1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * raid5.c : Multiple Devices driver for Linux
   4 *	   Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   5 *	   Copyright (C) 1999, 2000 Ingo Molnar
   6 *	   Copyright (C) 2002, 2003 H. Peter Anvin
   7 *
   8 * RAID-4/5/6 management functions.
   9 * Thanks to Penguin Computing for making the RAID-6 development possible
  10 * by donating a test server!
 
 
 
 
 
 
 
 
 
  11 */
  12
  13/*
  14 * BITMAP UNPLUGGING:
  15 *
  16 * The sequencing for updating the bitmap reliably is a little
  17 * subtle (and I got it wrong the first time) so it deserves some
  18 * explanation.
  19 *
  20 * We group bitmap updates into batches.  Each batch has a number.
  21 * We may write out several batches at once, but that isn't very important.
  22 * conf->seq_write is the number of the last batch successfully written.
  23 * conf->seq_flush is the number of the last batch that was closed to
  24 *    new additions.
  25 * When we discover that we will need to write to any block in a stripe
  26 * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  27 * the number of the batch it will be in. This is seq_flush+1.
  28 * When we are ready to do a write, if that batch hasn't been written yet,
  29 *   we plug the array and queue the stripe for later.
  30 * When an unplug happens, we increment bm_flush, thus closing the current
  31 *   batch.
  32 * When we notice that bm_flush > bm_write, we write out all pending updates
  33 * to the bitmap, and advance bm_write to where bm_flush was.
  34 * This may occasionally write a bit out twice, but is sure never to
  35 * miss any bits.
  36 */
  37
  38#include <linux/blkdev.h>
  39#include <linux/kthread.h>
  40#include <linux/raid/pq.h>
  41#include <linux/async_tx.h>
  42#include <linux/module.h>
  43#include <linux/async.h>
  44#include <linux/seq_file.h>
  45#include <linux/cpu.h>
  46#include <linux/slab.h>
  47#include <linux/ratelimit.h>
  48#include <linux/nodemask.h>
  49
  50#include <trace/events/block.h>
  51#include <linux/list_sort.h>
  52
  53#include "md.h"
  54#include "raid5.h"
  55#include "raid0.h"
  56#include "md-bitmap.h"
  57#include "raid5-log.h"
  58
  59#define UNSUPPORTED_MDDEV_FLAGS	(1L << MD_FAILFAST_SUPPORTED)
  60
  61#define cpu_to_group(cpu) cpu_to_node(cpu)
  62#define ANY_GROUP NUMA_NO_NODE
 
  63
  64static bool devices_handle_discard_safely = false;
  65module_param(devices_handle_discard_safely, bool, 0644);
  66MODULE_PARM_DESC(devices_handle_discard_safely,
  67		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  68static struct workqueue_struct *raid5_wq;
 
 
 
  69
  70static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  71{
  72	int hash = (sect >> RAID5_STRIPE_SHIFT(conf)) & HASH_MASK;
  73	return &conf->stripe_hashtbl[hash];
  74}
  75
  76static inline int stripe_hash_locks_hash(struct r5conf *conf, sector_t sect)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  77{
  78	return (sect >> RAID5_STRIPE_SHIFT(conf)) & STRIPE_HASH_LOCKS_MASK;
  79}
  80
  81static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  82{
  83	spin_lock_irq(conf->hash_locks + hash);
  84	spin_lock(&conf->device_lock);
  85}
  86
  87static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  88{
  89	spin_unlock(&conf->device_lock);
  90	spin_unlock_irq(conf->hash_locks + hash);
  91}
  92
  93static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
  94{
  95	int i;
  96	spin_lock_irq(conf->hash_locks);
  97	for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
  98		spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
  99	spin_lock(&conf->device_lock);
 100}
 101
 102static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 103{
 104	int i;
 105	spin_unlock(&conf->device_lock);
 106	for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 107		spin_unlock(conf->hash_locks + i);
 108	spin_unlock_irq(conf->hash_locks);
 109}
 110
 111/* Find first data disk in a raid6 stripe */
 112static inline int raid6_d0(struct stripe_head *sh)
 113{
 114	if (sh->ddf_layout)
 115		/* ddf always start from first device */
 116		return 0;
 117	/* md starts just after Q block */
 118	if (sh->qd_idx == sh->disks - 1)
 119		return 0;
 120	else
 121		return sh->qd_idx + 1;
 122}
 123static inline int raid6_next_disk(int disk, int raid_disks)
 124{
 125	disk++;
 126	return (disk < raid_disks) ? disk : 0;
 127}
 128
 129/* When walking through the disks in a raid5, starting at raid6_d0,
 130 * We need to map each disk to a 'slot', where the data disks are slot
 131 * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 132 * is raid_disks-1.  This help does that mapping.
 133 */
 134static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 135			     int *count, int syndrome_disks)
 136{
 137	int slot = *count;
 138
 139	if (sh->ddf_layout)
 140		(*count)++;
 141	if (idx == sh->pd_idx)
 142		return syndrome_disks;
 143	if (idx == sh->qd_idx)
 144		return syndrome_disks + 1;
 145	if (!sh->ddf_layout)
 146		(*count)++;
 147	return slot;
 148}
 149
 
 
 
 
 
 
 
 
 
 
 
 
 
 150static void print_raid5_conf (struct r5conf *conf);
 151
 152static int stripe_operations_active(struct stripe_head *sh)
 153{
 154	return sh->check_state || sh->reconstruct_state ||
 155	       test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 156	       test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 157}
 158
 159static bool stripe_is_lowprio(struct stripe_head *sh)
 160{
 161	return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 162		test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 163	       !test_bit(STRIPE_R5C_CACHING, &sh->state);
 164}
 165
 166static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 167{
 168	struct r5conf *conf = sh->raid_conf;
 169	struct r5worker_group *group;
 170	int thread_cnt;
 171	int i, cpu = sh->cpu;
 172
 173	if (!cpu_online(cpu)) {
 174		cpu = cpumask_any(cpu_online_mask);
 175		sh->cpu = cpu;
 176	}
 177
 178	if (list_empty(&sh->lru)) {
 179		struct r5worker_group *group;
 180		group = conf->worker_groups + cpu_to_group(cpu);
 181		if (stripe_is_lowprio(sh))
 182			list_add_tail(&sh->lru, &group->loprio_list);
 183		else
 184			list_add_tail(&sh->lru, &group->handle_list);
 185		group->stripes_cnt++;
 186		sh->group = group;
 187	}
 188
 189	if (conf->worker_cnt_per_group == 0) {
 190		md_wakeup_thread(conf->mddev->thread);
 191		return;
 192	}
 193
 194	group = conf->worker_groups + cpu_to_group(sh->cpu);
 195
 196	group->workers[0].working = true;
 197	/* at least one worker should run to avoid race */
 198	queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 199
 200	thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 201	/* wakeup more workers */
 202	for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 203		if (group->workers[i].working == false) {
 204			group->workers[i].working = true;
 205			queue_work_on(sh->cpu, raid5_wq,
 206				      &group->workers[i].work);
 207			thread_cnt--;
 208		}
 209	}
 210}
 211
 212static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 213			      struct list_head *temp_inactive_list)
 214{
 215	int i;
 216	int injournal = 0;	/* number of date pages with R5_InJournal */
 217
 218	BUG_ON(!list_empty(&sh->lru));
 219	BUG_ON(atomic_read(&conf->active_stripes)==0);
 220
 221	if (r5c_is_writeback(conf->log))
 222		for (i = sh->disks; i--; )
 223			if (test_bit(R5_InJournal, &sh->dev[i].flags))
 224				injournal++;
 225	/*
 226	 * In the following cases, the stripe cannot be released to cached
 227	 * lists. Therefore, we make the stripe write out and set
 228	 * STRIPE_HANDLE:
 229	 *   1. when quiesce in r5c write back;
 230	 *   2. when resync is requested fot the stripe.
 231	 */
 232	if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 233	    (conf->quiesce && r5c_is_writeback(conf->log) &&
 234	     !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 235		if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 236			r5c_make_stripe_write_out(sh);
 237		set_bit(STRIPE_HANDLE, &sh->state);
 238	}
 239
 240	if (test_bit(STRIPE_HANDLE, &sh->state)) {
 241		if (test_bit(STRIPE_DELAYED, &sh->state) &&
 242		    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 243			list_add_tail(&sh->lru, &conf->delayed_list);
 244		else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 245			   sh->bm_seq - conf->seq_write > 0)
 246			list_add_tail(&sh->lru, &conf->bitmap_list);
 247		else {
 248			clear_bit(STRIPE_DELAYED, &sh->state);
 249			clear_bit(STRIPE_BIT_DELAY, &sh->state);
 250			if (conf->worker_cnt_per_group == 0) {
 251				if (stripe_is_lowprio(sh))
 252					list_add_tail(&sh->lru,
 253							&conf->loprio_list);
 254				else
 255					list_add_tail(&sh->lru,
 256							&conf->handle_list);
 257			} else {
 258				raid5_wakeup_stripe_thread(sh);
 259				return;
 260			}
 261		}
 262		md_wakeup_thread(conf->mddev->thread);
 263	} else {
 264		BUG_ON(stripe_operations_active(sh));
 265		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 266			if (atomic_dec_return(&conf->preread_active_stripes)
 267			    < IO_THRESHOLD)
 268				md_wakeup_thread(conf->mddev->thread);
 269		atomic_dec(&conf->active_stripes);
 270		if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 271			if (!r5c_is_writeback(conf->log))
 272				list_add_tail(&sh->lru, temp_inactive_list);
 273			else {
 274				WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 275				if (injournal == 0)
 276					list_add_tail(&sh->lru, temp_inactive_list);
 277				else if (injournal == conf->raid_disks - conf->max_degraded) {
 278					/* full stripe */
 279					if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 280						atomic_inc(&conf->r5c_cached_full_stripes);
 281					if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 282						atomic_dec(&conf->r5c_cached_partial_stripes);
 283					list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 284					r5c_check_cached_full_stripe(conf);
 285				} else
 286					/*
 287					 * STRIPE_R5C_PARTIAL_STRIPE is set in
 288					 * r5c_try_caching_write(). No need to
 289					 * set it again.
 290					 */
 291					list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 292			}
 293		}
 294	}
 295}
 296
 297static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 298			     struct list_head *temp_inactive_list)
 299{
 300	if (atomic_dec_and_test(&sh->count))
 301		do_release_stripe(conf, sh, temp_inactive_list);
 302}
 303
 304/*
 305 * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 306 *
 307 * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 308 * given time. Adding stripes only takes device lock, while deleting stripes
 309 * only takes hash lock.
 310 */
 311static void release_inactive_stripe_list(struct r5conf *conf,
 312					 struct list_head *temp_inactive_list,
 313					 int hash)
 314{
 315	int size;
 316	bool do_wakeup = false;
 317	unsigned long flags;
 318
 319	if (hash == NR_STRIPE_HASH_LOCKS) {
 320		size = NR_STRIPE_HASH_LOCKS;
 321		hash = NR_STRIPE_HASH_LOCKS - 1;
 322	} else
 323		size = 1;
 324	while (size) {
 325		struct list_head *list = &temp_inactive_list[size - 1];
 326
 327		/*
 328		 * We don't hold any lock here yet, raid5_get_active_stripe() might
 329		 * remove stripes from the list
 330		 */
 331		if (!list_empty_careful(list)) {
 332			spin_lock_irqsave(conf->hash_locks + hash, flags);
 333			if (list_empty(conf->inactive_list + hash) &&
 334			    !list_empty(list))
 335				atomic_dec(&conf->empty_inactive_list_nr);
 336			list_splice_tail_init(list, conf->inactive_list + hash);
 337			do_wakeup = true;
 338			spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 339		}
 340		size--;
 341		hash--;
 342	}
 343
 344	if (do_wakeup) {
 345		wake_up(&conf->wait_for_stripe);
 346		if (atomic_read(&conf->active_stripes) == 0)
 347			wake_up(&conf->wait_for_quiescent);
 348		if (conf->retry_read_aligned)
 349			md_wakeup_thread(conf->mddev->thread);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 350	}
 351}
 352
 353/* should hold conf->device_lock already */
 354static int release_stripe_list(struct r5conf *conf,
 355			       struct list_head *temp_inactive_list)
 356{
 357	struct stripe_head *sh, *t;
 358	int count = 0;
 359	struct llist_node *head;
 360
 361	head = llist_del_all(&conf->released_stripes);
 362	head = llist_reverse_order(head);
 363	llist_for_each_entry_safe(sh, t, head, release_list) {
 364		int hash;
 365
 366		/* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 367		smp_mb();
 368		clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 369		/*
 370		 * Don't worry the bit is set here, because if the bit is set
 371		 * again, the count is always > 1. This is true for
 372		 * STRIPE_ON_UNPLUG_LIST bit too.
 373		 */
 374		hash = sh->hash_lock_index;
 375		__release_stripe(conf, sh, &temp_inactive_list[hash]);
 376		count++;
 377	}
 378
 379	return count;
 380}
 381
 382void raid5_release_stripe(struct stripe_head *sh)
 383{
 384	struct r5conf *conf = sh->raid_conf;
 385	unsigned long flags;
 386	struct list_head list;
 387	int hash;
 388	bool wakeup;
 389
 390	/* Avoid release_list until the last reference.
 391	 */
 392	if (atomic_add_unless(&sh->count, -1, 1))
 393		return;
 394
 395	if (unlikely(!conf->mddev->thread) ||
 396		test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 397		goto slow_path;
 398	wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 399	if (wakeup)
 400		md_wakeup_thread(conf->mddev->thread);
 401	return;
 402slow_path:
 403	/* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 404	if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
 405		INIT_LIST_HEAD(&list);
 406		hash = sh->hash_lock_index;
 407		do_release_stripe(conf, sh, &list);
 408		spin_unlock_irqrestore(&conf->device_lock, flags);
 409		release_inactive_stripe_list(conf, &list, hash);
 410	}
 411}
 412
 413static inline void remove_hash(struct stripe_head *sh)
 414{
 415	pr_debug("remove_hash(), stripe %llu\n",
 416		(unsigned long long)sh->sector);
 417
 418	hlist_del_init(&sh->hash);
 419}
 420
 421static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 422{
 423	struct hlist_head *hp = stripe_hash(conf, sh->sector);
 424
 425	pr_debug("insert_hash(), stripe %llu\n",
 426		(unsigned long long)sh->sector);
 427
 428	hlist_add_head(&sh->hash, hp);
 429}
 430
 
 431/* find an idle stripe, make sure it is unhashed, and return it. */
 432static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 433{
 434	struct stripe_head *sh = NULL;
 435	struct list_head *first;
 436
 437	if (list_empty(conf->inactive_list + hash))
 438		goto out;
 439	first = (conf->inactive_list + hash)->next;
 440	sh = list_entry(first, struct stripe_head, lru);
 441	list_del_init(first);
 442	remove_hash(sh);
 443	atomic_inc(&conf->active_stripes);
 444	BUG_ON(hash != sh->hash_lock_index);
 445	if (list_empty(conf->inactive_list + hash))
 446		atomic_inc(&conf->empty_inactive_list_nr);
 447out:
 448	return sh;
 449}
 450
 451static void shrink_buffers(struct stripe_head *sh)
 452{
 453	struct page *p;
 454	int i;
 455	int num = sh->raid_conf->pool_size;
 456
 457	for (i = 0; i < num ; i++) {
 458		WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 459		p = sh->dev[i].page;
 460		if (!p)
 461			continue;
 462		sh->dev[i].page = NULL;
 463		put_page(p);
 464	}
 465}
 466
 467static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 468{
 469	int i;
 470	int num = sh->raid_conf->pool_size;
 471
 472	for (i = 0; i < num; i++) {
 473		struct page *page;
 474
 475		if (!(page = alloc_page(gfp))) {
 476			return 1;
 477		}
 478		sh->dev[i].page = page;
 479		sh->dev[i].orig_page = page;
 480	}
 481
 482	return 0;
 483}
 484
 
