < conf->raid_disks * 2; primary++)
1840        if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1841            test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1842            r1_bio->bios[primary]->bi_end_io = NULL;
1843            rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1844            break;
1845        }
1846    r1_bio->read_disk = primary;
1847    vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
1848    for (i = 0; i < conf->raid_disks * 2; i++) {
1849        int j;
1850        struct bio *pbio = r1_bio->bios[primary];
1851        struct bio *sbio = r1_bio->bios[i];
1852        int size;
1853
1854        if (r1_bio->bios[i]->bi_end_io != end_sync_read)
1855            continue;
1856
1857        if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1858            for (j = vcnt; j-- ; ) {
1859                struct page *p, *s;
1860                p = pbio->bi_io_vec[j].bv_page;
1861                s = sbio->bi_io_vec[j].bv_page;
1862                if (memcmp(page_address(p),
1863                       page_address(s),
1864                       sbio->bi_io_vec[j].bv_len))
1865                    break;
1866            }
1867        } else
1868            j = 0;
1869        if (j >= 0)
1870            mddev->resync_mismatches += r1_bio->sectors;
1871        if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1872                  && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1873            /* No need to write to this device. */
1874            sbio->bi_end_io = NULL;
1875            rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1876            continue;
1877        }
1878        /* fixup the bio for reuse */
1879        sbio->bi_vcnt = vcnt;
1880        sbio->bi_size = r1_bio->sectors << 9;
1881        sbio->bi_idx = 0;
1882        sbio->bi_phys_segments = 0;
1883        sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1884        sbio->bi_flags |= 1 << BIO_UPTODATE;
1885        sbio->bi_next = NULL;
1886        sbio->bi_sector = r1_bio->sector +
1887            conf->mirrors[i].rdev->data_offset;
1888        sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1889        size = sbio->bi_size;
1890        for (j = 0; j < vcnt ; j++) {
1891            struct bio_vec *bi;
1892            bi = &sbio->bi_io_vec[j];
1893            bi->bv_offset = 0;
1894            if (size > PAGE_SIZE)
1895                bi->bv_len = PAGE_SIZE;
1896            else
1897                bi->bv_len = size;
1898            size -= PAGE_SIZE;
1899            memcpy(page_address(bi->bv_page),
1900                   page_address(pbio->bi_io_vec[j].bv_page),
1901                   PAGE_SIZE);
1902        }
1903    }
1904    return 0;
1905}
1906
1907static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
1908{
1909    struct r1conf *conf = mddev->private;
1910    int i;
1911    int disks = conf->raid_disks * 2;
1912    struct bio *bio, *wbio;
1913
1914    bio = r1_bio->bios[r1_bio->read_disk];
1915
1916    if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
1917        /* ouch - failed to read all of that. */
1918        if (!fix_sync_read_error(r1_bio))
1919            return;
1920
1921    if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1922        if (process_checks(r1_bio) < 0)
1923            return;
1924    /*
1925     * schedule writes
1926     */
1927    atomic_set(&r1_bio->remaining, 1);
1928    for (i = 0; i < disks ; i++) {
1929        wbio = r1_bio->bios[i];
1930        if (wbio->bi_end_io == NULL ||
1931            (wbio->bi_end_io == end_sync_read &&
1932             (i == r1_bio->read_disk ||
1933              !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1934            continue;
1935
1936        wbio->bi_rw = WRITE;
1937        wbio->bi_end_io = end_sync_write;
1938        atomic_inc(&r1_bio->remaining);
1939        md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1940
1941        generic_make_request(wbio);
1942    }
1943
1944    if (atomic_dec_and_test(&r1_bio->remaining)) {
1945        /* if we're here, all write(s) have completed, so clean up */
1946        int s = r1_bio->sectors;
1947        if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1948            test_bit(R1BIO_WriteError, &r1_bio->state))
1949            reschedule_retry(r1_bio);
1950        else {
1951            put_buf(r1_bio);
1952            md_done_sync(mddev, s, 1);
1953        }
1954    }
1955}
1956
1957/*
1958 * This is a kernel thread which:
1959 *
1960 * 1. Retries failed read operations on working mirrors.
1961 * 2. Updates the raid superblock when problems encounter.
1962 * 3. Performs writes following reads for array synchronising.
1963 */
1964
1965static void fix_read_error(struct r1conf *conf, int read_disk,
1966               sector_t sect, int sectors)
1967{
1968    struct mddev *mddev = conf->mddev;
1969    while(sectors) {
1970        int s = sectors;
1971        int d = read_disk;
1972        int success = 0;
1973        int start;
1974        struct md_rdev *rdev;
1975
1976        if (s > (PAGE_SIZE>>9))
1977            s = PAGE_SIZE >> 9;
1978
1979        do {
1980            /* Note: no rcu protection needed here
1981             * as this is synchronous in the raid1d thread
1982             * which is the thread that might remove
1983             * a device. If raid1d ever becomes multi-threaded....
