1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * raid10.c : Multiple Devices driver for Linux
   4 *
   5 * Copyright (C) 2000-2004 Neil Brown
   6 *
   7 * RAID-10 support for md.
   8 *
   9 * Base on code in raid1.c.  See raid1.c for further copyright information.
  10 */
  11
  12#include <linux/slab.h>
  13#include <linux/delay.h>
  14#include <linux/blkdev.h>
  15#include <linux/module.h>
  16#include <linux/seq_file.h>
  17#include <linux/ratelimit.h>
  18#include <linux/kthread.h>
  19#include <linux/raid/md_p.h>
  20#include <trace/events/block.h>
  21#include "md.h"
  22
  23#define RAID_1_10_NAME "raid10"
  24#include "raid10.h"
  25#include "raid0.h"
  26#include "md-bitmap.h"
  27
  28/*
  29 * RAID10 provides a combination of RAID0 and RAID1 functionality.
  30 * The layout of data is defined by
  31 *    chunk_size
  32 *    raid_disks
  33 *    near_copies (stored in low byte of layout)
  34 *    far_copies (stored in second byte of layout)
  35 *    far_offset (stored in bit 16 of layout )
  36 *    use_far_sets (stored in bit 17 of layout )
  37 *    use_far_sets_bugfixed (stored in bit 18 of layout )
  38 *
  39 * The data to be stored is divided into chunks using chunksize.  Each device
  40 * is divided into far_copies sections.   In each section, chunks are laid out
  41 * in a style similar to raid0, but near_copies copies of each chunk is stored
  42 * (each on a different drive).  The starting device for each section is offset
  43 * near_copies from the starting device of the previous section.  Thus there
  44 * are (near_copies * far_copies) of each chunk, and each is on a different
  45 * drive.  near_copies and far_copies must be at least one, and their product
  46 * is at most raid_disks.
  47 *
  48 * If far_offset is true, then the far_copies are handled a bit differently.
  49 * The copies are still in different stripes, but instead of being very far
  50 * apart on disk, there are adjacent stripes.
  51 *
  52 * The far and offset algorithms are handled slightly differently if
  53 * 'use_far_sets' is true.  In this case, the array's devices are grouped into
  54 * sets that are (near_copies * far_copies) in size.  The far copied stripes
  55 * are still shifted by 'near_copies' devices, but this shifting stays confined
  56 * to the set rather than the entire array.  This is done to improve the number
  57 * of device combinations that can fail without causing the array to fail.
  58 * Example 'far' algorithm w/o 'use_far_sets' (each letter represents a chunk
  59 * on a device):
  60 *    A B C D    A B C D E
  61 *      ...         ...
  62 *    D A B C    E A B C D
  63 * Example 'far' algorithm w/ 'use_far_sets' enabled (sets illustrated w/ []'s):
  64 *    [A B] [C D]    [A B] [C D E]
  65 *    |...| |...|    |...| | ... |
  66 *    [B A] [D C]    [B A] [E C D]
  67 */
  68
  69static void allow_barrier(struct r10conf *conf);
  70static void lower_barrier(struct r10conf *conf);
  71static int _enough(struct r10conf *conf, int previous, int ignore);
  72static int enough(struct r10conf *conf, int ignore);
  73static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
  74				int *skipped);
  75static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio);
  76static void end_reshape_write(struct bio *bio);
  77static void end_reshape(struct r10conf *conf);
  78
 
 
 
  79#include "raid1-10.c"
  80
  81#define NULL_CMD
  82#define cmd_before(conf, cmd) \
  83	do { \
  84		write_sequnlock_irq(&(conf)->resync_lock); \
  85		cmd; \
  86	} while (0)
  87#define cmd_after(conf) write_seqlock_irq(&(conf)->resync_lock)
  88
  89#define wait_event_barrier_cmd(conf, cond, cmd) \
  90	wait_event_cmd((conf)->wait_barrier, cond, cmd_before(conf, cmd), \
  91		       cmd_after(conf))
  92
  93#define wait_event_barrier(conf, cond) \
  94	wait_event_barrier_cmd(conf, cond, NULL_CMD)
  95
  96/*
  97 * for resync bio, r10bio pointer can be retrieved from the per-bio
  98 * 'struct resync_pages'.
  99 */
 100static inline struct r10bio *get_resync_r10bio(struct bio *bio)
 101{
 102	return get_resync_pages(bio)->raid_bio;
 103}
 104
 105static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
 106{
 107	struct r10conf *conf = data;
 108	int size = offsetof(struct r10bio, devs[conf->geo.raid_disks]);
 109
 110	/* allocate a r10bio with room for raid_disks entries in the
 111	 * bios array */
 112	return kzalloc(size, gfp_flags);
 113}
 114
 115#define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
 116/* amount of memory to reserve for resync requests */
 117#define RESYNC_WINDOW (1024*1024)
 118/* maximum number of concurrent requests, memory permitting */
 119#define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
 120#define CLUSTER_RESYNC_WINDOW (32 * RESYNC_WINDOW)
 121#define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
 122
 123/*
 124 * When performing a resync, we need to read and compare, so
 125 * we need as many pages are there are copies.
 126 * When performing a recovery, we need 2 bios, one for read,
 127 * one for write (we recover only one drive per r10buf)
 128 *
 129 */
 130static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
 131{
 132	struct r10conf *conf = data;
 133	struct r10bio *r10_bio;
 134	struct bio *bio;
 135	int j;
 136	int nalloc, nalloc_rp;
 137	struct resync_pages *rps;
 138
 139	r10_bio = r10bio_pool_alloc(gfp_flags, conf);
 140	if (!r10_bio)
 141		return NULL;
 142
 143	if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
 144	    test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
 145		nalloc = conf->copies; /* resync */
 146	else
 147		nalloc = 2; /* recovery */
 148
 149	/* allocate once for all bios */
 150	if (!conf->have_replacement)
 151		nalloc_rp = nalloc;
 152	else
 153		nalloc_rp = nalloc * 2;
 154	rps = kmalloc_array(nalloc_rp, sizeof(struct resync_pages), gfp_flags);
 155	if (!rps)
 156		goto out_free_r10bio;
 157
 158	/*
 159	 * Allocate bios.
 160	 */
 161	for (j = nalloc ; j-- ; ) {
 162		bio = bio_kmalloc(RESYNC_PAGES, gfp_flags);
 163		if (!bio)
 164			goto out_free_bio;
 165		bio_init(bio, NULL, bio->bi_inline_vecs, RESYNC_PAGES, 0);
 166		r10_bio->devs[j].bio = bio;
 167		if (!conf->have_replacement)
 168			continue;
 169		bio = bio_kmalloc(RESYNC_PAGES, gfp_flags);
 170		if (!bio)
 171			goto out_free_bio;
 172		bio_init(bio, NULL, bio->bi_inline_vecs, RESYNC_PAGES, 0);
 173		r10_bio->devs[j].repl_bio = bio;
 174	}
 175	/*
 176	 * Allocate RESYNC_PAGES data pages and attach them
 177	 * where needed.
 178	 */
 179	for (j = 0; j < nalloc; j++) {
 180		struct bio *rbio = r10_bio->devs[j].repl_bio;
 181		struct resync_pages *rp, *rp_repl;
 182
 183		rp = &rps[j];
 184		if (rbio)
 185			rp_repl = &rps[nalloc + j];
 186
 187		bio = r10_bio->devs[j].bio;
 188
 189		if (!j || test_bit(MD_RECOVERY_SYNC,
 190				   &conf->mddev->recovery)) {
 191			if (resync_alloc_pages(rp, gfp_flags))
 192				goto out_free_pages;
 193		} else {
 194			memcpy(rp, &rps[0], sizeof(*rp));
 195			resync_get_all_pages(rp);
 196		}
 197
 198		rp->raid_bio = r10_bio;
 199		bio->bi_private = rp;
 200		if (rbio) {
 201			memcpy(rp_repl, rp, sizeof(*rp));
 202			rbio->bi_private = rp_repl;
 203		}
 204	}
 205
 206	return r10_bio;
 207
 208out_free_pages:
 209	while (--j >= 0)
 210		resync_free_pages(&rps[j]);
 211
 212	j = 0;
 213out_free_bio:
 214	for ( ; j < nalloc; j++) {
 215		if (r10_bio->devs[j].bio)
 216			bio_uninit(r10_bio->devs[j].bio);
 217		kfree(r10_bio->devs[j].bio);
 218		if (r10_bio->devs[j].repl_bio)
 219			bio_uninit(r10_bio->devs[j].repl_bio);
 220		kfree(r10_bio->devs[j].repl_bio);
 221	}
 222	kfree(rps);
 223out_free_r10bio:
 224	rbio_pool_free(r10_bio, conf);
 225	return NULL;
 226}
 227
 228static void r10buf_pool_free(void *__r10_bio, void *data)
 229{
 230	struct r10conf *conf = data;
 231	struct r10bio *r10bio = __r10_bio;
 232	int j;
 233	struct resync_pages *rp = NULL;
 234
 235	for (j = conf->copies; j--; ) {
 236		struct bio *bio = r10bio->devs[j].bio;
 237
 238		if (bio) {
 239			rp = get_resync_pages(bio);
 240			resync_free_pages(rp);
 241			bio_uninit(bio);
 242			kfree(bio);
 243		}
 244
 245		bio = r10bio->devs[j].repl_bio;
 246		if (bio) {
 247			bio_uninit(bio);
 248			kfree(bio);
 249		}
 250	}
 251
 252	/* resync pages array stored in the 1st bio's .bi_private */
 253	kfree(rp);
 254
 255	rbio_pool_free(r10bio, conf);
 256}
 257
 258static void put_all_bios(struct r10conf *conf, struct r10bio *r10_bio)
 259{
 260	int i;
 261
 262	for (i = 0; i < conf->geo.raid_disks; i++) {
 263		struct bio **bio = & r10_bio->devs[i].bio;
 264		if (!BIO_SPECIAL(*bio))
 265			bio_put(*bio);
 266		*bio = NULL;
 267		bio = &r10_bio->devs[i].repl_bio;
 268		if (r10_bio->read_slot < 0 && !BIO_SPECIAL(*bio))
 269			bio_put(*bio);
 270		*bio = NULL;
 271	}
 272}
 273
 274static void free_r10bio(struct r10bio *r10_bio)
 275{
 276	struct r10conf *conf = r10_bio->mddev->private;
 277
 278	put_all_bios(conf, r10_bio);
 279	mempool_free(r10_bio, &conf->r10bio_pool);
 280}
 281
 282static void put_buf(struct r10bio *r10_bio)
 283{
 284	struct r10conf *conf = r10_bio->mddev->private;
 285
 286	mempool_free(r10_bio, &conf->r10buf_pool);
 287
 288	lower_barrier(conf);
 289}
 290
 291static void wake_up_barrier(struct r10conf *conf)
 292{
 293	if (wq_has_sleeper(&conf->wait_barrier))
 294		wake_up(&conf->wait_barrier);
 295}
 296
 297static void reschedule_retry(struct r10bio *r10_bio)
 298{
 299	unsigned long flags;
 300	struct mddev *mddev = r10_bio->mddev;
 301	struct r10conf *conf = mddev->private;
 302
 303	spin_lock_irqsave(&conf->device_lock, flags);
 304	list_add(&r10_bio->retry_list, &conf->retry_list);
 305	conf->nr_queued ++;
 306	spin_unlock_irqrestore(&conf->device_lock, flags);
 307
 308	/* wake up frozen array... */
 309	wake_up(&conf->wait_barrier);
 310
 311	md_wakeup_thread(mddev->thread);
 312}
 313
 314/*
 315 * raid_end_bio_io() is called when we have finished servicing a mirrored
 316 * operation and are ready to return a success/failure code to the buffer
 317 * cache layer.
 318 */
 319static void raid_end_bio_io(struct r10bio *r10_bio)
 320{
 321	struct bio *bio = r10_bio->master_bio;
 322	struct r10conf *conf = r10_bio->mddev->private;
 323
 324	if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
 325		bio->bi_status = BLK_STS_IOERR;
 326
 327	bio_endio(bio);
 328	/*
 329	 * Wake up any possible resync thread that waits for the device
 330	 * to go idle.
 331	 */
 332	allow_barrier(conf);
 333
 334	free_r10bio(r10_bio);
 335}
 336
 337/*
 338 * Update disk head position estimator based on IRQ completion info.
 339 */
 340static inline void update_head_pos(int slot, struct r10bio *r10_bio)
 341{
 342	struct r10conf *conf = r10_bio->mddev->private;
 343
 344	conf->mirrors[r10_bio->devs[slot].devnum].head_position =
 345		r10_bio->devs[slot].addr + (r10_bio->sectors);
 346}
 347
 348/*
 349 * Find the disk number which triggered given bio
 350 */
 351static int find_bio_disk(struct r10conf *conf, struct r10bio *r10_bio,
 352			 struct bio *bio, int *slotp, int *replp)
 353{
 354	int slot;
 355	int repl = 0;
 356
 357	for (slot = 0; slot < conf->geo.raid_disks; slot++) {
 358		if (r10_bio->devs[slot].bio == bio)
 359			break;
 360		if (r10_bio->devs[slot].repl_bio == bio) {
 361			repl = 1;
 362			break;
 363		}
 364	}
 365
 366	update_head_pos(slot, r10_bio);
 367
 368	if (slotp)
 369		*slotp = slot;
 370	if (replp)
 371		*replp = repl;
 372	return r10_bio->devs[slot].devnum;
 373}
 374
 375static void raid10_end_read_request(struct bio *bio)
 376{
 377	int uptodate = !bio->bi_status;
 378	struct r10bio *r10_bio = bio->bi_private;
 379	int slot;
 380	struct md_rdev *rdev;
 381	struct r10conf *conf = r10_bio->mddev->private;
 382
 383	slot = r10_bio->read_slot;
 384	rdev = r10_bio->devs[slot].rdev;
 385	/*
 386	 * this branch is our 'one mirror IO has finished' event handler:
 387	 */
 388	update_head_pos(slot, r10_bio);
 389
 390	if (uptodate) {
 391		/*
 392		 * Set R10BIO_Uptodate in our master bio, so that
 393		 * we will return a good error code to the higher
 394		 * levels even if IO on some other mirrored buffer fails.
 395		 *
 396		 * The 'master' represents the composite IO operation to
 397		 * user-side. So if something waits for IO, then it will
 398		 * wait for the 'master' bio.
 399		 */
 400		set_bit(R10BIO_Uptodate, &r10_bio->state);
 401	} else {
 402		/* If all other devices that store this block have
 403		 * failed, we want to return the error upwards rather
 404		 * than fail the last device.  Here we redefine
 405		 * "uptodate" to mean "Don't want to retry"
 406		 */
 407		if (!_enough(conf, test_bit(R10BIO_Previous, &r10_bio->state),
 408			     rdev->raid_disk))
 409			uptodate = 1;
 410	}
 411	if (uptodate) {
 412		raid_end_bio_io(r10_bio);
 413		rdev_dec_pending(rdev, conf->mddev);
 414	} else {
 415		/*
 416		 * oops, read error - keep the refcount on the rdev
 417		 */
 418		pr_err_ratelimited("md/raid10:%s: %pg: rescheduling sector %llu\n",
 419				   mdname(conf->mddev),
 420				   rdev->bdev,
 421				   (unsigned long long)r10_bio->sector);
 422		set_bit(R10BIO_ReadError, &r10_bio->state);
 423		reschedule_retry(r10_bio);
 424	}
 425}
 426
 427static void close_write(struct r10bio *r10_bio)
 428{
 429	struct mddev *mddev = r10_bio->mddev;
 430
 431	md_write_end(mddev);
 
 
 
 432}
 433
 434static void one_write_done(struct r10bio *r10_bio)
 435{
 436	if (atomic_dec_and_test(&r10_bio->remaining)) {
 437		if (test_bit(R10BIO_WriteError, &r10_bio->state))
 438			reschedule_retry(r10_bio);
 439		else {
 440			close_write(r10_bio);
 441			if (test_bit(R10BIO_MadeGood, &r10_bio->state))
 442				reschedule_retry(r10_bio);
 443			else
 444				raid_end_bio_io(r10_bio);
 445		}
 446	}
 447}
 448
 449static void raid10_end_write_request(struct bio *bio)
 450{
 451	struct r10bio *r10_bio = bio->bi_private;
 452	int dev;
 453	int dec_rdev = 1;
 454	struct r10conf *conf = r10_bio->mddev->private;
 455	int slot, repl;
 456	struct md_rdev *rdev = NULL;
 457	struct bio *to_put = NULL;
 458	bool discard_error;
 459
 460	discard_error = bio->bi_status && bio_op(bio) == REQ_OP_DISCARD;
 461
 462	dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
 463
 464	if (repl)
 465		rdev = conf->mirrors[dev].replacement;
 466	if (!rdev) {
 467		smp_rmb();
 468		repl = 0;
 469		rdev = conf->mirrors[dev].rdev;
 470	}
 471	/*
 472	 * this branch is our 'one mirror IO has finished' event handler:
 473	 */
 474	if (bio->bi_status && !discard_error) {
 475		if (repl)
 476			/* Never record new bad blocks to replacement,
 477			 * just fail it.
 478			 */
 479			md_error(rdev->mddev, rdev);
 480		else {
 481			set_bit(WriteErrorSeen,	&rdev->flags);
 482			if (!test_and_set_bit(WantReplacement, &rdev->flags))
 483				set_bit(MD_RECOVERY_NEEDED,
 484					&rdev->mddev->recovery);
 485
 486			dec_rdev = 0;
 487			if (test_bit(FailFast, &rdev->flags) &&
 488			    (bio->bi_opf & MD_FAILFAST)) {
 489				md_error(rdev->mddev, rdev);
 490			}
 491
 492			/*
 493			 * When the device is faulty, it is not necessary to
 494			 * handle write error.
 495			 */
 496			if (!test_bit(Faulty, &rdev->flags))
 497				set_bit(R10BIO_WriteError, &r10_bio->state);
 498			else {
 499				/* Fail the request */
 
 500				r10_bio->devs[slot].bio = NULL;
 501				to_put = bio;
 502				dec_rdev = 1;
 503			}
 504		}
 505	} else {
 506		/*
 507		 * Set R10BIO_Uptodate in our master bio, so that
 508		 * we will return a good error code for to the higher
 509		 * levels even if IO on some other mirrored buffer fails.
 510		 *
 511		 * The 'master' represents the composite IO operation to
 512		 * user-side. So if something waits for IO, then it will
 513		 * wait for the 'master' bio.
 514		 *
 
 
 
 
 515		 * Do not set R10BIO_Uptodate if the current device is
 516		 * rebuilding or Faulty. This is because we cannot use
 517		 * such device for properly reading the data back (we could
 518		 * potentially use it, if the current write would have felt
 519		 * before rdev->recovery_offset, but for simplicity we don't
 520		 * check this here.
 521		 */
 522		if (test_bit(In_sync, &rdev->flags) &&
 523		    !test_bit(Faulty, &rdev->flags))
 524			set_bit(R10BIO_Uptodate, &r10_bio->state);
 525
 526		/* Maybe we can clear some bad blocks. */
 527		if (rdev_has_badblock(rdev, r10_bio->devs[slot].addr,
 528				      r10_bio->sectors) &&
 529		    !discard_error) {
 
 530			bio_put(bio);
 531			if (repl)
 532				r10_bio->devs[slot].repl_bio = IO_MADE_GOOD;
 533			else
 534				r10_bio->devs[slot].bio = IO_MADE_GOOD;
 535			dec_rdev = 0;
 536			set_bit(R10BIO_MadeGood, &r10_bio->state);
 537		}
 538	}
 539
 540	/*
 541	 *
 542	 * Let's see if all mirrored write operations have finished
 543	 * already.
 544	 */
 545	one_write_done(r10_bio);
 546	if (dec_rdev)
 547		rdev_dec_pending(rdev, conf->mddev);
 548	if (to_put)
 549		bio_put(to_put);
 550}
 551
 552/*
 553 * RAID10 layout manager
 554 * As well as the chunksize and raid_disks count, there are two
 555 * parameters: near_copies and far_copies.
 556 * near_copies * far_copies must be <= raid_disks.
 557 * Normally one of these will be 1.
 558 * If both are 1, we get raid0.
 559 * If near_copies == raid_disks, we get raid1.
 560 *
 561 * Chunks are laid out in raid0 style with near_copies copies of the
 562 * first chunk, followed by near_copies copies of the next chunk and
 563 * so on.
 564 * If far_copies > 1, then after 1/far_copies of the array has been assigned
 565 * as described above, we start again with a device offset of near_copies.
 566 * So we effectively have another copy of the whole array further down all
 567 * the drives, but with blocks on different drives.
 568 * With this layout, and block is never stored twice on the one device.
 569 *
 570 * raid10_find_phys finds the sector offset of a given virtual sector
 571 * on each device that it is on.
 572 *
 573 * raid10_find_virt does the reverse mapping, from a device and a
 574 * sector offset to a virtual address
 575 */
 576
 577static void __raid10_find_phys(struct geom *geo, struct r10bio *r10bio)
 578{
 579	int n,f;
 580	sector_t sector;
 581	sector_t chunk;
 582	sector_t stripe;
 583	int dev;
 584	int slot = 0;
 585	int last_far_set_start, last_far_set_size;
 586
 587	last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
 588	last_far_set_start *= geo->far_set_size;
 589
 590	last_far_set_size = geo->far_set_size;
 591	last_far_set_size += (geo->raid_disks % geo->far_set_size);
 592
 593	/* now calculate first sector/dev */
 594	chunk = r10bio->sector >> geo->chunk_shift;
 595	sector = r10bio->sector & geo->chunk_mask;
 596
 597	chunk *= geo->near_copies;
 598	stripe = chunk;
 599	dev = sector_div(stripe, geo->raid_disks);
 600	if (geo->far_offset)
 601		stripe *= geo->far_copies;
 602
 603	sector += stripe << geo->chunk_shift;
 604
 605	/* and calculate all the others */
 606	for (n = 0; n < geo->near_copies; n++) {
 607		int d = dev;
 608		int set;
 609		sector_t s = sector;
 610		r10bio->devs[slot].devnum = d;
 611		r10bio->devs[slot].addr = s;
 612		slot++;
 613
 614		for (f = 1; f < geo->far_copies; f++) {
 615			set = d / geo->far_set_size;
 616			d += geo->near_copies;
 617
 618			if ((geo->raid_disks % geo->far_set_size) &&
 619			    (d > last_far_set_start)) {
 620				d -= last_far_set_start;
 621				d %= last_far_set_size;
 622				d += last_far_set_start;
 623			} else {
 624				d %= geo->far_set_size;
 625				d += geo->far_set_size * set;
 626			}
 627			s += geo->stride;
 628			r10bio->devs[slot].devnum = d;
 629			r10bio->devs[slot].addr = s;
 630			slot++;
 631		}
 632		dev++;
 633		if (dev >= geo->raid_disks) {
 634			dev = 0;
 635			sector += (geo->chunk_mask + 1);
 636		}
 637	}
 638}
 639
 640static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
 641{
 642	struct geom *geo = &conf->geo;
 643
 644	if (conf->reshape_progress != MaxSector &&
 645	    ((r10bio->sector >= conf->reshape_progress) !=
 646	     conf->mddev->reshape_backwards)) {
 647		set_bit(R10BIO_Previous, &r10bio->state);
 648		geo = &conf->prev;
 649	} else
 650		clear_bit(R10BIO_Previous, &r10bio->state);
 651
 652	__raid10_find_phys(geo, r10bio);
 653}
 654
 655static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
 656{
 657	sector_t offset, chunk, vchunk;
 658	/* Never use conf->prev as this is only called during resync
 659	 * or recovery, so reshape isn't happening
 660	 */
 661	struct geom *geo = &conf->geo;
 662	int far_set_start = (dev / geo->far_set_size) * geo->far_set_size;
 663	int far_set_size = geo->far_set_size;
 664	int last_far_set_start;
 665
 666	if (geo->raid_disks % geo->far_set_size) {
 667		last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
 668		last_far_set_start *= geo->far_set_size;
 669
 670		if (dev >= last_far_set_start) {
 671			far_set_size = geo->far_set_size;
 672			far_set_size += (geo->raid_disks % geo->far_set_size);
 673			far_set_start = last_far_set_start;
 674		}
 675	}
 676
 677	offset = sector & geo->chunk_mask;
 678	if (geo->far_offset) {
 679		int fc;
 680		chunk = sector >> geo->chunk_shift;
 681		fc = sector_div(chunk, geo->far_copies);
 682		dev -= fc * geo->near_copies;
 683		if (dev < far_set_start)
 684			dev += far_set_size;
 685	} else {
 686		while (sector >= geo->stride) {
 687			sector -= geo->stride;
 688			if (dev < (geo->near_copies + far_set_start))
 689				dev += far_set_size - geo->near_copies;
 690			else
 691				dev -= geo->near_copies;
 692		}
 693		chunk = sector >> geo->chunk_shift;
 694	}
 695	vchunk = chunk * geo->raid_disks + dev;
 696	sector_div(vchunk, geo->near_copies);
 697	return (vchunk << geo->chunk_shift) + offset;
 698}
 699
 700/*
 701 * This routine returns the disk from which the requested read should
 702 * be done. There is a per-array 'next expected sequential IO' sector
 703 * number - if this matches on the next IO then we use the last disk.
 704 * There is also a per-disk 'last know head position' sector that is
 705 * maintained from IRQ contexts, both the normal and the resync IO
 706 * completion handlers update this position correctly. If there is no
 707 * perfect sequential match then we pick the disk whose head is closest.
 708 *
 709 * If there are 2 mirrors in the same 2 devices, performance degrades
 710 * because position is mirror, not device based.
 711 *
 712 * The rdev for the device selected will have nr_pending incremented.
 713 */
 714
 715/*
 716 * FIXME: possibly should rethink readbalancing and do it differently
 717 * depending on near_copies / far_copies geometry.
 718 */
 719static struct md_rdev *read_balance(struct r10conf *conf,
 720				    struct r10bio *r10_bio,
 721				    int *max_sectors)
 722{
 723	const sector_t this_sector = r10_bio->sector;
 724	int disk, slot;
 725	int sectors = r10_bio->sectors;
 726	int best_good_sectors;
 727	sector_t new_distance, best_dist;
 728	struct md_rdev *best_dist_rdev, *best_pending_rdev, *rdev = NULL;
 729	int do_balance;
 730	int best_dist_slot, best_pending_slot;
 731	bool has_nonrot_disk = false;
 732	unsigned int min_pending;
 733	struct geom *geo = &conf->geo;
 734
 735	raid10_find_phys(conf, r10_bio);
 736	best_dist_slot = -1;
 737	min_pending = UINT_MAX;
 738	best_dist_rdev = NULL;
 739	best_pending_rdev = NULL;
 740	best_dist = MaxSector;
 741	best_good_sectors = 0;
 742	do_balance = 1;
 743	clear_bit(R10BIO_FailFast, &r10_bio->state);
 744
 745	if (raid1_should_read_first(conf->mddev, this_sector, sectors))
 