 485static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 486			    struct stripe_head *sh);
 487
 488static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 489{
 490	struct r5conf *conf = sh->raid_conf;
 491	int i, seq;
 492
 493	BUG_ON(atomic_read(&sh->count) != 0);
 494	BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 495	BUG_ON(stripe_operations_active(sh));
 496	BUG_ON(sh->batch_head);
 497
 498	pr_debug("init_stripe called, stripe %llu\n",
 499		(unsigned long long)sector);
 500retry:
 501	seq = read_seqcount_begin(&conf->gen_lock);
 
 502	sh->generation = conf->generation - previous;
 503	sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 504	sh->sector = sector;
 505	stripe_set_idx(sector, conf, previous, sh);
 506	sh->state = 0;
 507
 
 508	for (i = sh->disks; i--; ) {
 509		struct r5dev *dev = &sh->dev[i];
 510
 511		if (dev->toread || dev->read || dev->towrite || dev->written ||
 512		    test_bit(R5_LOCKED, &dev->flags)) {
 513			pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 514			       (unsigned long long)sh->sector, i, dev->toread,
 515			       dev->read, dev->towrite, dev->written,
 516			       test_bit(R5_LOCKED, &dev->flags));
 517			WARN_ON(1);
 518		}
 519		dev->flags = 0;
 520		dev->sector = raid5_compute_blocknr(sh, i, previous);
 521	}
 522	if (read_seqcount_retry(&conf->gen_lock, seq))
 523		goto retry;
 524	sh->overwrite_disks = 0;
 525	insert_hash(conf, sh);
 526	sh->cpu = smp_processor_id();
 527	set_bit(STRIPE_BATCH_READY, &sh->state);
 528}
 529
 530static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 531					 short generation)
 532{
 533	struct stripe_head *sh;
 
 534
 535	pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 536	hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 537		if (sh->sector == sector && sh->generation == generation)
 538			return sh;
 539	pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 540	return NULL;
 541}
 542
 543/*
 544 * Need to check if array has failed when deciding whether to:
 545 *  - start an array
 546 *  - remove non-faulty devices
 547 *  - add a spare
 548 *  - allow a reshape
 549 * This determination is simple when no reshape is happening.
 550 * However if there is a reshape, we need to carefully check
 551 * both the before and after sections.
 552 * This is because some failed devices may only affect one
 553 * of the two sections, and some non-in_sync devices may
 554 * be insync in the section most affected by failed devices.
 555 */
 556int raid5_calc_degraded(struct r5conf *conf)
 557{
 558	int degraded, degraded2;
 559	int i;
 560
 561	rcu_read_lock();
 562	degraded = 0;
 563	for (i = 0; i < conf->previous_raid_disks; i++) {
 564		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 565		if (rdev && test_bit(Faulty, &rdev->flags))
 566			rdev = rcu_dereference(conf->disks[i].replacement);
 567		if (!rdev || test_bit(Faulty, &rdev->flags))
 568			degraded++;
 569		else if (test_bit(In_sync, &rdev->flags))
 570			;
 571		else
 572			/* not in-sync or faulty.
 573			 * If the reshape increases the number of devices,
 574			 * this is being recovered by the reshape, so
 575			 * this 'previous' section is not in_sync.
 576			 * If the number of devices is being reduced however,
 577			 * the device can only be part of the array if
 578			 * we are reverting a reshape, so this section will
 579			 * be in-sync.
 580			 */
 581			if (conf->raid_disks >= conf->previous_raid_disks)
 582				degraded++;
 583	}
 584	rcu_read_unlock();
 585	if (conf->raid_disks == conf->previous_raid_disks)
 586		return degraded;
 587	rcu_read_lock();
 588	degraded2 = 0;
 589	for (i = 0; i < conf->raid_disks; i++) {
 590		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 591		if (rdev && test_bit(Faulty, &rdev->flags))
 592			rdev = rcu_dereference(conf->disks[i].replacement);
 593		if (!rdev || test_bit(Faulty, &rdev->flags))
 594			degraded2++;
 595		else if (test_bit(In_sync, &rdev->flags))
 596			;
 597		else
 598			/* not in-sync or faulty.
 599			 * If reshape increases the number of devices, this
 600			 * section has already been recovered, else it
 601			 * almost certainly hasn't.
 602			 */
 603			if (conf->raid_disks <= conf->previous_raid_disks)
 604				degraded2++;
 605	}
 606	rcu_read_unlock();
 607	if (degraded2 > degraded)
 608		return degraded2;
 609	return degraded;
 610}
 611
 612static int has_failed(struct r5conf *conf)
 613{
 614	int degraded;
 615
 616	if (conf->mddev->reshape_position == MaxSector)
 617		return conf->mddev->degraded > conf->max_degraded;
 618
 619	degraded = raid5_calc_degraded(conf);
 620	if (degraded > conf->max_degraded)
 621		return 1;
 622	return 0;
 623}
 624
 625struct stripe_head *
 626raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 627			int previous, int noblock, int noquiesce)
 628{
 629	struct stripe_head *sh;
 630	int hash = stripe_hash_locks_hash(conf, sector);
 631	int inc_empty_inactive_list_flag;
 632
 633	pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 634
 635	spin_lock_irq(conf->hash_locks + hash);
 636
 637	do {
 638		wait_event_lock_irq(conf->wait_for_quiescent,
 639				    conf->quiesce == 0 || noquiesce,
 640				    *(conf->hash_locks + hash));
 641		sh = __find_stripe(conf, sector, conf->generation - previous);
 642		if (!sh) {
 643			if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 644				sh = get_free_stripe(conf, hash);
 645				if (!sh && !test_bit(R5_DID_ALLOC,
 646						     &conf->cache_state))
 647					set_bit(R5_ALLOC_MORE,
 648						&conf->cache_state);
 649			}
 650			if (noblock && sh == NULL)
 651				break;
 652
 653			r5c_check_stripe_cache_usage(conf);
 654			if (!sh) {
 655				set_bit(R5_INACTIVE_BLOCKED,
 656					&conf->cache_state);
 657				r5l_wake_reclaim(conf->log, 0);
 658				wait_event_lock_irq(
 659					conf->wait_for_stripe,
 660					!list_empty(conf->inactive_list + hash) &&
 661					(atomic_read(&conf->active_stripes)
 662					 < (conf->max_nr_stripes * 3 / 4)
 663					 || !test_bit(R5_INACTIVE_BLOCKED,
 664						      &conf->cache_state)),
 665					*(conf->hash_locks + hash));
 666				clear_bit(R5_INACTIVE_BLOCKED,
 667					  &conf->cache_state);
 668			} else {
 669				init_stripe(sh, sector, previous);
 670				atomic_inc(&sh->count);
 671			}
 672		} else if (!atomic_inc_not_zero(&sh->count)) {
 673			spin_lock(&conf->device_lock);
 674			if (!atomic_read(&sh->count)) {
 675				if (!test_bit(STRIPE_HANDLE, &sh->state))
 676					atomic_inc(&conf->active_stripes);
 677				BUG_ON(list_empty(&sh->lru) &&
 678				       !test_bit(STRIPE_EXPANDING, &sh->state));
 679				inc_empty_inactive_list_flag = 0;
 680				if (!list_empty(conf->inactive_list + hash))
 681					inc_empty_inactive_list_flag = 1;
 682				list_del_init(&sh->lru);
 683				if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 684					atomic_inc(&conf->empty_inactive_list_nr);
 685				if (sh->group) {
 686					sh->group->stripes_cnt--;
 687					sh->group = NULL;
 688				}
 689			}
 690			atomic_inc(&sh->count);
 691			spin_unlock(&conf->device_lock);
 692		}
 693	} while (sh == NULL);
 694
 695	spin_unlock_irq(conf->hash_locks + hash);
 696	return sh;
 697}
 698
 699static bool is_full_stripe_write(struct stripe_head *sh)
 700{
 701	BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 702	return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 703}
 704
 705static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 706		__acquires(&sh1->stripe_lock)
 707		__acquires(&sh2->stripe_lock)
 708{
 709	if (sh1 > sh2) {
 710		spin_lock_irq(&sh2->stripe_lock);
 711		spin_lock_nested(&sh1->stripe_lock, 1);
 712	} else {
 713		spin_lock_irq(&sh1->stripe_lock);
 714		spin_lock_nested(&sh2->stripe_lock, 1);
 715	}
 716}
 717
 718static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 719		__releases(&sh1->stripe_lock)
 720		__releases(&sh2->stripe_lock)
 721{
 722	spin_unlock(&sh1->stripe_lock);
 723	spin_unlock_irq(&sh2->stripe_lock);
 724}
 725
 726/* Only freshly new full stripe normal write stripe can be added to a batch list */
 727static bool stripe_can_batch(struct stripe_head *sh)
 728{
 729	struct r5conf *conf = sh->raid_conf;
 730
 731	if (raid5_has_log(conf) || raid5_has_ppl(conf))
 732		return false;
 733	return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 734		!test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 735		is_full_stripe_write(sh);
 736}
 737
 738/* we only do back search */
 739static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
 740{
 741	struct stripe_head *head;
 742	sector_t head_sector, tmp_sec;
 743	int hash;
 744	int dd_idx;
 745	int inc_empty_inactive_list_flag;
 746
 747	/* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 748	tmp_sec = sh->sector;
 749	if (!sector_div(tmp_sec, conf->chunk_sectors))
 750		return;
 751	head_sector = sh->sector - RAID5_STRIPE_SECTORS(conf);
 752
 753	hash = stripe_hash_locks_hash(conf, head_sector);
 754	spin_lock_irq(conf->hash_locks + hash);
 755	head = __find_stripe(conf, head_sector, conf->generation);
 756	if (head && !atomic_inc_not_zero(&head->count)) {
 757		spin_lock(&conf->device_lock);
 758		if (!atomic_read(&head->count)) {
 759			if (!test_bit(STRIPE_HANDLE, &head->state))
 760				atomic_inc(&conf->active_stripes);
 761			BUG_ON(list_empty(&head->lru) &&
 762			       !test_bit(STRIPE_EXPANDING, &head->state));
 763			inc_empty_inactive_list_flag = 0;
 764			if (!list_empty(conf->inactive_list + hash))
 765				inc_empty_inactive_list_flag = 1;
 766			list_del_init(&head->lru);
 767			if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 768				atomic_inc(&conf->empty_inactive_list_nr);
 769			if (head->group) {
 770				head->group->stripes_cnt--;
 771				head->group = NULL;
 772			}
 773		}
 774		atomic_inc(&head->count);
 775		spin_unlock(&conf->device_lock);
 776	}
 777	spin_unlock_irq(conf->hash_locks + hash);
 778
 779	if (!head)
 780		return;
 781	if (!stripe_can_batch(head))
 782		goto out;
 783
 784	lock_two_stripes(head, sh);
 785	/* clear_batch_ready clear the flag */
 786	if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 787		goto unlock_out;
 788
 789	if (sh->batch_head)
 790		goto unlock_out;
 791
 792	dd_idx = 0;
 793	while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 794		dd_idx++;
 795	if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 796	    bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 797		goto unlock_out;
 798
 799	if (head->batch_head) {
 800		spin_lock(&head->batch_head->batch_lock);
 801		/* This batch list is already running */
 802		if (!stripe_can_batch(head)) {
 803			spin_unlock(&head->batch_head->batch_lock);
 804			goto unlock_out;
 805		}
 806		/*
 807		 * We must assign batch_head of this stripe within the
 808		 * batch_lock, otherwise clear_batch_ready of batch head
 809		 * stripe could clear BATCH_READY bit of this stripe and
 810		 * this stripe->batch_head doesn't get assigned, which
 811		 * could confuse clear_batch_ready for this stripe
 812		 */
 813		sh->batch_head = head->batch_head;
 814
 815		/*
 816		 * at this point, head's BATCH_READY could be cleared, but we
 817		 * can still add the stripe to batch list
 818		 */
 819		list_add(&sh->batch_list, &head->batch_list);
 820		spin_unlock(&head->batch_head->batch_lock);
 821	} else {
 822		head->batch_head = head;
 823		sh->batch_head = head->batch_head;
 824		spin_lock(&head->batch_lock);
 825		list_add_tail(&sh->batch_list, &head->batch_list);
 826		spin_unlock(&head->batch_lock);
 827	}
 828
 829	if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 830		if (atomic_dec_return(&conf->preread_active_stripes)
 831		    < IO_THRESHOLD)
 832			md_wakeup_thread(conf->mddev->thread);
 833
 834	if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 835		int seq = sh->bm_seq;
 836		if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 837		    sh->batch_head->bm_seq > seq)
 838			seq = sh->batch_head->bm_seq;
 839		set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 840		sh->batch_head->bm_seq = seq;
 841	}
 842
 843	atomic_inc(&sh->count);
 844unlock_out:
 845	unlock_two_stripes(head, sh);
 846out:
 847	raid5_release_stripe(head);
 848}
 849
 850/* Determine if 'data_offset' or 'new_data_offset' should be used
 851 * in this stripe_head.
 852 */
 853static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
 854{
 855	sector_t progress = conf->reshape_progress;
 856	/* Need a memory barrier to make sure we see the value
 857	 * of conf->generation, or ->data_offset that was set before
 858	 * reshape_progress was updated.
 859	 */
 860	smp_rmb();
 861	if (progress == MaxSector)
 862		return 0;
 863	if (sh->generation == conf->generation - 1)
 864		return 0;
 865	/* We are in a reshape, and this is a new-generation stripe,
 866	 * so use new_data_offset.
 867	 */
 868	return 1;
 869}
 870
 871static void dispatch_bio_list(struct bio_list *tmp)
 872{
 873	struct bio *bio;
 874
 875	while ((bio = bio_list_pop(tmp)))
 876		submit_bio_noacct(bio);
 877}
 878
 879static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
 880{
 881	const struct r5pending_data *da = list_entry(a,
 882				struct r5pending_data, sibling);
 883	const struct r5pending_data *db = list_entry(b,
 884				struct r5pending_data, sibling);
 885	if (da->sector > db->sector)
 886		return 1;
 887	if (da->sector < db->sector)
 888		return -1;
 889	return 0;
 890}
 891
 892static void dispatch_defer_bios(struct r5conf *conf, int target,
 893				struct bio_list *list)
 894{
 895	struct r5pending_data *data;
 896	struct list_head *first, *next = NULL;
 897	int cnt = 0;
 898
 899	if (conf->pending_data_cnt == 0)
 900		return;
 901
 902	list_sort(NULL, &conf->pending_list, cmp_stripe);
 903
 904	first = conf->pending_list.next;
 905
 906	/* temporarily move the head */
 907	if (conf->next_pending_data)
 908		list_move_tail(&conf->pending_list,
 909				&conf->next_pending_data->sibling);
 910
 911	while (!list_empty(&conf->pending_list)) {
 912		data = list_first_entry(&conf->pending_list,
 913			struct r5pending_data, sibling);
 914		if (&data->sibling == first)
 915			first = data->sibling.next;
 916		next = data->sibling.next;
 917
 918		bio_list_merge(list, &data->bios);
 919		list_move(&data->sibling, &conf->free_list);
 920		cnt++;
 921		if (cnt >= target)
 922			break;
 923	}
 924	conf->pending_data_cnt -= cnt;
 925	BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
 926
 927	if (next != &conf->pending_list)
 928		conf->next_pending_data = list_entry(next,
 929				struct r5pending_data, sibling);
 930	else
 931		conf->next_pending_data = NULL;
 932	/* list isn't empty */
 933	if (first != &conf->pending_list)
 934		list_move_tail(&conf->pending_list, first);
 935}
 936
 937static void flush_deferred_bios(struct r5conf *conf)
 938{
 939	struct bio_list tmp = BIO_EMPTY_LIST;
 940
 941	if (conf->pending_data_cnt == 0)
 942		return;
 943
 944	spin_lock(&conf->pending_bios_lock);
 945	dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
 946	BUG_ON(conf->pending_data_cnt != 0);
 947	spin_unlock(&conf->pending_bios_lock);
 948
 949	dispatch_bio_list(&tmp);
 950}
 951
 952static void defer_issue_bios(struct r5conf *conf, sector_t sector,
 953				struct bio_list *bios)
 954{
 955	struct bio_list tmp = BIO_EMPTY_LIST;
 956	struct r5pending_data *ent;
 957
 958	spin_lock(&conf->pending_bios_lock);
 959	ent = list_first_entry(&conf->free_list, struct r5pending_data,
 960							sibling);
 961	list_move_tail(&ent->sibling, &conf->pending_list);
 962	ent->sector = sector;
 963	bio_list_init(&ent->bios);
 964	bio_list_merge(&ent->bios, bios);
 965	conf->pending_data_cnt++;
 966	if (conf->pending_data_cnt >= PENDING_IO_MAX)
 967		dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
 968
 969	spin_unlock(&conf->pending_bios_lock);
 970
 971	dispatch_bio_list(&tmp);
 972}
 973
 974static void
 975raid5_end_read_request(struct bio *bi);
 976static void
 977raid5_end_write_request(struct bio *bi);
 978
 979static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 980{
 981	struct r5conf *conf = sh->raid_conf;
 982	int i, disks = sh->disks;
 983	struct stripe_head *head_sh = sh;
 984	struct bio_list pending_bios = BIO_EMPTY_LIST;
 985	bool should_defer;
 986
 987	might_sleep();
 988
 989	if (log_stripe(sh, s) == 0)
 990		return;
 991
 992	should_defer = conf->batch_bio_dispatch && conf->group_cnt;
 993
 994	for (i = disks; i--; ) {
 995		int op, op_flags = 0;
 996		int replace_only = 0;
 997		struct bio *bi, *rbi;
 998		struct md_rdev *rdev, *rrdev = NULL;
 999
1000		sh = head_sh;
1001		if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1002			op = REQ_OP_WRITE;
1003			if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1004				op_flags = REQ_FUA;
1005			if (test_bit(R5_Discard, &sh->dev[i].flags))
1006				op = REQ_OP_DISCARD;
1007		} else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1008			op = REQ_OP_READ;
1009		else if (test_and_clear_bit(R5_WantReplace,
1010					    &sh->dev[i].flags)) {
1011			op = REQ_OP_WRITE;
1012			replace_only = 1;
1013		} else
1014			continue;
1015		if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1016			op_flags |= REQ_SYNC;
1017
1018again:
1019		bi = &sh->dev[i].req;
1020		rbi = &sh->dev[i].rreq; /* For writing to replacement */
1021
 