1984             */
1985            sector_t first_bad;
1986            int bad_sectors;
1987
1988            rdev = conf->mirrors[d].rdev;
1989            if (rdev &&
1990                (test_bit(In_sync, &rdev->flags) ||
1991                 (!test_bit(Faulty, &rdev->flags) &&
1992                  rdev->recovery_offset >= sect + s)) &&
1993                is_badblock(rdev, sect, s,
1994                    &first_bad, &bad_sectors) == 0 &&
1995                sync_page_io(rdev, sect, s<<9,
1996                     conf->tmppage, READ, false))
1997                success = 1;
1998            else {
1999                d++;
2000                if (d == conf->raid_disks * 2)
2001                    d = 0;
2002            }
2003        } while (!success && d != read_disk);
2004
2005        if (!success) {
2006            /* Cannot read from anywhere - mark it bad */
2007            struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2008            if (!rdev_set_badblocks(rdev, sect, s, 0))
2009                md_error(mddev, rdev);
2010            break;
2011        }
2012        /* write it back and re-read */
2013        start = d;
2014        while (d != read_disk) {
2015            if (d==0)
2016                d = conf->raid_disks * 2;
2017            d--;
2018            rdev = conf->mirrors[d].rdev;
2019            if (rdev &&
2020                test_bit(In_sync, &rdev->flags))
2021                r1_sync_page_io(rdev, sect, s,
2022                        conf->tmppage, WRITE);
2023        }
2024        d = start;
2025        while (d != read_disk) {
2026            char b[BDEVNAME_SIZE];
2027            if (d==0)
2028                d = conf->raid_disks * 2;
2029            d--;
2030            rdev = conf->mirrors[d].rdev;
2031            if (rdev &&
2032                test_bit(In_sync, &rdev->flags)) {
2033                if (r1_sync_page_io(rdev, sect, s,
2034                            conf->tmppage, READ)) {
2035                    atomic_add(s, &rdev->corrected_errors);
2036                    printk(KERN_INFO
2037                           "md/raid1:%s: read error corrected "
2038                           "(%d sectors at %llu on %s)\n",
2039                           mdname(mddev), s,
2040                           (unsigned long long)(sect +
2041                               rdev->data_offset),
2042                           bdevname(rdev->bdev, b));
2043                }
2044            }
2045        }
2046        sectors -= s;
2047        sect += s;
2048    }
2049}
2050
2051static void bi_complete(struct bio *bio, int error)
2052{
2053    complete((struct completion *)bio->bi_private);
2054}
2055
2056static int submit_bio_wait(int rw, struct bio *bio)
2057{
2058    struct completion event;
2059    rw |= REQ_SYNC;
2060
2061    init_completion(&event);
2062    bio->bi_private = &event;
2063    bio->bi_end_io = bi_complete;
2064    submit_bio(rw, bio);
2065    wait_for_completion(&event);
2066
2067    return test_bit(BIO_UPTODATE, &bio->bi_flags);
2068}
2069
2070static int narrow_write_error(struct r1bio *r1_bio, int i)
2071{
2072    struct mddev *mddev = r1_bio->mddev;
2073    struct r1conf *conf = mddev->private;
2074    struct md_rdev *rdev = conf->mirrors[i].rdev;
2075    int vcnt, idx;
2076    struct bio_vec *vec;
2077
2078    /* bio has the data to be written to device 'i' where
2079     * we just recently had a write error.
2080     * We repeatedly clone the bio and trim down to one block,
2081     * then try the write. Where the write fails we record
2082     * a bad block.
2083     * It is conceivable that the bio doesn't exactly align with
2084     * blocks. We must handle this somehow.
2085     *
2086     * We currently own a reference on the rdev.
2087     */
2088
2089    int block_sectors;
2090    sector_t sector;
2091    int sectors;
2092    int sect_to_write = r1_bio->sectors;
2093    int ok = 1;
2094
2095    if (rdev->badblocks.shift < 0)
2096        return 0;
2097
2098    block_sectors = 1 << rdev->badblocks.shift;
2099    sector = r1_bio->sector;
2100    sectors = ((sector + block_sectors)
2101           & ~(sector_t)(block_sectors - 1))
2102        - sector;
2103
2104    if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2105        vcnt = r1_bio->behind_page_count;
2106        vec = r1_bio->behind_bvecs;
2107        idx = 0;
2108        while (vec[idx].bv_page == NULL)
2109            idx++;
2110    } else {
2111        vcnt = r1_bio->master_bio->bi_vcnt;
2112        vec = r1_bio->master_bio->bi_io_vec;
2113        idx = r1_bio->master_bio->bi_idx;
2114    }
2115    while (sect_to_write) {
2116        struct bio *wbio;
2117        if (sectors > sect_to_write)
2118            sectors = sect_to_write;
2119        /* Write at 'sector' for 'sectors'*/
2120
2121        wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
2122        memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
2123        wbio->bi_sector = r1_bio->sector;
2124        wbio->bi_rw = WRITE;
2125        wbio->bi_vcnt = vcnt;
2126        wbio->bi_size = r1_bio->sectors << 9;
2127        wbio->bi_idx = idx;
2128
2129        md_trim_bio(wbio, sector - r1_bio->sector, sectors);
2130        wbio->bi_sector += rdev->data_offset;
2131        wbio->bi_bdev = rdev->bdev;
2132        if (submit_bio_wait(WRITE, wbio) == 0)
2133            /* failure! */
2134            ok = rdev_set_badblocks(rdev, sector,
2135                        sectors, 0)
2136                && ok;
2137
2138        bio_put(wbio);
2139        sect_to_write -= sectors;
2140        sector += sectors;
2141        sectors = block_sectors;
2142    }
2143    return ok;
2144}
2145
2146static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2147{
2148    int m;
2149    int s = r1_bio->sectors;
2150    for (m = 0; m < conf->raid_disks * 2 ; m++) {
2151        struct md_rdev *rdev = conf->mirrors[m].rdev;
2152        struct bio *bio = r1_bio->bios[m];
2153        if (bio->bi_end_io == NULL)
2154            continue;
2155        if (test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2156            test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2157            rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2158        }
2159        if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2160            test_bit(R1BIO_WriteError, &r1_bio->state)) {
2161            if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2162                md_error(conf->mddev, rdev);
2163        }
2164    }
2165    put_buf(r1_bio);
2166    md_done_sync(conf->mddev, s, 1);
2167}
2168
2169static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2170{
2171    int m;
2172    for (m = 0; m < conf->raid_disks * 2 ; m++)
2173        if (r1_bio->bios[m] == IO_MADE_GOOD) {
2174            struct md_rdev *rdev = conf->mirrors[m].rdev;
2175            rdev_clear_badblocks(rdev,
2176                         r1_bio->sector,
2177                         r1_bio->sectors, 0);
2178            rdev_dec_pending(rdev, conf->mddev);
2179        } else if (r1_bio->bios[m] != NULL) {
2180            /* This drive got a write error. We need to
2181             * narrow down and record precise write
2182             * errors.