 
 
 
 
 
 
 
 
 746		do_balance = 0;
 747
 748	for (slot = 0; slot < conf->copies ; slot++) {
 749		sector_t first_bad;
 750		int bad_sectors;
 751		sector_t dev_sector;
 752		unsigned int pending;
 753		bool nonrot;
 754
 755		if (r10_bio->devs[slot].bio == IO_BLOCKED)
 756			continue;
 757		disk = r10_bio->devs[slot].devnum;
 758		rdev = conf->mirrors[disk].replacement;
 759		if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
 760		    r10_bio->devs[slot].addr + sectors >
 761		    rdev->recovery_offset)
 762			rdev = conf->mirrors[disk].rdev;
 763		if (rdev == NULL ||
 764		    test_bit(Faulty, &rdev->flags))
 765			continue;
 766		if (!test_bit(In_sync, &rdev->flags) &&
 767		    r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
 768			continue;
 769
 770		dev_sector = r10_bio->devs[slot].addr;
 771		if (is_badblock(rdev, dev_sector, sectors,
 772				&first_bad, &bad_sectors)) {
 773			if (best_dist < MaxSector)
 774				/* Already have a better slot */
 775				continue;
 776			if (first_bad <= dev_sector) {
 777				/* Cannot read here.  If this is the
 778				 * 'primary' device, then we must not read
 779				 * beyond 'bad_sectors' from another device.
 780				 */
 781				bad_sectors -= (dev_sector - first_bad);
 782				if (!do_balance && sectors > bad_sectors)
 783					sectors = bad_sectors;
 784				if (best_good_sectors > sectors)
 785					best_good_sectors = sectors;
 786			} else {
 787				sector_t good_sectors =
 788					first_bad - dev_sector;
 789				if (good_sectors > best_good_sectors) {
 790					best_good_sectors = good_sectors;
 791					best_dist_slot = slot;
 792					best_dist_rdev = rdev;
 793				}
 794				if (!do_balance)
 795					/* Must read from here */
 796					break;
 797			}
 798			continue;
 799		} else
 800			best_good_sectors = sectors;
 801
 802		if (!do_balance)
 803			break;
 804
 805		nonrot = bdev_nonrot(rdev->bdev);
 806		has_nonrot_disk |= nonrot;
 807		pending = atomic_read(&rdev->nr_pending);
 808		if (min_pending > pending && nonrot) {
 809			min_pending = pending;
 810			best_pending_slot = slot;
 811			best_pending_rdev = rdev;
 812		}
 813
 814		if (best_dist_slot >= 0)
 815			/* At least 2 disks to choose from so failfast is OK */
 816			set_bit(R10BIO_FailFast, &r10_bio->state);
 817		/* This optimisation is debatable, and completely destroys
 818		 * sequential read speed for 'far copies' arrays.  So only
 819		 * keep it for 'near' arrays, and review those later.
 820		 */
 821		if (geo->near_copies > 1 && !pending)
 822			new_distance = 0;
 823
 824		/* for far > 1 always use the lowest address */
 825		else if (geo->far_copies > 1)
 826			new_distance = r10_bio->devs[slot].addr;
 827		else
 828			new_distance = abs(r10_bio->devs[slot].addr -
 829					   conf->mirrors[disk].head_position);
 830
 831		if (new_distance < best_dist) {
 832			best_dist = new_distance;
 833			best_dist_slot = slot;
 834			best_dist_rdev = rdev;
 835		}
 836	}
 837	if (slot >= conf->copies) {
 838		if (has_nonrot_disk) {
 839			slot = best_pending_slot;
 840			rdev = best_pending_rdev;
 841		} else {
 842			slot = best_dist_slot;
 843			rdev = best_dist_rdev;
 844		}
 845	}
 846
 847	if (slot >= 0) {
 848		atomic_inc(&rdev->nr_pending);
 849		r10_bio->read_slot = slot;
 850	} else
 851		rdev = NULL;
 852	*max_sectors = best_good_sectors;
 853
 854	return rdev;
 855}
 856
 857static void flush_pending_writes(struct r10conf *conf)
 858{
 859	/* Any writes that have been queued but are awaiting
 860	 * bitmap updates get flushed here.
 861	 */
 862	spin_lock_irq(&conf->device_lock);
 863
 864	if (conf->pending_bio_list.head) {
 865		struct blk_plug plug;
 866		struct bio *bio;
 867
 868		bio = bio_list_get(&conf->pending_bio_list);
 869		spin_unlock_irq(&conf->device_lock);
 870
 871		/*
 872		 * As this is called in a wait_event() loop (see freeze_array),
 873		 * current->state might be TASK_UNINTERRUPTIBLE which will
 874		 * cause a warning when we prepare to wait again.  As it is
 875		 * rare that this path is taken, it is perfectly safe to force
 876		 * us to go around the wait_event() loop again, so the warning
 877		 * is a false-positive. Silence the warning by resetting
 878		 * thread state
 879		 */
 880		__set_current_state(TASK_RUNNING);
 881
 882		blk_start_plug(&plug);
 883		raid1_prepare_flush_writes(conf->mddev);
 884		wake_up(&conf->wait_barrier);
 885
 886		while (bio) { /* submit pending writes */
 887			struct bio *next = bio->bi_next;
 888
 889			raid1_submit_write(bio);
 890			bio = next;
 891			cond_resched();
 892		}
 893		blk_finish_plug(&plug);
 894	} else
 895		spin_unlock_irq(&conf->device_lock);
 896}
 897
 898/* Barriers....
 899 * Sometimes we need to suspend IO while we do something else,
 900 * either some resync/recovery, or reconfigure the array.
 901 * To do this we raise a 'barrier'.
 902 * The 'barrier' is a counter that can be raised multiple times
 903 * to count how many activities are happening which preclude
 904 * normal IO.
 905 * We can only raise the barrier if there is no pending IO.
 906 * i.e. if nr_pending == 0.
 907 * We choose only to raise the barrier if no-one is waiting for the
 908 * barrier to go down.  This means that as soon as an IO request
 909 * is ready, no other operations which require a barrier will start
 910 * until the IO request has had a chance.
 911 *
 912 * So: regular IO calls 'wait_barrier'.  When that returns there
 913 *    is no backgroup IO happening,  It must arrange to call
 914 *    allow_barrier when it has finished its IO.
 915 * backgroup IO calls must call raise_barrier.  Once that returns
 916 *    there is no normal IO happeing.  It must arrange to call
 917 *    lower_barrier when the particular background IO completes.
 918 */
 919
 920static void raise_barrier(struct r10conf *conf, int force)
 921{
 922	write_seqlock_irq(&conf->resync_lock);
 923
 924	if (WARN_ON_ONCE(force && !conf->barrier))
 925		force = false;
 926
 927	/* Wait until no block IO is waiting (unless 'force') */
 928	wait_event_barrier(conf, force || !conf->nr_waiting);
 929
 930	/* block any new IO from starting */
 931	WRITE_ONCE(conf->barrier, conf->barrier + 1);
 932
 933	/* Now wait for all pending IO to complete */
 934	wait_event_barrier(conf, !atomic_read(&conf->nr_pending) &&
 935				 conf->barrier < RESYNC_DEPTH);
 936
 937	write_sequnlock_irq(&conf->resync_lock);
 938}
 939
 940static void lower_barrier(struct r10conf *conf)
 941{
 942	unsigned long flags;
 943
 944	write_seqlock_irqsave(&conf->resync_lock, flags);
 945	WRITE_ONCE(conf->barrier, conf->barrier - 1);
 946	write_sequnlock_irqrestore(&conf->resync_lock, flags);
 947	wake_up(&conf->wait_barrier);
 948}
 949
 950static bool stop_waiting_barrier(struct r10conf *conf)
 951{
 952	struct bio_list *bio_list = current->bio_list;
 953	struct md_thread *thread;
 954
 955	/* barrier is dropped */
 956	if (!conf->barrier)
 957		return true;
 958
 959	/*
 960	 * If there are already pending requests (preventing the barrier from
 961	 * rising completely), and the pre-process bio queue isn't empty, then
 962	 * don't wait, as we need to empty that queue to get the nr_pending
 963	 * count down.
 964	 */
 965	if (atomic_read(&conf->nr_pending) && bio_list &&
 966	    (!bio_list_empty(&bio_list[0]) || !bio_list_empty(&bio_list[1])))
 967		return true;
 968
 969	/* daemon thread must exist while handling io */
 970	thread = rcu_dereference_protected(conf->mddev->thread, true);
 971	/*
 972	 * move on if io is issued from raid10d(), nr_pending is not released
 973	 * from original io(see handle_read_error()). All raise barrier is
 974	 * blocked until this io is done.
 975	 */
 976	if (thread->tsk == current) {
 977		WARN_ON_ONCE(atomic_read(&conf->nr_pending) == 0);
 978		return true;
 979	}
 980
 981	return false;
 982}
 983
 984static bool wait_barrier_nolock(struct r10conf *conf)
 985{
 986	unsigned int seq = read_seqbegin(&conf->resync_lock);
 987
 988	if (READ_ONCE(conf->barrier))
 989		return false;
 990
 991	atomic_inc(&conf->nr_pending);
 992	if (!read_seqretry(&conf->resync_lock, seq))
 993		return true;
 994
 995	if (atomic_dec_and_test(&conf->nr_pending))
 996		wake_up_barrier(conf);
 997
 998	return false;
 999}
1000
1001static bool wait_barrier(struct r10conf *conf, bool nowait)
1002{
1003	bool ret = true;
1004
1005	if (wait_barrier_nolock(conf))
1006		return true;
1007
1008	write_seqlock_irq(&conf->resync_lock);
1009	if (conf->barrier) {
1010		/* Return false when nowait flag is set */
1011		if (nowait) {
1012			ret = false;
1013		} else {
1014			conf->nr_waiting++;
1015			mddev_add_trace_msg(conf->mddev, "raid10 wait barrier");
1016			wait_event_barrier(conf, stop_waiting_barrier(conf));
1017			conf->nr_waiting--;
1018		}
1019		if (!conf->nr_waiting)
1020			wake_up(&conf->wait_barrier);
1021	}
1022	/* Only increment nr_pending when we wait */
1023	if (ret)
1024		atomic_inc(&conf->nr_pending);
1025	write_sequnlock_irq(&conf->resync_lock);
1026	return ret;
1027}
1028
1029static void allow_barrier(struct r10conf *conf)
1030{
1031	if ((atomic_dec_and_test(&conf->nr_pending)) ||
1032			(conf->array_freeze_pending))
1033		wake_up_barrier(conf);
1034}
1035
1036static void freeze_array(struct r10conf *conf, int extra)
1037{
1038	/* stop syncio and normal IO and wait for everything to
1039	 * go quiet.
1040	 * We increment barrier and nr_waiting, and then
1041	 * wait until nr_pending match nr_queued+extra
1042	 * This is called in the context of one normal IO request
1043	 * that has failed. Thus any sync request that might be pending
1044	 * will be blocked by nr_pending, and we need to wait for
1045	 * pending IO requests to complete or be queued for re-try.
1046	 * Thus the number queued (nr_queued) plus this request (extra)
1047	 * must match the number of pending IOs (nr_pending) before
1048	 * we continue.
1049	 */
1050	write_seqlock_irq(&conf->resync_lock);
1051	conf->array_freeze_pending++;
1052	WRITE_ONCE(conf->barrier, conf->barrier + 1);
1053	conf->nr_waiting++;
1054	wait_event_barrier_cmd(conf, atomic_read(&conf->nr_pending) ==
1055			conf->nr_queued + extra, flush_pending_writes(conf));
1056	conf->array_freeze_pending--;
1057	write_sequnlock_irq(&conf->resync_lock);
1058}
1059
1060static void unfreeze_array(struct r10conf *conf)
1061{
1062	/* reverse the effect of the freeze */
1063	write_seqlock_irq(&conf->resync_lock);
1064	WRITE_ONCE(conf->barrier, conf->barrier - 1);
1065	conf->nr_waiting--;
1066	wake_up(&conf->wait_barrier);
1067	write_sequnlock_irq(&conf->resync_lock);
1068}
1069
1070static sector_t choose_data_offset(struct r10bio *r10_bio,
1071				   struct md_rdev *rdev)
1072{
1073	if (!test_bit(MD_RECOVERY_RESHAPE, &rdev->mddev->recovery) ||
1074	    test_bit(R10BIO_Previous, &r10_bio->state))
1075		return rdev->data_offset;
1076	else
1077		return rdev->new_data_offset;
1078}
1079
1080static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
1081{
1082	struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb, cb);
1083	struct mddev *mddev = plug->cb.data;
1084	struct r10conf *conf = mddev->private;
1085	struct bio *bio;
1086
1087	if (from_schedule) {
1088		spin_lock_irq(&conf->device_lock);
1089		bio_list_merge(&conf->pending_bio_list, &plug->pending);
1090		spin_unlock_irq(&conf->device_lock);
1091		wake_up_barrier(conf);
1092		md_wakeup_thread(mddev->thread);
1093		kfree(plug);
1094		return;
1095	}
1096
1097	/* we aren't scheduling, so we can do the write-out directly. */
1098	bio = bio_list_get(&plug->pending);
1099	raid1_prepare_flush_writes(mddev);
1100	wake_up_barrier(conf);
1101
1102	while (bio) { /* submit pending writes */
1103		struct bio *next = bio->bi_next;
1104
1105		raid1_submit_write(bio);
1106		bio = next;
1107		cond_resched();
1108	}
1109	kfree(plug);
1110}
1111
1112/*
1113 * 1. Register the new request and wait if the reconstruction thread has put
1114 * up a bar for new requests. Continue immediately if no resync is active
1115 * currently.
1116 * 2. If IO spans the reshape position.  Need to wait for reshape to pass.
1117 */
1118static bool regular_request_wait(struct mddev *mddev, struct r10conf *conf,
1119				 struct bio *bio, sector_t sectors)
1120{
1121	/* Bail out if REQ_NOWAIT is set for the bio */
1122	if (!wait_barrier(conf, bio->bi_opf & REQ_NOWAIT)) {
1123		bio_wouldblock_error(bio);
1124		return false;
1125	}
1126	while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1127	    bio->bi_iter.bi_sector < conf->reshape_progress &&
1128	    bio->bi_iter.bi_sector + sectors > conf->reshape_progress) {
1129		allow_barrier(conf);
1130		if (bio->bi_opf & REQ_NOWAIT) {
1131			bio_wouldblock_error(bio);
1132			return false;
1133		}
1134		mddev_add_trace_msg(conf->mddev, "raid10 wait reshape");
1135		wait_event(conf->wait_barrier,
1136			   conf->reshape_progress <= bio->bi_iter.bi_sector ||
1137			   conf->reshape_progress >= bio->bi_iter.bi_sector +
1138			   sectors);
1139		wait_barrier(conf, false);
1140	}
1141	return true;
1142}
1143
1144static void raid10_read_request(struct mddev *mddev, struct bio *bio,
1145				struct r10bio *r10_bio, bool io_accounting)
1146{
1147	struct r10conf *conf = mddev->private;
1148	struct bio *read_bio;
1149	const enum req_op op = bio_op(bio);
1150	const blk_opf_t do_sync = bio->bi_opf & REQ_SYNC;
1151	int max_sectors;
1152	struct md_rdev *rdev;
1153	char b[BDEVNAME_SIZE];
1154	int slot = r10_bio->read_slot;
1155	struct md_rdev *err_rdev = NULL;
1156	gfp_t gfp = GFP_NOIO;
1157	int error;
1158
1159	if (slot >= 0 && r10_bio->devs[slot].rdev) {
1160		/*
1161		 * This is an error retry, but we cannot
1162		 * safely dereference the rdev in the r10_bio,
1163		 * we must use the one in conf.
1164		 * If it has already been disconnected (unlikely)
1165		 * we lose the device name in error messages.
1166		 */
1167		int disk;
1168		/*
1169		 * As we are blocking raid10, it is a little safer to
1170		 * use __GFP_HIGH.
1171		 */
1172		gfp = GFP_NOIO | __GFP_HIGH;
1173
1174		disk = r10_bio->devs[slot].devnum;
1175		err_rdev = conf->mirrors[disk].rdev;
1176		if (err_rdev)
1177			snprintf(b, sizeof(b), "%pg", err_rdev->bdev);
1178		else {
1179			strcpy(b, "???");
1180			/* This never gets dereferenced */
1181			err_rdev = r10_bio->devs[slot].rdev;
1182		}
1183	}
1184
1185	if (!regular_request_wait(mddev, conf, bio, r10_bio->sectors))
1186		return;
1187	rdev = read_balance(conf, r10_bio, &max_sectors);
1188	if (!rdev) {
1189		if (err_rdev) {
1190			pr_crit_ratelimited("md/raid10:%s: %s: unrecoverable I/O read error for block %llu\n",
1191					    mdname(mddev), b,
1192					    (unsigned long long)r10_bio->sector);
1193		}
1194		raid_end_bio_io(r10_bio);
1195		return;
1196	}
1197	if (err_rdev)
1198		pr_err_ratelimited("md/raid10:%s: %pg: redirecting sector %llu to another mirror\n",
1199				   mdname(mddev),
1200				   rdev->bdev,
1201				   (unsigned long long)r10_bio->sector);
1202	if (max_sectors < bio_sectors(bio)) {
1203		struct bio *split = bio_split(bio, max_sectors,
1204					      gfp, &conf->bio_split);
1205		if (IS_ERR(split)) {
1206			error = PTR_ERR(split);
1207			goto err_handle;
1208		}
1209		bio_chain(split, bio);
1210		allow_barrier(conf);
1211		submit_bio_noacct(bio);
1212		wait_barrier(conf, false);
1213		bio = split;
1214		r10_bio->master_bio = bio;
1215		r10_bio->sectors = max_sectors;
1216	}
1217	slot = r10_bio->read_slot;
1218
1219	if (io_accounting) {
1220		md_account_bio(mddev, &bio);
1221		r10_bio->master_bio = bio;
1222	}
1223	read_bio = bio_alloc_clone(rdev->bdev, bio, gfp, &mddev->bio_set);
1224
1225	r10_bio->devs[slot].bio = read_bio;
1226	r10_bio->devs[slot].rdev = rdev;
1227
1228	read_bio->bi_iter.bi_sector = r10_bio->devs[slot].addr +
1229		choose_data_offset(r10_bio, rdev);
1230	read_bio->bi_end_io = raid10_end_read_request;
1231	read_bio->bi_opf = op | do_sync;
1232	if (test_bit(FailFast, &rdev->flags) &&
1233	    test_bit(R10BIO_FailFast, &r10_bio->state))
1234	        read_bio->bi_opf |= MD_FAILFAST;
1235	read_bio->bi_private = r10_bio;
1236	mddev_trace_remap(mddev, read_bio, r10_bio->sector);
 
 
 
1237	submit_bio_noacct(read_bio);
1238	return;
1239err_handle:
1240	atomic_dec(&rdev->nr_pending);
1241	bio->bi_status = errno_to_blk_status(error);
1242	set_bit(R10BIO_Uptodate, &r10_bio->state);
1243	raid_end_bio_io(r10_bio);
1244}
1245
1246static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
1247				  struct bio *bio, bool replacement,
1248				  int n_copy)
1249{
1250	const enum req_op op = bio_op(bio);
1251	const blk_opf_t do_sync = bio->bi_opf & REQ_SYNC;
1252	const blk_opf_t do_fua = bio->bi_opf & REQ_FUA;
1253	const blk_opf_t do_atomic = bio->bi_opf & REQ_ATOMIC;
1254	unsigned long flags;
1255	struct r10conf *conf = mddev->private;
1256	struct md_rdev *rdev;
1257	int devnum = r10_bio->devs[n_copy].devnum;
1258	struct bio *mbio;
1259
1260	rdev = replacement ? conf->mirrors[devnum].replacement :
1261			     conf->mirrors[devnum].rdev;
1262
1263	mbio = bio_alloc_clone(rdev->bdev, bio, GFP_NOIO, &mddev->bio_set);
1264	if (replacement)
1265		r10_bio->devs[n_copy].repl_bio = mbio;
1266	else
1267		r10_bio->devs[n_copy].bio = mbio;
1268
1269	mbio->bi_iter.bi_sector	= (r10_bio->devs[n_copy].addr +
1270				   choose_data_offset(r10_bio, rdev));
1271	mbio->bi_end_io	= raid10_end_write_request;
1272	mbio->bi_opf = op | do_sync | do_fua | do_atomic;
1273	if (!replacement && test_bit(FailFast,
1274				     &conf->mirrors[devnum].rdev->flags)
1275			 && enough(conf, devnum))
1276		mbio->bi_opf |= MD_FAILFAST;
1277	mbio->bi_private = r10_bio;
1278	mddev_trace_remap(mddev, mbio, r10_bio->sector);
 
 
 