 
 
 
 
 
 
 
1022		rcu_read_lock();
1023		rrdev = rcu_dereference(conf->disks[i].replacement);
1024		smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1025		rdev = rcu_dereference(conf->disks[i].rdev);
1026		if (!rdev) {
1027			rdev = rrdev;
1028			rrdev = NULL;
1029		}
1030		if (op_is_write(op)) {
1031			if (replace_only)
1032				rdev = NULL;
1033			if (rdev == rrdev)
1034				/* We raced and saw duplicates */
1035				rrdev = NULL;
1036		} else {
1037			if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1038				rdev = rrdev;
1039			rrdev = NULL;
1040		}
1041
1042		if (rdev && test_bit(Faulty, &rdev->flags))
1043			rdev = NULL;
1044		if (rdev)
1045			atomic_inc(&rdev->nr_pending);
1046		if (rrdev && test_bit(Faulty, &rrdev->flags))
1047			rrdev = NULL;
1048		if (rrdev)
1049			atomic_inc(&rrdev->nr_pending);
1050		rcu_read_unlock();
1051
1052		/* We have already checked bad blocks for reads.  Now
1053		 * need to check for writes.  We never accept write errors
1054		 * on the replacement, so we don't to check rrdev.
1055		 */
1056		while (op_is_write(op) && rdev &&
1057		       test_bit(WriteErrorSeen, &rdev->flags)) {
1058			sector_t first_bad;
1059			int bad_sectors;
1060			int bad = is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
1061					      &first_bad, &bad_sectors);
1062			if (!bad)
1063				break;
1064
1065			if (bad < 0) {
1066				set_bit(BlockedBadBlocks, &rdev->flags);
1067				if (!conf->mddev->external &&
1068				    conf->mddev->sb_flags) {
1069					/* It is very unlikely, but we might
1070					 * still need to write out the
1071					 * bad block log - better give it
1072					 * a chance*/
1073					md_check_recovery(conf->mddev);
1074				}
1075				/*
1076				 * Because md_wait_for_blocked_rdev
1077				 * will dec nr_pending, we must
1078				 * increment it first.
1079				 */
1080				atomic_inc(&rdev->nr_pending);
1081				md_wait_for_blocked_rdev(rdev, conf->mddev);
1082			} else {
1083				/* Acknowledged bad block - skip the write */
1084				rdev_dec_pending(rdev, conf->mddev);
1085				rdev = NULL;
1086			}
1087		}
1088
1089		if (rdev) {
1090			if (s->syncing || s->expanding || s->expanded
1091			    || s->replacing)
1092				md_sync_acct(rdev->bdev, RAID5_STRIPE_SECTORS(conf));
1093
1094			set_bit(STRIPE_IO_STARTED, &sh->state);
1095
1096			bio_set_dev(bi, rdev->bdev);
1097			bio_set_op_attrs(bi, op, op_flags);
1098			bi->bi_end_io = op_is_write(op)
1099				? raid5_end_write_request
1100				: raid5_end_read_request;
1101			bi->bi_private = sh;
1102
1103			pr_debug("%s: for %llu schedule op %d on disc %d\n",
1104				__func__, (unsigned long long)sh->sector,
1105				bi->bi_opf, i);
1106			atomic_inc(&sh->count);
1107			if (sh != head_sh)
1108				atomic_inc(&head_sh->count);
1109			if (use_new_offset(conf, sh))
1110				bi->bi_iter.bi_sector = (sh->sector
1111						 + rdev->new_data_offset);
1112			else
1113				bi->bi_iter.bi_sector = (sh->sector
1114						 + rdev->data_offset);
1115			if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1116				bi->bi_opf |= REQ_NOMERGE;
1117
1118			if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1119				WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1120
1121			if (!op_is_write(op) &&
1122			    test_bit(R5_InJournal, &sh->dev[i].flags))
1123				/*
1124				 * issuing read for a page in journal, this
1125				 * must be preparing for prexor in rmw; read
1126				 * the data into orig_page
1127				 */
1128				sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1129			else
1130				sh->dev[i].vec.bv_page = sh->dev[i].page;
1131			bi->bi_vcnt = 1;
1132			bi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1133			bi->bi_io_vec[0].bv_offset = 0;
1134			bi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1135			bi->bi_write_hint = sh->dev[i].write_hint;
1136			if (!rrdev)
1137				sh->dev[i].write_hint = RWH_WRITE_LIFE_NOT_SET;
1138			/*
1139			 * If this is discard request, set bi_vcnt 0. We don't
1140			 * want to confuse SCSI because SCSI will replace payload
1141			 */
1142			if (op == REQ_OP_DISCARD)
1143				bi->bi_vcnt = 0;
1144			if (rrdev)
1145				set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1146
1147			if (conf->mddev->gendisk)
1148				trace_block_bio_remap(bi->bi_disk->queue,
1149						      bi, disk_devt(conf->mddev->gendisk),
1150						      sh->dev[i].sector);
1151			if (should_defer && op_is_write(op))
1152				bio_list_add(&pending_bios, bi);
1153			else
1154				submit_bio_noacct(bi);
1155		}
1156		if (rrdev) {
1157			if (s->syncing || s->expanding || s->expanded
1158			    || s->replacing)
1159				md_sync_acct(rrdev->bdev, RAID5_STRIPE_SECTORS(conf));
1160
1161			set_bit(STRIPE_IO_STARTED, &sh->state);
1162
1163			bio_set_dev(rbi, rrdev->bdev);
1164			bio_set_op_attrs(rbi, op, op_flags);
1165			BUG_ON(!op_is_write(op));
1166			rbi->bi_end_io = raid5_end_write_request;
1167			rbi->bi_private = sh;
1168
1169			pr_debug("%s: for %llu schedule op %d on "
1170				 "replacement disc %d\n",
1171				__func__, (unsigned long long)sh->sector,
1172				rbi->bi_opf, i);
1173			atomic_inc(&sh->count);
1174			if (sh != head_sh)
1175				atomic_inc(&head_sh->count);
1176			if (use_new_offset(conf, sh))
1177				rbi->bi_iter.bi_sector = (sh->sector
1178						  + rrdev->new_data_offset);
1179			else
1180				rbi->bi_iter.bi_sector = (sh->sector
1181						  + rrdev->data_offset);
1182			if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1183				WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1184			sh->dev[i].rvec.bv_page = sh->dev[i].page;
1185			rbi->bi_vcnt = 1;
1186			rbi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1187			rbi->bi_io_vec[0].bv_offset = 0;
1188			rbi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1189			rbi->bi_write_hint = sh->dev[i].write_hint;
1190			sh->dev[i].write_hint = RWH_WRITE_LIFE_NOT_SET;
1191			/*
1192			 * If this is discard request, set bi_vcnt 0. We don't
1193			 * want to confuse SCSI because SCSI will replace payload
1194			 */
1195			if (op == REQ_OP_DISCARD)
1196				rbi->bi_vcnt = 0;
1197			if (conf->mddev->gendisk)
1198				trace_block_bio_remap(rbi->bi_disk->queue,
1199						      rbi, disk_devt(conf->mddev->gendisk),
1200						      sh->dev[i].sector);
1201			if (should_defer && op_is_write(op))
1202				bio_list_add(&pending_bios, rbi);
1203			else
1204				submit_bio_noacct(rbi);
1205		}
1206		if (!rdev && !rrdev) {
1207			if (op_is_write(op))
1208				set_bit(STRIPE_DEGRADED, &sh->state);
1209			pr_debug("skip op %d on disc %d for sector %llu\n",
1210				bi->bi_opf, i, (unsigned long long)sh->sector);
1211			clear_bit(R5_LOCKED, &sh->dev[i].flags);
1212			set_bit(STRIPE_HANDLE, &sh->state);
1213		}
1214
1215		if (!head_sh->batch_head)
1216			continue;
1217		sh = list_first_entry(&sh->batch_list, struct stripe_head,
1218				      batch_list);
1219		if (sh != head_sh)
1220			goto again;
1221	}
1222
1223	if (should_defer && !bio_list_empty(&pending_bios))
1224		defer_issue_bios(conf, head_sh->sector, &pending_bios);
1225}
1226
1227static struct dma_async_tx_descriptor *
1228async_copy_data(int frombio, struct bio *bio, struct page **page,
1229	sector_t sector, struct dma_async_tx_descriptor *tx,
1230	struct stripe_head *sh, int no_skipcopy)
1231{
1232	struct bio_vec bvl;
1233	struct bvec_iter iter;
1234	struct page *bio_page;
 
1235	int page_offset;
1236	struct async_submit_ctl submit;
1237	enum async_tx_flags flags = 0;
1238	struct r5conf *conf = sh->raid_conf;
1239
1240	if (bio->bi_iter.bi_sector >= sector)
1241		page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1242	else
1243		page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1244
1245	if (frombio)
1246		flags |= ASYNC_TX_FENCE;
1247	init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1248
1249	bio_for_each_segment(bvl, bio, iter) {
1250		int len = bvl.bv_len;
1251		int clen;
1252		int b_offset = 0;
1253
1254		if (page_offset < 0) {
1255			b_offset = -page_offset;
1256			page_offset += b_offset;
1257			len -= b_offset;
1258		}
1259
1260		if (len > 0 && page_offset + len > RAID5_STRIPE_SIZE(conf))
1261			clen = RAID5_STRIPE_SIZE(conf) - page_offset;
1262		else
1263			clen = len;
1264
1265		if (clen > 0) {
1266			b_offset += bvl.bv_offset;
1267			bio_page = bvl.bv_page;
1268			if (frombio) {
1269				if (conf->skip_copy &&
1270				    b_offset == 0 && page_offset == 0 &&
1271				    clen == RAID5_STRIPE_SIZE(conf) &&
1272				    !no_skipcopy)
1273					*page = bio_page;
1274				else
1275					tx = async_memcpy(*page, bio_page, page_offset,
1276						  b_offset, clen, &submit);
1277			} else
1278				tx = async_memcpy(bio_page, *page, b_offset,
1279						  page_offset, clen, &submit);
1280		}
1281		/* chain the operations */
1282		submit.depend_tx = tx;
1283
1284		if (clen < len) /* hit end of page */
1285			break;
1286		page_offset +=  len;
1287	}
1288
1289	return tx;
1290}
1291
1292static void ops_complete_biofill(void *stripe_head_ref)
1293{
1294	struct stripe_head *sh = stripe_head_ref;
1295	int i;
1296	struct r5conf *conf = sh->raid_conf;
 
1297
1298	pr_debug("%s: stripe %llu\n", __func__,
1299		(unsigned long long)sh->sector);
1300
1301	/* clear completed biofills */
 
1302	for (i = sh->disks; i--; ) {
1303		struct r5dev *dev = &sh->dev[i];
1304
1305		/* acknowledge completion of a biofill operation */
1306		/* and check if we need to reply to a read request,
1307		 * new R5_Wantfill requests are held off until
1308		 * !STRIPE_BIOFILL_RUN
1309		 */
1310		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1311			struct bio *rbi, *rbi2;
1312
1313			BUG_ON(!dev->read);
1314			rbi = dev->read;
1315			dev->read = NULL;
1316			while (rbi && rbi->bi_iter.bi_sector <
1317				dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1318				rbi2 = r5_next_bio(conf, rbi, dev->sector);
1319				bio_endio(rbi);
 
 
 
1320				rbi = rbi2;
1321			}
1322		}
1323	}
 
1324	clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1325
 
 
1326	set_bit(STRIPE_HANDLE, &sh->state);
1327	raid5_release_stripe(sh);
1328}
1329
1330static void ops_run_biofill(struct stripe_head *sh)
1331{
1332	struct dma_async_tx_descriptor *tx = NULL;
 