2183             */
2184            if (!narrow_write_error(r1_bio, m)) {
2185                md_error(conf->mddev,
2186                     conf->mirrors[m].rdev);
2187                /* an I/O failed, we can't clear the bitmap */
2188                set_bit(R1BIO_Degraded, &r1_bio->state);
2189            }
2190            rdev_dec_pending(conf->mirrors[m].rdev,
2191                     conf->mddev);
2192        }
2193    if (test_bit(R1BIO_WriteError, &r1_bio->state))
2194        close_write(r1_bio);
2195    raid_end_bio_io(r1_bio);
2196}
2197
2198static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2199{
2200    int disk;
2201    int max_sectors;
2202    struct mddev *mddev = conf->mddev;
2203    struct bio *bio;
2204    char b[BDEVNAME_SIZE];
2205    struct md_rdev *rdev;
2206
2207    clear_bit(R1BIO_ReadError, &r1_bio->state);
2208    /* we got a read error. Maybe the drive is bad. Maybe just
2209     * the block and we can fix it.
2210     * We freeze all other IO, and try reading the block from
2211     * other devices. When we find one, we re-write
2212     * and check it that fixes the read error.
2213     * This is all done synchronously while the array is
2214     * frozen
2215     */
2216    if (mddev->ro == 0) {
2217        freeze_array(conf);
2218        fix_read_error(conf, r1_bio->read_disk,
2219                   r1_bio->sector, r1_bio->sectors);
2220        unfreeze_array(conf);
2221    } else
2222        md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
2223
2224    bio = r1_bio->bios[r1_bio->read_disk];
2225    bdevname(bio->bi_bdev, b);
2226read_more:
2227    disk = read_balance(conf, r1_bio, &max_sectors);
2228    if (disk == -1) {
2229        printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
2230               " read error for block %llu\n",
2231               mdname(mddev), b, (unsigned long long)r1_bio->sector);
2232        raid_end_bio_io(r1_bio);
2233    } else {
2234        const unsigned long do_sync
2235            = r1_bio->master_bio->bi_rw & REQ_SYNC;
2236        if (bio) {
2237            r1_bio->bios[r1_bio->read_disk] =
2238                mddev->ro ? IO_BLOCKED : NULL;
2239            bio_put(bio);
2240        }
2241        r1_bio->read_disk = disk;
2242        bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
2243        md_trim_bio(bio, r1_bio->sector - bio->bi_sector, max_sectors);
2244        r1_bio->bios[r1_bio->read_disk] = bio;
2245        rdev = conf->mirrors[disk].rdev;
2246        printk_ratelimited(KERN_ERR
2247                   "md/raid1:%s: redirecting sector %llu"
2248                   " to other mirror: %s\n",
2249                   mdname(mddev),
2250                   (unsigned long long)r1_bio->sector,
2251                   bdevname(rdev->bdev, b));
2252        bio->bi_sector = r1_bio->sector + rdev->data_offset;
2253        bio->bi_bdev = rdev->bdev;
2254        bio->bi_end_io = raid1_end_read_request;
2255        bio->bi_rw = READ | do_sync;
2256        bio->bi_private = r1_bio;
2257        if (max_sectors < r1_bio->sectors) {
2258            /* Drat - have to split this up more */
2259            struct bio *mbio = r1_bio->master_bio;
2260            int sectors_handled = (r1_bio->sector + max_sectors
2261                           - mbio->bi_sector);
2262            r1_bio->sectors = max_sectors;
2263            spin_lock_irq(&conf->device_lock);
2264            if (mbio->bi_phys_segments == 0)
2265                mbio->bi_phys_segments = 2;
2266            else
2267                mbio->bi_phys_segments++;
2268            spin_unlock_irq(&conf->device_lock);
2269            generic_make_request(bio);
2270            bio = NULL;
2271
2272            r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
2273
2274            r1_bio->master_bio = mbio;
2275            r1_bio->sectors = (mbio->bi_size >> 9)
2276                      - sectors_handled;
2277            r1_bio->state = 0;
2278            set_bit(R1BIO_ReadError, &r1_bio->state);
2279            r1_bio->mddev = mddev;
2280            r1_bio->sector = mbio->bi_sector + sectors_handled;
2281
2282            goto read_more;
2283        } else
2284            generic_make_request(bio);
2285    }
2286}
2287
2288static void raid1d(struct mddev *mddev)
2289{
2290    struct r1bio *r1_bio;
2291    unsigned long flags;
2292    struct r1conf *conf = mddev->private;
2293    struct list_head *head = &conf->retry_list;
2294    struct blk_plug plug;
2295
2296    md_check_recovery(mddev);
2297
2298    blk_start_plug(&plug);
2299    for (;;) {
2300
2301        flush_pending_writes(conf);
2302
2303        spin_lock_irqsave(&conf->device_lock, flags);
2304        if (list_empty(head)) {
2305            spin_unlock_irqrestore(&conf->device_lock, flags);
2306            break;
2307        }
2308        r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2309        list_del(head->prev);