1279	/* flush_pending_writes() needs access to the rdev so...*/
1280	mbio->bi_bdev = (void *)rdev;
1281
1282	atomic_inc(&r10_bio->remaining);
1283
1284	if (!raid1_add_bio_to_plug(mddev, mbio, raid10_unplug, conf->copies)) {
1285		spin_lock_irqsave(&conf->device_lock, flags);
1286		bio_list_add(&conf->pending_bio_list, mbio);
1287		spin_unlock_irqrestore(&conf->device_lock, flags);
1288		md_wakeup_thread(mddev->thread);
1289	}
1290}
1291
1292static void wait_blocked_dev(struct mddev *mddev, struct r10bio *r10_bio)
1293{
 
1294	struct r10conf *conf = mddev->private;
1295	struct md_rdev *blocked_rdev;
1296	int i;
1297
1298retry_wait:
1299	blocked_rdev = NULL;
1300	for (i = 0; i < conf->copies; i++) {
1301		struct md_rdev *rdev, *rrdev;
1302
1303		rdev = conf->mirrors[i].rdev;
1304		if (rdev) {
 
 
 
 
 
 
 
 
 
 
 
 
 
1305			sector_t dev_sector = r10_bio->devs[i].addr;
 
 
1306
1307			/*
1308			 * Discard request doesn't care the write result
1309			 * so it doesn't need to wait blocked disk here.
1310			 */
1311			if (test_bit(WriteErrorSeen, &rdev->flags) &&
1312			    r10_bio->sectors &&
1313			    rdev_has_badblock(rdev, dev_sector,
1314					      r10_bio->sectors) < 0)
 
 
1315				/*
1316				 * Mustn't write here until the bad
1317				 * block is acknowledged
1318				 */
 
1319				set_bit(BlockedBadBlocks, &rdev->flags);
1320
1321			if (rdev_blocked(rdev)) {
1322				blocked_rdev = rdev;
1323				atomic_inc(&rdev->nr_pending);
1324				break;
1325			}
1326		}
1327
1328		rrdev = conf->mirrors[i].replacement;
1329		if (rrdev && rdev_blocked(rrdev)) {
1330			atomic_inc(&rrdev->nr_pending);
1331			blocked_rdev = rrdev;
1332			break;
1333		}
1334	}
1335
1336	if (unlikely(blocked_rdev)) {
1337		/* Have to wait for this device to get unblocked, then retry */
1338		allow_barrier(conf);
1339		mddev_add_trace_msg(conf->mddev,
1340			"raid10 %s wait rdev %d blocked",
1341			__func__, blocked_rdev->raid_disk);
1342		md_wait_for_blocked_rdev(blocked_rdev, mddev);
1343		wait_barrier(conf, false);
1344		goto retry_wait;
1345	}
1346}
1347
1348static void raid10_write_request(struct mddev *mddev, struct bio *bio,
1349				 struct r10bio *r10_bio)
1350{
1351	struct r10conf *conf = mddev->private;
1352	int i, k;
1353	sector_t sectors;
1354	int max_sectors;
1355	int error;
1356
1357	if ((mddev_is_clustered(mddev) &&
1358	     md_cluster_ops->area_resyncing(mddev, WRITE,
1359					    bio->bi_iter.bi_sector,
1360					    bio_end_sector(bio)))) {
1361		DEFINE_WAIT(w);
1362		/* Bail out if REQ_NOWAIT is set for the bio */
1363		if (bio->bi_opf & REQ_NOWAIT) {
1364			bio_wouldblock_error(bio);
1365			return;
1366		}
1367		for (;;) {
1368			prepare_to_wait(&conf->wait_barrier,
1369					&w, TASK_IDLE);
1370			if (!md_cluster_ops->area_resyncing(mddev, WRITE,
1371				 bio->bi_iter.bi_sector, bio_end_sector(bio)))
1372				break;
1373			schedule();
1374		}
1375		finish_wait(&conf->wait_barrier, &w);
1376	}
1377
1378	sectors = r10_bio->sectors;
1379	if (!regular_request_wait(mddev, conf, bio, sectors))
1380		return;
1381	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1382	    (mddev->reshape_backwards
1383	     ? (bio->bi_iter.bi_sector < conf->reshape_safe &&
1384		bio->bi_iter.bi_sector + sectors > conf->reshape_progress)
1385	     : (bio->bi_iter.bi_sector + sectors > conf->reshape_safe &&
1386		bio->bi_iter.bi_sector < conf->reshape_progress))) {
1387		/* Need to update reshape_position in metadata */
1388		mddev->reshape_position = conf->reshape_progress;
1389		set_mask_bits(&mddev->sb_flags, 0,
1390			      BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1391		md_wakeup_thread(mddev->thread);
1392		if (bio->bi_opf & REQ_NOWAIT) {
1393			allow_barrier(conf);
1394			bio_wouldblock_error(bio);
1395			return;
1396		}
1397		mddev_add_trace_msg(conf->mddev,
1398			"raid10 wait reshape metadata");
1399		wait_event(mddev->sb_wait,
1400			   !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
1401
1402		conf->reshape_safe = mddev->reshape_position;
1403	}
1404
1405	/* first select target devices under rcu_lock and
1406	 * inc refcount on their rdev.  Record them by setting
1407	 * bios[x] to bio
1408	 * If there are known/acknowledged bad blocks on any device
1409	 * on which we have seen a write error, we want to avoid
1410	 * writing to those blocks.  This potentially requires several
1411	 * writes to write around the bad blocks.  Each set of writes
1412	 * gets its own r10_bio with a set of bios attached.
1413	 */
1414
1415	r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
1416	raid10_find_phys(conf, r10_bio);
1417
1418	wait_blocked_dev(mddev, r10_bio);
1419
1420	max_sectors = r10_bio->sectors;
1421
1422	for (i = 0;  i < conf->copies; i++) {
1423		int d = r10_bio->devs[i].devnum;
1424		struct md_rdev *rdev, *rrdev;
1425
1426		rdev = conf->mirrors[d].rdev;
1427		rrdev = conf->mirrors[d].replacement;
1428		if (rdev && (test_bit(Faulty, &rdev->flags)))
1429			rdev = NULL;
1430		if (rrdev && (test_bit(Faulty, &rrdev->flags)))
1431			rrdev = NULL;
1432
1433		r10_bio->devs[i].bio = NULL;
1434		r10_bio->devs[i].repl_bio = NULL;
1435
1436		if (!rdev && !rrdev)
 
1437			continue;
 
1438		if (rdev && test_bit(WriteErrorSeen, &rdev->flags)) {
1439			sector_t first_bad;
1440			sector_t dev_sector = r10_bio->devs[i].addr;
1441			int bad_sectors;
1442			int is_bad;
1443
1444			is_bad = is_badblock(rdev, dev_sector, max_sectors,
1445					     &first_bad, &bad_sectors);
1446			if (is_bad && first_bad <= dev_sector) {
1447				/* Cannot write here at all */
1448				bad_sectors -= (dev_sector - first_bad);
1449				if (bad_sectors < max_sectors)
1450					/* Mustn't write more than bad_sectors
1451					 * to other devices yet
1452					 */
1453					max_sectors = bad_sectors;
 
 
 
 
 
 
 
 
1454				continue;
1455			}
1456			if (is_bad) {
1457				int good_sectors;
1458
1459				/*
1460				 * We cannot atomically write this, so just
1461				 * error in that case. It could be possible to
1462				 * atomically write other mirrors, but the
1463				 * complexity of supporting that is not worth
1464				 * the benefit.
1465				 */
1466				if (bio->bi_opf & REQ_ATOMIC) {
1467					error = -EIO;
1468					goto err_handle;
1469				}
1470
1471				good_sectors = first_bad - dev_sector;
1472				if (good_sectors < max_sectors)
1473					max_sectors = good_sectors;
1474			}
1475		}
1476		if (rdev) {
1477			r10_bio->devs[i].bio = bio;
1478			atomic_inc(&rdev->nr_pending);
1479		}
1480		if (rrdev) {
1481			r10_bio->devs[i].repl_bio = bio;
1482			atomic_inc(&rrdev->nr_pending);
1483		}
1484	}
1485
1486	if (max_sectors < r10_bio->sectors)
1487		r10_bio->sectors = max_sectors;
1488
1489	if (r10_bio->sectors < bio_sectors(bio)) {
1490		struct bio *split = bio_split(bio, r10_bio->sectors,
1491					      GFP_NOIO, &conf->bio_split);
1492		if (IS_ERR(split)) {
1493			error = PTR_ERR(split);
1494			goto err_handle;
1495		}
1496		bio_chain(split, bio);
1497		allow_barrier(conf);
1498		submit_bio_noacct(bio);
1499		wait_barrier(conf, false);
1500		bio = split;
1501		r10_bio->master_bio = bio;
1502	}
1503
1504	md_account_bio(mddev, &bio);
1505	r10_bio->master_bio = bio;
1506	atomic_set(&r10_bio->remaining, 1);
 
1507
1508	for (i = 0; i < conf->copies; i++) {
1509		if (r10_bio->devs[i].bio)
1510			raid10_write_one_disk(mddev, r10_bio, bio, false, i);
1511		if (r10_bio->devs[i].repl_bio)
1512			raid10_write_one_disk(mddev, r10_bio, bio, true, i);
1513	}
1514	one_write_done(r10_bio);
1515	return;
1516err_handle:
1517	for (k = 0;  k < i; k++) {
1518		int d = r10_bio->devs[k].devnum;
1519		struct md_rdev *rdev = conf->mirrors[d].rdev;
1520		struct md_rdev *rrdev = conf->mirrors[d].replacement;
1521
1522		if (r10_bio->devs[k].bio) {
1523			rdev_dec_pending(rdev, mddev);
1524			r10_bio->devs[k].bio = NULL;
1525		}
1526		if (r10_bio->devs[k].repl_bio) {
1527			rdev_dec_pending(rrdev, mddev);
1528			r10_bio->devs[k].repl_bio = NULL;
1529		}
1530	}
1531
1532	bio->bi_status = errno_to_blk_status(error);
1533	set_bit(R10BIO_Uptodate, &r10_bio->state);
1534	raid_end_bio_io(r10_bio);
1535}
1536
1537static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
1538{
1539	struct r10conf *conf = mddev->private;
1540	struct r10bio *r10_bio;
1541
1542	r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
1543
1544	r10_bio->master_bio = bio;
1545	r10_bio->sectors = sectors;
1546
1547	r10_bio->mddev = mddev;
1548	r10_bio->sector = bio->bi_iter.bi_sector;
1549	r10_bio->state = 0;
1550	r10_bio->read_slot = -1;
1551	memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) *
1552			conf->geo.raid_disks);
1553
1554	if (bio_data_dir(bio) == READ)
1555		raid10_read_request(mddev, bio, r10_bio, true);
1556	else
1557		raid10_write_request(mddev, bio, r10_bio);
1558}
1559
1560static void raid_end_discard_bio(struct r10bio *r10bio)
1561{
1562	struct r10conf *conf = r10bio->mddev->private;
1563	struct r10bio *first_r10bio;
1564
1565	while (atomic_dec_and_test(&r10bio->remaining)) {
1566
1567		allow_barrier(conf);
1568
1569		if (!test_bit(R10BIO_Discard, &r10bio->state)) {
1570			first_r10bio = (struct r10bio *)r10bio->master_bio;
1571			free_r10bio(r10bio);
1572			r10bio = first_r10bio;
1573		} else {
1574			md_write_end(r10bio->mddev);
1575			bio_endio(r10bio->master_bio);
1576			free_r10bio(r10bio);
1577			break;
1578		}
1579	}
1580}
1581
1582static void raid10_end_discard_request(struct bio *bio)
1583{
1584	struct r10bio *r10_bio = bio->bi_private;
1585	struct r10conf *conf = r10_bio->mddev->private;
1586	struct md_rdev *rdev = NULL;
1587	int dev;
1588	int slot, repl;
1589
1590	/*
1591	 * We don't care the return value of discard bio
1592	 */
1593	if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
1594		set_bit(R10BIO_Uptodate, &r10_bio->state);
1595
1596	dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
1597	rdev = repl ? conf->mirrors[dev].replacement :
1598		      conf->mirrors[dev].rdev;
1599
1600	raid_end_discard_bio(r10_bio);
1601	rdev_dec_pending(rdev, conf->mddev);
1602}
1603
1604/*
1605 * There are some limitations to handle discard bio
1606 * 1st, the discard size is bigger than stripe_size*2.
1607 * 2st, if the discard bio spans reshape progress, we use the old way to
1608 * handle discard bio
1609 */
1610static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
1611{
1612	struct r10conf *conf = mddev->private;
1613	struct geom *geo = &conf->geo;
1614	int far_copies = geo->far_copies;
1615	bool first_copy = true;
1616	struct r10bio *r10_bio, *first_r10bio;
1617	struct bio *split;
1618	int disk;
1619	sector_t chunk;
1620	unsigned int stripe_size;
1621	unsigned int stripe_data_disks;
1622	sector_t split_size;
1623	sector_t bio_start, bio_end;
1624	sector_t first_stripe_index, last_stripe_index;
1625	sector_t start_disk_offset;
1626	unsigned int start_disk_index;
1627	sector_t end_disk_offset;
1628	unsigned int end_disk_index;
1629	unsigned int remainder;
1630
1631	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
1632		return -EAGAIN;
1633
1634	if (WARN_ON_ONCE(bio->bi_opf & REQ_NOWAIT)) {
1635		bio_wouldblock_error(bio);
1636		return 0;
1637	}
1638	wait_barrier(conf, false);
1639
1640	/*
1641	 * Check reshape again to avoid reshape happens after checking
1642	 * MD_RECOVERY_RESHAPE and before wait_barrier
1643	 */
1644	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
1645		goto out;
1646
1647	if (geo->near_copies)
1648		stripe_data_disks = geo->raid_disks / geo->near_copies +
1649					geo->raid_disks % geo->near_copies;
1650	else
1651		stripe_data_disks = geo->raid_disks;
1652
1653	stripe_size = stripe_data_disks << geo->chunk_shift;
1654
1655	bio_start = bio->bi_iter.bi_sector;
1656	bio_end = bio_end_sector(bio);
1657
1658	/*
1659	 * Maybe one discard bio is smaller than strip size or across one
1660	 * stripe and discard region is larger than one stripe size. For far
1661	 * offset layout, if the discard region is not aligned with stripe
1662	 * size, there is hole when we submit discard bio to member disk.
1663	 * For simplicity, we only handle discard bio which discard region
1664	 * is bigger than stripe_size * 2
1665	 */
1666	if (bio_sectors(bio) < stripe_size*2)
1667		goto out;
1668
1669	/*
1670	 * Keep bio aligned with strip size.
1671	 */
1672	div_u64_rem(bio_start, stripe_size, &remainder);
1673	if (remainder) {
1674		split_size = stripe_size - remainder;
1675		split = bio_split(bio, split_size, GFP_NOIO, &conf->bio_split);
1676		if (IS_ERR(split)) {
1677			bio->bi_status = errno_to_blk_status(PTR_ERR(split));
1678			bio_endio(bio);
1679			return 0;
1680		}
1681		bio_chain(split, bio);
1682		allow_barrier(conf);
1683		/* Resend the fist split part */
1684		submit_bio_noacct(split);
1685		wait_barrier(conf, false);
1686	}
1687	div_u64_rem(bio_end, stripe_size, &remainder);
1688	if (remainder) {
1689		split_size = bio_sectors(bio) - remainder;
1690		split = bio_split(bio, split_size, GFP_NOIO, &conf->bio_split);
1691		if (IS_ERR(split)) {
1692			bio->bi_status = errno_to_blk_status(PTR_ERR(split));
1693			bio_endio(bio);
1694			return 0;
1695		}
1696		bio_chain(split, bio);
1697		allow_barrier(conf);
1698		/* Resend the second split part */
1699		submit_bio_noacct(bio);
1700		bio = split;
1701		wait_barrier(conf, false);
1702	}
1703
1704	bio_start = bio->bi_iter.bi_sector;
1705	bio_end = bio_end_sector(bio);
1706
1707	/*
1708	 * Raid10 uses chunk as the unit to store data. It's similar like raid0.
1709	 * One stripe contains the chunks from all member disk (one chunk from
1710	 * one disk at the same HBA address). For layout detail, see 'man md 4'
1711	 */
1712	chunk = bio_start >> geo->chunk_shift;
1713	chunk *= geo->near_copies;
1714	first_stripe_index = chunk;
1715	start_disk_index = sector_div(first_stripe_index, geo->raid_disks);
1716	if (geo->far_offset)
1717		first_stripe_index *= geo->far_copies;
1718	start_disk_offset = (bio_start & geo->chunk_mask) +
1719				(first_stripe_index << geo->chunk_shift);
1720
1721	chunk = bio_end >> geo->chunk_shift;
1722	chunk *= geo->near_copies;
1723	last_stripe_index = chunk;
1724	end_disk_index = sector_div(last_stripe_index, geo->raid_disks);
1725	if (geo->far_offset)
1726		last_stripe_index *= geo->far_copies;
1727	end_disk_offset = (bio_end & geo->chunk_mask) +
1728				(last_stripe_index << geo->chunk_shift);
1729
1730retry_discard:
1731	r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
1732	r10_bio->mddev = mddev;
1733	r10_bio->state = 0;
1734	r10_bio->sectors = 0;
1735	memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * geo->raid_disks);
1736	wait_blocked_dev(mddev, r10_bio);
1737
1738	/*
1739	 * For far layout it needs more than one r10bio to cover all regions.
1740	 * Inspired by raid10_sync_request, we can use the first r10bio->master_bio
1741	 * to record the discard bio. Other r10bio->master_bio record the first
1742	 * r10bio. The first r10bio only release after all other r10bios finish.
1743	 * The discard bio returns only first r10bio finishes
1744	 */
1745	if (first_copy) {
1746		r10_bio->master_bio = bio;
1747		set_bit(R10BIO_Discard, &r10_bio->state);
1748		first_copy = false;
1749		first_r10bio = r10_bio;
1750	} else
1751		r10_bio->master_bio = (struct bio *)first_r10bio;
1752
1753	/*
1754	 * first select target devices under rcu_lock and
1755	 * inc refcount on their rdev.  Record them by setting
1756	 * bios[x] to bio
1757	 */
1758	for (disk = 0; disk < geo->raid_disks; disk++) {
1759		struct md_rdev *rdev, *rrdev;
1760
1761		rdev = conf->mirrors[disk].rdev;
1762		rrdev = conf->mirrors[disk].replacement;
1763		r10_bio->devs[disk].bio = NULL;
1764		r10_bio->devs[disk].repl_bio = NULL;
1765
1766		if (rdev && (test_bit(Faulty, &rdev->flags)))
1767			rdev = NULL;
1768		if (rrdev && (test_bit(Faulty, &rrdev->flags)))
1769			rrdev = NULL;
1770		if (!rdev && !rrdev)
1771			continue;
1772
1773		if (rdev) {
1774			r10_bio->devs[disk].bio = bio;
1775			atomic_inc(&rdev->nr_pending);
1776		}
1777		if (rrdev) {
1778			r10_bio->devs[disk].repl_bio = bio;
1779			atomic_inc(&rrdev->nr_pending);
1780		}
1781	}
1782
1783	atomic_set(&r10_bio->remaining, 1);
1784	for (disk = 0; disk < geo->raid_disks; disk++) {
1785		sector_t dev_start, dev_end;
1786		struct bio *mbio, *rbio = NULL;
1787
1788		/*
1789		 * Now start to calculate the start and end address for each disk.
1790		 * The space between dev_start and dev_end is the discard region.
1791		 *
1792		 * For dev_start, it needs to consider three conditions:
1793		 * 1st, the disk is before start_disk, you can imagine the disk in
1794		 * the next stripe. So the dev_start is the start address of next
1795		 * stripe.
1796		 * 2st, the disk is after start_disk, it means the disk is at the
1797		 * same stripe of first disk
1798		 * 3st, the first disk itself, we can use start_disk_offset directly
1799		 */
1800		if (disk < start_disk_index)
1801			dev_start = (first_stripe_index + 1) * mddev->chunk_sectors;
1802		else if (disk > start_disk_index)
1803			dev_start = first_stripe_index * mddev->chunk_sectors;
1804		else
1805			dev_start = start_disk_offset;
1806
1807		if (disk < end_disk_index)
1808			dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
1809		else if (disk > end_disk_index)
1810			dev_end = last_stripe_index * mddev->chunk_sectors;
1811		else
1812			dev_end = end_disk_offset;
1813
1814		/*
1815		 * It only handles discard bio which size is >= stripe size, so
1816		 * dev_end > dev_start all the time.
1817		 * It doesn't need to use rcu lock to get rdev here. We already
1818		 * add rdev->nr_pending in the first loop.
1819		 */
1820		if (r10_bio->devs[disk].bio) {
1821			struct md_rdev *rdev = conf->mirrors[disk].rdev;
1822			mbio = bio_alloc_clone(bio->bi_bdev, bio, GFP_NOIO,
1823					       &mddev->bio_set);
1824			mbio->bi_end_io = raid10_end_discard_request;
1825			mbio->bi_private = r10_bio;
1826			r10_bio->devs[disk].bio = mbio;
1827			r10_bio->devs[disk].devnum = disk;
1828			atomic_inc(&r10_bio->remaining);
1829			md_submit_discard_bio(mddev, rdev, mbio,
1830					dev_start + choose_data_offset(r10_bio, rdev),
1831					dev_end - dev_start);
1832			bio_endio(mbio);
1833		}
1834		if (r10_bio->devs[disk].repl_bio) {
1835			struct md_rdev *rrdev = conf->mirrors[disk].replacement;
1836			rbio = bio_alloc_clone(bio->bi_bdev, bio, GFP_NOIO,
1837					       &mddev->bio_set);
1838			rbio->bi_end_io = raid10_end_discard_request;
1839			rbio->bi_private = r10_bio;
1840			r10_bio->devs[disk].repl_bio = rbio;
1841			r10_bio->devs[disk].devnum = disk;
1842			atomic_inc(&r10_bio->remaining);
1843			md_submit_discard_bio(mddev, rrdev, rbio,
1844					dev_start + choose_data_offset(r10_bio, rrdev),
1845					dev_end - dev_start);
1846			bio_endio(rbio);
1847		}
1848	}
1849
1850	if (!geo->far_offset && --far_copies) {
1851		first_stripe_index += geo->stride >> geo->chunk_shift;
1852		start_disk_offset += geo->stride;
1853		last_stripe_index += geo->stride >> geo->chunk_shift;
1854		end_disk_offset += geo->stride;
1855		atomic_inc(&first_r10bio->remaining);
1856		raid_end_discard_bio(r10_bio);
1857		wait_barrier(conf, false);
1858		goto retry_discard;
1859	}
1860
1861	raid_end_discard_bio(r10_bio);
1862
1863	return 0;
1864out:
1865	allow_barrier(conf);
1866	return -EAGAIN;
1867}
1868
1869static bool raid10_make_request(struct mddev *mddev, struct bio *bio)
1870{
1871	struct r10conf *conf = mddev->private;
1872	sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
1873	int chunk_sects = chunk_mask + 1;
1874	int sectors = bio_sectors(bio);
1875
1876	if (unlikely(bio->bi_opf & REQ_PREFLUSH)
1877	    && md_flush_request(mddev, bio))
1878		return true;
1879
1880	md_write_start(mddev, bio);
 