1333	struct async_submit_ctl submit;
1334	int i;
1335	struct r5conf *conf = sh->raid_conf;
1336
1337	BUG_ON(sh->batch_head);
1338	pr_debug("%s: stripe %llu\n", __func__,
1339		(unsigned long long)sh->sector);
1340
1341	for (i = sh->disks; i--; ) {
1342		struct r5dev *dev = &sh->dev[i];
1343		if (test_bit(R5_Wantfill, &dev->flags)) {
1344			struct bio *rbi;
1345			spin_lock_irq(&sh->stripe_lock);
1346			dev->read = rbi = dev->toread;
1347			dev->toread = NULL;
1348			spin_unlock_irq(&sh->stripe_lock);
1349			while (rbi && rbi->bi_iter.bi_sector <
1350				dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1351				tx = async_copy_data(0, rbi, &dev->page,
1352						     dev->sector, tx, sh, 0);
1353				rbi = r5_next_bio(conf, rbi, dev->sector);
1354			}
1355		}
1356	}
1357
1358	atomic_inc(&sh->count);
1359	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1360	async_trigger_callback(&submit);
1361}
1362
1363static void mark_target_uptodate(struct stripe_head *sh, int target)
1364{
1365	struct r5dev *tgt;
1366
1367	if (target < 0)
1368		return;
1369
1370	tgt = &sh->dev[target];
1371	set_bit(R5_UPTODATE, &tgt->flags);
1372	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1373	clear_bit(R5_Wantcompute, &tgt->flags);
1374}
1375
1376static void ops_complete_compute(void *stripe_head_ref)
1377{
1378	struct stripe_head *sh = stripe_head_ref;
1379
1380	pr_debug("%s: stripe %llu\n", __func__,
1381		(unsigned long long)sh->sector);
1382
1383	/* mark the computed target(s) as uptodate */
1384	mark_target_uptodate(sh, sh->ops.target);
1385	mark_target_uptodate(sh, sh->ops.target2);
1386
1387	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1388	if (sh->check_state == check_state_compute_run)
1389		sh->check_state = check_state_compute_result;
1390	set_bit(STRIPE_HANDLE, &sh->state);
1391	raid5_release_stripe(sh);
1392}
1393
1394/* return a pointer to the address conversion region of the scribble buffer */
1395static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1396{
1397	return percpu->scribble + i * percpu->scribble_obj_size;
1398}
1399
1400/* return a pointer to the address conversion region of the scribble buffer */
1401static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1402				 struct raid5_percpu *percpu, int i)
1403{
1404	return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
1405}
1406
1407static struct dma_async_tx_descriptor *
1408ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1409{
1410	int disks = sh->disks;
1411	struct page **xor_srcs = to_addr_page(percpu, 0);
1412	int target = sh->ops.target;
1413	struct r5dev *tgt = &sh->dev[target];
1414	struct page *xor_dest = tgt->page;
1415	int count = 0;
1416	struct dma_async_tx_descriptor *tx;
1417	struct async_submit_ctl submit;
1418	int i;
1419
1420	BUG_ON(sh->batch_head);
1421
1422	pr_debug("%s: stripe %llu block: %d\n",
1423		__func__, (unsigned long long)sh->sector, target);
1424	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1425
1426	for (i = disks; i--; )
1427		if (i != target)
1428			xor_srcs[count++] = sh->dev[i].page;
1429
1430	atomic_inc(&sh->count);
1431
1432	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1433			  ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1434	if (unlikely(count == 1))
1435		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0,
1436				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1437	else
1438		tx = async_xor(xor_dest, xor_srcs, 0, count,
1439				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1440
1441	return tx;
1442}
1443
1444/* set_syndrome_sources - populate source buffers for gen_syndrome
1445 * @srcs - (struct page *) array of size sh->disks
1446 * @sh - stripe_head to parse
1447 *
1448 * Populates srcs in proper layout order for the stripe and returns the
1449 * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1450 * destination buffer is recorded in srcs[count] and the Q destination
1451 * is recorded in srcs[count+1]].
1452 */
1453static int set_syndrome_sources(struct page **srcs,
1454				struct stripe_head *sh,
1455				int srctype)
1456{
1457	int disks = sh->disks;
1458	int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1459	int d0_idx = raid6_d0(sh);
1460	int count;
1461	int i;
1462
1463	for (i = 0; i < disks; i++)
1464		srcs[i] = NULL;
1465
1466	count = 0;
1467	i = d0_idx;
1468	do {
1469		int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1470		struct r5dev *dev = &sh->dev[i];
1471
1472		if (i == sh->qd_idx || i == sh->pd_idx ||
1473		    (srctype == SYNDROME_SRC_ALL) ||
1474		    (srctype == SYNDROME_SRC_WANT_DRAIN &&
1475		     (test_bit(R5_Wantdrain, &dev->flags) ||
1476		      test_bit(R5_InJournal, &dev->flags))) ||
1477		    (srctype == SYNDROME_SRC_WRITTEN &&
1478		     (dev->written ||
1479		      test_bit(R5_InJournal, &dev->flags)))) {
1480			if (test_bit(R5_InJournal, &dev->flags))
1481				srcs[slot] = sh->dev[i].orig_page;
1482			else
1483				srcs[slot] = sh->dev[i].page;
1484		}
1485		i = raid6_next_disk(i, disks);
1486	} while (i != d0_idx);
1487
1488	return syndrome_disks;
1489}
1490
1491static struct dma_async_tx_descriptor *
1492ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1493{
1494	int disks = sh->disks;
1495	struct page **blocks = to_addr_page(percpu, 0);
1496	int target;
1497	int qd_idx = sh->qd_idx;
1498	struct dma_async_tx_descriptor *tx;
1499	struct async_submit_ctl submit;
1500	struct r5dev *tgt;
1501	struct page *dest;
1502	int i;
1503	int count;
1504
1505	BUG_ON(sh->batch_head);
1506	if (sh->ops.target < 0)
1507		target = sh->ops.target2;
1508	else if (sh->ops.target2 < 0)
1509		target = sh->ops.target;
1510	else
1511		/* we should only have one valid target */
1512		BUG();
1513	BUG_ON(target < 0);
1514	pr_debug("%s: stripe %llu block: %d\n",
1515		__func__, (unsigned long long)sh->sector, target);
1516
1517	tgt = &sh->dev[target];
1518	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1519	dest = tgt->page;
1520
1521	atomic_inc(&sh->count);
1522
1523	if (target == qd_idx) {
1524		count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1525		blocks[count] = NULL; /* regenerating p is not necessary */
1526		BUG_ON(blocks[count+1] != dest); /* q should already be set */
1527		init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1528				  ops_complete_compute, sh,
1529				  to_addr_conv(sh, percpu, 0));
1530		tx = async_gen_syndrome(blocks, 0, count+2,
1531				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1532	} else {
1533		/* Compute any data- or p-drive using XOR */
1534		count = 0;
1535		for (i = disks; i-- ; ) {
1536			if (i == target || i == qd_idx)
1537				continue;
1538			blocks[count++] = sh->dev[i].page;
1539		}
1540
1541		init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1542				  NULL, ops_complete_compute, sh,
1543				  to_addr_conv(sh, percpu, 0));
1544		tx = async_xor(dest, blocks, 0, count,
1545				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1546	}
1547
1548	return tx;
1549}
1550
1551static struct dma_async_tx_descriptor *
1552ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1553{
1554	int i, count, disks = sh->disks;
1555	int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1556	int d0_idx = raid6_d0(sh);
1557	int faila = -1, failb = -1;
1558	int target = sh->ops.target;
1559	int target2 = sh->ops.target2;
1560	struct r5dev *tgt = &sh->dev[target];
1561	struct r5dev *tgt2 = &sh->dev[target2];
1562	struct dma_async_tx_descriptor *tx;
1563	struct page **blocks = to_addr_page(percpu, 0);
1564	struct async_submit_ctl submit;
1565
1566	BUG_ON(sh->batch_head);
1567	pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1568		 __func__, (unsigned long long)sh->sector, target, target2);
1569	BUG_ON(target < 0 || target2 < 0);
1570	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1571	BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1572
1573	/* we need to open-code set_syndrome_sources to handle the
1574	 * slot number conversion for 'faila' and 'failb'
1575	 */
1576	for (i = 0; i < disks ; i++)
1577		blocks[i] = NULL;
1578	count = 0;
1579	i = d0_idx;
1580	do {
1581		int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1582
1583		blocks[slot] = sh->dev[i].page;
1584
1585		if (i == target)
1586			faila = slot;
1587		if (i == target2)
1588			failb = slot;
1589		i = raid6_next_disk(i, disks);
1590	} while (i != d0_idx);
1591
1592	BUG_ON(faila == failb);
1593	if (failb < faila)
1594		swap(faila, failb);
1595	pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1596		 __func__, (unsigned long long)sh->sector, faila, failb);
1597
1598	atomic_inc(&sh->count);
1599
1600	if (failb == syndrome_disks+1) {
1601		/* Q disk is one of the missing disks */
1602		if (faila == syndrome_disks) {
1603			/* Missing P+Q, just recompute */
1604			init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1605					  ops_complete_compute, sh,
1606					  to_addr_conv(sh, percpu, 0));
1607			return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1608						  RAID5_STRIPE_SIZE(sh->raid_conf),
1609						  &submit);
1610		} else {
1611			struct page *dest;
1612			int data_target;
1613			int qd_idx = sh->qd_idx;
1614
1615			/* Missing D+Q: recompute D from P, then recompute Q */
1616			if (target == qd_idx)
1617				data_target = target2;
1618			else
1619				data_target = target;
1620
1621			count = 0;
1622			for (i = disks; i-- ; ) {
1623				if (i == data_target || i == qd_idx)
1624					continue;
1625				blocks[count++] = sh->dev[i].page;
1626			}
1627			dest = sh->dev[data_target].page;
1628			init_async_submit(&submit,
1629					  ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1630					  NULL, NULL, NULL,
1631					  to_addr_conv(sh, percpu, 0));
1632			tx = async_xor(dest, blocks, 0, count,
1633				       RAID5_STRIPE_SIZE(sh->raid_conf),
1634				       &submit);
1635
1636			count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1637			init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1638					  ops_complete_compute, sh,
1639					  to_addr_conv(sh, percpu, 0));
1640			return async_gen_syndrome(blocks, 0, count+2,
1641						  RAID5_STRIPE_SIZE(sh->raid_conf),
1642						  &submit);
1643		}
1644	} else {
1645		init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1646				  ops_complete_compute, sh,
1647				  to_addr_conv(sh, percpu, 0));
1648		if (failb == syndrome_disks) {
1649			/* We're missing D+P. */
1650			return async_raid6_datap_recov(syndrome_disks+2,
1651						RAID5_STRIPE_SIZE(sh->raid_conf),
1652						faila,
1653						blocks, &submit);
1654		} else {
1655			/* We're missing D+D. */
1656			return async_raid6_2data_recov(syndrome_disks+2,
1657						RAID5_STRIPE_SIZE(sh->raid_conf),
1658						faila, failb,
1659						blocks, &submit);
1660		}
1661	}
1662}
1663
 
1664static void ops_complete_prexor(void *stripe_head_ref)
1665{
1666	struct stripe_head *sh = stripe_head_ref;
1667
1668	pr_debug("%s: stripe %llu\n", __func__,
1669		(unsigned long long)sh->sector);
1670
1671	if (r5c_is_writeback(sh->raid_conf->log))
1672		/*
1673		 * raid5-cache write back uses orig_page during prexor.
1674		 * After prexor, it is time to free orig_page
1675		 */
1676		r5c_release_extra_page(sh);
1677}
1678
1679static struct dma_async_tx_descriptor *
1680ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1681		struct dma_async_tx_descriptor *tx)
1682{
1683	int disks = sh->disks;
1684	struct page **xor_srcs = to_addr_page(percpu, 0);
1685	int count = 0, pd_idx = sh->pd_idx, i;
1686	struct async_submit_ctl submit;
1687
1688	/* existing parity data subtracted */
1689	struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1690
1691	BUG_ON(sh->batch_head);
1692	pr_debug("%s: stripe %llu\n", __func__,
1693		(unsigned long long)sh->sector);
1694
1695	for (i = disks; i--; ) {
1696		struct r5dev *dev = &sh->dev[i];
1697		/* Only process blocks that are known to be uptodate */
1698		if (test_bit(R5_InJournal, &dev->flags))
1699			xor_srcs[count++] = dev->orig_page;
1700		else if (test_bit(R5_Wantdrain, &dev->flags))
1701			xor_srcs[count++] = dev->page;
1702	}
1703
1704	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1705			  ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1706	tx = async_xor(xor_dest, xor_srcs, 0, count,
1707			RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1708
1709	return tx;
1710}
1711
1712static struct dma_async_tx_descriptor *
1713ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1714		struct dma_async_tx_descriptor *tx)
1715{
1716	struct page **blocks = to_addr_page(percpu, 0);
1717	int count;
1718	struct async_submit_ctl submit;
1719
1720	pr_debug("%s: stripe %llu\n", __func__,
1721		(unsigned long long)sh->sector);
1722
1723	count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
1724
1725	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1726			  ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1727	tx = async_gen_syndrome(blocks, 0, count+2,
1728			RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1729
1730	return tx;
1731}
1732
1733static struct dma_async_tx_descriptor *
1734ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1735{
1736	struct r5conf *conf = sh->raid_conf;
1737	int disks = sh->disks;
1738	int i;
1739	struct stripe_head *head_sh = sh;
1740
1741	pr_debug("%s: stripe %llu\n", __func__,
1742		(unsigned long long)sh->sector);
1743
1744	for (i = disks; i--; ) {
1745		struct r5dev *dev;
1746		struct bio *chosen;
1747
1748		sh = head_sh;
1749		if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1750			struct bio *wbi;
1751
1752again:
1753			dev = &sh->dev[i];
1754			/*
1755			 * clear R5_InJournal, so when rewriting a page in
1756			 * journal, it is not skipped by r5l_log_stripe()
1757			 */
1758			clear_bit(R5_InJournal, &dev->flags);
1759			spin_lock_irq(&sh->stripe_lock);
1760			chosen = dev->towrite;
1761			dev->towrite = NULL;
1762			sh->overwrite_disks = 0;
1763			BUG_ON(dev->written);
1764			wbi = dev->written = chosen;
1765			spin_unlock_irq(&sh->stripe_lock);
1766			WARN_ON(dev->page != dev->orig_page);
1767
1768			while (wbi && wbi->bi_iter.bi_sector <
1769				dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1770				if (wbi->bi_opf & REQ_FUA)
1771					set_bit(R5_WantFUA, &dev->flags);
1772				if (wbi->bi_opf & REQ_SYNC)
1773					set_bit(R5_SyncIO, &dev->flags);
1774				if (bio_op(wbi) == REQ_OP_DISCARD)
1775					set_bit(R5_Discard, &dev->flags);
1776				else {
1777					tx = async_copy_data(1, wbi, &dev->page,
1778							     dev->sector, tx, sh,
1779							     r5c_is_writeback(conf->log));
1780					if (dev->page != dev->orig_page &&
1781					    !r5c_is_writeback(conf->log)) {
1782						set_bit(R5_SkipCopy, &dev->flags);
1783						clear_bit(R5_UPTODATE, &dev->flags);
1784						clear_bit(R5_OVERWRITE, &dev->flags);
1785					}
1786				}
1787				wbi = r5_next_bio(conf, wbi, dev->sector);
1788			}
1789
1790			if (head_sh->batch_head) {
1791				sh = list_first_entry(&sh->batch_list,
1792						      struct stripe_head,
1793						      batch_list);
1794				if (sh == head_sh)
1795					continue;
1796				goto again;
1797			}
1798		}
1799	}
1800
1801	return tx;
1802}
1803
1804static void ops_complete_reconstruct(void *stripe_head_ref)
1805{
1806	struct stripe_head *sh = stripe_head_ref;
1807	int disks = sh->disks;
1808	int pd_idx = sh->pd_idx;
1809	int qd_idx = sh->qd_idx;
1810	int i;
1811	bool fua = false, sync = false, discard = false;
1812
1813	pr_debug("%s: stripe %llu\n", __func__,
1814		(unsigned long long)sh->sector);
1815
1816	for (i = disks; i--; ) {
1817		fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1818		sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1819		discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1820	}
1821
1822	for (i = disks; i--; ) {
1823		struct r5dev *dev = &sh->dev[i];
1824
1825		if (dev->written || i == pd_idx || i == qd_idx) {
1826			if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
1827				set_bit(R5_UPTODATE, &dev->flags);
1828				if (test_bit(STRIPE_EXPAND_READY, &sh->state))
1829					set_bit(R5_Expanded, &dev->flags);
1830			}
1831			if (fua)
1832				set_bit(R5_WantFUA, &dev->flags);
1833			if (sync)
1834				set_bit(R5_SyncIO, &dev->flags);
1835		}
1836	}
1837
1838	if (sh->reconstruct_state == reconstruct_state_drain_run)
1839		sh->reconstruct_state = reconstruct_state_drain_result;
1840	else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1841		sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1842	else {
1843		BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1844		sh->reconstruct_state = reconstruct_state_result;
1845	}
1846
1847	set_bit(STRIPE_HANDLE, &sh->state);
1848	raid5_release_stripe(sh);
1849}
1850
1851static void
1852ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1853		     struct dma_async_tx_descriptor *tx)
1854{
1855	int disks = sh->disks;
1856	struct page **xor_srcs;
1857	struct async_submit_ctl submit;
1858	int count, pd_idx = sh->pd_idx, i;
1859	struct page *xor_dest;
1860	int prexor = 0;
1861	unsigned long flags;
1862	int j = 0;
1863	struct stripe_head *head_sh = sh;
1864	int last_stripe;
1865
1866	pr_debug("%s: stripe %llu\n", __func__,
1867		(unsigned long long)sh->sector);
1868
1869	for (i = 0; i < sh->disks; i++) {
1870		if (pd_idx == i)
1871			continue;
1872		if (!test_bit(R5_Discard, &sh->dev[i].flags))
1873			break;
1874	}
1875	if (i >= sh->disks) {
1876		atomic_inc(&sh->count);
1877		set_bit(R5_Discard, &sh->dev[pd_idx].flags);
1878		ops_complete_reconstruct(sh);
1879		return;
1880	}
1881again:
1882	count = 0;
1883	xor_srcs = to_addr_page(percpu, j);
1884	/* check if prexor is active which means only process blocks
1885	 * that are part of a read-modify-write (written)
1886	 */
1887	if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1888		prexor = 1;
1889		xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1890		for (i = disks; i--; ) {
1891			struct r5dev *dev = &sh->dev[i];
1892			if (head_sh->dev[i].written ||
1893			    test_bit(R5_InJournal, &head_sh->dev[i].flags))
1894				xor_srcs[count++] = dev->page;
1895		}
1896	} else {
1897		xor_dest = sh->dev[pd_idx].page;
1898		for (i = disks; i--; ) {
1899			struct r5dev *dev = &sh->dev[i];
1900			if (i != pd_idx)
1901				xor_srcs[count++] = dev->page;
1902		}
1903	}
1904
1905	/* 1/ if we prexor'd then the dest is reused as a source
1906	 * 2/ if we did not prexor then we are redoing the parity
1907	 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1908	 * for the synchronous xor case
1909	 */
1910	last_stripe = !head_sh->batch_head ||
1911		list_first_entry(&sh->batch_list,
1912				 struct stripe_head, batch_list) == head_sh;
1913	if (last_stripe) {
1914		flags = ASYNC_TX_ACK |
1915			(prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1916
1917		atomic_inc(&head_sh->count);
1918		init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
1919				  to_addr_conv(sh, percpu, j));
1920	} else {
1921		flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
1922		init_async_submit(&submit, flags, tx, NULL, NULL,
1923				  to_addr_conv(sh, percpu, j));
1924	}
1925
 