2310        conf->nr_queued--;
2311        spin_unlock_irqrestore(&conf->device_lock, flags);
2312
2313        mddev = r1_bio->mddev;
2314        conf = mddev->private;
2315        if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2316            if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2317                test_bit(R1BIO_WriteError, &r1_bio->state))
2318                handle_sync_write_finished(conf, r1_bio);
2319            else
2320                sync_request_write(mddev, r1_bio);
2321        } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2322               test_bit(R1BIO_WriteError, &r1_bio->state))
2323            handle_write_finished(conf, r1_bio);
2324        else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2325            handle_read_error(conf, r1_bio);
2326        else
2327            /* just a partial read to be scheduled from separate
2328             * context
2329             */
2330            generic_make_request(r1_bio->bios[r1_bio->read_disk]);
2331
2332        cond_resched();
2333        if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2334            md_check_recovery(mddev);
2335    }
2336    blk_finish_plug(&plug);
2337}
2338
2339
2340static int init_resync(struct r1conf *conf)
2341{
2342    int buffs;
2343
2344    buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2345    BUG_ON(conf->r1buf_pool);
2346    conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
2347                      conf->poolinfo);
2348    if (!conf->r1buf_pool)
2349        return -ENOMEM;
2350    conf->next_resync = 0;
2351    return 0;
2352}
2353
2354/*
2355 * perform a "sync" on one "block"
2356 *
2357 * We need to make sure that no normal I/O request - particularly write
2358 * requests - conflict with active sync requests.
2359 *
2360 * This is achieved by tracking pending requests and a 'barrier' concept
2361 * that can be installed to exclude normal IO requests.
2362 */
2363
2364static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
2365{
2366    struct r1conf *conf = mddev->private;
2367    struct r1bio *r1_bio;
2368    struct bio *bio;
2369    sector_t max_sector, nr_sectors;
2370    int disk = -1;
2371    int i;
2372    int wonly = -1;
2373    int write_targets = 0, read_targets = 0;
2374    sector_t sync_blocks;
2375    int still_degraded = 0;
2376    int good_sectors = RESYNC_SECTORS;
2377    int min_bad = 0; /* number of sectors that are bad in all devices */
2378
2379    if (!conf->r1buf_pool)
2380        if (init_resync(conf))
2381            return 0;
2382
2383    max_sector = mddev->dev_sectors;
2384    if (sector_nr >= max_sector) {
2385        /* If we aborted, we need to abort the
2386         * sync on the 'current' bitmap chunk (there will
2387         * only be one in raid1 resync.
2388         * We can find the current addess in mddev->curr_resync
2389         */
2390        if (mddev->curr_resync < max_sector) /* aborted */
2391            bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2392                        &sync_blocks, 1);
2393        else /* completed sync */
2394            conf->fullsync = 0;
2395
2396        bitmap_close_sync(mddev->bitmap);
2397        close_sync(conf);
2398        return 0;
2399    }
2400
2401    if (mddev->bitmap == NULL &&
2402        mddev->recovery_cp == MaxSector &&
2403        !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2404        conf->fullsync == 0) {
2405        *skipped = 1;
2406        return max_sector - sector_nr;
2407    }
2408    /* before building a request, check if we can skip these blocks..
2409     * This call the bitmap_start_sync doesn't actually record anything
2410     */
2411    if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2412        !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2413        /* We can skip this block, and probably several more */
2414        *skipped = 1;
2415        return sync_blocks;
2416    }
2417    /*
2418     * If there is non-resync activity waiting for a turn,
2419     * and resync is going fast enough,
2420     * then let it though before starting on this new sync request.
2421     */
2422    if (!go_faster && conf->nr_waiting)
2423        msleep_interruptible(1000);
2424
2425    bitmap_cond_end_sync(mddev->bitmap, sector_nr);
2426    r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
2427    raise_barrier(conf);
2428
2429    conf->next_resync = sector_nr;
2430
2431    rcu_read_lock();
2432    /*
2433     * If we get a correctably read error during resync or recovery,
2434     * we might want to read from a different device. So we
2435     * flag all drives that could conceivably be read from for READ,
2436     * and any others (which will be non-In_sync devices) for WRITE.
2437     * If a read fails, we try reading from something else for which READ
2438     * is OK.