1881
1882	if (unlikely(bio_op(bio) == REQ_OP_DISCARD))
1883		if (!raid10_handle_discard(mddev, bio))
1884			return true;
1885
1886	/*
1887	 * If this request crosses a chunk boundary, we need to split
1888	 * it.
1889	 */
1890	if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
1891		     sectors > chunk_sects
1892		     && (conf->geo.near_copies < conf->geo.raid_disks
1893			 || conf->prev.near_copies <
1894			 conf->prev.raid_disks)))
1895		sectors = chunk_sects -
1896			(bio->bi_iter.bi_sector &
1897			 (chunk_sects - 1));
1898	__make_request(mddev, bio, sectors);
1899
1900	/* In case raid10d snuck in to freeze_array */
1901	wake_up_barrier(conf);
1902	return true;
1903}
1904
1905static void raid10_status(struct seq_file *seq, struct mddev *mddev)
1906{
1907	struct r10conf *conf = mddev->private;
1908	int i;
1909
1910	lockdep_assert_held(&mddev->lock);
1911
1912	if (conf->geo.near_copies < conf->geo.raid_disks)
1913		seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
1914	if (conf->geo.near_copies > 1)
1915		seq_printf(seq, " %d near-copies", conf->geo.near_copies);
1916	if (conf->geo.far_copies > 1) {
1917		if (conf->geo.far_offset)
1918			seq_printf(seq, " %d offset-copies", conf->geo.far_copies);
1919		else
1920			seq_printf(seq, " %d far-copies", conf->geo.far_copies);
1921		if (conf->geo.far_set_size != conf->geo.raid_disks)
1922			seq_printf(seq, " %d devices per set", conf->geo.far_set_size);
1923	}
1924	seq_printf(seq, " [%d/%d] [", conf->geo.raid_disks,
1925					conf->geo.raid_disks - mddev->degraded);
1926	for (i = 0; i < conf->geo.raid_disks; i++) {
1927		struct md_rdev *rdev = READ_ONCE(conf->mirrors[i].rdev);
1928
1929		seq_printf(seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1930	}
1931	seq_printf(seq, "]");
1932}
1933
1934/* check if there are enough drives for
1935 * every block to appear on atleast one.
1936 * Don't consider the device numbered 'ignore'
1937 * as we might be about to remove it.
1938 */
1939static int _enough(struct r10conf *conf, int previous, int ignore)
1940{
1941	int first = 0;
1942	int has_enough = 0;
1943	int disks, ncopies;
1944	if (previous) {
1945		disks = conf->prev.raid_disks;
1946		ncopies = conf->prev.near_copies;
1947	} else {
1948		disks = conf->geo.raid_disks;
1949		ncopies = conf->geo.near_copies;
1950	}
1951
1952	do {
1953		int n = conf->copies;
1954		int cnt = 0;
1955		int this = first;
1956		while (n--) {
1957			struct md_rdev *rdev;
1958			if (this != ignore &&
1959			    (rdev = conf->mirrors[this].rdev) &&
1960			    test_bit(In_sync, &rdev->flags))
1961				cnt++;
1962			this = (this+1) % disks;
1963		}
1964		if (cnt == 0)
1965			goto out;
1966		first = (first + ncopies) % disks;
1967	} while (first != 0);
1968	has_enough = 1;
1969out:
1970	return has_enough;
1971}
1972
1973static int enough(struct r10conf *conf, int ignore)
1974{
1975	/* when calling 'enough', both 'prev' and 'geo' must
1976	 * be stable.
1977	 * This is ensured if ->reconfig_mutex or ->device_lock
1978	 * is held.
1979	 */
1980	return _enough(conf, 0, ignore) &&
1981		_enough(conf, 1, ignore);
1982}
1983
1984/**
1985 * raid10_error() - RAID10 error handler.
1986 * @mddev: affected md device.
1987 * @rdev: member device to fail.
1988 *
1989 * The routine acknowledges &rdev failure and determines new @mddev state.
1990 * If it failed, then:
1991 *	- &MD_BROKEN flag is set in &mddev->flags.
1992 * Otherwise, it must be degraded:
1993 *	- recovery is interrupted.
1994 *	- &mddev->degraded is bumped.
1995 *
1996 * @rdev is marked as &Faulty excluding case when array is failed and
1997 * &mddev->fail_last_dev is off.
1998 */
1999static void raid10_error(struct mddev *mddev, struct md_rdev *rdev)
2000{
2001	struct r10conf *conf = mddev->private;
2002	unsigned long flags;
2003
2004	spin_lock_irqsave(&conf->device_lock, flags);
2005
2006	if (test_bit(In_sync, &rdev->flags) && !enough(conf, rdev->raid_disk)) {
2007		set_bit(MD_BROKEN, &mddev->flags);
2008
2009		if (!mddev->fail_last_dev) {
2010			spin_unlock_irqrestore(&conf->device_lock, flags);
2011			return;
2012		}
2013	}
2014	if (test_and_clear_bit(In_sync, &rdev->flags))
2015		mddev->degraded++;
2016
2017	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2018	set_bit(Blocked, &rdev->flags);
2019	set_bit(Faulty, &rdev->flags);
2020	set_mask_bits(&mddev->sb_flags, 0,
2021		      BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2022	spin_unlock_irqrestore(&conf->device_lock, flags);
2023	pr_crit("md/raid10:%s: Disk failure on %pg, disabling device.\n"
2024		"md/raid10:%s: Operation continuing on %d devices.\n",
2025		mdname(mddev), rdev->bdev,
2026		mdname(mddev), conf->geo.raid_disks - mddev->degraded);
2027}
2028
2029static void print_conf(struct r10conf *conf)
2030{
2031	int i;
2032	struct md_rdev *rdev;
2033
2034	pr_debug("RAID10 conf printout:\n");
2035	if (!conf) {
2036		pr_debug("(!conf)\n");
2037		return;
2038	}
2039	pr_debug(" --- wd:%d rd:%d\n", conf->geo.raid_disks - conf->mddev->degraded,
2040		 conf->geo.raid_disks);
2041
2042	lockdep_assert_held(&conf->mddev->reconfig_mutex);
2043	for (i = 0; i < conf->geo.raid_disks; i++) {
2044		rdev = conf->mirrors[i].rdev;
2045		if (rdev)
2046			pr_debug(" disk %d, wo:%d, o:%d, dev:%pg\n",
2047				 i, !test_bit(In_sync, &rdev->flags),
2048				 !test_bit(Faulty, &rdev->flags),
2049				 rdev->bdev);
2050	}
2051}
2052
2053static void close_sync(struct r10conf *conf)
2054{
2055	wait_barrier(conf, false);
2056	allow_barrier(conf);
2057
2058	mempool_exit(&conf->r10buf_pool);
2059}
2060
2061static int raid10_spare_active(struct mddev *mddev)
2062{
2063	int i;
2064	struct r10conf *conf = mddev->private;
2065	struct raid10_info *tmp;
2066	int count = 0;
2067	unsigned long flags;
2068
2069	/*
2070	 * Find all non-in_sync disks within the RAID10 configuration
2071	 * and mark them in_sync
2072	 */
2073	for (i = 0; i < conf->geo.raid_disks; i++) {
2074		tmp = conf->mirrors + i;
2075		if (tmp->replacement
2076		    && tmp->replacement->recovery_offset == MaxSector
2077		    && !test_bit(Faulty, &tmp->replacement->flags)
2078		    && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
2079			/* Replacement has just become active */
2080			if (!tmp->rdev
2081			    || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
2082				count++;
2083			if (tmp->rdev) {
2084				/* Replaced device not technically faulty,
2085				 * but we need to be sure it gets removed
2086				 * and never re-added.
2087				 */
2088				set_bit(Faulty, &tmp->rdev->flags);
2089				sysfs_notify_dirent_safe(
2090					tmp->rdev->sysfs_state);
2091			}
2092			sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
2093		} else if (tmp->rdev
2094			   && tmp->rdev->recovery_offset == MaxSector
2095			   && !test_bit(Faulty, &tmp->rdev->flags)
2096			   && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
2097			count++;
2098			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
2099		}
2100	}
2101	spin_lock_irqsave(&conf->device_lock, flags);
2102	mddev->degraded -= count;
2103	spin_unlock_irqrestore(&conf->device_lock, flags);
2104
2105	print_conf(conf);
2106	return count;
2107}
2108
2109static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
2110{
2111	struct r10conf *conf = mddev->private;
2112	int err = -EEXIST;
2113	int mirror, repl_slot = -1;
2114	int first = 0;
2115	int last = conf->geo.raid_disks - 1;
2116	struct raid10_info *p;
2117
2118	if (mddev->recovery_cp < MaxSector)
2119		/* only hot-add to in-sync arrays, as recovery is
2120		 * very different from resync
2121		 */
2122		return -EBUSY;
2123	if (rdev->saved_raid_disk < 0 && !_enough(conf, 1, -1))
2124		return -EINVAL;
2125
 
 
 
2126	if (rdev->raid_disk >= 0)
2127		first = last = rdev->raid_disk;
2128
2129	if (rdev->saved_raid_disk >= first &&
2130	    rdev->saved_raid_disk < conf->geo.raid_disks &&
2131	    conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
2132		mirror = rdev->saved_raid_disk;
2133	else
2134		mirror = first;
2135	for ( ; mirror <= last ; mirror++) {
2136		p = &conf->mirrors[mirror];
2137		if (p->recovery_disabled == mddev->recovery_disabled)
2138			continue;
2139		if (p->rdev) {
2140			if (test_bit(WantReplacement, &p->rdev->flags) &&
2141			    p->replacement == NULL && repl_slot < 0)
2142				repl_slot = mirror;
2143			continue;
2144		}
2145
2146		err = mddev_stack_new_rdev(mddev, rdev);
2147		if (err)
2148			return err;
 
2149		p->head_position = 0;
2150		p->recovery_disabled = mddev->recovery_disabled - 1;
2151		rdev->raid_disk = mirror;
2152		err = 0;
2153		if (rdev->saved_raid_disk != mirror)
2154			conf->fullsync = 1;
2155		WRITE_ONCE(p->rdev, rdev);
2156		break;
2157	}
2158
2159	if (err && repl_slot >= 0) {
2160		p = &conf->mirrors[repl_slot];
2161		clear_bit(In_sync, &rdev->flags);
2162		set_bit(Replacement, &rdev->flags);
2163		rdev->raid_disk = repl_slot;
2164		err = mddev_stack_new_rdev(mddev, rdev);
2165		if (err)
2166			return err;
 
2167		conf->fullsync = 1;
2168		WRITE_ONCE(p->replacement, rdev);
2169	}
2170
2171	print_conf(conf);
2172	return err;
2173}
2174
2175static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
2176{
2177	struct r10conf *conf = mddev->private;
2178	int err = 0;
2179	int number = rdev->raid_disk;
2180	struct md_rdev **rdevp;
2181	struct raid10_info *p;
2182
2183	print_conf(conf);
2184	if (unlikely(number >= mddev->raid_disks))
2185		return 0;
2186	p = conf->mirrors + number;
2187	if (rdev == p->rdev)
2188		rdevp = &p->rdev;
2189	else if (rdev == p->replacement)
2190		rdevp = &p->replacement;
2191	else
2192		return 0;
2193
2194	if (test_bit(In_sync, &rdev->flags) ||
2195	    atomic_read(&rdev->nr_pending)) {
2196		err = -EBUSY;
2197		goto abort;
2198	}
2199	/* Only remove non-faulty devices if recovery
2200	 * is not possible.
2201	 */
2202	if (!test_bit(Faulty, &rdev->flags) &&
2203	    mddev->recovery_disabled != p->recovery_disabled &&
2204	    (!p->replacement || p->replacement == rdev) &&
2205	    number < conf->geo.raid_disks &&
2206	    enough(conf, -1)) {
2207		err = -EBUSY;
2208		goto abort;
2209	}
2210	WRITE_ONCE(*rdevp, NULL);
2211	if (p->replacement) {
2212		/* We must have just cleared 'rdev' */
2213		WRITE_ONCE(p->rdev, p->replacement);
2214		clear_bit(Replacement, &p->replacement->flags);
2215		WRITE_ONCE(p->replacement, NULL);
2216	}
2217
2218	clear_bit(WantReplacement, &rdev->flags);
2219	err = md_integrity_register(mddev);
2220
2221abort:
2222
2223	print_conf(conf);
2224	return err;
2225}
2226
2227static void __end_sync_read(struct r10bio *r10_bio, struct bio *bio, int d)
2228{
2229	struct r10conf *conf = r10_bio->mddev->private;
2230
2231	if (!bio->bi_status)
2232		set_bit(R10BIO_Uptodate, &r10_bio->state);
2233	else
2234		/* The write handler will notice the lack of
2235		 * R10BIO_Uptodate and record any errors etc
2236		 */
2237		atomic_add(r10_bio->sectors,
2238			   &conf->mirrors[d].rdev->corrected_errors);
2239
2240	/* for reconstruct, we always reschedule after a read.
2241	 * for resync, only after all reads
2242	 */
2243	rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
2244	if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
2245	    atomic_dec_and_test(&r10_bio->remaining)) {
2246		/* we have read all the blocks,
2247		 * do the comparison in process context in raid10d
2248		 */
2249		reschedule_retry(r10_bio);
2250	}
2251}
2252
2253static void end_sync_read(struct bio *bio)
2254{
2255	struct r10bio *r10_bio = get_resync_r10bio(bio);
2256	struct r10conf *conf = r10_bio->mddev->private;
2257	int d = find_bio_disk(conf, r10_bio, bio, NULL, NULL);
2258
2259	__end_sync_read(r10_bio, bio, d);
2260}
2261
2262static void end_reshape_read(struct bio *bio)
2263{
2264	/* reshape read bio isn't allocated from r10buf_pool */
2265	struct r10bio *r10_bio = bio->bi_private;
2266
2267	__end_sync_read(r10_bio, bio, r10_bio->read_slot);
2268}
2269
2270static void end_sync_request(struct r10bio *r10_bio)
2271{
2272	struct mddev *mddev = r10_bio->mddev;
2273
2274	while (atomic_dec_and_test(&r10_bio->remaining)) {
2275		if (r10_bio->master_bio == NULL) {
2276			/* the primary of several recovery bios */
2277			sector_t s = r10_bio->sectors;
2278			if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
2279			    test_bit(R10BIO_WriteError, &r10_bio->state))
2280				reschedule_retry(r10_bio);
2281			else
2282				put_buf(r10_bio);
2283			md_done_sync(mddev, s, 1);
2284			break;
2285		} else {
2286			struct r10bio *r10_bio2 = (struct r10bio *)r10_bio->master_bio;
2287			if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
2288			    test_bit(R10BIO_WriteError, &r10_bio->state))
2289				reschedule_retry(r10_bio);
2290			else
2291				put_buf(r10_bio);
2292			r10_bio = r10_bio2;
2293		}
2294	}
2295}
2296
2297static void end_sync_write(struct bio *bio)
2298{
2299	struct r10bio *r10_bio = get_resync_r10bio(bio);
2300	struct mddev *mddev = r10_bio->mddev;
2301	struct r10conf *conf = mddev->private;
2302	int d;
 
 
2303	int slot;
2304	int repl;
2305	struct md_rdev *rdev = NULL;
2306
2307	d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
2308	if (repl)
2309		rdev = conf->mirrors[d].replacement;
2310	else
2311		rdev = conf->mirrors[d].rdev;
2312
2313	if (bio->bi_status) {
2314		if (repl)
2315			md_error(mddev, rdev);
2316		else {
2317			set_bit(WriteErrorSeen, &rdev->flags);
2318			if (!test_and_set_bit(WantReplacement, &rdev->flags))
2319				set_bit(MD_RECOVERY_NEEDED,
2320					&rdev->mddev->recovery);
2321			set_bit(R10BIO_WriteError, &r10_bio->state);
2322		}
2323	} else if (rdev_has_badblock(rdev, r10_bio->devs[slot].addr,
2324				     r10_bio->sectors)) {
 
 
2325		set_bit(R10BIO_MadeGood, &r10_bio->state);
2326	}
2327
2328	rdev_dec_pending(rdev, mddev);
2329
2330	end_sync_request(r10_bio);
2331}
2332
2333/*
2334 * Note: sync and recover and handled very differently for raid10
2335 * This code is for resync.
2336 * For resync, we read through virtual addresses and read all blocks.
2337 * If there is any error, we schedule a write.  The lowest numbered
2338 * drive is authoritative.
2339 * However requests come for physical address, so we need to map.
2340 * For every physical address there are raid_disks/copies virtual addresses,
2341 * which is always are least one, but is not necessarly an integer.
2342 * This means that a physical address can span multiple chunks, so we may
2343 * have to submit multiple io requests for a single sync request.
2344 */
2345/*
2346 * We check if all blocks are in-sync and only write to blocks that
2347 * aren't in sync
2348 */
2349static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
2350{
2351	struct r10conf *conf = mddev->private;
2352	int i, first;
2353	struct bio *tbio, *fbio;
2354	int vcnt;
2355	struct page **tpages, **fpages;
2356
2357	atomic_set(&r10_bio->remaining, 1);
2358
2359	/* find the first device with a block */
2360	for (i=0; i<conf->copies; i++)
2361		if (!r10_bio->devs[i].bio->bi_status)
2362			break;
2363
2364	if (i == conf->copies)
2365		goto done;
2366
2367	first = i;
2368	fbio = r10_bio->devs[i].bio;
2369	fbio->bi_iter.bi_size = r10_bio->sectors << 9;
2370	fbio->bi_iter.bi_idx = 0;
2371	fpages = get_resync_pages(fbio)->pages;
2372
2373	vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9);
2374	/* now find blocks with errors */
2375	for (i=0 ; i < conf->copies ; i++) {
2376		int  j, d;
2377		struct md_rdev *rdev;
2378		struct resync_pages *rp;
2379
2380		tbio = r10_bio->devs[i].bio;
2381
2382		if (tbio->bi_end_io != end_sync_read)
2383			continue;
2384		if (i == first)
2385			continue;
2386
2387		tpages = get_resync_pages(tbio)->pages;
2388		d = r10_bio->devs[i].devnum;
2389		rdev = conf->mirrors[d].rdev;
2390		if (!r10_bio->devs[i].bio->bi_status) {
2391			/* We know that the bi_io_vec layout is the same for
2392			 * both 'first' and 'i', so we just compare them.
2393			 * All vec entries are PAGE_SIZE;
2394			 */
2395			int sectors = r10_bio->sectors;
2396			for (j = 0; j < vcnt; j++) {
2397				int len = PAGE_SIZE;
2398				if (sectors < (len / 512))
2399					len = sectors * 512;
2400				if (memcmp(page_address(fpages[j]),
2401					   page_address(tpages[j]),
2402					   len))
2403					break;
2404				sectors -= len/512;
2405			}
2406			if (j == vcnt)
2407				continue;
2408			atomic64_add(r10_bio->sectors, &mddev->resync_mismatches);
2409			if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
2410				/* Don't fix anything. */
2411				continue;
2412		} else if (test_bit(FailFast, &rdev->flags)) {
2413			/* Just give up on this device */
2414			md_error(rdev->mddev, rdev);
2415			continue;
2416		}
2417		/* Ok, we need to write this bio, either to correct an
2418		 * inconsistency or to correct an unreadable block.
2419		 * First we need to fixup bv_offset, bv_len and
2420		 * bi_vecs, as the read request might have corrupted these
2421		 */
2422		rp = get_resync_pages(tbio);
2423		bio_reset(tbio, conf->mirrors[d].rdev->bdev, REQ_OP_WRITE);
2424
2425		md_bio_reset_resync_pages(tbio, rp, fbio->bi_iter.bi_size);
2426
2427		rp->raid_bio = r10_bio;
2428		tbio->bi_private = rp;
2429		tbio->bi_iter.bi_sector = r10_bio->devs[i].addr;
2430		tbio->bi_end_io = end_sync_write;
2431
2432		bio_copy_data(tbio, fbio);
2433
2434		atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2435		atomic_inc(&r10_bio->remaining);
2436		md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(tbio));
2437
2438		if (test_bit(FailFast, &conf->mirrors[d].rdev->flags))
2439			tbio->bi_opf |= MD_FAILFAST;
2440		tbio->bi_iter.bi_sector += conf->mirrors[d].rdev->data_offset;
2441		submit_bio_noacct(tbio);
2442	}
2443
2444	/* Now write out to any replacement devices
2445	 * that are active
2446	 */
2447	for (i = 0; i < conf->copies; i++) {
2448		int d;
2449
2450		tbio = r10_bio->devs[i].repl_bio;
2451		if (!tbio || !tbio->bi_end_io)
2452			continue;
2453		if (r10_bio->devs[i].bio->bi_end_io != end_sync_write
2454		    && r10_bio->devs[i].bio != fbio)
2455			bio_copy_data(tbio, fbio);
2456		d = r10_bio->devs[i].devnum;
2457		atomic_inc(&r10_bio->remaining);
2458		md_sync_acct(conf->mirrors[d].replacement->bdev,
2459			     bio_sectors(tbio));
2460		submit_bio_noacct(tbio);
2461	}
2462
2463done:
2464	if (atomic_dec_and_test(&r10_bio->remaining)) {
2465		md_done_sync(mddev, r10_bio->sectors, 1);
2466		put_buf(r10_bio);
2467	}
2468}
2469
2470/*
2471 * Now for the recovery code.
2472 * Recovery happens across physical sectors.
2473 * We recover all non-is_sync drives by finding the virtual address of
2474 * each, and then choose a working drive that also has that virt address.
2475 * There is a separate r10_bio for each non-in_sync drive.
2476 * Only the first two slots are in use. The first for reading,
2477 * The second for writing.
2478 *
2479 */
2480static void fix_recovery_read_error(struct r10bio *r10_bio)
2481{
2482	/* We got a read error during recovery.
2483	 * We repeat the read in smaller page-sized sections.
2484	 * If a read succeeds, write it to the new device or record
2485	 * a bad block if we cannot.
2486	 * If a read fails, record a bad block on both old and
2487	 * new devices.
2488	 */
2489	struct mddev *mddev = r10_bio->mddev;
2490	struct r10conf *conf = mddev->private;
2491	struct bio *bio = r10_bio->devs[0].bio;
2492	sector_t sect = 0;
2493	int sectors = r10_bio->sectors;
2494	int idx = 0;
2495	int dr = r10_bio->devs[0].devnum;
2496	int dw = r10_bio->devs[1].devnum;
2497	struct page **pages = get_resync_pages(bio)->pages;
2498
2499	while (sectors) {
2500		int s = sectors;
2501		struct md_rdev *rdev;
2502		sector_t addr;
2503		int ok;
2504
2505		if (s > (PAGE_SIZE>>9))
2506			s = PAGE_SIZE >> 9;
2507
2508		rdev = conf->mirrors[dr].rdev;
2509		addr = r10_bio->devs[0].addr + sect;
2510		ok = sync_page_io(rdev,
2511				  addr,
2512				  s << 9,
2513				  pages[idx],
2514				  REQ_OP_READ, false);
2515		if (ok) {
2516			rdev = conf->mirrors[dw].rdev;
2517			addr = r10_bio->devs[1].addr + sect;
2518			ok = sync_page_io(rdev,
2519					  addr,
2520					  s << 9,
2521					  pages[idx],
2522					  REQ_OP_WRITE, false);
2523			if (!ok) {
2524				set_bit(WriteErrorSeen, &rdev->flags);
2525				if (!test_and_set_bit(WantReplacement,
2526						      &rdev->flags))
2527					set_bit(MD_RECOVERY_NEEDED,
2528						&rdev->mddev->recovery);
2529			}
2530		}
2531		if (!ok) {
2532			/* We don't worry if we cannot set a bad block -
2533			 * it really is bad so there is no loss in not
2534			 * recording it yet
2535			 */
2536			rdev_set_badblocks(rdev, addr, s, 0);
2537
2538			if (rdev != conf->mirrors[dw].rdev) {
2539				/* need bad block on destination too */
2540				struct md_rdev *rdev2 = conf->mirrors[dw].rdev;
2541				addr = r10_bio->devs[1].addr + sect;
2542				ok = rdev_set_badblocks(rdev2, addr, s, 0);
2543				if (!ok) {
2544					/* just abort the recovery */
2545					pr_notice("md/raid10:%s: recovery aborted due to read error\n",
2546						  mdname(mddev));
2547
2548					conf->mirrors[dw].recovery_disabled
2549						= mddev->recovery_disabled;
2550					set_bit(MD_RECOVERY_INTR,
2551						&mddev->recovery);
2552					break;
2553				}
2554			}
2555		}
2556
2557		sectors -= s;
2558		sect += s;
2559		idx++;
2560	}
2561}
2562
2563static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
2564{
2565	struct r10conf *conf = mddev->private;
2566	int d;
2567	struct bio *wbio = r10_bio->devs[1].bio;
2568	struct bio *wbio2 = r10_bio->devs[1].repl_bio;
2569
2570	/* Need to test wbio2->bi_end_io before we call
2571	 * submit_bio_noacct as if the former is NULL,
2572	 * the latter is free to free wbio2.
2573	 */
2574	if (wbio2 && !wbio2->bi_end_io)
2575		wbio2 = NULL;
2576
2577	if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
2578		fix_recovery_read_error(r10_bio);
2579		if (wbio->bi_end_io)
2580			end_sync_request(r10_bio);
2581		if (wbio2)
2582			end_sync_request(r10_bio);
2583		return;
2584	}
2585
2586	/*
2587	 * share the pages with the first bio
2588	 * and submit the write request
2589	 */
2590	d = r10_bio->devs[1].devnum;
2591	if (wbio->bi_end_io) {
2592		atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2593		md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(wbio));
2594		submit_bio_noacct(wbio);
2595	}
2596	if (wbio2) {
2597		atomic_inc(&conf->mirrors[d].replacement->nr_pending);
2598		md_sync_acct(conf->mirrors[d].replacement->bdev,
2599			     bio_sectors(wbio2));
2600		submit_bio_noacct(wbio2);
2601	}
2602}
2603
2604static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
2605			    int sectors, struct page *page, enum req_op op)
2606{
2607	if (rdev_has_badblock(rdev, sector, sectors) &&
2608	    (op == REQ_OP_READ || test_bit(WriteErrorSeen, &rdev->flags)))
 