 
1926	if (unlikely(count == 1))
1927		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0,
1928				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1929	else
1930		tx = async_xor(xor_dest, xor_srcs, 0, count,
1931				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1932	if (!last_stripe) {
1933		j++;
1934		sh = list_first_entry(&sh->batch_list, struct stripe_head,
1935				      batch_list);
1936		goto again;
1937	}
1938}
1939
1940static void
1941ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1942		     struct dma_async_tx_descriptor *tx)
1943{
1944	struct async_submit_ctl submit;
1945	struct page **blocks;
1946	int count, i, j = 0;
1947	struct stripe_head *head_sh = sh;
1948	int last_stripe;
1949	int synflags;
1950	unsigned long txflags;
1951
1952	pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1953
1954	for (i = 0; i < sh->disks; i++) {
1955		if (sh->pd_idx == i || sh->qd_idx == i)
1956			continue;
1957		if (!test_bit(R5_Discard, &sh->dev[i].flags))
1958			break;
1959	}
1960	if (i >= sh->disks) {
1961		atomic_inc(&sh->count);
1962		set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
1963		set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
1964		ops_complete_reconstruct(sh);
1965		return;
1966	}
1967
1968again:
1969	blocks = to_addr_page(percpu, j);
1970
1971	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1972		synflags = SYNDROME_SRC_WRITTEN;
1973		txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
1974	} else {
1975		synflags = SYNDROME_SRC_ALL;
1976		txflags = ASYNC_TX_ACK;
1977	}
1978
1979	count = set_syndrome_sources(blocks, sh, synflags);
1980	last_stripe = !head_sh->batch_head ||
1981		list_first_entry(&sh->batch_list,
1982				 struct stripe_head, batch_list) == head_sh;
1983
1984	if (last_stripe) {
1985		atomic_inc(&head_sh->count);
1986		init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
1987				  head_sh, to_addr_conv(sh, percpu, j));
1988	} else
1989		init_async_submit(&submit, 0, tx, NULL, NULL,
1990				  to_addr_conv(sh, percpu, j));
1991	tx = async_gen_syndrome(blocks, 0, count+2,
1992			RAID5_STRIPE_SIZE(sh->raid_conf),  &submit);
1993	if (!last_stripe) {
1994		j++;
1995		sh = list_first_entry(&sh->batch_list, struct stripe_head,
1996				      batch_list);
1997		goto again;
1998	}
1999}
2000
2001static void ops_complete_check(void *stripe_head_ref)
2002{
2003	struct stripe_head *sh = stripe_head_ref;
2004
2005	pr_debug("%s: stripe %llu\n", __func__,
2006		(unsigned long long)sh->sector);
2007
2008	sh->check_state = check_state_check_result;
2009	set_bit(STRIPE_HANDLE, &sh->state);
2010	raid5_release_stripe(sh);
2011}
2012
2013static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2014{
2015	int disks = sh->disks;
2016	int pd_idx = sh->pd_idx;
2017	int qd_idx = sh->qd_idx;
2018	struct page *xor_dest;
2019	struct page **xor_srcs = to_addr_page(percpu, 0);
2020	struct dma_async_tx_descriptor *tx;
2021	struct async_submit_ctl submit;
2022	int count;
2023	int i;
2024
2025	pr_debug("%s: stripe %llu\n", __func__,
2026		(unsigned long long)sh->sector);
2027
2028	BUG_ON(sh->batch_head);
2029	count = 0;
2030	xor_dest = sh->dev[pd_idx].page;
2031	xor_srcs[count++] = xor_dest;
2032	for (i = disks; i--; ) {
2033		if (i == pd_idx || i == qd_idx)
2034			continue;
2035		xor_srcs[count++] = sh->dev[i].page;
2036	}
2037
2038	init_async_submit(&submit, 0, NULL, NULL, NULL,
2039			  to_addr_conv(sh, percpu, 0));
2040	tx = async_xor_val(xor_dest, xor_srcs, 0, count,
2041			   RAID5_STRIPE_SIZE(sh->raid_conf),
2042			   &sh->ops.zero_sum_result, &submit);
2043
2044	atomic_inc(&sh->count);
2045	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2046	tx = async_trigger_callback(&submit);
2047}
2048
2049static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2050{
2051	struct page **srcs = to_addr_page(percpu, 0);
2052	struct async_submit_ctl submit;
2053	int count;
2054
2055	pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2056		(unsigned long long)sh->sector, checkp);
2057
2058	BUG_ON(sh->batch_head);
2059	count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
2060	if (!checkp)
2061		srcs[count] = NULL;
2062
2063	atomic_inc(&sh->count);
2064	init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2065			  sh, to_addr_conv(sh, percpu, 0));
2066	async_syndrome_val(srcs, 0, count+2,
2067			   RAID5_STRIPE_SIZE(sh->raid_conf),
2068			   &sh->ops.zero_sum_result, percpu->spare_page, &submit);
2069}
2070
2071static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2072{
2073	int overlap_clear = 0, i, disks = sh->disks;
2074	struct dma_async_tx_descriptor *tx = NULL;
2075	struct r5conf *conf = sh->raid_conf;
2076	int level = conf->level;
2077	struct raid5_percpu *percpu;
2078	unsigned long cpu;
2079
2080	cpu = get_cpu();
2081	percpu = per_cpu_ptr(conf->percpu, cpu);
2082	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2083		ops_run_biofill(sh);
2084		overlap_clear++;
2085	}
2086
2087	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2088		if (level < 6)
2089			tx = ops_run_compute5(sh, percpu);
2090		else {
2091			if (sh->ops.target2 < 0 || sh->ops.target < 0)
2092				tx = ops_run_compute6_1(sh, percpu);
2093			else
2094				tx = ops_run_compute6_2(sh, percpu);
2095		}
2096		/* terminate the chain if reconstruct is not set to be run */
2097		if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2098			async_tx_ack(tx);
2099	}
2100
2101	if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2102		if (level < 6)
2103			tx = ops_run_prexor5(sh, percpu, tx);
2104		else
2105			tx = ops_run_prexor6(sh, percpu, tx);
2106	}
2107
2108	if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2109		tx = ops_run_partial_parity(sh, percpu, tx);
2110
2111	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2112		tx = ops_run_biodrain(sh, tx);
2113		overlap_clear++;
2114	}
2115
2116	if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2117		if (level < 6)
2118			ops_run_reconstruct5(sh, percpu, tx);
2119		else
2120			ops_run_reconstruct6(sh, percpu, tx);
2121	}
2122
2123	if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2124		if (sh->check_state == check_state_run)
2125			ops_run_check_p(sh, percpu);
2126		else if (sh->check_state == check_state_run_q)
2127			ops_run_check_pq(sh, percpu, 0);
2128		else if (sh->check_state == check_state_run_pq)
2129			ops_run_check_pq(sh, percpu, 1);
2130		else
2131			BUG();
2132	}
2133
2134	if (overlap_clear && !sh->batch_head)
2135		for (i = disks; i--; ) {
2136			struct r5dev *dev = &sh->dev[i];
2137			if (test_and_clear_bit(R5_Overlap, &dev->flags))
2138				wake_up(&sh->raid_conf->wait_for_overlap);
2139		}
2140	put_cpu();
2141}
2142
2143static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
 
2144{
2145	if (sh->ppl_page)
2146		__free_page(sh->ppl_page);
2147	kmem_cache_free(sc, sh);
2148}
2149
2150static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2151	int disks, struct r5conf *conf)
2152{
2153	struct stripe_head *sh;
2154	int i;
2155
2156	sh = kmem_cache_zalloc(sc, gfp);
2157	if (sh) {
2158		spin_lock_init(&sh->stripe_lock);
2159		spin_lock_init(&sh->batch_lock);
2160		INIT_LIST_HEAD(&sh->batch_list);
2161		INIT_LIST_HEAD(&sh->lru);
2162		INIT_LIST_HEAD(&sh->r5c);
2163		INIT_LIST_HEAD(&sh->log_list);
2164		atomic_set(&sh->count, 1);
2165		sh->raid_conf = conf;
2166		sh->log_start = MaxSector;
2167		for (i = 0; i < disks; i++) {
2168			struct r5dev *dev = &sh->dev[i];
2169
2170			bio_init(&dev->req, &dev->vec, 1);
2171			bio_init(&dev->rreq, &dev->rvec, 1);
2172		}
 
 
 
 
 
 
2173
2174		if (raid5_has_ppl(conf)) {
2175			sh->ppl_page = alloc_page(gfp);
2176			if (!sh->ppl_page) {
2177				free_stripe(sc, sh);
2178				sh = NULL;
2179			}
2180		}
2181	}
2182	return sh;
2183}
2184static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
 
 
 
 
2185{
2186	struct stripe_head *sh;
2187
2188	sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2189	if (!sh)
2190		return 0;
2191
2192	if (grow_buffers(sh, gfp)) {
 
 
 
 
 
2193		shrink_buffers(sh);
2194		free_stripe(conf->slab_cache, sh);
2195		return 0;
2196	}
2197	sh->hash_lock_index =
2198		conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2199	/* we just created an active stripe so... */
 
2200	atomic_inc(&conf->active_stripes);
2201
2202	raid5_release_stripe(sh);
2203	conf->max_nr_stripes++;
2204	return 1;
2205}
2206
2207static int grow_stripes(struct r5conf *conf, int num)
2208{
2209	struct kmem_cache *sc;
2210	size_t namelen = sizeof(conf->cache_name[0]);
2211	int devs = max(conf->raid_disks, conf->previous_raid_disks);
2212
2213	if (conf->mddev->gendisk)
2214		snprintf(conf->cache_name[0], namelen,
2215			"raid%d-%s", conf->level, mdname(conf->mddev));
2216	else
2217		snprintf(conf->cache_name[0], namelen,
2218			"raid%d-%p", conf->level, conf->mddev);
2219	snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2220
2221	conf->active_name = 0;
2222	sc = kmem_cache_create(conf->cache_name[conf->active_name],
2223			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2224			       0, 0, NULL);
2225	if (!sc)
2226		return 1;
2227	conf->slab_cache = sc;
2228	conf->pool_size = devs;
2229	while (num--)
2230		if (!grow_one_stripe(conf, GFP_KERNEL))
2231			return 1;
2232
2233	return 0;
2234}
2235
2236/**
2237 * scribble_alloc - allocate percpu scribble buffer for required size
2238 *		    of the scribble region
2239 * @percpu: from for_each_present_cpu() of the caller
2240 * @num: total number of disks in the array
2241 * @cnt: scribble objs count for required size of the scribble region
2242 *
2243 * The scribble buffer size must be enough to contain:
2244 * 1/ a struct page pointer for each device in the array +2
2245 * 2/ room to convert each entry in (1) to its corresponding dma
2246 *    (dma_map_page()) or page (page_address()) address.
2247 *
2248 * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2249 * calculate over all devices (not just the data blocks), using zeros in place
2250 * of the P and Q blocks.
2251 */
2252static int scribble_alloc(struct raid5_percpu *percpu,
2253			  int num, int cnt)
2254{
2255	size_t obj_size =
2256		sizeof(struct page *) * (num+2) +
2257		sizeof(addr_conv_t) * (num+2);
2258	void *scribble;
2259
2260	/*
2261	 * If here is in raid array suspend context, it is in memalloc noio
2262	 * context as well, there is no potential recursive memory reclaim
2263	 * I/Os with the GFP_KERNEL flag.
2264	 */
2265	scribble = kvmalloc_array(cnt, obj_size, GFP_KERNEL);
2266	if (!scribble)
2267		return -ENOMEM;
2268
2269	kvfree(percpu->scribble);
2270
2271	percpu->scribble = scribble;
2272	percpu->scribble_obj_size = obj_size;
2273	return 0;
2274}
2275
2276static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2277{
2278	unsigned long cpu;
2279	int err = 0;
2280
2281	/*
2282	 * Never shrink. And mddev_suspend() could deadlock if this is called
2283	 * from raid5d. In that case, scribble_disks and scribble_sectors
2284	 * should equal to new_disks and new_sectors
2285	 */
2286	if (conf->scribble_disks >= new_disks &&
2287	    conf->scribble_sectors >= new_sectors)
2288		return 0;
2289	mddev_suspend(conf->mddev);
2290	get_online_cpus();
2291
2292	for_each_present_cpu(cpu) {
2293		struct raid5_percpu *percpu;
2294
2295		percpu = per_cpu_ptr(conf->percpu, cpu);
2296		err = scribble_alloc(percpu, new_disks,
2297				     new_sectors / RAID5_STRIPE_SECTORS(conf));
2298		if (err)
2299			break;
2300	}
2301
2302	put_online_cpus();
2303	mddev_resume(conf->mddev);
2304	if (!err) {
2305		conf->scribble_disks = new_disks;
2306		conf->scribble_sectors = new_sectors;
2307	}
2308	return err;
2309}
2310
2311static int resize_stripes(struct r5conf *conf, int newsize)
2312{
2313	/* Make all the stripes able to hold 'newsize' devices.
2314	 * New slots in each stripe get 'page' set to a new page.
2315	 *
2316	 * This happens in stages:
2317	 * 1/ create a new kmem_cache and allocate the required number of
2318	 *    stripe_heads.
2319	 * 2/ gather all the old stripe_heads and transfer the pages across
2320	 *    to the new stripe_heads.  This will have the side effect of
2321	 *    freezing the array as once all stripe_heads have been collected,
2322	 *    no IO will be possible.  Old stripe heads are freed once their
2323	 *    pages have been transferred over, and the old kmem_cache is
2324	 *    freed when all stripes are done.
2325	 * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2326	 *    we simple return a failure status - no need to clean anything up.
2327	 * 4/ allocate new pages for the new slots in the new stripe_heads.
2328	 *    If this fails, we don't bother trying the shrink the
2329	 *    stripe_heads down again, we just leave them as they are.
2330	 *    As each stripe_head is processed the new one is released into
2331	 *    active service.
2332	 *
2333	 * Once step2 is started, we cannot afford to wait for a write,
2334	 * so we use GFP_NOIO allocations.
2335	 */
2336	struct stripe_head *osh, *nsh;
2337	LIST_HEAD(newstripes);
2338	struct disk_info *ndisks;
2339	int err = 0;
 