2439     */
2440
2441    r1_bio->mddev = mddev;
2442    r1_bio->sector = sector_nr;
2443    r1_bio->state = 0;
2444    set_bit(R1BIO_IsSync, &r1_bio->state);
2445
2446    for (i = 0; i < conf->raid_disks * 2; i++) {
2447        struct md_rdev *rdev;
2448        bio = r1_bio->bios[i];
2449
2450        /* take from bio_init */
2451        bio->bi_next = NULL;
2452        bio->bi_flags &= ~(BIO_POOL_MASK-1);
2453        bio->bi_flags |= 1 << BIO_UPTODATE;
2454        bio->bi_rw = READ;
2455        bio->bi_vcnt = 0;
2456        bio->bi_idx = 0;
2457        bio->bi_phys_segments = 0;
2458        bio->bi_size = 0;
2459        bio->bi_end_io = NULL;
2460        bio->bi_private = NULL;
2461
2462        rdev = rcu_dereference(conf->mirrors[i].rdev);
2463        if (rdev == NULL ||
2464            test_bit(Faulty, &rdev->flags)) {
2465            if (i < conf->raid_disks)
2466                still_degraded = 1;
2467        } else if (!test_bit(In_sync, &rdev->flags)) {
2468            bio->bi_rw = WRITE;
2469            bio->bi_end_io = end_sync_write;
2470            write_targets ++;
2471        } else {
2472            /* may need to read from here */
2473            sector_t first_bad = MaxSector;
2474            int bad_sectors;
2475
2476            if (is_badblock(rdev, sector_nr, good_sectors,
2477                    &first_bad, &bad_sectors)) {
2478                if (first_bad > sector_nr)
2479                    good_sectors = first_bad - sector_nr;
2480                else {
2481                    bad_sectors -= (sector_nr - first_bad);
2482                    if (min_bad == 0 ||
2483                        min_bad > bad_sectors)
2484                        min_bad = bad_sectors;
2485                }
2486            }
2487            if (sector_nr < first_bad) {
2488                if (test_bit(WriteMostly, &rdev->flags)) {
2489                    if (wonly < 0)
2490                        wonly = i;
2491                } else {
2492                    if (disk < 0)
2493                        disk = i;
2494                }
2495                bio->bi_rw = READ;
2496                bio->bi_end_io = end_sync_read;
2497                read_targets++;
2498            } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2499                test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2500                !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2501                /*
2502                 * The device is suitable for reading (InSync),
2503                 * but has bad block(s) here. Let's try to correct them,
2504                 * if we are doing resync or repair. Otherwise, leave
2505                 * this device alone for this sync request.
2506                 */
2507                bio->bi_rw = WRITE;
2508                bio->bi_end_io = end_sync_write;
2509                write_targets++;
2510            }
2511        }
2512        if (bio->bi_end_io) {
2513            atomic_inc(&rdev->nr_pending);
2514            bio->bi_sector = sector_nr + rdev->data_offset;
2515            bio->bi_bdev = rdev->bdev;
2516            bio->bi_private = r1_bio;
2517        }
2518    }
2519    rcu_read_unlock();
2520    if (disk < 0)
2521        disk = wonly;
2522    r1_bio->read_disk = disk;
2523
2524    if (read_targets == 0 && min_bad > 0) {
2525        /* These sectors are bad on all InSync devices, so we
2526         * need to mark them bad on all write targets
2527         */
2528        int ok = 1;
2529        for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2530            if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2531                struct md_rdev *rdev = conf->mirrors[i].rdev;
2532                ok = rdev_set_badblocks(rdev, sector_nr,
2533                            min_bad, 0
2534                    ) && ok;
2535            }
2536        set_bit(MD_CHANGE_DEVS, &mddev->flags);
2537        *skipped = 1;
2538        put_buf(r1_bio);
2539
2540        if (!ok) {
2541            /* Cannot record the badblocks, so need to
2542             * abort the resync.
2543             * If there are multiple read targets, could just
2544             * fail the really bad ones ???
2545             */
2546            conf->recovery_disabled = mddev->recovery_disabled;
2547            set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2548            return 0;
2549        } else
2550            return min_bad;
2551
2552    }
2553    if (min_bad > 0 && min_bad < good_sectors) {
2554        /* only resync enough to reach the next bad->good
2555         * transition */
2556        good_sectors = min_bad;
2557    }
2558
2559    if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2560        /* extra read targets are also write targets */
2561        write_targets += read_targets-1;
2562
2563    if (write_targets == 0 || read_targets == 0) {
2564        /* There is nowhere to write, so all non-sync
2565         * drives must be failed - so we are finished
2566         */
2567        sector_t rv;
2568        if (min_bad > 0)
2569            max_sector = sector_nr + min_bad;
2570        rv = max_sector - sector_nr;
2571        *skipped = 1;
2572        put_buf(r1_bio);
2573        return rv;
2574    }
2575
2576    if (max_sector > mddev->resync_max)
2577        max_sector = mddev->resync_max; /* Don't do IO beyond here */
2578    if (max_sector > sector_nr + good_sectors)
2579        max_sector = sector_nr + good_sectors;
2580    nr_sectors = 0;
2581    sync_blocks = 0;
2582    do {
2583        struct page *page;
2584        int len = PAGE_SIZE;
2585        if (sector_nr + (len>>9) > max_sector)
2586            len = (max_sector - sector_nr) << 9;
2587        if (len == 0)
2588            break;
2589        if (sync_blocks == 0) {