 
 
2609		return -1;
2610	if (sync_page_io(rdev, sector, sectors << 9, page, op, false))
2611		/* success */
2612		return 1;
2613	if (op == REQ_OP_WRITE) {
2614		set_bit(WriteErrorSeen, &rdev->flags);
2615		if (!test_and_set_bit(WantReplacement, &rdev->flags))
2616			set_bit(MD_RECOVERY_NEEDED,
2617				&rdev->mddev->recovery);
2618	}
2619	/* need to record an error - either for the block or the device */
2620	if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2621		md_error(rdev->mddev, rdev);
2622	return 0;
2623}
2624
2625/*
2626 * This is a kernel thread which:
2627 *
2628 *	1.	Retries failed read operations on working mirrors.
2629 *	2.	Updates the raid superblock when problems encounter.
2630 *	3.	Performs writes following reads for array synchronising.
2631 */
2632
2633static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)
2634{
2635	int sect = 0; /* Offset from r10_bio->sector */
2636	int sectors = r10_bio->sectors, slot = r10_bio->read_slot;
2637	struct md_rdev *rdev;
2638	int d = r10_bio->devs[slot].devnum;
2639
2640	/* still own a reference to this rdev, so it cannot
2641	 * have been cleared recently.
2642	 */
2643	rdev = conf->mirrors[d].rdev;
2644
2645	if (test_bit(Faulty, &rdev->flags))
2646		/* drive has already been failed, just ignore any
2647		   more fix_read_error() attempts */
2648		return;
2649
2650	if (exceed_read_errors(mddev, rdev)) {
2651		r10_bio->devs[slot].bio = IO_BLOCKED;
2652		return;
2653	}
2654
2655	while(sectors) {
2656		int s = sectors;
2657		int sl = slot;
2658		int success = 0;
2659		int start;
2660
2661		if (s > (PAGE_SIZE>>9))
2662			s = PAGE_SIZE >> 9;
2663
2664		do {
 
 
 
2665			d = r10_bio->devs[sl].devnum;
2666			rdev = conf->mirrors[d].rdev;
2667			if (rdev &&
2668			    test_bit(In_sync, &rdev->flags) &&
2669			    !test_bit(Faulty, &rdev->flags) &&
2670			    rdev_has_badblock(rdev,
2671					      r10_bio->devs[sl].addr + sect,
2672					      s) == 0) {
2673				atomic_inc(&rdev->nr_pending);
2674				success = sync_page_io(rdev,
2675						       r10_bio->devs[sl].addr +
2676						       sect,
2677						       s<<9,
2678						       conf->tmppage,
2679						       REQ_OP_READ, false);
2680				rdev_dec_pending(rdev, mddev);
2681				if (success)
2682					break;
2683			}
2684			sl++;
2685			if (sl == conf->copies)
2686				sl = 0;
2687		} while (sl != slot);
2688
2689		if (!success) {
2690			/* Cannot read from anywhere, just mark the block
2691			 * as bad on the first device to discourage future
2692			 * reads.
2693			 */
2694			int dn = r10_bio->devs[slot].devnum;
2695			rdev = conf->mirrors[dn].rdev;
2696
2697			if (!rdev_set_badblocks(
2698				    rdev,
2699				    r10_bio->devs[slot].addr
2700				    + sect,
2701				    s, 0)) {
2702				md_error(mddev, rdev);
2703				r10_bio->devs[slot].bio
2704					= IO_BLOCKED;
2705			}
2706			break;
2707		}
2708
2709		start = sl;
2710		/* write it back and re-read */
2711		while (sl != slot) {
2712			if (sl==0)
2713				sl = conf->copies;
2714			sl--;
2715			d = r10_bio->devs[sl].devnum;
2716			rdev = conf->mirrors[d].rdev;
2717			if (!rdev ||
2718			    test_bit(Faulty, &rdev->flags) ||
2719			    !test_bit(In_sync, &rdev->flags))
2720				continue;
2721
2722			atomic_inc(&rdev->nr_pending);
2723			if (r10_sync_page_io(rdev,
2724					     r10_bio->devs[sl].addr +
2725					     sect,
2726					     s, conf->tmppage, REQ_OP_WRITE)
2727			    == 0) {
2728				/* Well, this device is dead */
2729				pr_notice("md/raid10:%s: read correction write failed (%d sectors at %llu on %pg)\n",
2730					  mdname(mddev), s,
2731					  (unsigned long long)(
2732						  sect +
2733						  choose_data_offset(r10_bio,
2734								     rdev)),
2735					  rdev->bdev);
2736				pr_notice("md/raid10:%s: %pg: failing drive\n",
2737					  mdname(mddev),
2738					  rdev->bdev);
2739			}
2740			rdev_dec_pending(rdev, mddev);
2741		}
2742		sl = start;
2743		while (sl != slot) {
2744			if (sl==0)
2745				sl = conf->copies;
2746			sl--;
2747			d = r10_bio->devs[sl].devnum;
2748			rdev = conf->mirrors[d].rdev;
2749			if (!rdev ||
2750			    test_bit(Faulty, &rdev->flags) ||
2751			    !test_bit(In_sync, &rdev->flags))
2752				continue;
2753
2754			atomic_inc(&rdev->nr_pending);
2755			switch (r10_sync_page_io(rdev,
2756					     r10_bio->devs[sl].addr +
2757					     sect,
2758					     s, conf->tmppage, REQ_OP_READ)) {
2759			case 0:
2760				/* Well, this device is dead */
2761				pr_notice("md/raid10:%s: unable to read back corrected sectors (%d sectors at %llu on %pg)\n",
2762				       mdname(mddev), s,
2763				       (unsigned long long)(
2764					       sect +
2765					       choose_data_offset(r10_bio, rdev)),
2766				       rdev->bdev);
2767				pr_notice("md/raid10:%s: %pg: failing drive\n",
2768				       mdname(mddev),
2769				       rdev->bdev);
2770				break;
2771			case 1:
2772				pr_info("md/raid10:%s: read error corrected (%d sectors at %llu on %pg)\n",
2773				       mdname(mddev), s,
2774				       (unsigned long long)(
2775					       sect +
2776					       choose_data_offset(r10_bio, rdev)),
2777				       rdev->bdev);
2778				atomic_add(s, &rdev->corrected_errors);
2779			}
2780
2781			rdev_dec_pending(rdev, mddev);
2782		}
2783
2784		sectors -= s;
2785		sect += s;
2786	}
2787}
2788
2789static int narrow_write_error(struct r10bio *r10_bio, int i)
2790{
2791	struct bio *bio = r10_bio->master_bio;
2792	struct mddev *mddev = r10_bio->mddev;
2793	struct r10conf *conf = mddev->private;
2794	struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev;
2795	/* bio has the data to be written to slot 'i' where
2796	 * we just recently had a write error.
2797	 * We repeatedly clone the bio and trim down to one block,
2798	 * then try the write.  Where the write fails we record
2799	 * a bad block.
2800	 * It is conceivable that the bio doesn't exactly align with
2801	 * blocks.  We must handle this.
2802	 *
2803	 * We currently own a reference to the rdev.
2804	 */
2805
2806	int block_sectors;
2807	sector_t sector;
2808	int sectors;
2809	int sect_to_write = r10_bio->sectors;
2810	int ok = 1;
2811
2812	if (rdev->badblocks.shift < 0)
2813		return 0;
2814
2815	block_sectors = roundup(1 << rdev->badblocks.shift,
2816				bdev_logical_block_size(rdev->bdev) >> 9);
2817	sector = r10_bio->sector;
2818	sectors = ((r10_bio->sector + block_sectors)
2819		   & ~(sector_t)(block_sectors - 1))
2820		- sector;
2821
2822	while (sect_to_write) {
2823		struct bio *wbio;
2824		sector_t wsector;
2825		if (sectors > sect_to_write)
2826			sectors = sect_to_write;
2827		/* Write at 'sector' for 'sectors' */
2828		wbio = bio_alloc_clone(rdev->bdev, bio, GFP_NOIO,
2829				       &mddev->bio_set);
2830		bio_trim(wbio, sector - bio->bi_iter.bi_sector, sectors);
2831		wsector = r10_bio->devs[i].addr + (sector - r10_bio->sector);
2832		wbio->bi_iter.bi_sector = wsector +
2833				   choose_data_offset(r10_bio, rdev);
2834		wbio->bi_opf = REQ_OP_WRITE;
2835
2836		if (submit_bio_wait(wbio) < 0)
2837			/* Failure! */
2838			ok = rdev_set_badblocks(rdev, wsector,
2839						sectors, 0)
2840				&& ok;
2841
2842		bio_put(wbio);
2843		sect_to_write -= sectors;
2844		sector += sectors;
2845		sectors = block_sectors;
2846	}
2847	return ok;
2848}
2849
2850static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
2851{
2852	int slot = r10_bio->read_slot;
2853	struct bio *bio;
2854	struct r10conf *conf = mddev->private;
2855	struct md_rdev *rdev = r10_bio->devs[slot].rdev;
2856
2857	/* we got a read error. Maybe the drive is bad.  Maybe just
2858	 * the block and we can fix it.
2859	 * We freeze all other IO, and try reading the block from
2860	 * other devices.  When we find one, we re-write
2861	 * and check it that fixes the read error.
2862	 * This is all done synchronously while the array is
2863	 * frozen.
2864	 */
2865	bio = r10_bio->devs[slot].bio;
2866	bio_put(bio);
2867	r10_bio->devs[slot].bio = NULL;
2868
2869	if (mddev->ro)
2870		r10_bio->devs[slot].bio = IO_BLOCKED;
2871	else if (!test_bit(FailFast, &rdev->flags)) {
2872		freeze_array(conf, 1);
2873		fix_read_error(conf, mddev, r10_bio);
2874		unfreeze_array(conf);
2875	} else
2876		md_error(mddev, rdev);
2877
2878	rdev_dec_pending(rdev, mddev);
2879	r10_bio->state = 0;
2880	raid10_read_request(mddev, r10_bio->master_bio, r10_bio, false);
2881	/*
2882	 * allow_barrier after re-submit to ensure no sync io
2883	 * can be issued while regular io pending.
2884	 */
2885	allow_barrier(conf);
2886}
2887
2888static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
2889{
2890	/* Some sort of write request has finished and it
2891	 * succeeded in writing where we thought there was a
2892	 * bad block.  So forget the bad block.
2893	 * Or possibly if failed and we need to record
2894	 * a bad block.
2895	 */
2896	int m;
2897	struct md_rdev *rdev;
2898
2899	if (test_bit(R10BIO_IsSync, &r10_bio->state) ||
2900	    test_bit(R10BIO_IsRecover, &r10_bio->state)) {
2901		for (m = 0; m < conf->copies; m++) {
2902			int dev = r10_bio->devs[m].devnum;
2903			rdev = conf->mirrors[dev].rdev;
2904			if (r10_bio->devs[m].bio == NULL ||
2905				r10_bio->devs[m].bio->bi_end_io == NULL)
2906				continue;
2907			if (!r10_bio->devs[m].bio->bi_status) {
2908				rdev_clear_badblocks(
2909					rdev,
2910					r10_bio->devs[m].addr,
2911					r10_bio->sectors, 0);
2912			} else {
2913				if (!rdev_set_badblocks(
2914					    rdev,
2915					    r10_bio->devs[m].addr,
2916					    r10_bio->sectors, 0))
2917					md_error(conf->mddev, rdev);
2918			}
2919			rdev = conf->mirrors[dev].replacement;
2920			if (r10_bio->devs[m].repl_bio == NULL ||
2921				r10_bio->devs[m].repl_bio->bi_end_io == NULL)
2922				continue;
2923
2924			if (!r10_bio->devs[m].repl_bio->bi_status) {
2925				rdev_clear_badblocks(
2926					rdev,
2927					r10_bio->devs[m].addr,
2928					r10_bio->sectors, 0);
2929			} else {
2930				if (!rdev_set_badblocks(
2931					    rdev,
2932					    r10_bio->devs[m].addr,
2933					    r10_bio->sectors, 0))
2934					md_error(conf->mddev, rdev);
2935			}
2936		}
2937		put_buf(r10_bio);
2938	} else {
2939		bool fail = false;
2940		for (m = 0; m < conf->copies; m++) {
2941			int dev = r10_bio->devs[m].devnum;
2942			struct bio *bio = r10_bio->devs[m].bio;
2943			rdev = conf->mirrors[dev].rdev;
2944			if (bio == IO_MADE_GOOD) {
2945				rdev_clear_badblocks(
2946					rdev,
2947					r10_bio->devs[m].addr,
2948					r10_bio->sectors, 0);
2949				rdev_dec_pending(rdev, conf->mddev);
2950			} else if (bio != NULL && bio->bi_status) {
2951				fail = true;
2952				if (!narrow_write_error(r10_bio, m))
2953					md_error(conf->mddev, rdev);
 
 
 
2954				rdev_dec_pending(rdev, conf->mddev);
2955			}
2956			bio = r10_bio->devs[m].repl_bio;
2957			rdev = conf->mirrors[dev].replacement;
2958			if (rdev && bio == IO_MADE_GOOD) {
2959				rdev_clear_badblocks(
2960					rdev,
2961					r10_bio->devs[m].addr,
2962					r10_bio->sectors, 0);
2963				rdev_dec_pending(rdev, conf->mddev);
2964			}
2965		}
2966		if (fail) {
2967			spin_lock_irq(&conf->device_lock);
2968			list_add(&r10_bio->retry_list, &conf->bio_end_io_list);
2969			conf->nr_queued++;
2970			spin_unlock_irq(&conf->device_lock);
2971			/*
2972			 * In case freeze_array() is waiting for condition
2973			 * nr_pending == nr_queued + extra to be true.
2974			 */
2975			wake_up(&conf->wait_barrier);
2976			md_wakeup_thread(conf->mddev->thread);
2977		} else {
2978			if (test_bit(R10BIO_WriteError,
2979				     &r10_bio->state))
2980				close_write(r10_bio);
2981			raid_end_bio_io(r10_bio);
2982		}
2983	}
2984}
2985
2986static void raid10d(struct md_thread *thread)
2987{
2988	struct mddev *mddev = thread->mddev;
2989	struct r10bio *r10_bio;
2990	unsigned long flags;
2991	struct r10conf *conf = mddev->private;
2992	struct list_head *head = &conf->retry_list;
2993	struct blk_plug plug;
2994
2995	md_check_recovery(mddev);
2996
2997	if (!list_empty_careful(&conf->bio_end_io_list) &&
2998	    !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2999		LIST_HEAD(tmp);
3000		spin_lock_irqsave(&conf->device_lock, flags);
3001		if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
3002			while (!list_empty(&conf->bio_end_io_list)) {
3003				list_move(conf->bio_end_io_list.prev, &tmp);
3004				conf->nr_queued--;
3005			}
3006		}
3007		spin_unlock_irqrestore(&conf->device_lock, flags);
3008		while (!list_empty(&tmp)) {
3009			r10_bio = list_first_entry(&tmp, struct r10bio,
3010						   retry_list);
3011			list_del(&r10_bio->retry_list);
 
 
3012
3013			if (test_bit(R10BIO_WriteError,
3014				     &r10_bio->state))
3015				close_write(r10_bio);
3016			raid_end_bio_io(r10_bio);
3017		}
3018	}
3019
3020	blk_start_plug(&plug);
3021	for (;;) {
3022
3023		flush_pending_writes(conf);
3024
3025		spin_lock_irqsave(&conf->device_lock, flags);
3026		if (list_empty(head)) {
3027			spin_unlock_irqrestore(&conf->device_lock, flags);
3028			break;
3029		}
3030		r10_bio = list_entry(head->prev, struct r10bio, retry_list);
3031		list_del(head->prev);
3032		conf->nr_queued--;
3033		spin_unlock_irqrestore(&conf->device_lock, flags);
3034
3035		mddev = r10_bio->mddev;
3036		conf = mddev->private;
3037		if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
3038		    test_bit(R10BIO_WriteError, &r10_bio->state))
3039			handle_write_completed(conf, r10_bio);
3040		else if (test_bit(R10BIO_IsReshape, &r10_bio->state))
3041			reshape_request_write(mddev, r10_bio);
3042		else if (test_bit(R10BIO_IsSync, &r10_bio->state))
3043			sync_request_write(mddev, r10_bio);
3044		else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
3045			recovery_request_write(mddev, r10_bio);
3046		else if (test_bit(R10BIO_ReadError, &r10_bio->state))
3047			handle_read_error(mddev, r10_bio);
3048		else
3049			WARN_ON_ONCE(1);
3050
3051		cond_resched();
3052		if (mddev->sb_flags & ~(1<<MD_SB_CHANGE_PENDING))
3053			md_check_recovery(mddev);
3054	}
3055	blk_finish_plug(&plug);
3056}
3057
3058static int init_resync(struct r10conf *conf)
3059{
3060	int ret, buffs, i;
3061
3062	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
3063	BUG_ON(mempool_initialized(&conf->r10buf_pool));
3064	conf->have_replacement = 0;
3065	for (i = 0; i < conf->geo.raid_disks; i++)
3066		if (conf->mirrors[i].replacement)
3067			conf->have_replacement = 1;
3068	ret = mempool_init(&conf->r10buf_pool, buffs,
3069			   r10buf_pool_alloc, r10buf_pool_free, conf);
3070	if (ret)
3071		return ret;
3072	conf->next_resync = 0;
3073	return 0;
3074}
3075
3076static struct r10bio *raid10_alloc_init_r10buf(struct r10conf *conf)
3077{
3078	struct r10bio *r10bio = mempool_alloc(&conf->r10buf_pool, GFP_NOIO);
3079	struct rsync_pages *rp;
3080	struct bio *bio;
3081	int nalloc;
3082	int i;
3083
3084	if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
3085	    test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
3086		nalloc = conf->copies; /* resync */
3087	else
3088		nalloc = 2; /* recovery */
3089
3090	for (i = 0; i < nalloc; i++) {
3091		bio = r10bio->devs[i].bio;
3092		rp = bio->bi_private;
3093		bio_reset(bio, NULL, 0);
3094		bio->bi_private = rp;
3095		bio = r10bio->devs[i].repl_bio;
3096		if (bio) {
3097			rp = bio->bi_private;
3098			bio_reset(bio, NULL, 0);
3099			bio->bi_private = rp;
3100		}
3101	}
3102	return r10bio;
3103}
3104
3105/*
3106 * Set cluster_sync_high since we need other nodes to add the
3107 * range [cluster_sync_low, cluster_sync_high] to suspend list.
3108 */
3109static void raid10_set_cluster_sync_high(struct r10conf *conf)
3110{
3111	sector_t window_size;
3112	int extra_chunk, chunks;
3113
3114	/*
3115	 * First, here we define "stripe" as a unit which across
3116	 * all member devices one time, so we get chunks by use
3117	 * raid_disks / near_copies. Otherwise, if near_copies is
3118	 * close to raid_disks, then resync window could increases
3119	 * linearly with the increase of raid_disks, which means
3120	 * we will suspend a really large IO window while it is not
3121	 * necessary. If raid_disks is not divisible by near_copies,
3122	 * an extra chunk is needed to ensure the whole "stripe" is
3123	 * covered.
3124	 */
3125
3126	chunks = conf->geo.raid_disks / conf->geo.near_copies;
3127	if (conf->geo.raid_disks % conf->geo.near_copies == 0)
3128		extra_chunk = 0;
3129	else
3130		extra_chunk = 1;
3131	window_size = (chunks + extra_chunk) * conf->mddev->chunk_sectors;
3132
3133	/*
3134	 * At least use a 32M window to align with raid1's resync window
3135	 */
3136	window_size = (CLUSTER_RESYNC_WINDOW_SECTORS > window_size) ?
3137			CLUSTER_RESYNC_WINDOW_SECTORS : window_size;
3138
3139	conf->cluster_sync_high = conf->cluster_sync_low + window_size;
3140}
3141
3142/*
3143 * perform a "sync" on one "block"
3144 *
3145 * We need to make sure that no normal I/O request - particularly write
3146 * requests - conflict with active sync requests.
3147 *
3148 * This is achieved by tracking pending requests and a 'barrier' concept
3149 * that can be installed to exclude normal IO requests.
3150 *
3151 * Resync and recovery are handled very differently.
3152 * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
3153 *
3154 * For resync, we iterate over virtual addresses, read all copies,
3155 * and update if there are differences.  If only one copy is live,
3156 * skip it.
3157 * For recovery, we iterate over physical addresses, read a good
3158 * value for each non-in_sync drive, and over-write.
3159 *
3160 * So, for recovery we may have several outstanding complex requests for a
3161 * given address, one for each out-of-sync device.  We model this by allocating
3162 * a number of r10_bio structures, one for each out-of-sync device.
3163 * As we setup these structures, we collect all bio's together into a list
3164 * which we then process collectively to add pages, and then process again
3165 * to pass to submit_bio_noacct.
3166 *
3167 * The r10_bio structures are linked using a borrowed master_bio pointer.
3168 * This link is counted in ->remaining.  When the r10_bio that points to NULL
3169 * has its remaining count decremented to 0, the whole complex operation
3170 * is complete.
3171 *
3172 */
3173
3174static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
3175				    sector_t max_sector, int *skipped)
3176{
3177	struct r10conf *conf = mddev->private;
3178	struct r10bio *r10_bio;
3179	struct bio *biolist = NULL, *bio;
3180	sector_t nr_sectors;
3181	int i;
3182	int max_sync;
3183	sector_t sync_blocks;
3184	sector_t sectors_skipped = 0;
3185	int chunks_skipped = 0;
3186	sector_t chunk_mask = conf->geo.chunk_mask;
3187	int page_idx = 0;
3188	int error_disk = -1;
3189
3190	/*
3191	 * Allow skipping a full rebuild for incremental assembly
3192	 * of a clean array, like RAID1 does.
3193	 */
3194	if (mddev->bitmap == NULL &&
3195	    mddev->recovery_cp == MaxSector &&
3196	    mddev->reshape_position == MaxSector &&
3197	    !test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
3198	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
3199	    !test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
3200	    conf->fullsync == 0) {
3201		*skipped = 1;
3202		return mddev->dev_sectors - sector_nr;
3203	}
3204
3205	if (!mempool_initialized(&conf->r10buf_pool))
3206		if (init_resync(conf))
3207			return 0;
3208
3209 skipped:
 
 
 