2340	struct kmem_cache *sc;
2341	int i;
2342	int hash, cnt;
2343
2344	md_allow_write(conf->mddev);
 
 
 
 
 
2345
2346	/* Step 1 */
2347	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2348			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2349			       0, 0, NULL);
2350	if (!sc)
2351		return -ENOMEM;
2352
2353	/* Need to ensure auto-resizing doesn't interfere */
2354	mutex_lock(&conf->cache_size_mutex);
2355
2356	for (i = conf->max_nr_stripes; i; i--) {
2357		nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2358		if (!nsh)
2359			break;
2360
 
 
 
 
 
2361		list_add(&nsh->lru, &newstripes);
2362	}
2363	if (i) {
2364		/* didn't get enough, give up */
2365		while (!list_empty(&newstripes)) {
2366			nsh = list_entry(newstripes.next, struct stripe_head, lru);
2367			list_del(&nsh->lru);
2368			free_stripe(sc, nsh);
2369		}
2370		kmem_cache_destroy(sc);
2371		mutex_unlock(&conf->cache_size_mutex);
2372		return -ENOMEM;
2373	}
2374	/* Step 2 - Must use GFP_NOIO now.
2375	 * OK, we have enough stripes, start collecting inactive
2376	 * stripes and copying them over
2377	 */
2378	hash = 0;
2379	cnt = 0;
2380	list_for_each_entry(nsh, &newstripes, lru) {
2381		lock_device_hash_lock(conf, hash);
2382		wait_event_cmd(conf->wait_for_stripe,
2383				    !list_empty(conf->inactive_list + hash),
2384				    unlock_device_hash_lock(conf, hash),
2385				    lock_device_hash_lock(conf, hash));
2386		osh = get_free_stripe(conf, hash);
2387		unlock_device_hash_lock(conf, hash);
2388
2389		for(i=0; i<conf->pool_size; i++) {
2390			nsh->dev[i].page = osh->dev[i].page;
2391			nsh->dev[i].orig_page = osh->dev[i].page;
2392		}
2393		nsh->hash_lock_index = hash;
2394		free_stripe(conf->slab_cache, osh);
2395		cnt++;
2396		if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2397		    !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2398			hash++;
2399			cnt = 0;
2400		}
2401	}
2402	kmem_cache_destroy(conf->slab_cache);
2403
2404	/* Step 3.
2405	 * At this point, we are holding all the stripes so the array
2406	 * is completely stalled, so now is a good time to resize
2407	 * conf->disks and the scribble region
2408	 */
2409	ndisks = kcalloc(newsize, sizeof(struct disk_info), GFP_NOIO);
2410	if (ndisks) {
2411		for (i = 0; i < conf->pool_size; i++)
2412			ndisks[i] = conf->disks[i];
2413
2414		for (i = conf->pool_size; i < newsize; i++) {
2415			ndisks[i].extra_page = alloc_page(GFP_NOIO);
2416			if (!ndisks[i].extra_page)
2417				err = -ENOMEM;
2418		}
2419
2420		if (err) {
2421			for (i = conf->pool_size; i < newsize; i++)
2422				if (ndisks[i].extra_page)
2423					put_page(ndisks[i].extra_page);
2424			kfree(ndisks);
2425		} else {
2426			kfree(conf->disks);
2427			conf->disks = ndisks;
2428		}
2429	} else
2430		err = -ENOMEM;
2431
2432	mutex_unlock(&conf->cache_size_mutex);
 
 
 
 
2433
2434	conf->slab_cache = sc;
2435	conf->active_name = 1-conf->active_name;
 
 
 
 
 
 
 
 
 
 
2436
2437	/* Step 4, return new stripes to service */
2438	while(!list_empty(&newstripes)) {
2439		nsh = list_entry(newstripes.next, struct stripe_head, lru);
2440		list_del_init(&nsh->lru);
2441
2442		for (i=conf->raid_disks; i < newsize; i++)
2443			if (nsh->dev[i].page == NULL) {
2444				struct page *p = alloc_page(GFP_NOIO);
2445				nsh->dev[i].page = p;
2446				nsh->dev[i].orig_page = p;
2447				if (!p)
2448					err = -ENOMEM;
2449			}
2450		raid5_release_stripe(nsh);
2451	}
2452	/* critical section pass, GFP_NOIO no longer needed */
2453
2454	if (!err)
2455		conf->pool_size = newsize;
 
2456	return err;
2457}
2458
2459static int drop_one_stripe(struct r5conf *conf)
2460{
2461	struct stripe_head *sh;
2462	int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2463
2464	spin_lock_irq(conf->hash_locks + hash);
2465	sh = get_free_stripe(conf, hash);
2466	spin_unlock_irq(conf->hash_locks + hash);
2467	if (!sh)
2468		return 0;
2469	BUG_ON(atomic_read(&sh->count));
2470	shrink_buffers(sh);
2471	free_stripe(conf->slab_cache, sh);
2472	atomic_dec(&conf->active_stripes);
2473	conf->max_nr_stripes--;
2474	return 1;
2475}
2476
2477static void shrink_stripes(struct r5conf *conf)
2478{
2479	while (conf->max_nr_stripes &&
2480	       drop_one_stripe(conf))
2481		;
2482
2483	kmem_cache_destroy(conf->slab_cache);
 
2484	conf->slab_cache = NULL;
2485}
2486
2487static void raid5_end_read_request(struct bio * bi)
2488{
2489	struct stripe_head *sh = bi->bi_private;
2490	struct r5conf *conf = sh->raid_conf;
2491	int disks = sh->disks, i;
 
2492	char b[BDEVNAME_SIZE];
2493	struct md_rdev *rdev = NULL;
2494	sector_t s;
2495
2496	for (i=0 ; i<disks; i++)
2497		if (bi == &sh->dev[i].req)
2498			break;
2499
2500	pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2501		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
2502		bi->bi_status);
2503	if (i == disks) {
2504		bio_reset(bi);
2505		BUG();
2506		return;
2507	}
2508	if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2509		/* If replacement finished while this request was outstanding,
2510		 * 'replacement' might be NULL already.
2511		 * In that case it moved down to 'rdev'.
2512		 * rdev is not removed until all requests are finished.
2513		 */
2514		rdev = conf->disks[i].replacement;
2515	if (!rdev)
2516		rdev = conf->disks[i].rdev;
2517
2518	if (use_new_offset(conf, sh))
2519		s = sh->sector + rdev->new_data_offset;
2520	else
2521		s = sh->sector + rdev->data_offset;
2522	if (!bi->bi_status) {
2523		set_bit(R5_UPTODATE, &sh->dev[i].flags);
2524		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2525			/* Note that this cannot happen on a
2526			 * replacement device.  We just fail those on
2527			 * any error
2528			 */
2529			pr_info_ratelimited(
2530				"md/raid:%s: read error corrected (%lu sectors at %llu on %s)\n",
2531				mdname(conf->mddev), RAID5_STRIPE_SECTORS(conf),
 
 
2532				(unsigned long long)s,
2533				bdevname(rdev->bdev, b));
2534			atomic_add(RAID5_STRIPE_SECTORS(conf), &rdev->corrected_errors);
2535			clear_bit(R5_ReadError, &sh->dev[i].flags);
2536			clear_bit(R5_ReWrite, &sh->dev[i].flags);
2537		} else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2538			clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2539
2540		if (test_bit(R5_InJournal, &sh->dev[i].flags))
2541			/*
2542			 * end read for a page in journal, this
2543			 * must be preparing for prexor in rmw
2544			 */
2545			set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2546
2547		if (atomic_read(&rdev->read_errors))
2548			atomic_set(&rdev->read_errors, 0);
2549	} else {
2550		const char *bdn = bdevname(rdev->bdev, b);
2551		int retry = 0;
2552		int set_bad = 0;
2553
2554		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2555		if (!(bi->bi_status == BLK_STS_PROTECTION))
2556			atomic_inc(&rdev->read_errors);
2557		if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2558			pr_warn_ratelimited(
2559				"md/raid:%s: read error on replacement device (sector %llu on %s).\n",
 
 
2560				mdname(conf->mddev),
2561				(unsigned long long)s,
2562				bdn);
2563		else if (conf->mddev->degraded >= conf->max_degraded) {
2564			set_bad = 1;
2565			pr_warn_ratelimited(
2566				"md/raid:%s: read error not correctable (sector %llu on %s).\n",
 
 
2567				mdname(conf->mddev),
2568				(unsigned long long)s,
2569				bdn);
2570		} else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2571			/* Oh, no!!! */
2572			set_bad = 1;
2573			pr_warn_ratelimited(
2574				"md/raid:%s: read error NOT corrected!! (sector %llu on %s).\n",
 
 
2575				mdname(conf->mddev),
2576				(unsigned long long)s,
2577				bdn);
2578		} else if (atomic_read(&rdev->read_errors)
2579			 > conf->max_nr_stripes) {
2580			if (!test_bit(Faulty, &rdev->flags)) {
2581				pr_warn("md/raid:%s: %d read_errors > %d stripes\n",
2582				    mdname(conf->mddev),
2583				    atomic_read(&rdev->read_errors),
2584				    conf->max_nr_stripes);
2585				pr_warn("md/raid:%s: Too many read errors, failing device %s.\n",
2586				    mdname(conf->mddev), bdn);
2587			}
2588		} else
2589			retry = 1;
2590		if (set_bad && test_bit(In_sync, &rdev->flags)
2591		    && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2592			retry = 1;
2593		if (retry)
2594			if (sh->qd_idx >= 0 && sh->pd_idx == i)
2595				set_bit(R5_ReadError, &sh->dev[i].flags);
2596			else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2597				set_bit(R5_ReadError, &sh->dev[i].flags);
2598				clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2599			} else
2600				set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2601		else {
2602			clear_bit(R5_ReadError, &sh->dev[i].flags);
2603			clear_bit(R5_ReWrite, &sh->dev[i].flags);
2604			if (!(set_bad
2605			      && test_bit(In_sync, &rdev->flags)
2606			      && rdev_set_badblocks(
2607				      rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0)))
2608				md_error(conf->mddev, rdev);
2609		}
2610	}
2611	rdev_dec_pending(rdev, conf->mddev);
2612	bio_reset(bi);
2613	clear_bit(R5_LOCKED, &sh->dev[i].flags);
2614	set_bit(STRIPE_HANDLE, &sh->state);
2615	raid5_release_stripe(sh);
2616}
2617
2618static void raid5_end_write_request(struct bio *bi)
2619{
2620	struct stripe_head *sh = bi->bi_private;
2621	struct r5conf *conf = sh->raid_conf;
2622	int disks = sh->disks, i;
2623	struct md_rdev *rdev;
 