2590            if (!bitmap_start_sync(mddev->bitmap, sector_nr,
2591                           &sync_blocks, still_degraded) &&
2592                !conf->fullsync &&
2593                !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2594                break;
2595            BUG_ON(sync_blocks < (PAGE_SIZE>>9));
2596            if ((len >> 9) > sync_blocks)
2597                len = sync_blocks<<9;
2598        }
2599
2600        for (i = 0 ; i < conf->raid_disks * 2; i++) {
2601            bio = r1_bio->bios[i];
2602            if (bio->bi_end_io) {
2603                page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2604                if (bio_add_page(bio, page, len, 0) == 0) {
2605                    /* stop here */
2606                    bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2607                    while (i > 0) {
2608                        i--;
2609                        bio = r1_bio->bios[i];
2610                        if (bio->bi_end_io==NULL)
2611                            continue;
2612                        /* remove last page from this bio */
2613                        bio->bi_vcnt--;
2614                        bio->bi_size -= len;
2615                        bio->bi_flags &= ~(1<< BIO_SEG_VALID);
2616                    }
2617                    goto bio_full;
2618                }
2619            }
2620        }
2621        nr_sectors += len>>9;
2622        sector_nr += len>>9;
2623        sync_blocks -= (len>>9);
2624    } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
2625 bio_full:
2626    r1_bio->sectors = nr_sectors;
2627
2628    /* For a user-requested sync, we read all readable devices and do a
2629     * compare
2630     */
2631    if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2632        atomic_set(&r1_bio->remaining, read_targets);
2633        for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
2634            bio = r1_bio->bios[i];
2635            if (bio->bi_end_io == end_sync_read) {
2636                read_targets--;
2637                md_sync_acct(bio->bi_bdev, nr_sectors);
2638                generic_make_request(bio);
2639            }
2640        }
2641    } else {
2642        atomic_set(&r1_bio->remaining, 1);
2643        bio = r1_bio->bios[r1_bio->read_disk];
2644        md_sync_acct(bio->bi_bdev, nr_sectors);
2645        generic_make_request(bio);
2646
2647    }
2648    return nr_sectors;
2649}
2650
2651static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
2652{
2653    if (sectors)
2654        return sectors;
2655
2656    return mddev->dev_sectors;
2657}
2658
2659static struct r1conf *setup_conf(struct mddev *mddev)
2660{
2661    struct r1conf *conf;
2662    int i;
2663    struct raid1_info *disk;
2664    struct md_rdev *rdev;
2665    int err = -ENOMEM;
2666
2667    conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
2668    if (!conf)
2669        goto abort;
2670
2671    conf->mirrors = kzalloc(sizeof(struct raid1_info)
2672                * mddev->raid_disks * 2,
2673                 GFP_KERNEL);
2674    if (!conf->mirrors)
2675        goto abort;
2676
2677    conf->tmppage = alloc_page(GFP_KERNEL);
2678    if (!conf->tmppage)
2679        goto abort;
2680
2681    conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2682    if (!conf->poolinfo)
2683        goto abort;
2684    conf->poolinfo->raid_disks = mddev->raid_disks * 2;
2685    conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2686                      r1bio_pool_free,
2687                      conf->poolinfo);
2688    if (!conf->r1bio_pool)
2689        goto abort;
2690
2691    conf->poolinfo->mddev = mddev;
2692
2693    err = -EINVAL;
2694    spin_lock_init(&conf->device_lock);
2695    rdev_for_each(rdev, mddev) {
2696        struct request_queue *q;
2697        int disk_idx = rdev->raid_disk;
2698        if (disk_idx >= mddev->raid_disks
2699            || disk_idx < 0)
2700            continue;
2701        if (test_bit(Replacement, &rdev->flags))
2702            disk = conf->mirrors + conf->raid_disks + disk_idx;
2703        else
2704            disk = conf->mirrors + disk_idx;
2705
2706        if (disk->rdev)
2707            goto abort;
2708        disk->rdev = rdev;
2709        q = bdev_get_queue(rdev->bdev);
2710        if (q->merge_bvec_fn)
2711            mddev->merge_check_needed = 1;
2712
2713        disk->head_position = 0;
2714        disk->seq_start = MaxSector;
2715    }
2716    conf->raid_disks = mddev->raid_disks;
2717    conf->mddev = mddev;
2718    INIT_LIST_HEAD(&conf->retry_list);
2719
2720    spin_lock_init(&conf->resync_lock);
2721    init_waitqueue_head(&conf->wait_barrier);
2722
2723    bio_list_init(&conf->pending_bio_list);
2724    conf->pending_count = 0;
2725    conf->recovery_disabled = mddev->recovery_disabled - 1;
2726
2727    err = -EIO;
2728    for (i = 0; i < conf->raid_disks * 2; i++) {
2729
2730        disk = conf->mirrors + i;
2731
2732        if (i < conf->raid_disks &&
2733            disk[conf->raid_disks].rdev) {
2734            /* This slot has a replacement. */
2735            if (!disk->rdev) {
2736                /* No original, just make the replacement
2737                 * a recovering spare
2738                 */
2739                disk->rdev =
2740                    disk[conf->raid_disks].rdev;
2741                disk[conf->raid_disks].rdev = NULL;
2742            } else if (!test_bit(In_sync, &disk->rdev->flags))
2743                /* Original is not in_sync - bad */
2744                goto abort;
2745        }
2746
2747        if (!disk->rdev ||
2748            !test_bit(In_sync, &disk->rdev->flags)) {
2749            disk->head_position = 0;
2750            if (disk->rdev &&
2751                (disk->rdev->saved_raid_disk < 0))
2752                conf->fullsync = 1;