 
3210	if (sector_nr >= max_sector) {
3211		conf->cluster_sync_low = 0;
3212		conf->cluster_sync_high = 0;
3213
3214		/* If we aborted, we need to abort the
3215		 * sync on the 'current' bitmap chucks (there can
3216		 * be several when recovering multiple devices).
3217		 * as we may have started syncing it but not finished.
3218		 * We can find the current address in
3219		 * mddev->curr_resync, but for recovery,
3220		 * we need to convert that to several
3221		 * virtual addresses.
3222		 */
3223		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
3224			end_reshape(conf);
3225			close_sync(conf);
3226			return 0;
3227		}
3228
3229		if (mddev->curr_resync < max_sector) { /* aborted */
3230			if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
3231				mddev->bitmap_ops->end_sync(mddev,
3232							    mddev->curr_resync,
3233							    &sync_blocks);
3234			else for (i = 0; i < conf->geo.raid_disks; i++) {
3235				sector_t sect =
3236					raid10_find_virt(conf, mddev->curr_resync, i);
3237
3238				mddev->bitmap_ops->end_sync(mddev, sect,
3239							    &sync_blocks);
3240			}
3241		} else {
3242			/* completed sync */
3243			if ((!mddev->bitmap || conf->fullsync)
3244			    && conf->have_replacement
3245			    && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3246				/* Completed a full sync so the replacements
3247				 * are now fully recovered.
3248				 */
3249				for (i = 0; i < conf->geo.raid_disks; i++) {
3250					struct md_rdev *rdev =
3251						conf->mirrors[i].replacement;
3252
3253					if (rdev)
3254						rdev->recovery_offset = MaxSector;
3255				}
3256			}
3257			conf->fullsync = 0;
3258		}
3259		mddev->bitmap_ops->close_sync(mddev);
3260		close_sync(conf);
3261		*skipped = 1;
3262		return sectors_skipped;
3263	}
3264
3265	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3266		return reshape_request(mddev, sector_nr, skipped);
3267
3268	if (chunks_skipped >= conf->geo.raid_disks) {
3269		pr_err("md/raid10:%s: %s fails\n", mdname(mddev),
3270			test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?  "resync" : "recovery");
3271		if (error_disk >= 0 &&
3272		    !test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3273			/*
3274			 * recovery fails, set mirrors.recovery_disabled,
3275			 * device shouldn't be added to there.
3276			 */
3277			conf->mirrors[error_disk].recovery_disabled =
3278						mddev->recovery_disabled;
3279			return 0;
3280		}
3281		/*
3282		 * if there has been nothing to do on any drive,
3283		 * then there is nothing to do at all.
3284		 */
3285		*skipped = 1;
3286		return (max_sector - sector_nr) + sectors_skipped;
3287	}
3288
3289	if (max_sector > mddev->resync_max)
3290		max_sector = mddev->resync_max; /* Don't do IO beyond here */
3291
3292	/* make sure whole request will fit in a chunk - if chunks
3293	 * are meaningful
3294	 */
3295	if (conf->geo.near_copies < conf->geo.raid_disks &&
3296	    max_sector > (sector_nr | chunk_mask))
3297		max_sector = (sector_nr | chunk_mask) + 1;
3298
3299	/*
3300	 * If there is non-resync activity waiting for a turn, then let it
3301	 * though before starting on this new sync request.
3302	 */
3303	if (conf->nr_waiting)
3304		schedule_timeout_uninterruptible(1);
3305
3306	/* Again, very different code for resync and recovery.
3307	 * Both must result in an r10bio with a list of bios that
3308	 * have bi_end_io, bi_sector, bi_bdev set,
3309	 * and bi_private set to the r10bio.
3310	 * For recovery, we may actually create several r10bios
3311	 * with 2 bios in each, that correspond to the bios in the main one.
3312	 * In this case, the subordinate r10bios link back through a
3313	 * borrowed master_bio pointer, and the counter in the master
3314	 * includes a ref from each subordinate.
3315	 */
3316	/* First, we decide what to do and set ->bi_end_io
3317	 * To end_sync_read if we want to read, and
3318	 * end_sync_write if we will want to write.
3319	 */
3320
3321	max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
3322	if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3323		/* recovery... the complicated one */
3324		int j;
3325		r10_bio = NULL;
3326
3327		for (i = 0 ; i < conf->geo.raid_disks; i++) {
3328			bool still_degraded;
3329			struct r10bio *rb2;
3330			sector_t sect;
3331			bool must_sync;
3332			int any_working;
3333			struct raid10_info *mirror = &conf->mirrors[i];
3334			struct md_rdev *mrdev, *mreplace;
3335
3336			mrdev = mirror->rdev;
3337			mreplace = mirror->replacement;
3338
3339			if (mrdev && (test_bit(Faulty, &mrdev->flags) ||
3340			    test_bit(In_sync, &mrdev->flags)))
3341				mrdev = NULL;
3342			if (mreplace && test_bit(Faulty, &mreplace->flags))
3343				mreplace = NULL;
3344
3345			if (!mrdev && !mreplace)
3346				continue;
3347
3348			still_degraded = false;
3349			/* want to reconstruct this device */
3350			rb2 = r10_bio;
3351			sect = raid10_find_virt(conf, sector_nr, i);
3352			if (sect >= mddev->resync_max_sectors)
3353				/* last stripe is not complete - don't
3354				 * try to recover this sector.
3355				 */
3356				continue;
3357			/* Unless we are doing a full sync, or a replacement
3358			 * we only need to recover the block if it is set in
3359			 * the bitmap
3360			 */
3361			must_sync = mddev->bitmap_ops->start_sync(mddev, sect,
3362								  &sync_blocks,
3363								  true);
3364			if (sync_blocks < max_sync)
3365				max_sync = sync_blocks;
3366			if (!must_sync &&
3367			    mreplace == NULL &&
3368			    !conf->fullsync) {
3369				/* yep, skip the sync_blocks here, but don't assume
3370				 * that there will never be anything to do here
3371				 */
3372				chunks_skipped = -1;
3373				continue;
3374			}
3375			if (mrdev)
3376				atomic_inc(&mrdev->nr_pending);
3377			if (mreplace)
3378				atomic_inc(&mreplace->nr_pending);
3379
3380			r10_bio = raid10_alloc_init_r10buf(conf);
3381			r10_bio->state = 0;
3382			raise_barrier(conf, rb2 != NULL);
3383			atomic_set(&r10_bio->remaining, 0);
3384
3385			r10_bio->master_bio = (struct bio*)rb2;
3386			if (rb2)
3387				atomic_inc(&rb2->remaining);
3388			r10_bio->mddev = mddev;
3389			set_bit(R10BIO_IsRecover, &r10_bio->state);
3390			r10_bio->sector = sect;
3391
3392			raid10_find_phys(conf, r10_bio);
3393
3394			/* Need to check if the array will still be
3395			 * degraded
3396			 */
3397			for (j = 0; j < conf->geo.raid_disks; j++) {
3398				struct md_rdev *rdev = conf->mirrors[j].rdev;
3399
3400				if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3401					still_degraded = false;
3402					break;
3403				}
3404			}
3405
3406			must_sync = mddev->bitmap_ops->start_sync(mddev, sect,
3407						&sync_blocks, still_degraded);
3408
3409			any_working = 0;
3410			for (j=0; j<conf->copies;j++) {
3411				int k;
3412				int d = r10_bio->devs[j].devnum;
3413				sector_t from_addr, to_addr;
3414				struct md_rdev *rdev = conf->mirrors[d].rdev;
3415				sector_t sector, first_bad;
3416				int bad_sectors;
3417				if (!rdev ||
3418				    !test_bit(In_sync, &rdev->flags))
3419					continue;
3420				/* This is where we read from */
3421				any_working = 1;
3422				sector = r10_bio->devs[j].addr;
3423
3424				if (is_badblock(rdev, sector, max_sync,
3425						&first_bad, &bad_sectors)) {
3426					if (first_bad > sector)
3427						max_sync = first_bad - sector;
3428					else {
3429						bad_sectors -= (sector
3430								- first_bad);
3431						if (max_sync > bad_sectors)
3432							max_sync = bad_sectors;
3433						continue;
3434					}
3435				}
3436				bio = r10_bio->devs[0].bio;
3437				bio->bi_next = biolist;
3438				biolist = bio;
3439				bio->bi_end_io = end_sync_read;
3440				bio->bi_opf = REQ_OP_READ;
3441				if (test_bit(FailFast, &rdev->flags))
3442					bio->bi_opf |= MD_FAILFAST;
3443				from_addr = r10_bio->devs[j].addr;
3444				bio->bi_iter.bi_sector = from_addr +
3445					rdev->data_offset;
3446				bio_set_dev(bio, rdev->bdev);
3447				atomic_inc(&rdev->nr_pending);
3448				/* and we write to 'i' (if not in_sync) */
3449
3450				for (k=0; k<conf->copies; k++)
3451					if (r10_bio->devs[k].devnum == i)
3452						break;
3453				BUG_ON(k == conf->copies);
3454				to_addr = r10_bio->devs[k].addr;
3455				r10_bio->devs[0].devnum = d;
3456				r10_bio->devs[0].addr = from_addr;
3457				r10_bio->devs[1].devnum = i;
3458				r10_bio->devs[1].addr = to_addr;
3459
3460				if (mrdev) {
3461					bio = r10_bio->devs[1].bio;
3462					bio->bi_next = biolist;
3463					biolist = bio;
3464					bio->bi_end_io = end_sync_write;
3465					bio->bi_opf = REQ_OP_WRITE;
3466					bio->bi_iter.bi_sector = to_addr
3467						+ mrdev->data_offset;
3468					bio_set_dev(bio, mrdev->bdev);
3469					atomic_inc(&r10_bio->remaining);
3470				} else
3471					r10_bio->devs[1].bio->bi_end_io = NULL;
3472
3473				/* and maybe write to replacement */
3474				bio = r10_bio->devs[1].repl_bio;
3475				if (bio)
3476					bio->bi_end_io = NULL;
3477				/* Note: if replace is not NULL, then bio
3478				 * cannot be NULL as r10buf_pool_alloc will
3479				 * have allocated it.
3480				 */
3481				if (!mreplace)
3482					break;
3483				bio->bi_next = biolist;
3484				biolist = bio;
3485				bio->bi_end_io = end_sync_write;
3486				bio->bi_opf = REQ_OP_WRITE;
3487				bio->bi_iter.bi_sector = to_addr +
3488					mreplace->data_offset;
3489				bio_set_dev(bio, mreplace->bdev);
3490				atomic_inc(&r10_bio->remaining);
3491				break;
3492			}
3493			if (j == conf->copies) {
3494				/* Cannot recover, so abort the recovery or
3495				 * record a bad block */
3496				if (any_working) {
3497					/* problem is that there are bad blocks
3498					 * on other device(s)
3499					 */
3500					int k;
3501					for (k = 0; k < conf->copies; k++)
3502						if (r10_bio->devs[k].devnum == i)
3503							break;
3504					if (mrdev && !test_bit(In_sync,
3505						      &mrdev->flags)
3506					    && !rdev_set_badblocks(
3507						    mrdev,
3508						    r10_bio->devs[k].addr,
3509						    max_sync, 0))
3510						any_working = 0;
3511					if (mreplace &&
3512					    !rdev_set_badblocks(
3513						    mreplace,
3514						    r10_bio->devs[k].addr,
3515						    max_sync, 0))
3516						any_working = 0;
3517				}
3518				if (!any_working)  {
3519					if (!test_and_set_bit(MD_RECOVERY_INTR,
3520							      &mddev->recovery))
3521						pr_warn("md/raid10:%s: insufficient working devices for recovery.\n",
3522						       mdname(mddev));
3523					mirror->recovery_disabled
3524						= mddev->recovery_disabled;
3525				} else {
3526					error_disk = i;
3527				}
3528				put_buf(r10_bio);
3529				if (rb2)
3530					atomic_dec(&rb2->remaining);
3531				r10_bio = rb2;
3532				if (mrdev)
3533					rdev_dec_pending(mrdev, mddev);
3534				if (mreplace)
3535					rdev_dec_pending(mreplace, mddev);
3536				break;
3537			}
3538			if (mrdev)
3539				rdev_dec_pending(mrdev, mddev);
3540			if (mreplace)
3541				rdev_dec_pending(mreplace, mddev);
3542			if (r10_bio->devs[0].bio->bi_opf & MD_FAILFAST) {
3543				/* Only want this if there is elsewhere to
3544				 * read from. 'j' is currently the first
3545				 * readable copy.
3546				 */
3547				int targets = 1;
3548				for (; j < conf->copies; j++) {
3549					int d = r10_bio->devs[j].devnum;
3550					if (conf->mirrors[d].rdev &&
3551					    test_bit(In_sync,
3552						      &conf->mirrors[d].rdev->flags))
3553						targets++;
3554				}
3555				if (targets == 1)
3556					r10_bio->devs[0].bio->bi_opf
3557						&= ~MD_FAILFAST;
3558			}
3559		}
3560		if (biolist == NULL) {
3561			while (r10_bio) {
3562				struct r10bio *rb2 = r10_bio;
3563				r10_bio = (struct r10bio*) rb2->master_bio;
3564				rb2->master_bio = NULL;
3565				put_buf(rb2);
3566			}
3567			goto giveup;
3568		}
3569	} else {
3570		/* resync. Schedule a read for every block at this virt offset */
3571		int count = 0;
3572
3573		/*
3574		 * Since curr_resync_completed could probably not update in
3575		 * time, and we will set cluster_sync_low based on it.
3576		 * Let's check against "sector_nr + 2 * RESYNC_SECTORS" for
3577		 * safety reason, which ensures curr_resync_completed is
3578		 * updated in bitmap_cond_end_sync.
3579		 */
3580		mddev->bitmap_ops->cond_end_sync(mddev, sector_nr,
3581					mddev_is_clustered(mddev) &&
3582					(sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
3583
3584		if (!mddev->bitmap_ops->start_sync(mddev, sector_nr,
3585						   &sync_blocks,
3586						   mddev->degraded) &&
3587		    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
3588						 &mddev->recovery)) {
3589			/* We can skip this block */
3590			*skipped = 1;
3591			return sync_blocks + sectors_skipped;
3592		}
3593		if (sync_blocks < max_sync)
3594			max_sync = sync_blocks;
3595		r10_bio = raid10_alloc_init_r10buf(conf);
3596		r10_bio->state = 0;
3597
3598		r10_bio->mddev = mddev;
3599		atomic_set(&r10_bio->remaining, 0);
3600		raise_barrier(conf, 0);
3601		conf->next_resync = sector_nr;
3602
3603		r10_bio->master_bio = NULL;
3604		r10_bio->sector = sector_nr;
3605		set_bit(R10BIO_IsSync, &r10_bio->state);
3606		raid10_find_phys(conf, r10_bio);
3607		r10_bio->sectors = (sector_nr | chunk_mask) - sector_nr + 1;
3608
3609		for (i = 0; i < conf->copies; i++) {
3610			int d = r10_bio->devs[i].devnum;
3611			sector_t first_bad, sector;
3612			int bad_sectors;
3613			struct md_rdev *rdev;
3614
3615			if (r10_bio->devs[i].repl_bio)
3616				r10_bio->devs[i].repl_bio->bi_end_io = NULL;
3617
3618			bio = r10_bio->devs[i].bio;
3619			bio->bi_status = BLK_STS_IOERR;
3620			rdev = conf->mirrors[d].rdev;
3621			if (rdev == NULL || test_bit(Faulty, &rdev->flags))
3622				continue;
3623
3624			sector = r10_bio->devs[i].addr;
3625			if (is_badblock(rdev, sector, max_sync,
3626					&first_bad, &bad_sectors)) {
3627				if (first_bad > sector)
3628					max_sync = first_bad - sector;
3629				else {
3630					bad_sectors -= (sector - first_bad);
3631					if (max_sync > bad_sectors)
3632						max_sync = bad_sectors;
3633					continue;
3634				}
3635			}
3636			atomic_inc(&rdev->nr_pending);
3637			atomic_inc(&r10_bio->remaining);
3638			bio->bi_next = biolist;
3639			biolist = bio;
3640			bio->bi_end_io = end_sync_read;
3641			bio->bi_opf = REQ_OP_READ;
3642			if (test_bit(FailFast, &rdev->flags))
3643				bio->bi_opf |= MD_FAILFAST;
3644			bio->bi_iter.bi_sector = sector + rdev->data_offset;
3645			bio_set_dev(bio, rdev->bdev);
3646			count++;
3647
3648			rdev = conf->mirrors[d].replacement;
3649			if (rdev == NULL || test_bit(Faulty, &rdev->flags))
3650				continue;
3651
3652			atomic_inc(&rdev->nr_pending);
3653
3654			/* Need to set up for writing to the replacement */
3655			bio = r10_bio->devs[i].repl_bio;
3656			bio->bi_status = BLK_STS_IOERR;
3657
3658			sector = r10_bio->devs[i].addr;
3659			bio->bi_next = biolist;
3660			biolist = bio;
3661			bio->bi_end_io = end_sync_write;
3662			bio->bi_opf = REQ_OP_WRITE;
3663			if (test_bit(FailFast, &rdev->flags))
3664				bio->bi_opf |= MD_FAILFAST;
3665			bio->bi_iter.bi_sector = sector + rdev->data_offset;
3666			bio_set_dev(bio, rdev->bdev);
3667			count++;
3668		}
3669
3670		if (count < 2) {
3671			for (i=0; i<conf->copies; i++) {
3672				int d = r10_bio->devs[i].devnum;
3673				if (r10_bio->devs[i].bio->bi_end_io)
3674					rdev_dec_pending(conf->mirrors[d].rdev,
3675							 mddev);
3676				if (r10_bio->devs[i].repl_bio &&
3677				    r10_bio->devs[i].repl_bio->bi_end_io)
3678					rdev_dec_pending(
3679						conf->mirrors[d].replacement,
3680						mddev);
3681			}
3682			put_buf(r10_bio);
3683			biolist = NULL;
3684			goto giveup;
3685		}
3686	}
3687
3688	nr_sectors = 0;
3689	if (sector_nr + max_sync < max_sector)
3690		max_sector = sector_nr + max_sync;
3691	do {
3692		struct page *page;
3693		int len = PAGE_SIZE;
3694		if (sector_nr + (len>>9) > max_sector)
3695			len = (max_sector - sector_nr) << 9;
3696		if (len == 0)
3697			break;
3698		for (bio= biolist ; bio ; bio=bio->bi_next) {
3699			struct resync_pages *rp = get_resync_pages(bio);
3700			page = resync_fetch_page(rp, page_idx);
3701			if (WARN_ON(!bio_add_page(bio, page, len, 0))) {
3702				bio->bi_status = BLK_STS_RESOURCE;
3703				bio_endio(bio);
3704				goto giveup;
3705			}
3706		}
3707		nr_sectors += len>>9;
3708		sector_nr += len>>9;
3709	} while (++page_idx < RESYNC_PAGES);
3710	r10_bio->sectors = nr_sectors;
3711
3712	if (mddev_is_clustered(mddev) &&
3713	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3714		/* It is resync not recovery */
3715		if (conf->cluster_sync_high < sector_nr + nr_sectors) {
3716			conf->cluster_sync_low = mddev->curr_resync_completed;
3717			raid10_set_cluster_sync_high(conf);
3718			/* Send resync message */
3719			md_cluster_ops->resync_info_update(mddev,
3720						conf->cluster_sync_low,
3721						conf->cluster_sync_high);
3722		}
3723	} else if (mddev_is_clustered(mddev)) {
3724		/* This is recovery not resync */
3725		sector_t sect_va1, sect_va2;
3726		bool broadcast_msg = false;
3727
3728		for (i = 0; i < conf->geo.raid_disks; i++) {
3729			/*
3730			 * sector_nr is a device address for recovery, so we
3731			 * need translate it to array address before compare
3732			 * with cluster_sync_high.
3733			 */
3734			sect_va1 = raid10_find_virt(conf, sector_nr, i);
3735
3736			if (conf->cluster_sync_high < sect_va1 + nr_sectors) {
3737				broadcast_msg = true;
3738				/*
3739				 * curr_resync_completed is similar as
3740				 * sector_nr, so make the translation too.
3741				 */
3742				sect_va2 = raid10_find_virt(conf,
3743					mddev->curr_resync_completed, i);
3744
3745				if (conf->cluster_sync_low == 0 ||
3746				    conf->cluster_sync_low > sect_va2)
3747					conf->cluster_sync_low = sect_va2;
3748			}
3749		}
3750		if (broadcast_msg) {
3751			raid10_set_cluster_sync_high(conf);
3752			md_cluster_ops->resync_info_update(mddev,
3753						conf->cluster_sync_low,
3754						conf->cluster_sync_high);
3755		}
3756	}
3757
3758	while (biolist) {
3759		bio = biolist;
3760		biolist = biolist->bi_next;
3761
3762		bio->bi_next = NULL;
3763		r10_bio = get_resync_r10bio(bio);
3764		r10_bio->sectors = nr_sectors;
3765
3766		if (bio->bi_end_io == end_sync_read) {
3767			md_sync_acct_bio(bio, nr_sectors);
3768			bio->bi_status = 0;
3769			submit_bio_noacct(bio);
3770		}
3771	}
3772
3773	if (sectors_skipped)
3774		/* pretend they weren't skipped, it makes
3775		 * no important difference in this case
3776		 */
3777		md_done_sync(mddev, sectors_skipped, 1);
3778
3779	return sectors_skipped + nr_sectors;
3780 giveup:
3781	/* There is nowhere to write, so all non-sync
3782	 * drives must be failed or in resync, all drives
3783	 * have a bad block, so try the next chunk...
3784	 */
3785	if (sector_nr + max_sync < max_sector)
3786		max_sector = sector_nr + max_sync;
3787
3788	sectors_skipped += (max_sector - sector_nr);
3789	chunks_skipped ++;
3790	sector_nr = max_sector;
3791	goto skipped;
3792}
3793
3794static sector_t
3795raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)
3796{
3797	sector_t size;
3798	struct r10conf *conf = mddev->private;
3799
3800	if (!raid_disks)
3801		raid_disks = min(conf->geo.raid_disks,
3802				 conf->prev.raid_disks);
3803	if (!sectors)
3804		sectors = conf->dev_sectors;
3805
3806	size = sectors >> conf->geo.chunk_shift;
3807	sector_div(size, conf->geo.far_copies);
3808	size = size * raid_disks;
3809	sector_div(size, conf->geo.near_copies);
3810
3811	return size << conf->geo.chunk_shift;
3812}
3813
3814static void calc_sectors(struct r10conf *conf, sector_t size)
3815{
3816	/* Calculate the number of sectors-per-device that will
3817	 * actually be used, and set conf->dev_sectors and
3818	 * conf->stride
3819	 */
3820
3821	size = size >> conf->geo.chunk_shift;
3822	sector_div(size, conf->geo.far_copies);
3823	size = size * conf->geo.raid_disks;
3824	sector_div(size, conf->geo.near_copies);
3825	/* 'size' is now the number of chunks in the array */
3826	/* calculate "used chunks per device" */
3827	size = size * conf->copies;
3828
3829	/* We need to round up when dividing by raid_disks to
3830	 * get the stride size.
3831	 */
3832	size = DIV_ROUND_UP_SECTOR_T(size, conf->geo.raid_disks);
3833
3834	conf->dev_sectors = size << conf->geo.chunk_shift;
3835
3836	if (conf->geo.far_offset)
3837		conf->geo.stride = 1 << conf->geo.chunk_shift;
3838	else {
3839		sector_div(size, conf->geo.far_copies);
3840		conf->geo.stride = size << conf->geo.chunk_shift;
3841	}
3842}
3843
3844enum geo_type {geo_new, geo_old, geo_start};
3845static int setup_geo(struct geom *geo, struct mddev *mddev, enum geo_type new)
3846{
3847	int nc, fc, fo;
3848	int layout, chunk, disks;
3849	switch (new) {
3850	case geo_old:
3851		layout = mddev->layout;
3852		chunk = mddev->chunk_sectors;
3853		disks = mddev->raid_disks - mddev->delta_disks;
3854		break;
3855	case geo_new:
3856		layout = mddev->new_layout;
3857		chunk = mddev->new_chunk_sectors;
3858		disks = mddev->raid_disks;
3859		break;
3860	default: /* avoid 'may be unused' warnings */
3861	case geo_start: /* new when starting reshape - raid_disks not
3862			 * updated yet. */
3863		layout = mddev->new_layout;
3864		chunk = mddev->new_chunk_sectors;
3865		disks = mddev->raid_disks + mddev->delta_disks;
3866		break;
3867	}
3868	if (layout >> 19)
3869		return -1;
3870	if (chunk < (PAGE_SIZE >> 9) ||
3871	    !is_power_of_2(chunk))
3872		return -2;
3873	nc = layout & 255;
3874	fc = (layout >> 8) & 255;
3875	fo = layout & (1<<16);
3876	geo->raid_disks = disks;
3877	geo->near_copies = nc;
3878	geo->far_copies = fc;
3879	geo->far_offset = fo;
3880	switch (layout >> 17) {
3881	case 0:	/* original layout.  simple but not always optimal */
3882		geo->far_set_size = disks;
3883		break;
3884	case 1: /* "improved" layout which was buggy.  Hopefully no-one is
3885		 * actually using this, but leave code here just in case.*/
3886		geo->far_set_size = disks/fc;
3887		WARN(geo->far_set_size < fc,
3888		     "This RAID10 layout does not provide data safety - please backup and create new array\n");
3889		break;
3890	case 2: /* "improved" layout fixed to match documentation */
3891		geo->far_set_size = fc * nc;
3892		break;
3893	default: /* Not a valid layout */
3894		return -1;
3895	}
3896	geo->chunk_mask = chunk - 1;
3897	geo->chunk_shift = ffz(~chunk);
3898	return nc*fc;
3899}
3900
3901static void raid10_free_conf(struct r10conf *conf)
3902{
3903	if (!conf)
3904		return;
3905
3906	mempool_exit(&conf->r10bio_pool);
3907	kfree(conf->mirrors);
3908	kfree(conf->mirrors_old);
3909	kfree(conf->mirrors_new);
3910	safe_put_page(conf->tmppage);
3911	bioset_exit(&conf->bio_split);
3912	kfree(conf);
3913}
3914
3915static struct r10conf *setup_conf(struct mddev *mddev)
3916{
3917	struct r10conf *conf = NULL;
3918	int err = -EINVAL;
3919	struct geom geo;
3920	int copies;
3921
3922	copies = setup_geo(&geo, mddev, geo_new);
3923
3924	if (copies == -2) {
3925		pr_warn("md/raid10:%s: chunk size must be at least PAGE_SIZE(%ld) and be a power of 2.\n",
3926			mdname(mddev), PAGE_SIZE);
3927		goto out;
3928	}
3929
3930	if (copies < 2 || copies > mddev->raid_disks) {
3931		pr_warn("md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
3932			mdname(mddev), mddev->new_layout);
3933		goto out;
3934	}
3935
3936	err = -ENOMEM;
3937	conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL);
3938	if (!conf)
3939		goto out;
3940
3941	/* FIXME calc properly */
3942	conf->mirrors = kcalloc(mddev->raid_disks + max(0, -mddev->delta_disks),
3943				sizeof(struct raid10_info),
3944				GFP_KERNEL);
3945	if (!conf->mirrors)
3946		goto out;
3947
3948	conf->tmppage = alloc_page(GFP_KERNEL);
3949	if (!conf->tmppage)
3950		goto out;
3951
3952	conf->geo = geo;
3953	conf->copies = copies;
3954	err = mempool_init(&conf->r10bio_pool, NR_RAID_BIOS, r10bio_pool_alloc,
3955			   rbio_pool_free, conf);
3956	if (err)
3957		goto out;
3958
3959	err = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
3960	if (err)
3961		goto out;
3962
3963	calc_sectors(conf, mddev->dev_sectors);
3964	if (mddev->reshape_position == MaxSector) {
3965		conf->prev = conf->geo;
3966		conf->reshape_progress = MaxSector;
3967	} else {
3968		if (setup_geo(&conf->prev, mddev, geo_old) != conf->copies) {
3969			err = -EINVAL;
3970			goto out;
3971		}
3972		conf->reshape_progress = mddev->reshape_position;
3973		if (conf->prev.far_offset)
3974			conf->prev.stride = 1 << conf->prev.chunk_shift;
3975		else
3976			/* far_copies must be 1 */
3977			conf->prev.stride = conf->dev_sectors;
3978	}
3979	conf->reshape_safe = conf->reshape_progress;
3980	spin_lock_init(&conf->device_lock);
3981	INIT_LIST_HEAD(&conf->retry_list);
3982	INIT_LIST_HEAD(&conf->bio_end_io_list);
3983
3984	seqlock_init(&conf->resync_lock);
3985	init_waitqueue_head(&conf->wait_barrier);
3986	atomic_set(&conf->nr_pending, 0);
3987
3988	err = -ENOMEM;
3989	rcu_assign_pointer(conf->thread,
3990			   md_register_thread(raid10d, mddev, "raid10"));
3991	if (!conf->thread)
3992		goto out;
3993
3994	conf->mddev = mddev;
3995	return conf;
3996
3997 out:
3998	raid10_free_conf(conf);
3999	return ERR_PTR(err);
4000}
4001
4002static unsigned int raid10_nr_stripes(struct r10conf *conf)
4003{
4004	unsigned int raid_disks = conf->geo.raid_disks;
4005
4006	if (conf->geo.raid_disks % conf->geo.near_copies)
4007		return raid_disks;
4008	return raid_disks / conf->geo.near_copies;
4009}
4010
4011static int raid10_set_queue_limits(struct mddev *mddev)
4012{
4013	struct r10conf *conf = mddev->private;
4014	struct queue_limits lim;
4015	int err;
4016
4017	md_init_stacking_limits(&lim);
4018	lim.max_write_zeroes_sectors = 0;
4019	lim.io_min = mddev->chunk_sectors << 9;
4020	lim.io_opt = lim.io_min * raid10_nr_stripes(conf);
4021	lim.features |= BLK_FEAT_ATOMIC_WRITES_STACKED;
4022	err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
4023	if (err)
4024		return err;
4025	return queue_limits_set(mddev->gendisk->queue, &lim);
4026}
4027
4028static int raid10_run(struct mddev *mddev)
4029{
4030	struct r10conf *conf;
4031	int i, disk_idx;
4032	struct raid10_info *disk;
4033	struct md_rdev *rdev;
4034	sector_t size;
4035	sector_t min_offset_diff = 0;
4036	int first = 1;
4037	int ret = -EIO;
4038
4039	if (mddev->private == NULL) {
4040		conf = setup_conf(mddev);
4041		if (IS_ERR(conf))
4042			return PTR_ERR(conf);
4043		mddev->private = conf;
4044	}
4045	conf = mddev->private;
4046	if (!conf)
4047		goto out;
4048
4049	rcu_assign_pointer(mddev->thread, conf->thread);
4050	rcu_assign_pointer(conf->thread, NULL);
4051
4052	if (mddev_is_clustered(conf->mddev)) {
4053		int fc, fo;
4054
4055		fc = (mddev->layout >> 8) & 255;
4056		fo = mddev->layout & (1<<16);
4057		if (fc > 1 || fo > 0) {
4058			pr_err("only near layout is supported by clustered"
4059				" raid10\n");
4060			goto out_free_conf;
4061		}
4062	}
4063
 