2624	sector_t first_bad;
2625	int bad_sectors;
2626	int replacement = 0;
2627
2628	for (i = 0 ; i < disks; i++) {
2629		if (bi == &sh->dev[i].req) {
2630			rdev = conf->disks[i].rdev;
2631			break;
2632		}
2633		if (bi == &sh->dev[i].rreq) {
2634			rdev = conf->disks[i].replacement;
2635			if (rdev)
2636				replacement = 1;
2637			else
2638				/* rdev was removed and 'replacement'
2639				 * replaced it.  rdev is not removed
2640				 * until all requests are finished.
2641				 */
2642				rdev = conf->disks[i].rdev;
2643			break;
2644		}
2645	}
2646	pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2647		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
2648		bi->bi_status);
2649	if (i == disks) {
2650		bio_reset(bi);
2651		BUG();
2652		return;
2653	}
2654
2655	if (replacement) {
2656		if (bi->bi_status)
2657			md_error(conf->mddev, rdev);
2658		else if (is_badblock(rdev, sh->sector,
2659				     RAID5_STRIPE_SECTORS(conf),
2660				     &first_bad, &bad_sectors))
2661			set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2662	} else {
2663		if (bi->bi_status) {
2664			set_bit(STRIPE_DEGRADED, &sh->state);
2665			set_bit(WriteErrorSeen, &rdev->flags);
2666			set_bit(R5_WriteError, &sh->dev[i].flags);
2667			if (!test_and_set_bit(WantReplacement, &rdev->flags))
2668				set_bit(MD_RECOVERY_NEEDED,
2669					&rdev->mddev->recovery);
2670		} else if (is_badblock(rdev, sh->sector,
2671				       RAID5_STRIPE_SECTORS(conf),
2672				       &first_bad, &bad_sectors)) {
2673			set_bit(R5_MadeGood, &sh->dev[i].flags);
2674			if (test_bit(R5_ReadError, &sh->dev[i].flags))
2675				/* That was a successful write so make
2676				 * sure it looks like we already did
2677				 * a re-write.
2678				 */
2679				set_bit(R5_ReWrite, &sh->dev[i].flags);
2680		}
2681	}
2682	rdev_dec_pending(rdev, conf->mddev);
2683
2684	if (sh->batch_head && bi->bi_status && !replacement)
2685		set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2686
2687	bio_reset(bi);
2688	if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2689		clear_bit(R5_LOCKED, &sh->dev[i].flags);
2690	set_bit(STRIPE_HANDLE, &sh->state);
2691	raid5_release_stripe(sh);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2692
2693	if (sh->batch_head && sh != sh->batch_head)
2694		raid5_release_stripe(sh->batch_head);
2695}
2696
2697static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2698{
2699	char b[BDEVNAME_SIZE];
2700	struct r5conf *conf = mddev->private;
2701	unsigned long flags;
2702	pr_debug("raid456: error called\n");
2703
2704	spin_lock_irqsave(&conf->device_lock, flags);
2705
2706	if (test_bit(In_sync, &rdev->flags) &&
2707	    mddev->degraded == conf->max_degraded) {
2708		/*
2709		 * Don't allow to achieve failed state
2710		 * Don't try to recover this device
2711		 */
2712		conf->recovery_disabled = mddev->recovery_disabled;
2713		spin_unlock_irqrestore(&conf->device_lock, flags);
2714		return;
2715	}
2716
2717	set_bit(Faulty, &rdev->flags);
2718	clear_bit(In_sync, &rdev->flags);
2719	mddev->degraded = raid5_calc_degraded(conf);
2720	spin_unlock_irqrestore(&conf->device_lock, flags);
2721	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2722
2723	set_bit(Blocked, &rdev->flags);
2724	set_mask_bits(&mddev->sb_flags, 0,
2725		      BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2726	pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
2727		"md/raid:%s: Operation continuing on %d devices.\n",
2728		mdname(mddev),
2729		bdevname(rdev->bdev, b),
2730		mdname(mddev),
2731		conf->raid_disks - mddev->degraded);
2732	r5c_update_on_rdev_error(mddev, rdev);
2733}
2734
2735/*
2736 * Input: a 'big' sector number,
2737 * Output: index of the data and parity disk, and the sector # in them.
2738 */
2739sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2740			      int previous, int *dd_idx,
2741			      struct stripe_head *sh)
2742{
2743	sector_t stripe, stripe2;
2744	sector_t chunk_number;
2745	unsigned int chunk_offset;
2746	int pd_idx, qd_idx;
2747	int ddf_layout = 0;
2748	sector_t new_sector;
2749	int algorithm = previous ? conf->prev_algo
2750				 : conf->algorithm;
2751	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2752					 : conf->chunk_sectors;
2753	int raid_disks = previous ? conf->previous_raid_disks
2754				  : conf->raid_disks;
2755	int data_disks = raid_disks - conf->max_degraded;
2756
2757	/* First compute the information on this sector */
2758
2759	/*
2760	 * Compute the chunk number and the sector offset inside the chunk
2761	 */
2762	chunk_offset = sector_div(r_sector, sectors_per_chunk);
2763	chunk_number = r_sector;
2764
2765	/*
2766	 * Compute the stripe number
2767	 */
2768	stripe = chunk_number;
2769	*dd_idx = sector_div(stripe, data_disks);
2770	stripe2 = stripe;
2771	/*
2772	 * Select the parity disk based on the user selected algorithm.
2773	 */
2774	pd_idx = qd_idx = -1;
2775	switch(conf->level) {
2776	case 4:
2777		pd_idx = data_disks;
2778		break;
2779	case 5:
2780		switch (algorithm) {
2781		case ALGORITHM_LEFT_ASYMMETRIC:
2782			pd_idx = data_disks - sector_div(stripe2, raid_disks);
2783			if (*dd_idx >= pd_idx)
2784				(*dd_idx)++;
2785			break;
2786		case ALGORITHM_RIGHT_ASYMMETRIC:
2787			pd_idx = sector_div(stripe2, raid_disks);
2788			if (*dd_idx >= pd_idx)
2789				(*dd_idx)++;
2790			break;
2791		case ALGORITHM_LEFT_SYMMETRIC:
2792			pd_idx = data_disks - sector_div(stripe2, raid_disks);
2793			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2794			break;
2795		case ALGORITHM_RIGHT_SYMMETRIC:
2796			pd_idx = sector_div(stripe2, raid_disks);
2797			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2798			break;
2799		case ALGORITHM_PARITY_0:
2800			pd_idx = 0;
2801			(*dd_idx)++;
2802			break;
2803		case ALGORITHM_PARITY_N:
2804			pd_idx = data_disks;
2805			break;
2806		default:
2807			BUG();
2808		}
2809		break;
2810	case 6:
2811
2812		switch (algorithm) {
2813		case ALGORITHM_LEFT_ASYMMETRIC:
2814			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2815			qd_idx = pd_idx + 1;
2816			if (pd_idx == raid_disks-1) {
2817				(*dd_idx)++;	/* Q D D D P */
2818				qd_idx = 0;
2819			} else if (*dd_idx >= pd_idx)
2820				(*dd_idx) += 2; /* D D P Q D */
2821			break;
2822		case ALGORITHM_RIGHT_ASYMMETRIC:
2823			pd_idx = sector_div(stripe2, raid_disks);
2824			qd_idx = pd_idx + 1;
2825			if (pd_idx == raid_disks-1) {
2826				(*dd_idx)++;	/* Q D D D P */
2827				qd_idx = 0;
2828			} else if (*dd_idx >= pd_idx)
2829				(*dd_idx) += 2; /* D D P Q D */
2830			break;
2831		case ALGORITHM_LEFT_SYMMETRIC:
2832			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2833			qd_idx = (pd_idx + 1) % raid_disks;
2834			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2835			break;
2836		case ALGORITHM_RIGHT_SYMMETRIC:
2837			pd_idx = sector_div(stripe2, raid_disks);
2838			qd_idx = (pd_idx + 1) % raid_disks;
2839			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2840			break;
2841
2842		case ALGORITHM_PARITY_0:
2843			pd_idx = 0;
2844			qd_idx = 1;
2845			(*dd_idx) += 2;
2846			break;
2847		case ALGORITHM_PARITY_N:
2848			pd_idx = data_disks;
2849			qd_idx = data_disks + 1;
2850			break;
2851
2852		case ALGORITHM_ROTATING_ZERO_RESTART:
2853			/* Exactly the same as RIGHT_ASYMMETRIC, but or
2854			 * of blocks for computing Q is different.
2855			 */
2856			pd_idx = sector_div(stripe2, raid_disks);
2857			qd_idx = pd_idx + 1;
2858			if (pd_idx == raid_disks-1) {
2859				(*dd_idx)++;	/* Q D D D P */
2860				qd_idx = 0;
2861			} else if (*dd_idx >= pd_idx)
2862				(*dd_idx) += 2; /* D D P Q D */
2863			ddf_layout = 1;
2864			break;
2865
2866		case ALGORITHM_ROTATING_N_RESTART:
2867			/* Same a left_asymmetric, by first stripe is
2868			 * D D D P Q  rather than
2869			 * Q D D D P
2870			 */
2871			stripe2 += 1;
2872			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2873			qd_idx = pd_idx + 1;
2874			if (pd_idx == raid_disks-1) {
2875				(*dd_idx)++;	/* Q D D D P */
2876				qd_idx = 0;
2877			} else if (*dd_idx >= pd_idx)
2878				(*dd_idx) += 2; /* D D P Q D */
2879			ddf_layout = 1;
2880			break;
2881
2882		case ALGORITHM_ROTATING_N_CONTINUE:
2883			/* Same as left_symmetric but Q is before P */
2884			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2885			qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2886			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2887			ddf_layout = 1;
2888			break;
2889
2890		case ALGORITHM_LEFT_ASYMMETRIC_6:
2891			/* RAID5 left_asymmetric, with Q on last device */
2892			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2893			if (*dd_idx >= pd_idx)
2894				(*dd_idx)++;
2895			qd_idx = raid_disks - 1;
2896			break;
2897
2898		case ALGORITHM_RIGHT_ASYMMETRIC_6:
2899			pd_idx = sector_div(stripe2, raid_disks-1);
2900			if (*dd_idx >= pd_idx)
2901				(*dd_idx)++;
2902			qd_idx = raid_disks - 1;
2903			break;
2904
2905		case ALGORITHM_LEFT_SYMMETRIC_6:
2906			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2907			*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2908			qd_idx = raid_disks - 1;
2909			break;
2910
2911		case ALGORITHM_RIGHT_SYMMETRIC_6:
2912			pd_idx = sector_div(stripe2, raid_disks-1);
2913			*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2914			qd_idx = raid_disks - 1;
2915			break;
2916
2917		case ALGORITHM_PARITY_0_6:
2918			pd_idx = 0;
2919			(*dd_idx)++;
2920			qd_idx = raid_disks - 1;
2921			break;
2922
2923		default:
2924			BUG();
2925		}
2926		break;
2927	}
2928
2929	if (sh) {
2930		sh->pd_idx = pd_idx;
2931		sh->qd_idx = qd_idx;
2932		sh->ddf_layout = ddf_layout;
2933	}
2934	/*
2935	 * Finally, compute the new sector number
2936	 */
2937	new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2938	return new_sector;
2939}
2940
2941sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
 
2942{
2943	struct r5conf *conf = sh->raid_conf;
2944	int raid_disks = sh->disks;
2945	int data_disks = raid_disks - conf->max_degraded;
2946	sector_t new_sector = sh->sector, check;
2947	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2948					 : conf->chunk_sectors;
2949	int algorithm = previous ? conf->prev_algo
2950				 : conf->algorithm;
2951	sector_t stripe;
2952	int chunk_offset;
2953	sector_t chunk_number;
2954	int dummy1, dd_idx = i;
2955	sector_t r_sector;
2956	struct stripe_head sh2;
2957
 
2958	chunk_offset = sector_div(new_sector, sectors_per_chunk);
2959	stripe = new_sector;
2960
2961	if (i == sh->pd_idx)
2962		return 0;
2963	switch(conf->level) {
2964	case 4: break;
2965	case 5:
2966		switch (algorithm) {
2967		case ALGORITHM_LEFT_ASYMMETRIC:
2968		case ALGORITHM_RIGHT_ASYMMETRIC:
2969			if (i > sh->pd_idx)
2970				i--;
2971			break;
2972		case ALGORITHM_LEFT_SYMMETRIC:
2973		case ALGORITHM_RIGHT_SYMMETRIC:
2974			if (i < sh->pd_idx)
2975				i += raid_disks;
2976			i -= (sh->pd_idx + 1);
2977			break;
2978		case ALGORITHM_PARITY_0:
2979			i -= 1;
2980			break;
2981		case ALGORITHM_PARITY_N:
2982			break;
2983		default:
2984			BUG();
2985		}
2986		break;
2987	case 6:
2988		if (i == sh->qd_idx)
2989			return 0; /* It is the Q disk */
2990		switch (algorithm) {
2991		case ALGORITHM_LEFT_ASYMMETRIC:
2992		case ALGORITHM_RIGHT_ASYMMETRIC:
2993		case ALGORITHM_ROTATING_ZERO_RESTART:
2994		case ALGORITHM_ROTATING_N_RESTART:
2995			if (sh->pd_idx == raid_disks-1)
2996				i--;	/* Q D D D P */
2997			else if (i > sh->pd_idx)
2998				i -= 2; /* D D P Q D */
2999			break;
3000		case ALGORITHM_LEFT_SYMMETRIC:
3001		case ALGORITHM_RIGHT_SYMMETRIC:
3002			if (sh->pd_idx == raid_disks-1)
3003				i--; /* Q D D D P */
3004			else {
3005				/* D D P Q D */
3006				if (i < sh->pd_idx)
3007					i += raid_disks;
3008				i -= (sh->pd_idx + 2);
3009			}
3010			break;
3011		case ALGORITHM_PARITY_0:
3012			i -= 2;
3013			break;
3014		case ALGORITHM_PARITY_N:
3015			break;
3016		case ALGORITHM_ROTATING_N_CONTINUE:
3017			/* Like left_symmetric, but P is before Q */
3018			if (sh->pd_idx == 0)
3019				i--;	/* P D D D Q */
3020			else {
3021				/* D D Q P D */
3022				if (i < sh->pd_idx)
3023					i += raid_disks;
3024				i -= (sh->pd_idx + 1);
3025			}
3026			break;
3027		case ALGORITHM_LEFT_ASYMMETRIC_6:
3028		case ALGORITHM_RIGHT_ASYMMETRIC_6:
3029			if (i > sh->pd_idx)
3030				i--;
3031			break;
3032		case ALGORITHM_LEFT_SYMMETRIC_6:
3033		case ALGORITHM_RIGHT_SYMMETRIC_6:
3034			if (i < sh->pd_idx)
3035				i += data_disks + 1;
3036			i -= (sh->pd_idx + 1);
3037			break;
3038		case ALGORITHM_PARITY_0_6:
3039			i -= 1;
3040			break;
3041		default:
3042			BUG();
3043		}
3044		break;
3045	}
3046
3047	chunk_number = stripe * data_disks + i;
3048	r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3049
3050	check = raid5_compute_sector(conf, r_sector,
3051				     previous, &dummy1, &sh2);
3052	if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3053		|| sh2.qd_idx != sh->qd_idx) {
3054		pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3055			mdname(conf->mddev));
3056		return 0;
3057	}
3058	return r_sector;
3059}
3060
3061/*
3062 * There are cases where we want handle_stripe_dirtying() and
3063 * schedule_reconstruction() to delay towrite to some dev of a stripe.
3064 *
3065 * This function checks whether we want to delay the towrite. Specifically,
3066 * we delay the towrite when:
3067 *
3068 *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3069 *      stripe has data in journal (for other devices).
3070 *
3071 *      In this case, when reading data for the non-overwrite dev, it is
3072 *      necessary to handle complex rmw of write back cache (prexor with
3073 *      orig_page, and xor with page). To keep read path simple, we would
3074 *      like to flush data in journal to RAID disks first, so complex rmw
3075 *      is handled in the write patch (handle_stripe_dirtying).
3076 *
3077 *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3078 *
3079 *      It is important to be able to flush all stripes in raid5-cache.
3080 *      Therefore, we need reserve some space on the journal device for
3081 *      these flushes. If flush operation includes pending writes to the
3082 *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3083 *      for the flush out. If we exclude these pending writes from flush
3084 *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3085 *      Therefore, excluding pending writes in these cases enables more
3086 *      efficient use of the journal device.
3087 *
3088 *      Note: To make sure the stripe makes progress, we only delay
3089 *      towrite for stripes with data already in journal (injournal > 0).
3090 *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3091 *      no_space_stripes list.
3092 *
3093 *   3. during journal failure
3094 *      In journal failure, we try to flush all cached data to raid disks
3095 *      based on data in stripe cache. The array is read-only to upper
3096 *      layers, so we would skip all pending writes.
3097 *
3098 */
3099static inline bool delay_towrite(struct r5conf *conf,
3100				 struct r5dev *dev,
3101				 struct stripe_head_state *s)
3102{
3103	/* case 1 above */
3104	if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3105	    !test_bit(R5_Insync, &dev->flags) && s->injournal)
3106		return true;
3107	/* case 2 above */
3108	if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3109	    s->injournal > 0)
3110		return true;
3111	/* case 3 above */
3112	if (s->log_failed && s->injournal)
3113		return true;
3114	return false;
3115}
3116
3117static void
3118schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3119			 int rcw, int expand)
3120{
3121	int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3122	struct r5conf *conf = sh->raid_conf;
3123	int level = conf->level;
3124
3125	if (rcw) {
3126		/*
3127		 * In some cases, handle_stripe_dirtying initially decided to
3128		 * run rmw and allocates extra page for prexor. However, rcw is
3129		 * cheaper later on. We need to free the extra page now,
3130		 * because we won't be able to do that in ops_complete_prexor().
3131		 */
3132		r5c_release_extra_page(sh);
3133
3134		for (i = disks; i--; ) {
3135			struct r5dev *dev = &sh->dev[i];
3136
3137			if (dev->towrite && !delay_towrite(conf, dev, s)) {
3138				set_bit(R5_LOCKED, &dev->flags);
3139				set_bit(R5_Wantdrain, &dev->flags);
3140				if (!expand)
3141					clear_bit(R5_UPTODATE, &dev->flags);
3142				s->locked++;
3143			} else if (test_bit(R5_InJournal, &dev->flags)) {
3144				set_bit(R5_LOCKED, &dev->flags);
3145				s->locked++;
3146			}
3147		}
3148		/* if we are not expanding this is a proper write request, and
3149		 * there will be bios with new data to be drained into the
3150		 * stripe cache
3151		 */
3152		if (!expand) {
3153			if (!s->locked)
3154				/* False alarm, nothing to do */
3155				return;
3156			sh->reconstruct_state = reconstruct_state_drain_run;
3157			set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3158		} else
3159			sh->reconstruct_state = reconstruct_state_run;
3160
3161		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3162
 
 
 
 
 
 
 
 
 
 
 
3163		if (s->locked + conf->max_degraded == disks)
3164			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3165				atomic_inc(&conf->pending_full_writes);
3166	} else {
 
3167		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3168			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3169		BUG_ON(level == 6 &&
3170			(!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3171			   test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
 