2753        }
2754    }
2755
2756    err = -ENOMEM;
2757    conf->thread = md_register_thread(raid1d, mddev, "raid1");
2758    if (!conf->thread) {
2759        printk(KERN_ERR
2760               "md/raid1:%s: couldn't allocate thread\n",
2761               mdname(mddev));
2762        goto abort;
2763    }
2764
2765    return conf;
2766
2767 abort:
2768    if (conf) {
2769        if (conf->r1bio_pool)
2770            mempool_destroy(conf->r1bio_pool);
2771        kfree(conf->mirrors);
2772        safe_put_page(conf->tmppage);
2773        kfree(conf->poolinfo);
2774        kfree(conf);
2775    }
2776    return ERR_PTR(err);
2777}
2778
2779static int stop(struct mddev *mddev);
2780static int run(struct mddev *mddev)
2781{
2782    struct r1conf *conf;
2783    int i;
2784    struct md_rdev *rdev;
2785    int ret;
2786
2787    if (mddev->level != 1) {
2788        printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2789               mdname(mddev), mddev->level);
2790        return -EIO;
2791    }
2792    if (mddev->reshape_position != MaxSector) {
2793        printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2794               mdname(mddev));
2795        return -EIO;
2796    }
2797    /*
2798     * copy the already verified devices into our private RAID1
2799     * bookkeeping area. [whatever we allocate in run(),
2800     * should be freed in stop()]
2801     */
2802    if (mddev->private == NULL)
2803        conf = setup_conf(mddev);
2804    else
2805        conf = mddev->private;
2806
2807    if (IS_ERR(conf))
2808        return PTR_ERR(conf);
2809
2810    rdev_for_each(rdev, mddev) {
2811        if (!mddev->gendisk)
2812            continue;
2813        disk_stack_limits(mddev->gendisk, rdev->bdev,
2814                  rdev->data_offset << 9);
2815    }
2816
2817    mddev->degraded = 0;
2818    for (i=0; i < conf->raid_disks; i++)
2819        if (conf->mirrors[i].rdev == NULL ||
2820            !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2821            test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2822            mddev->degraded++;
2823
2824    if (conf->raid_disks - mddev->degraded == 1)
2825        mddev->recovery_cp = MaxSector;
2826
2827    if (mddev->recovery_cp != MaxSector)
2828        printk(KERN_NOTICE "md/raid1:%s: not clean"
2829               " -- starting background reconstruction\n",
2830               mdname(mddev));
2831    printk(KERN_INFO
2832        "md/raid1:%s: active with %d out of %d mirrors\n",
2833        mdname(mddev), mddev->raid_disks - mddev->degraded,
2834        mddev->raid_disks);
2835
2836    /*
2837     * Ok, everything is just fine now
2838     */
2839    mddev->thread = conf->thread;
2840    conf->thread = NULL;
2841    mddev->private = conf;
2842
2843    md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2844
2845    if (mddev->queue) {
2846        mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2847        mddev->queue->backing_dev_info.congested_data = mddev;
2848        blk_queue_merge_bvec(mddev->queue, raid1_mergeable_bvec);
2849    }
2850
2851    ret = md_integrity_register(mddev);
2852    if (ret)
2853        stop(mddev);
2854    return ret;
2855}
2856
2857static int stop(struct mddev *mddev)
2858{
2859    struct r1conf *conf = mddev->private;
2860    struct bitmap *bitmap = mddev->bitmap;
2861
2862    /* wait for behind writes to complete */
2863    if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2864        printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2865               mdname(mddev));
2866        /* need to kick something here to make sure I/O goes? */
2867        wait_event(bitmap->behind_wait,
2868               atomic_read(&bitmap->behind_writes) == 0);
2869    }
2870
2871    raise_barrier(conf);
2872    lower_barrier(conf);
2873
2874    md_unregister_thread(&mddev->thread);
2875    if (conf->r1bio_pool)
2876        mempool_destroy(conf->r1bio_pool);
2877    kfree(conf->mirrors);
2878    kfree(conf->poolinfo);
2879    kfree(conf);
2880    mddev->private = NULL;
2881    return 0;
2882}
2883
2884static int raid1_resize(struct mddev *mddev, sector_t sectors)
2885{
2886    /* no resync is happening, and there is enough space
2887     * on all devices, so we can resize.
2888     * We need to make sure resync covers any new space.
2889     * If the array is shrinking we should possibly wait until
2890     * any io in the removed space completes, but it hardly seems
2891     * worth it.
2892     */
2893    sector_t newsize = raid1_size(mddev, sectors, 0);
2894    if (mddev->external_size &&
2895        mddev->array_sectors > newsize)
2896        return -EINVAL;
2897    if (mddev->bitmap) {
2898        int ret = bitmap_resize(mddev->bitmap, newsize, 0, 0);
2899        if (ret)
2900            return ret;
2901    }
2902    md_set_array_sectors(mddev, newsize);
2903    set_capacity(mddev->gendisk, mddev->array_sectors);
2904    revalidate_disk(mddev->gendisk);
2905    if (sectors > mddev->dev_sectors &&
2906        mddev->recovery_cp > mddev->dev_sectors) {
2907        mddev->recovery_cp = mddev->dev_sectors;
2908        set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2909    }
2910    mddev->dev_sectors = sectors;
2911    mddev->resync_max_sectors = sectors;
2912    return 0;
2913}
2914
2915static int raid1_reshape(struct mddev *mddev)
2916{
2917    /* We need to:
2918     * 1/ resize the r1bio_pool
2919     * 2/ resize conf->mirrors
2920     *
2921     * We allocate a new r1bio_pool if we can.
2922     * Then raise a device barrier and wait until all IO stops.
2923     * Then resize conf->mirrors and swap in the new r1bio pool.
2924     *
2925     * At the same time, we "pack" the devices so that all the missing
2926     * devices have the higher raid_disk numbers.