 
 
 
 
 
4064	rdev_for_each(rdev, mddev) {
4065		long long diff;
4066
4067		disk_idx = rdev->raid_disk;
4068		if (disk_idx < 0)
4069			continue;
4070		if (disk_idx >= conf->geo.raid_disks &&
4071		    disk_idx >= conf->prev.raid_disks)
4072			continue;
4073		disk = conf->mirrors + disk_idx;
4074
4075		if (test_bit(Replacement, &rdev->flags)) {
4076			if (disk->replacement)
4077				goto out_free_conf;
4078			disk->replacement = rdev;
4079		} else {
4080			if (disk->rdev)
4081				goto out_free_conf;
4082			disk->rdev = rdev;
4083		}
4084		diff = (rdev->new_data_offset - rdev->data_offset);
4085		if (!mddev->reshape_backwards)
4086			diff = -diff;
4087		if (diff < 0)
4088			diff = 0;
4089		if (first || diff < min_offset_diff)
4090			min_offset_diff = diff;
4091
 
 
 
 
4092		disk->head_position = 0;
4093		first = 0;
4094	}
4095
4096	if (!mddev_is_dm(conf->mddev)) {
4097		int err = raid10_set_queue_limits(mddev);
4098
4099		if (err) {
4100			ret = err;
4101			goto out_free_conf;
4102		}
4103	}
4104
4105	/* need to check that every block has at least one working mirror */
4106	if (!enough(conf, -1)) {
4107		pr_err("md/raid10:%s: not enough operational mirrors.\n",
4108		       mdname(mddev));
4109		goto out_free_conf;
4110	}
4111
4112	if (conf->reshape_progress != MaxSector) {
4113		/* must ensure that shape change is supported */
4114		if (conf->geo.far_copies != 1 &&
4115		    conf->geo.far_offset == 0)
4116			goto out_free_conf;
4117		if (conf->prev.far_copies != 1 &&
4118		    conf->prev.far_offset == 0)
4119			goto out_free_conf;
4120	}
4121
4122	mddev->degraded = 0;
4123	for (i = 0;
4124	     i < conf->geo.raid_disks
4125		     || i < conf->prev.raid_disks;
4126	     i++) {
4127
4128		disk = conf->mirrors + i;
4129
4130		if (!disk->rdev && disk->replacement) {
4131			/* The replacement is all we have - use it */
4132			disk->rdev = disk->replacement;
4133			disk->replacement = NULL;
4134			clear_bit(Replacement, &disk->rdev->flags);
4135		}
4136
4137		if (!disk->rdev ||
4138		    !test_bit(In_sync, &disk->rdev->flags)) {
4139			disk->head_position = 0;
4140			mddev->degraded++;
4141			if (disk->rdev &&
4142			    disk->rdev->saved_raid_disk < 0)
4143				conf->fullsync = 1;
4144		}
4145
4146		if (disk->replacement &&
4147		    !test_bit(In_sync, &disk->replacement->flags) &&
4148		    disk->replacement->saved_raid_disk < 0) {
4149			conf->fullsync = 1;
4150		}
4151
4152		disk->recovery_disabled = mddev->recovery_disabled - 1;
4153	}
4154
4155	if (mddev->recovery_cp != MaxSector)
4156		pr_notice("md/raid10:%s: not clean -- starting background reconstruction\n",
4157			  mdname(mddev));
4158	pr_info("md/raid10:%s: active with %d out of %d devices\n",
4159		mdname(mddev), conf->geo.raid_disks - mddev->degraded,
4160		conf->geo.raid_disks);
4161	/*
4162	 * Ok, everything is just fine now
4163	 */
4164	mddev->dev_sectors = conf->dev_sectors;
4165	size = raid10_size(mddev, 0, 0);
4166	md_set_array_sectors(mddev, size);
4167	mddev->resync_max_sectors = size;
4168	set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
4169
4170	if (md_integrity_register(mddev))
4171		goto out_free_conf;
4172
4173	if (conf->reshape_progress != MaxSector) {
4174		unsigned long before_length, after_length;
4175
4176		before_length = ((1 << conf->prev.chunk_shift) *
4177				 conf->prev.far_copies);
4178		after_length = ((1 << conf->geo.chunk_shift) *
4179				conf->geo.far_copies);
4180
4181		if (max(before_length, after_length) > min_offset_diff) {
4182			/* This cannot work */
4183			pr_warn("md/raid10: offset difference not enough to continue reshape\n");
4184			goto out_free_conf;
4185		}
4186		conf->offset_diff = min_offset_diff;
4187
4188		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4189		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4190		set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4191		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4192	}
4193
4194	return 0;
4195
4196out_free_conf:
4197	md_unregister_thread(mddev, &mddev->thread);
4198	raid10_free_conf(conf);
4199	mddev->private = NULL;
4200out:
4201	return ret;
4202}
4203
4204static void raid10_free(struct mddev *mddev, void *priv)
4205{
4206	raid10_free_conf(priv);
4207}
4208
4209static void raid10_quiesce(struct mddev *mddev, int quiesce)
4210{
4211	struct r10conf *conf = mddev->private;
4212
4213	if (quiesce)
4214		raise_barrier(conf, 0);
4215	else
4216		lower_barrier(conf);
4217}
4218
4219static int raid10_resize(struct mddev *mddev, sector_t sectors)
4220{
4221	/* Resize of 'far' arrays is not supported.
4222	 * For 'near' and 'offset' arrays we can set the
4223	 * number of sectors used to be an appropriate multiple
4224	 * of the chunk size.
4225	 * For 'offset', this is far_copies*chunksize.
4226	 * For 'near' the multiplier is the LCM of
4227	 * near_copies and raid_disks.
4228	 * So if far_copies > 1 && !far_offset, fail.
4229	 * Else find LCM(raid_disks, near_copy)*far_copies and
4230	 * multiply by chunk_size.  Then round to this number.
4231	 * This is mostly done by raid10_size()
4232	 */
4233	struct r10conf *conf = mddev->private;
4234	sector_t oldsize, size;
4235	int ret;
4236
4237	if (mddev->reshape_position != MaxSector)
4238		return -EBUSY;
4239
4240	if (conf->geo.far_copies > 1 && !conf->geo.far_offset)
4241		return -EINVAL;
4242
4243	oldsize = raid10_size(mddev, 0, 0);
4244	size = raid10_size(mddev, sectors, 0);
4245	if (mddev->external_size &&
4246	    mddev->array_sectors > size)
4247		return -EINVAL;
4248
4249	ret = mddev->bitmap_ops->resize(mddev, size, 0, false);
4250	if (ret)
4251		return ret;
4252
4253	md_set_array_sectors(mddev, size);
4254	if (sectors > mddev->dev_sectors &&
4255	    mddev->recovery_cp > oldsize) {
4256		mddev->recovery_cp = oldsize;
4257		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4258	}
4259	calc_sectors(conf, sectors);
4260	mddev->dev_sectors = conf->dev_sectors;
4261	mddev->resync_max_sectors = size;
4262	return 0;
4263}
4264
4265static void *raid10_takeover_raid0(struct mddev *mddev, sector_t size, int devs)
4266{
4267	struct md_rdev *rdev;
4268	struct r10conf *conf;
4269
4270	if (mddev->degraded > 0) {
4271		pr_warn("md/raid10:%s: Error: degraded raid0!\n",
4272			mdname(mddev));
4273		return ERR_PTR(-EINVAL);
4274	}
4275	sector_div(size, devs);
4276
4277	/* Set new parameters */
4278	mddev->new_level = 10;
4279	/* new layout: far_copies = 1, near_copies = 2 */
4280	mddev->new_layout = (1<<8) + 2;
4281	mddev->new_chunk_sectors = mddev->chunk_sectors;
4282	mddev->delta_disks = mddev->raid_disks;
4283	mddev->raid_disks *= 2;
4284	/* make sure it will be not marked as dirty */
4285	mddev->recovery_cp = MaxSector;
4286	mddev->dev_sectors = size;
4287
4288	conf = setup_conf(mddev);
4289	if (!IS_ERR(conf)) {
4290		rdev_for_each(rdev, mddev)
4291			if (rdev->raid_disk >= 0) {
4292				rdev->new_raid_disk = rdev->raid_disk * 2;
4293				rdev->sectors = size;
4294			}
4295	}
4296
4297	return conf;
4298}
4299
4300static void *raid10_takeover(struct mddev *mddev)
4301{
4302	struct r0conf *raid0_conf;
4303
4304	/* raid10 can take over:
4305	 *  raid0 - providing it has only two drives
4306	 */
4307	if (mddev->level == 0) {
4308		/* for raid0 takeover only one zone is supported */
4309		raid0_conf = mddev->private;
4310		if (raid0_conf->nr_strip_zones > 1) {
4311			pr_warn("md/raid10:%s: cannot takeover raid 0 with more than one zone.\n",
4312				mdname(mddev));
4313			return ERR_PTR(-EINVAL);
4314		}
4315		return raid10_takeover_raid0(mddev,
4316			raid0_conf->strip_zone->zone_end,
4317			raid0_conf->strip_zone->nb_dev);
4318	}
4319	return ERR_PTR(-EINVAL);
4320}
4321
4322static int raid10_check_reshape(struct mddev *mddev)
4323{
4324	/* Called when there is a request to change
4325	 * - layout (to ->new_layout)
4326	 * - chunk size (to ->new_chunk_sectors)
4327	 * - raid_disks (by delta_disks)
4328	 * or when trying to restart a reshape that was ongoing.
4329	 *
4330	 * We need to validate the request and possibly allocate
4331	 * space if that might be an issue later.
4332	 *
4333	 * Currently we reject any reshape of a 'far' mode array,
4334	 * allow chunk size to change if new is generally acceptable,
4335	 * allow raid_disks to increase, and allow
4336	 * a switch between 'near' mode and 'offset' mode.
4337	 */
4338	struct r10conf *conf = mddev->private;
4339	struct geom geo;
4340
4341	if (conf->geo.far_copies != 1 && !conf->geo.far_offset)
4342		return -EINVAL;
4343
4344	if (setup_geo(&geo, mddev, geo_start) != conf->copies)
4345		/* mustn't change number of copies */
4346		return -EINVAL;
4347	if (geo.far_copies > 1 && !geo.far_offset)
4348		/* Cannot switch to 'far' mode */
4349		return -EINVAL;
4350
4351	if (mddev->array_sectors & geo.chunk_mask)
4352			/* not factor of array size */
4353			return -EINVAL;
4354
4355	if (!enough(conf, -1))
4356		return -EINVAL;
4357
4358	kfree(conf->mirrors_new);
4359	conf->mirrors_new = NULL;
4360	if (mddev->delta_disks > 0) {
4361		/* allocate new 'mirrors' list */
4362		conf->mirrors_new =
4363			kcalloc(mddev->raid_disks + mddev->delta_disks,
4364				sizeof(struct raid10_info),
4365				GFP_KERNEL);
4366		if (!conf->mirrors_new)
4367			return -ENOMEM;
4368	}
4369	return 0;
4370}
4371
4372/*
4373 * Need to check if array has failed when deciding whether to:
4374 *  - start an array
4375 *  - remove non-faulty devices
4376 *  - add a spare
4377 *  - allow a reshape
4378 * This determination is simple when no reshape is happening.
4379 * However if there is a reshape, we need to carefully check
4380 * both the before and after sections.
4381 * This is because some failed devices may only affect one
4382 * of the two sections, and some non-in_sync devices may
4383 * be insync in the section most affected by failed devices.
4384 */
4385static int calc_degraded(struct r10conf *conf)
4386{
4387	int degraded, degraded2;
4388	int i;
4389
4390	degraded = 0;
4391	/* 'prev' section first */
4392	for (i = 0; i < conf->prev.raid_disks; i++) {
4393		struct md_rdev *rdev = conf->mirrors[i].rdev;
4394
4395		if (!rdev || test_bit(Faulty, &rdev->flags))
4396			degraded++;
4397		else if (!test_bit(In_sync, &rdev->flags))
4398			/* When we can reduce the number of devices in
4399			 * an array, this might not contribute to
4400			 * 'degraded'.  It does now.
4401			 */
4402			degraded++;
4403	}
4404	if (conf->geo.raid_disks == conf->prev.raid_disks)
4405		return degraded;
4406	degraded2 = 0;
4407	for (i = 0; i < conf->geo.raid_disks; i++) {
4408		struct md_rdev *rdev = conf->mirrors[i].rdev;
4409
4410		if (!rdev || test_bit(Faulty, &rdev->flags))
4411			degraded2++;
4412		else if (!test_bit(In_sync, &rdev->flags)) {
4413			/* If reshape is increasing the number of devices,
4414			 * this section has already been recovered, so
4415			 * it doesn't contribute to degraded.
4416			 * else it does.
4417			 */
4418			if (conf->geo.raid_disks <= conf->prev.raid_disks)
4419				degraded2++;
4420		}
4421	}
4422	if (degraded2 > degraded)
4423		return degraded2;
4424	return degraded;
4425}
4426
4427static int raid10_start_reshape(struct mddev *mddev)
4428{
4429	/* A 'reshape' has been requested. This commits
4430	 * the various 'new' fields and sets MD_RECOVER_RESHAPE
4431	 * This also checks if there are enough spares and adds them
4432	 * to the array.
4433	 * We currently require enough spares to make the final
4434	 * array non-degraded.  We also require that the difference
4435	 * between old and new data_offset - on each device - is
4436	 * enough that we never risk over-writing.
4437	 */
4438
4439	unsigned long before_length, after_length;
4440	sector_t min_offset_diff = 0;
4441	int first = 1;
4442	struct geom new;
4443	struct r10conf *conf = mddev->private;
4444	struct md_rdev *rdev;
4445	int spares = 0;
4446	int ret;
4447
4448	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4449		return -EBUSY;
4450
4451	if (setup_geo(&new, mddev, geo_start) != conf->copies)
4452		return -EINVAL;
4453
4454	before_length = ((1 << conf->prev.chunk_shift) *
4455			 conf->prev.far_copies);
4456	after_length = ((1 << conf->geo.chunk_shift) *
4457			conf->geo.far_copies);
4458
4459	rdev_for_each(rdev, mddev) {
4460		if (!test_bit(In_sync, &rdev->flags)
4461		    && !test_bit(Faulty, &rdev->flags))
4462			spares++;
4463		if (rdev->raid_disk >= 0) {
4464			long long diff = (rdev->new_data_offset
4465					  - rdev->data_offset);
4466			if (!mddev->reshape_backwards)
4467				diff = -diff;
4468			if (diff < 0)
4469				diff = 0;
4470			if (first || diff < min_offset_diff)
4471				min_offset_diff = diff;
4472			first = 0;
4473		}
4474	}
4475
4476	if (max(before_length, after_length) > min_offset_diff)
4477		return -EINVAL;
4478
4479	if (spares < mddev->delta_disks)
4480		return -EINVAL;
4481
4482	conf->offset_diff = min_offset_diff;
4483	spin_lock_irq(&conf->device_lock);
4484	if (conf->mirrors_new) {
4485		memcpy(conf->mirrors_new, conf->mirrors,
4486		       sizeof(struct raid10_info)*conf->prev.raid_disks);
4487		smp_mb();
4488		kfree(conf->mirrors_old);
4489		conf->mirrors_old = conf->mirrors;
4490		conf->mirrors = conf->mirrors_new;
4491		conf->mirrors_new = NULL;
4492	}
4493	setup_geo(&conf->geo, mddev, geo_start);
4494	smp_mb();
4495	if (mddev->reshape_backwards) {
4496		sector_t size = raid10_size(mddev, 0, 0);
4497		if (size < mddev->array_sectors) {
4498			spin_unlock_irq(&conf->device_lock);
4499			pr_warn("md/raid10:%s: array size must be reduce before number of disks\n",
4500				mdname(mddev));
4501			return -EINVAL;
4502		}
4503		mddev->resync_max_sectors = size;
4504		conf->reshape_progress = size;
4505	} else
4506		conf->reshape_progress = 0;
4507	conf->reshape_safe = conf->reshape_progress;
4508	spin_unlock_irq(&conf->device_lock);
4509
4510	if (mddev->delta_disks && mddev->bitmap) {
4511		struct mdp_superblock_1 *sb = NULL;
4512		sector_t oldsize, newsize;
4513
4514		oldsize = raid10_size(mddev, 0, 0);
4515		newsize = raid10_size(mddev, 0, conf->geo.raid_disks);
4516
4517		if (!mddev_is_clustered(mddev)) {
4518			ret = mddev->bitmap_ops->resize(mddev, newsize, 0, false);
4519			if (ret)
4520				goto abort;
4521			else
4522				goto out;
4523		}
4524
4525		rdev_for_each(rdev, mddev) {
4526			if (rdev->raid_disk > -1 &&
4527			    !test_bit(Faulty, &rdev->flags))
4528				sb = page_address(rdev->sb_page);
4529		}
4530
4531		/*
4532		 * some node is already performing reshape, and no need to
4533		 * call bitmap_ops->resize again since it should be called when
4534		 * receiving BITMAP_RESIZE msg
4535		 */
4536		if ((sb && (le32_to_cpu(sb->feature_map) &
4537			    MD_FEATURE_RESHAPE_ACTIVE)) || (oldsize == newsize))
4538			goto out;
4539
4540		ret = mddev->bitmap_ops->resize(mddev, newsize, 0, false);
4541		if (ret)
4542			goto abort;
4543
4544		ret = md_cluster_ops->resize_bitmaps(mddev, newsize, oldsize);
4545		if (ret) {
4546			mddev->bitmap_ops->resize(mddev, oldsize, 0, false);
4547			goto abort;
4548		}
4549	}
4550out:
4551	if (mddev->delta_disks > 0) {
4552		rdev_for_each(rdev, mddev)
4553			if (rdev->raid_disk < 0 &&
4554			    !test_bit(Faulty, &rdev->flags)) {
4555				if (raid10_add_disk(mddev, rdev) == 0) {
4556					if (rdev->raid_disk >=
4557					    conf->prev.raid_disks)
4558						set_bit(In_sync, &rdev->flags);
4559					else
4560						rdev->recovery_offset = 0;
4561
4562					/* Failure here is OK */
4563					sysfs_link_rdev(mddev, rdev);
4564				}
4565			} else if (rdev->raid_disk >= conf->prev.raid_disks
4566				   && !test_bit(Faulty, &rdev->flags)) {
4567				/* This is a spare that was manually added */
4568				set_bit(In_sync, &rdev->flags);
4569			}
4570	}
4571	/* When a reshape changes the number of devices,
4572	 * ->degraded is measured against the larger of the
4573	 * pre and  post numbers.
4574	 */
4575	spin_lock_irq(&conf->device_lock);
4576	mddev->degraded = calc_degraded(conf);
4577	spin_unlock_irq(&conf->device_lock);
4578	mddev->raid_disks = conf->geo.raid_disks;
4579	mddev->reshape_position = conf->reshape_progress;
4580	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
4581
4582	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4583	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4584	clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
4585	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4586	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4587	conf->reshape_checkpoint = jiffies;
4588	md_new_event();
4589	return 0;
4590
4591abort:
4592	mddev->recovery = 0;
4593	spin_lock_irq(&conf->device_lock);
4594	conf->geo = conf->prev;
4595	mddev->raid_disks = conf->geo.raid_disks;
4596	rdev_for_each(rdev, mddev)
4597		rdev->new_data_offset = rdev->data_offset;
4598	smp_wmb();
4599	conf->reshape_progress = MaxSector;
4600	conf->reshape_safe = MaxSector;
4601	mddev->reshape_position = MaxSector;
4602	spin_unlock_irq(&conf->device_lock);
4603	return ret;
4604}
4605
4606/* Calculate the last device-address that could contain
4607 * any block from the chunk that includes the array-address 's'
4608 * and report the next address.
4609 * i.e. the address returned will be chunk-aligned and after
4610 * any data that is in the chunk containing 's'.
4611 */
4612static sector_t last_dev_address(sector_t s, struct geom *geo)
4613{
4614	s = (s | geo->chunk_mask) + 1;
4615	s >>= geo->chunk_shift;
4616	s *= geo->near_copies;
4617	s = DIV_ROUND_UP_SECTOR_T(s, geo->raid_disks);
4618	s *= geo->far_copies;
4619	s <<= geo->chunk_shift;
4620	return s;
4621}
4622
4623/* Calculate the first device-address that could contain
4624 * any block from the chunk that includes the array-address 's'.
4625 * This too will be the start of a chunk
4626 */
