linux/drivers/md/raid1.c
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   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 Ƙstergaard" <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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