2927     */
2928    mempool_t *newpool, *oldpool;
2929    struct pool_info *newpoolinfo;
2930    struct raid1_info *newmirrors;
2931    struct r1conf *conf = mddev->private;
2932    int cnt, raid_disks;
2933    unsigned long flags;
2934    int d, d2, err;
2935
2936    /* Cannot change chunk_size, layout, or level */
2937    if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2938        mddev->layout != mddev->new_layout ||
2939        mddev->level != mddev->new_level) {
2940        mddev->new_chunk_sectors = mddev->chunk_sectors;
2941        mddev->new_layout = mddev->layout;
2942        mddev->new_level = mddev->level;
2943        return -EINVAL;
2944    }
2945
2946    err = md_allow_write(mddev);
2947    if (err)
2948        return err;
2949
2950    raid_disks = mddev->raid_disks + mddev->delta_disks;
2951
2952    if (raid_disks < conf->raid_disks) {
2953        cnt=0;
2954        for (d= 0; d < conf->raid_disks; d++)
2955            if (conf->mirrors[d].rdev)
2956                cnt++;
2957        if (cnt > raid_disks)
2958            return -EBUSY;
2959    }
2960
2961    newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2962    if (!newpoolinfo)
2963        return -ENOMEM;
2964    newpoolinfo->mddev = mddev;
2965    newpoolinfo->raid_disks = raid_disks * 2;
2966
2967    newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2968                 r1bio_pool_free, newpoolinfo);
2969    if (!newpool) {
2970        kfree(newpoolinfo);
2971        return -ENOMEM;
2972    }
2973    newmirrors = kzalloc(sizeof(struct raid1_info) * raid_disks * 2,
2974                 GFP_KERNEL);
2975    if (!newmirrors) {
2976        kfree(newpoolinfo);
2977        mempool_destroy(newpool);
2978        return -ENOMEM;
2979    }
2980
2981    raise_barrier(conf);
2982
2983    /* ok, everything is stopped */
2984    oldpool = conf->r1bio_pool;
2985    conf->r1bio_pool = newpool;
2986
2987    for (d = d2 = 0; d < conf->raid_disks; d++) {
2988        struct md_rdev *rdev = conf->mirrors[d].rdev;
2989        if (rdev && rdev->raid_disk != d2) {
2990            sysfs_unlink_rdev(mddev, rdev);
2991            rdev->raid_disk = d2;
2992            sysfs_unlink_rdev(mddev, rdev);
2993            if (sysfs_link_rdev(mddev, rdev))
2994                printk(KERN_WARNING
2995                       "md/raid1:%s: cannot register rd%d\n",
2996                       mdname(mddev), rdev->raid_disk);
2997        }
2998        if (rdev)
2999            newmirrors[d2++].rdev = rdev;
3000    }
3001    kfree(conf->mirrors);
3002    conf->mirrors = newmirrors;
3003    kfree(conf->poolinfo);
3004    conf->poolinfo = newpoolinfo;
3005
3006    spin_lock_irqsave(&conf->device_lock, flags);
3007    mddev->degraded += (raid_disks - conf->raid_disks);
3008    spin_unlock_irqrestore(&conf->device_lock, flags);
3009    conf->raid_disks = mddev->raid_disks = raid_disks;
3010    mddev->delta_disks = 0;
3011
3012    lower_barrier(conf);
3013
3014    set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3015    md_wakeup_thread(mddev->thread);
3016
3017    mempool_destroy(oldpool);
3018    return 0;
3019}
3020
3021static void raid1_quiesce(struct mddev *mddev, int state)
3022{
3023    struct r1conf *conf = mddev->private;
3024
3025    switch(state) {
3026    case 2: /* wake for suspend */
3027        wake_up(&conf->wait_barrier);
3028        break;
3029    case 1:
3030        raise_barrier(conf);
3031        break;
3032    case 0:
3033        lower_barrier(conf);
3034        break;
3035    }
3036}
3037
3038static void *raid1_takeover(struct mddev *mddev)
3039{
3040    /* raid1 can take over:
3041     * raid5 with 2 devices, any layout or chunk size
3042     */
3043    if (mddev->level == 5 && mddev->raid_disks == 2) {
3044        struct r1conf *conf;
3045        mddev->new_level = 1;
3046        mddev->new_layout = 0;
3047        mddev->new_chunk_sectors = 0;
3048        conf = setup_conf(mddev);
3049        if (!IS_ERR(conf))
3050            conf->barrier = 1;
3051        return conf;
3052    }
3053    return ERR_PTR(-EINVAL);
3054}
3055
3056static struct md_personality raid1_personality =
3057{
3058    .name = "raid1",
3059    .level = 1,
3060    .owner = THIS_MODULE,
3061    .make_request = make_request,
3062    .run = run,
3063    .stop = stop,
3064    .status = status,
3065    .error_handler = error,
3066    .hot_add_disk = raid1_add_disk,
3067    .hot_remove_disk= raid1_remove_disk,
3068    .spare_active = raid1_spare_active,
3069    .sync_request = sync_request,
3070    .resize = raid1_resize,
3071    .size = raid1_size,
3072    .check_reshape = raid1_reshape,
3073    .quiesce = raid1_quiesce,
3074    .takeover = raid1_takeover,
3075};
3076
3077static int __init raid_init(void)
3078{
3079    return register_md_personality(&raid1_personality);
3080}
3081
3082static void raid_exit(void)
3083{
3084    unregister_md_personality(&raid1_personality);
3085}
3086
3087module_init(raid_init);
3088module_exit(raid_exit);
3089MODULE_LICENSE("GPL");
3090MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3091MODULE_ALIAS("md-personality-3"); /* RAID1 */
3092MODULE_ALIAS("md-raid1");
3093MODULE_ALIAS("md-level-1");
3094
3095module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);
3096

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