4627static sector_t first_dev_address(sector_t s, struct geom *geo)
4628{
4629	s >>= geo->chunk_shift;
4630	s *= geo->near_copies;
4631	sector_div(s, geo->raid_disks);
4632	s *= geo->far_copies;
4633	s <<= geo->chunk_shift;
4634	return s;
4635}
4636
4637static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
4638				int *skipped)
4639{
4640	/* We simply copy at most one chunk (smallest of old and new)
4641	 * at a time, possibly less if that exceeds RESYNC_PAGES,
4642	 * or we hit a bad block or something.
4643	 * This might mean we pause for normal IO in the middle of
4644	 * a chunk, but that is not a problem as mddev->reshape_position
4645	 * can record any location.
4646	 *
4647	 * If we will want to write to a location that isn't
4648	 * yet recorded as 'safe' (i.e. in metadata on disk) then
4649	 * we need to flush all reshape requests and update the metadata.
4650	 *
4651	 * When reshaping forwards (e.g. to more devices), we interpret
4652	 * 'safe' as the earliest block which might not have been copied
4653	 * down yet.  We divide this by previous stripe size and multiply
4654	 * by previous stripe length to get lowest device offset that we
4655	 * cannot write to yet.
4656	 * We interpret 'sector_nr' as an address that we want to write to.
4657	 * From this we use last_device_address() to find where we might
4658	 * write to, and first_device_address on the  'safe' position.
4659	 * If this 'next' write position is after the 'safe' position,
4660	 * we must update the metadata to increase the 'safe' position.
4661	 *
4662	 * When reshaping backwards, we round in the opposite direction
4663	 * and perform the reverse test:  next write position must not be
4664	 * less than current safe position.
4665	 *
4666	 * In all this the minimum difference in data offsets
4667	 * (conf->offset_diff - always positive) allows a bit of slack,
4668	 * so next can be after 'safe', but not by more than offset_diff
4669	 *
4670	 * We need to prepare all the bios here before we start any IO
4671	 * to ensure the size we choose is acceptable to all devices.
4672	 * The means one for each copy for write-out and an extra one for
4673	 * read-in.
4674	 * We store the read-in bio in ->master_bio and the others in
4675	 * ->devs[x].bio and ->devs[x].repl_bio.
4676	 */
4677	struct r10conf *conf = mddev->private;
4678	struct r10bio *r10_bio;
4679	sector_t next, safe, last;
4680	int max_sectors;
4681	int nr_sectors;
4682	int s;
4683	struct md_rdev *rdev;
4684	int need_flush = 0;
4685	struct bio *blist;
4686	struct bio *bio, *read_bio;
4687	int sectors_done = 0;
4688	struct page **pages;
4689
4690	if (sector_nr == 0) {
4691		/* If restarting in the middle, skip the initial sectors */
4692		if (mddev->reshape_backwards &&
4693		    conf->reshape_progress < raid10_size(mddev, 0, 0)) {
4694			sector_nr = (raid10_size(mddev, 0, 0)
4695				     - conf->reshape_progress);
4696		} else if (!mddev->reshape_backwards &&
4697			   conf->reshape_progress > 0)
4698			sector_nr = conf->reshape_progress;
4699		if (sector_nr) {
4700			mddev->curr_resync_completed = sector_nr;
4701			sysfs_notify_dirent_safe(mddev->sysfs_completed);
4702			*skipped = 1;
4703			return sector_nr;
4704		}
4705	}
4706
4707	/* We don't use sector_nr to track where we are up to
4708	 * as that doesn't work well for ->reshape_backwards.
4709	 * So just use ->reshape_progress.
4710	 */
4711	if (mddev->reshape_backwards) {
4712		/* 'next' is the earliest device address that we might
4713		 * write to for this chunk in the new layout
4714		 */
4715		next = first_dev_address(conf->reshape_progress - 1,
4716					 &conf->geo);
4717
4718		/* 'safe' is the last device address that we might read from
4719		 * in the old layout after a restart
4720		 */
4721		safe = last_dev_address(conf->reshape_safe - 1,
4722					&conf->prev);
4723
4724		if (next + conf->offset_diff < safe)
4725			need_flush = 1;
4726
4727		last = conf->reshape_progress - 1;
4728		sector_nr = last & ~(sector_t)(conf->geo.chunk_mask
4729					       & conf->prev.chunk_mask);
4730		if (sector_nr + RESYNC_SECTORS < last)
4731			sector_nr = last + 1 - RESYNC_SECTORS;
4732	} else {
4733		/* 'next' is after the last device address that we
4734		 * might write to for this chunk in the new layout
4735		 */
4736		next = last_dev_address(conf->reshape_progress, &conf->geo);
4737
4738		/* 'safe' is the earliest device address that we might
4739		 * read from in the old layout after a restart
4740		 */
4741		safe = first_dev_address(conf->reshape_safe, &conf->prev);
4742
4743		/* Need to update metadata if 'next' might be beyond 'safe'
4744		 * as that would possibly corrupt data
4745		 */
4746		if (next > safe + conf->offset_diff)
4747			need_flush = 1;
4748
4749		sector_nr = conf->reshape_progress;
4750		last  = sector_nr | (conf->geo.chunk_mask
4751				     & conf->prev.chunk_mask);
4752
4753		if (sector_nr + RESYNC_SECTORS <= last)
4754			last = sector_nr + RESYNC_SECTORS - 1;
4755	}
4756
4757	if (need_flush ||
4758	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4759		/* Need to update reshape_position in metadata */
4760		wait_barrier(conf, false);
4761		mddev->reshape_position = conf->reshape_progress;
4762		if (mddev->reshape_backwards)
4763			mddev->curr_resync_completed = raid10_size(mddev, 0, 0)
4764				- conf->reshape_progress;
4765		else
4766			mddev->curr_resync_completed = conf->reshape_progress;
4767		conf->reshape_checkpoint = jiffies;
4768		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
4769		md_wakeup_thread(mddev->thread);
4770		wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
4771			   test_bit(MD_RECOVERY_INTR, &mddev->recovery));
4772		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
4773			allow_barrier(conf);
4774			return sectors_done;
4775		}
4776		conf->reshape_safe = mddev->reshape_position;
4777		allow_barrier(conf);
4778	}
4779
4780	raise_barrier(conf, 0);
4781read_more:
4782	/* Now schedule reads for blocks from sector_nr to last */
4783	r10_bio = raid10_alloc_init_r10buf(conf);
4784	r10_bio->state = 0;
4785	raise_barrier(conf, 1);
4786	atomic_set(&r10_bio->remaining, 0);
4787	r10_bio->mddev = mddev;
4788	r10_bio->sector = sector_nr;
4789	set_bit(R10BIO_IsReshape, &r10_bio->state);
4790	r10_bio->sectors = last - sector_nr + 1;
4791	rdev = read_balance(conf, r10_bio, &max_sectors);
4792	BUG_ON(!test_bit(R10BIO_Previous, &r10_bio->state));
4793
4794	if (!rdev) {
4795		/* Cannot read from here, so need to record bad blocks
4796		 * on all the target devices.
4797		 */
4798		// FIXME
4799		mempool_free(r10_bio, &conf->r10buf_pool);
4800		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4801		return sectors_done;
4802	}
4803
4804	read_bio = bio_alloc_bioset(rdev->bdev, RESYNC_PAGES, REQ_OP_READ,
4805				    GFP_KERNEL, &mddev->bio_set);
4806	read_bio->bi_iter.bi_sector = (r10_bio->devs[r10_bio->read_slot].addr
4807			       + rdev->data_offset);
4808	read_bio->bi_private = r10_bio;
4809	read_bio->bi_end_io = end_reshape_read;
4810	r10_bio->master_bio = read_bio;
4811	r10_bio->read_slot = r10_bio->devs[r10_bio->read_slot].devnum;
4812
4813	/*
4814	 * Broadcast RESYNC message to other nodes, so all nodes would not
4815	 * write to the region to avoid conflict.
4816	*/
4817	if (mddev_is_clustered(mddev) && conf->cluster_sync_high <= sector_nr) {
4818		struct mdp_superblock_1 *sb = NULL;
4819		int sb_reshape_pos = 0;
4820
4821		conf->cluster_sync_low = sector_nr;
4822		conf->cluster_sync_high = sector_nr + CLUSTER_RESYNC_WINDOW_SECTORS;
4823		sb = page_address(rdev->sb_page);
4824		if (sb) {
4825			sb_reshape_pos = le64_to_cpu(sb->reshape_position);
4826			/*
4827			 * Set cluster_sync_low again if next address for array
4828			 * reshape is less than cluster_sync_low. Since we can't
4829			 * update cluster_sync_low until it has finished reshape.
4830			 */
4831			if (sb_reshape_pos < conf->cluster_sync_low)
4832				conf->cluster_sync_low = sb_reshape_pos;
4833		}
4834
4835		md_cluster_ops->resync_info_update(mddev, conf->cluster_sync_low,
4836							  conf->cluster_sync_high);
4837	}
4838
4839	/* Now find the locations in the new layout */
4840	__raid10_find_phys(&conf->geo, r10_bio);
4841
4842	blist = read_bio;
4843	read_bio->bi_next = NULL;
4844
4845	for (s = 0; s < conf->copies*2; s++) {
4846		struct bio *b;
4847		int d = r10_bio->devs[s/2].devnum;
4848		struct md_rdev *rdev2;
4849		if (s&1) {
4850			rdev2 = conf->mirrors[d].replacement;
4851			b = r10_bio->devs[s/2].repl_bio;
4852		} else {
4853			rdev2 = conf->mirrors[d].rdev;
4854			b = r10_bio->devs[s/2].bio;
4855		}
4856		if (!rdev2 || test_bit(Faulty, &rdev2->flags))
4857			continue;
4858
4859		bio_set_dev(b, rdev2->bdev);
4860		b->bi_iter.bi_sector = r10_bio->devs[s/2].addr +
4861			rdev2->new_data_offset;
4862		b->bi_end_io = end_reshape_write;
4863		b->bi_opf = REQ_OP_WRITE;
4864		b->bi_next = blist;
4865		blist = b;
4866	}
4867
4868	/* Now add as many pages as possible to all of these bios. */
4869
4870	nr_sectors = 0;
4871	pages = get_resync_pages(r10_bio->devs[0].bio)->pages;
4872	for (s = 0 ; s < max_sectors; s += PAGE_SIZE >> 9) {
4873		struct page *page = pages[s / (PAGE_SIZE >> 9)];
4874		int len = (max_sectors - s) << 9;
4875		if (len > PAGE_SIZE)
4876			len = PAGE_SIZE;
4877		for (bio = blist; bio ; bio = bio->bi_next) {
4878			if (WARN_ON(!bio_add_page(bio, page, len, 0))) {
4879				bio->bi_status = BLK_STS_RESOURCE;
4880				bio_endio(bio);
4881				return sectors_done;
4882			}
4883		}
4884		sector_nr += len >> 9;
4885		nr_sectors += len >> 9;
4886	}
4887	r10_bio->sectors = nr_sectors;
4888
4889	/* Now submit the read */
4890	md_sync_acct_bio(read_bio, r10_bio->sectors);
4891	atomic_inc(&r10_bio->remaining);
4892	read_bio->bi_next = NULL;
4893	submit_bio_noacct(read_bio);
4894	sectors_done += nr_sectors;
4895	if (sector_nr <= last)
4896		goto read_more;
4897
4898	lower_barrier(conf);
4899
4900	/* Now that we have done the whole section we can
4901	 * update reshape_progress
4902	 */
4903	if (mddev->reshape_backwards)
4904		conf->reshape_progress -= sectors_done;
4905	else
4906		conf->reshape_progress += sectors_done;
4907
4908	return sectors_done;
4909}
4910
4911static void end_reshape_request(struct r10bio *r10_bio);
4912static int handle_reshape_read_error(struct mddev *mddev,
4913				     struct r10bio *r10_bio);
4914static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio)
4915{
4916	/* Reshape read completed.  Hopefully we have a block
4917	 * to write out.
4918	 * If we got a read error then we do sync 1-page reads from
4919	 * elsewhere until we find the data - or give up.
4920	 */
4921	struct r10conf *conf = mddev->private;
4922	int s;
4923
4924	if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
4925		if (handle_reshape_read_error(mddev, r10_bio) < 0) {
4926			/* Reshape has been aborted */
4927			md_done_sync(mddev, r10_bio->sectors, 0);
4928			return;
4929		}
4930
4931	/* We definitely have the data in the pages, schedule the
4932	 * writes.
4933	 */
4934	atomic_set(&r10_bio->remaining, 1);
4935	for (s = 0; s < conf->copies*2; s++) {
4936		struct bio *b;
4937		int d = r10_bio->devs[s/2].devnum;
4938		struct md_rdev *rdev;
4939		if (s&1) {
4940			rdev = conf->mirrors[d].replacement;
4941			b = r10_bio->devs[s/2].repl_bio;
4942		} else {
4943			rdev = conf->mirrors[d].rdev;
4944			b = r10_bio->devs[s/2].bio;
4945		}
4946		if (!rdev || test_bit(Faulty, &rdev->flags))
4947			continue;
4948
4949		atomic_inc(&rdev->nr_pending);
4950		md_sync_acct_bio(b, r10_bio->sectors);
4951		atomic_inc(&r10_bio->remaining);
4952		b->bi_next = NULL;
4953		submit_bio_noacct(b);
4954	}
4955	end_reshape_request(r10_bio);
4956}
4957
4958static void end_reshape(struct r10conf *conf)
4959{
4960	if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery))
4961		return;
4962
4963	spin_lock_irq(&conf->device_lock);
4964	conf->prev = conf->geo;
4965	md_finish_reshape(conf->mddev);
4966	smp_wmb();
4967	conf->reshape_progress = MaxSector;
4968	conf->reshape_safe = MaxSector;
4969	spin_unlock_irq(&conf->device_lock);
4970
4971	mddev_update_io_opt(conf->mddev, raid10_nr_stripes(conf));
 
4972	conf->fullsync = 0;
4973}
4974
4975static void raid10_update_reshape_pos(struct mddev *mddev)
4976{
4977	struct r10conf *conf = mddev->private;
4978	sector_t lo, hi;
4979
4980	md_cluster_ops->resync_info_get(mddev, &lo, &hi);
4981	if (((mddev->reshape_position <= hi) && (mddev->reshape_position >= lo))
4982	    || mddev->reshape_position == MaxSector)
4983		conf->reshape_progress = mddev->reshape_position;
4984	else
4985		WARN_ON_ONCE(1);
4986}
4987
4988static int handle_reshape_read_error(struct mddev *mddev,
4989				     struct r10bio *r10_bio)
4990{
4991	/* Use sync reads to get the blocks from somewhere else */
4992	int sectors = r10_bio->sectors;
4993	struct r10conf *conf = mddev->private;
4994	struct r10bio *r10b;
4995	int slot = 0;
4996	int idx = 0;
4997	struct page **pages;
4998
4999	r10b = kmalloc(struct_size(r10b, devs, conf->copies), GFP_NOIO);
5000	if (!r10b) {
5001		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5002		return -ENOMEM;
5003	}
5004
5005	/* reshape IOs share pages from .devs[0].bio */
5006	pages = get_resync_pages(r10_bio->devs[0].bio)->pages;
5007
5008	r10b->sector = r10_bio->sector;
5009	__raid10_find_phys(&conf->prev, r10b);
5010
5011	while (sectors) {
5012		int s = sectors;
5013		int success = 0;
5014		int first_slot = slot;
5015
5016		if (s > (PAGE_SIZE >> 9))
5017			s = PAGE_SIZE >> 9;
5018
5019		while (!success) {
5020			int d = r10b->devs[slot].devnum;
5021			struct md_rdev *rdev = conf->mirrors[d].rdev;
5022			sector_t addr;
5023			if (rdev == NULL ||
5024			    test_bit(Faulty, &rdev->flags) ||
5025			    !test_bit(In_sync, &rdev->flags))
5026				goto failed;
5027
5028			addr = r10b->devs[slot].addr + idx * PAGE_SIZE;
5029			atomic_inc(&rdev->nr_pending);
5030			success = sync_page_io(rdev,
5031					       addr,
5032					       s << 9,
5033					       pages[idx],
5034					       REQ_OP_READ, false);
5035			rdev_dec_pending(rdev, mddev);
5036			if (success)
5037				break;
5038		failed:
5039			slot++;
5040			if (slot >= conf->copies)
5041				slot = 0;
5042			if (slot == first_slot)
5043				break;
5044		}
5045		if (!success) {
5046			/* couldn't read this block, must give up */
5047			set_bit(MD_RECOVERY_INTR,
5048				&mddev->recovery);
5049			kfree(r10b);
5050			return -EIO;
5051		}
5052		sectors -= s;
5053		idx++;
5054	}
5055	kfree(r10b);
5056	return 0;
5057}
5058
5059static void end_reshape_write(struct bio *bio)
5060{
5061	struct r10bio *r10_bio = get_resync_r10bio(bio);
5062	struct mddev *mddev = r10_bio->mddev;
5063	struct r10conf *conf = mddev->private;
5064	int d;
5065	int slot;
5066	int repl;
5067	struct md_rdev *rdev = NULL;
5068
5069	d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
5070	rdev = repl ? conf->mirrors[d].replacement :
5071		      conf->mirrors[d].rdev;
5072
5073	if (bio->bi_status) {
5074		/* FIXME should record badblock */
5075		md_error(mddev, rdev);
5076	}
5077
5078	rdev_dec_pending(rdev, mddev);
5079	end_reshape_request(r10_bio);
5080}
5081
5082static void end_reshape_request(struct r10bio *r10_bio)
5083{
5084	if (!atomic_dec_and_test(&r10_bio->remaining))
5085		return;
5086	md_done_sync(r10_bio->mddev, r10_bio->sectors, 1);
5087	bio_put(r10_bio->master_bio);
5088	put_buf(r10_bio);
5089}
5090
5091static void raid10_finish_reshape(struct mddev *mddev)
5092{
5093	struct r10conf *conf = mddev->private;
5094
5095	if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5096		return;
5097
5098	if (mddev->delta_disks > 0) {
5099		if (mddev->recovery_cp > mddev->resync_max_sectors) {
5100			mddev->recovery_cp = mddev->resync_max_sectors;
5101			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5102		}
5103		mddev->resync_max_sectors = mddev->array_sectors;
5104	} else {
5105		int d;
5106		for (d = conf->geo.raid_disks ;
5107		     d < conf->geo.raid_disks - mddev->delta_disks;
5108		     d++) {
5109			struct md_rdev *rdev = conf->mirrors[d].rdev;
5110			if (rdev)
5111				clear_bit(In_sync, &rdev->flags);
5112			rdev = conf->mirrors[d].replacement;
5113			if (rdev)
5114				clear_bit(In_sync, &rdev->flags);
5115		}
5116	}
5117	mddev->layout = mddev->new_layout;
5118	mddev->chunk_sectors = 1 << conf->geo.chunk_shift;
5119	mddev->reshape_position = MaxSector;
5120	mddev->delta_disks = 0;
5121	mddev->reshape_backwards = 0;
5122}
5123
5124static struct md_personality raid10_personality =
5125{
5126	.name		= "raid10",
5127	.level		= 10,
5128	.owner		= THIS_MODULE,
5129	.make_request	= raid10_make_request,
5130	.run		= raid10_run,
5131	.free		= raid10_free,
5132	.status		= raid10_status,
5133	.error_handler	= raid10_error,
5134	.hot_add_disk	= raid10_add_disk,
5135	.hot_remove_disk= raid10_remove_disk,
5136	.spare_active	= raid10_spare_active,
5137	.sync_request	= raid10_sync_request,
5138	.quiesce	= raid10_quiesce,
5139	.size		= raid10_size,
5140	.resize		= raid10_resize,
5141	.takeover	= raid10_takeover,
5142	.check_reshape	= raid10_check_reshape,
5143	.start_reshape	= raid10_start_reshape,
5144	.finish_reshape	= raid10_finish_reshape,
5145	.update_reshape_pos = raid10_update_reshape_pos,
5146};
5147
5148static int __init raid_init(void)
5149{
5150	return register_md_personality(&raid10_personality);
5151}
5152
5153static void raid_exit(void)
5154{
5155	unregister_md_personality(&raid10_personality);
5156}
5157
5158module_init(raid_init);
5159module_exit(raid_exit);
5160MODULE_LICENSE("GPL");
5161MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
5162MODULE_ALIAS("md-personality-9"); /* RAID10 */
5163MODULE_ALIAS("md-raid10");
5164MODULE_ALIAS("md-level-10");