 
3172
3173		for (i = disks; i--; ) {
3174			struct r5dev *dev = &sh->dev[i];
3175			if (i == pd_idx || i == qd_idx)
3176				continue;
3177
3178			if (dev->towrite &&
3179			    (test_bit(R5_UPTODATE, &dev->flags) ||
3180			     test_bit(R5_Wantcompute, &dev->flags))) {
3181				set_bit(R5_Wantdrain, &dev->flags);
3182				set_bit(R5_LOCKED, &dev->flags);
3183				clear_bit(R5_UPTODATE, &dev->flags);
3184				s->locked++;
3185			} else if (test_bit(R5_InJournal, &dev->flags)) {
3186				set_bit(R5_LOCKED, &dev->flags);
3187				s->locked++;
3188			}
3189		}
3190		if (!s->locked)
3191			/* False alarm - nothing to do */
3192			return;
3193		sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3194		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3195		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3196		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3197	}
3198
3199	/* keep the parity disk(s) locked while asynchronous operations
3200	 * are in flight
3201	 */
3202	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3203	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3204	s->locked++;
3205
3206	if (level == 6) {
3207		int qd_idx = sh->qd_idx;
3208		struct r5dev *dev = &sh->dev[qd_idx];
3209
3210		set_bit(R5_LOCKED, &dev->flags);
3211		clear_bit(R5_UPTODATE, &dev->flags);
3212		s->locked++;
3213	}
3214
3215	if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3216	    test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3217	    !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3218	    test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3219		set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3220
3221	pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3222		__func__, (unsigned long long)sh->sector,
3223		s->locked, s->ops_request);
3224}
3225
3226/*
3227 * Each stripe/dev can have one or more bion attached.
3228 * toread/towrite point to the first in a chain.
3229 * The bi_next chain must be in order.
3230 */
3231static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
3232			  int forwrite, int previous)
3233{
3234	struct bio **bip;
3235	struct r5conf *conf = sh->raid_conf;
3236	int firstwrite=0;
3237
3238	pr_debug("adding bi b#%llu to stripe s#%llu\n",
3239		(unsigned long long)bi->bi_iter.bi_sector,
3240		(unsigned long long)sh->sector);
3241
3242	spin_lock_irq(&sh->stripe_lock);
3243	sh->dev[dd_idx].write_hint = bi->bi_write_hint;
3244	/* Don't allow new IO added to stripes in batch list */
3245	if (sh->batch_head)
3246		goto overlap;
3247	if (forwrite) {
3248		bip = &sh->dev[dd_idx].towrite;
3249		if (*bip == NULL)
3250			firstwrite = 1;
3251	} else
3252		bip = &sh->dev[dd_idx].toread;
3253	while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3254		if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3255			goto overlap;
3256		bip = & (*bip)->bi_next;
3257	}
3258	if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3259		goto overlap;
3260
3261	if (forwrite && raid5_has_ppl(conf)) {
3262		/*
3263		 * With PPL only writes to consecutive data chunks within a
3264		 * stripe are allowed because for a single stripe_head we can
3265		 * only have one PPL entry at a time, which describes one data
3266		 * range. Not really an overlap, but wait_for_overlap can be
3267		 * used to handle this.
3268		 */
3269		sector_t sector;
3270		sector_t first = 0;
3271		sector_t last = 0;
3272		int count = 0;
3273		int i;
3274
3275		for (i = 0; i < sh->disks; i++) {
3276			if (i != sh->pd_idx &&
3277			    (i == dd_idx || sh->dev[i].towrite)) {
3278				sector = sh->dev[i].sector;
3279				if (count == 0 || sector < first)
3280					first = sector;
3281				if (sector > last)
3282					last = sector;
3283				count++;
3284			}
3285		}
3286
3287		if (first + conf->chunk_sectors * (count - 1) != last)
3288			goto overlap;
3289	}
3290
3291	if (!forwrite || previous)
3292		clear_bit(STRIPE_BATCH_READY, &sh->state);
3293
3294	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3295	if (*bip)
3296		bi->bi_next = *bip;
3297	*bip = bi;
3298	bio_inc_remaining(bi);
3299	md_write_inc(conf->mddev, bi);
3300
3301	if (forwrite) {
3302		/* check if page is covered */
3303		sector_t sector = sh->dev[dd_idx].sector;
3304		for (bi=sh->dev[dd_idx].towrite;
3305		     sector < sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf) &&
3306			     bi && bi->bi_iter.bi_sector <= sector;
3307		     bi = r5_next_bio(conf, bi, sh->dev[dd_idx].sector)) {
3308			if (bio_end_sector(bi) >= sector)
3309				sector = bio_end_sector(bi);
3310		}
3311		if (sector >= sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf))
3312			if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3313				sh->overwrite_disks++;
3314	}
 
3315
3316	pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
3317		(unsigned long long)(*bip)->bi_iter.bi_sector,
3318		(unsigned long long)sh->sector, dd_idx);
3319
3320	if (conf->mddev->bitmap && firstwrite) {
3321		/* Cannot hold spinlock over bitmap_startwrite,
3322		 * but must ensure this isn't added to a batch until
3323		 * we have added to the bitmap and set bm_seq.
3324		 * So set STRIPE_BITMAP_PENDING to prevent
3325		 * batching.
3326		 * If multiple add_stripe_bio() calls race here they
3327		 * much all set STRIPE_BITMAP_PENDING.  So only the first one
3328		 * to complete "bitmap_startwrite" gets to set
3329		 * STRIPE_BIT_DELAY.  This is important as once a stripe
3330		 * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3331		 * any more.
3332		 */
3333		set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3334		spin_unlock_irq(&sh->stripe_lock);
3335		md_bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3336				     RAID5_STRIPE_SECTORS(conf), 0);
3337		spin_lock_irq(&sh->stripe_lock);
3338		clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3339		if (!sh->batch_head) {
3340			sh->bm_seq = conf->seq_flush+1;
3341			set_bit(STRIPE_BIT_DELAY, &sh->state);
3342		}
3343	}
3344	spin_unlock_irq(&sh->stripe_lock);
3345
3346	if (stripe_can_batch(sh))
3347		stripe_add_to_batch_list(conf, sh);
3348	return 1;
3349
3350 overlap:
3351	set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3352	spin_unlock_irq(&sh->stripe_lock);
3353	return 0;
3354}
3355
3356static void end_reshape(struct r5conf *conf);
3357
3358static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3359			    struct stripe_head *sh)
3360{
3361	int sectors_per_chunk =
3362		previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3363	int dd_idx;
3364	int chunk_offset = sector_div(stripe, sectors_per_chunk);
3365	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3366
3367	raid5_compute_sector(conf,
3368			     stripe * (disks - conf->max_degraded)
3369			     *sectors_per_chunk + chunk_offset,
3370			     previous,
3371			     &dd_idx, sh);
3372}
3373
3374static void
3375handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3376		     struct stripe_head_state *s, int disks)
 
3377{
3378	int i;
3379	BUG_ON(sh->batch_head);
3380	for (i = disks; i--; ) {
3381		struct bio *bi;
3382		int bitmap_end = 0;
3383
3384		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3385			struct md_rdev *rdev;
3386			rcu_read_lock();
3387			rdev = rcu_dereference(conf->disks[i].rdev);
3388			if (rdev && test_bit(In_sync, &rdev->flags) &&
3389			    !test_bit(Faulty, &rdev->flags))
3390				atomic_inc(&rdev->nr_pending);
3391			else
3392				rdev = NULL;
3393			rcu_read_unlock();
3394			if (rdev) {
3395				if (!rdev_set_badblocks(
3396					    rdev,
3397					    sh->sector,
3398					    RAID5_STRIPE_SECTORS(conf), 0))
3399					md_error(conf->mddev, rdev);
3400				rdev_dec_pending(rdev, conf->mddev);
3401			}
3402		}
3403		spin_lock_irq(&sh->stripe_lock);
3404		/* fail all writes first */
3405		bi = sh->dev[i].towrite;
3406		sh->dev[i].towrite = NULL;
3407		sh->overwrite_disks = 0;
3408		spin_unlock_irq(&sh->stripe_lock);
3409		if (bi)
3410			bitmap_end = 1;
3411
3412		log_stripe_write_finished(sh);
3413
3414		if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3415			wake_up(&conf->wait_for_overlap);
3416
3417		while (bi && bi->bi_iter.bi_sector <
3418			sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3419			struct bio *nextbi = r5_next_bio(conf, bi, sh->dev[i].sector);
3420
3421			md_write_end(conf->mddev);
3422			bio_io_error(bi);
 
 
 
3423			bi = nextbi;
3424		}
3425		if (bitmap_end)
3426			md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3427					   RAID5_STRIPE_SECTORS(conf), 0, 0);
3428		bitmap_end = 0;
3429		/* and fail all 'written' */
3430		bi = sh->dev[i].written;
3431		sh->dev[i].written = NULL;
3432		if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3433			WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3434			sh->dev[i].page = sh->dev[i].orig_page;
3435		}
3436
3437		if (bi) bitmap_end = 1;
3438		while (bi && bi->bi_iter.bi_sector <
3439		       sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3440			struct bio *bi2 = r5_next_bio(conf, bi, sh->dev[i].sector);
3441
3442			md_write_end(conf->mddev);
3443			bio_io_error(bi);
 
 
 
3444			bi = bi2;
3445		}
3446
3447		/* fail any reads if this device is non-operational and
3448		 * the data has not reached the cache yet.
3449		 */
3450		if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3451		    s->failed > conf->max_degraded &&
3452		    (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3453		      test_bit(R5_ReadError, &sh->dev[i].flags))) {
3454			spin_lock_irq(&sh->stripe_lock);
3455			bi = sh->dev[i].toread;
3456			sh->dev[i].toread = NULL;
3457			spin_unlock_irq(&sh->stripe_lock);
3458			if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3459				wake_up(&conf->wait_for_overlap);
3460			if (bi)
3461				s->to_read--;
3462			while (bi && bi->bi_iter.bi_sector <
3463			       sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3464				struct bio *nextbi =
3465					r5_next_bio(conf, bi, sh->dev[i].sector);
3466
3467				bio_io_error(bi);
 
 
 
3468				bi = nextbi;
3469			}
3470		}
 
3471		if (bitmap_end)
3472			md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3473					   RAID5_STRIPE_SECTORS(conf), 0, 0);
3474		/* If we were in the middle of a write the parity block might
3475		 * still be locked - so just clear all R5_LOCKED flags
3476		 */
3477		clear_bit(R5_LOCKED, &sh->dev[i].flags);
3478	}
3479	s->to_write = 0;
3480	s->written = 0;
3481
3482	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3483		if (atomic_dec_and_test(&conf->pending_full_writes))
3484			md_wakeup_thread(conf->mddev->thread);
3485}
3486
3487static void
3488handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3489		   struct stripe_head_state *s)
3490{
3491	int abort = 0;
3492	int i;
3493
3494	BUG_ON(sh->batch_head);
3495	clear_bit(STRIPE_SYNCING, &sh->state);
3496	if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3497		wake_up(&conf->wait_for_overlap);
3498	s->syncing = 0;
3499	s->replacing = 0;
3500	/* There is nothing more to do for sync/check/repair.
3501	 * Don't even need to abort as that is handled elsewhere
3502	 * if needed, and not always wanted e.g. if there is a known
3503	 * bad block here.
3504	 * For recover/replace we need to record a bad block on all
3505	 * non-sync devices, or abort the recovery
3506	 */
3507	if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3508		/* During recovery devices cannot be removed, so
3509		 * locking and refcounting of rdevs is not needed
3510		 */
3511		rcu_read_lock();
3512		for (i = 0; i < conf->raid_disks; i++) {
3513			struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3514			if (rdev
3515			    && !test_bit(Faulty, &rdev->flags)
3516			    && !test_bit(In_sync, &rdev->flags)
3517			    && !rdev_set_badblocks(rdev, sh->sector,
3518						   RAID5_STRIPE_SECTORS(conf), 0))
3519				abort = 1;
3520			rdev = rcu_dereference(conf->disks[i].replacement);
3521			if (rdev
3522			    && !test_bit(Faulty, &rdev->flags)
3523			    && !test_bit(In_sync, &rdev->flags)
3524			    && !rdev_set_badblocks(rdev, sh->sector,
3525						   RAID5_STRIPE_SECTORS(conf), 0))
3526				abort = 1;
3527		}
3528		rcu_read_unlock();
3529		if (abort)
3530			conf->recovery_disabled =
3531				conf->mddev->recovery_disabled;
3532	}
3533	md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), !abort);
3534}
3535
3536static int want_replace(struct stripe_head *sh, int disk_idx)
3537{
3538	struct md_rdev *rdev;
3539	int rv = 0;
3540
3541	rcu_read_lock();
3542	rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3543	if (rdev
3544	    && !test_bit(Faulty, &rdev->flags)
3545	    && !test_bit(In_sync, &rdev->flags)
3546	    && (rdev->recovery_offset <= sh->sector
3547		|| rdev->mddev->recovery_cp <= sh->sector))
3548		rv = 1;
3549	rcu_read_unlock();
3550	return rv;
3551}
3552
3553static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3554			   int disk_idx, int disks)
3555{
3556	struct r5dev *dev = &sh->dev[disk_idx];
3557	struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3558				  &sh->dev[s->failed_num[1]] };
3559	int i;
3560	bool force_rcw = (sh->raid_conf->rmw_level == PARITY_DISABLE_RMW);
3561
3562
3563	if (test_bit(R5_LOCKED, &dev->flags) ||
3564	    test_bit(R5_UPTODATE, &dev->flags))
3565		/* No point reading this as we already have it or have
3566		 * decided to get it.
3567		 */
3568		return 0;
3569
3570	if (dev->toread ||
3571	    (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3572		/* We need this block to directly satisfy a request */
3573		return 1;
3574
3575	if (s->syncing || s->expanding ||
3576	    (s->replacing && want_replace(sh, disk_idx)))
3577		/* When syncing, or expanding we read everything.
3578		 * When replacing, we need the replaced block.
3579		 */
3580		return 1;
3581
3582	if ((s->failed >= 1 && fdev[0]->toread) ||
3583	    (s->failed >= 2 && fdev[1]->toread))
3584		/* If we want to read from a failed device, then
3585		 * we need to actually read every other device.
3586		 */
3587		return 1;
3588
3589	/* Sometimes neither read-modify-write nor reconstruct-write
3590	 * cycles can work.  In those cases we read every block we
3591	 * can.  Then the parity-update is certain to have enough to
3592	 * work with.
3593	 * This can only be a problem when we need to write something,
3594	 * and some device has failed.  If either of those tests
3595	 * fail we need look no further.
3596	 */
3597	if (!s->failed || !s->to_write)
3598		return 0;
3599
3600	if (test_bit(R5_Insync, &dev->flags) &&
3601	    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3602		/* Pre-reads at not permitted until after short delay
3603		 * to gather multiple requests.  However if this
3604		 * device is no Insync, the block could only be computed
3605		 * and there is no need to delay that.
3606		 */
3607		return 0;
3608
3609	for (i = 0; i < s->failed && i < 2; i++) {
3610		if (fdev[i]->towrite &&
3611		    !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3612		    !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3613			/* If we have a partial write to a failed
3614			 * device, then we will need to reconstruct
3615			 * the content of that device, so all other
3616			 * devices must be read.
3617			 */
3618			return 1;
3619
3620		if (s->failed >= 2 &&
3621		    (fdev[i]->towrite ||
3622		     s->failed_num[i] == sh->pd_idx ||
3623		     s->failed_num[i] == sh->qd_idx) &&
3624		    !test_bit(R5_UPTODATE, &fdev[i]->flags))
3625			/* In max degraded raid6, If the failed disk is P, Q,
3626			 * or we want to read the failed disk, we need to do
3627			 * reconstruct-write.
3628			 */
3629			force_rcw = true;
3630	}
3631
3632	/* If we are forced to do a reconstruct-write, because parity
3633	 * cannot be trusted and we are currently recovering it, there
3634	 * is extra need to be careful.
3635	 * If one of the devices that we would need to read, because
3636	 * it is not being overwritten (and maybe not written at all)
3637	 * is missing/faulty, then we need to read everything we can.
3638	 */
3639	if (!force_rcw &&
3640	    sh->sector < sh->raid_conf->mddev->recovery_cp)
3641		/* reconstruct-write isn't being forced */
3642		return 0;
3643	for (i = 0; i < s->failed && i < 2; i++) {
3644		if (s->failed_num[i] != sh->pd_idx &&
3645		    s->failed_num[i] != sh->qd_idx &&
3646		    !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3647		    !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3648			return 1;
3649	}
3650
3651	return 0;
3652}
3653
3654/* fetch_block - checks the given member device to see if its data needs
3655 * to be read or computed to satisfy a request.
3656 *
3657 * Returns 1 when no more member devices need to be checked, otherwise returns
3658 * 0 to tell the loop in handle_stripe_fill to continue
3659 */
3660static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3661		       int disk_idx, int disks)
3662{
3663	struct r5dev *dev = &sh->dev[disk_idx];
 
 
3664
3665	/* is the data in this block needed, and can we get it? */
3666	if (need_this_block(sh, s, disk_idx, disks)) {
 
 
 
 
 
 
 
 
 
 
3667		/* we would like to get this block, possibly by computing it,
3668		 * otherwise read it if the backing disk is insync
3669		 */
3670		BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3671		BUG_ON(test_bit(R5_Wantread, &dev->flags));
3672		BUG_ON(sh->batch_head);
3673
3674		/*
3675		 * In the raid6 case if the only non-uptodate disk is P
3676		 * then we already trusted P to compute the other failed
3677		 * drives. It is safe to compute rather than re-read P.
3678		 * In other cases we only compute blocks from failed
3679		 * devices, otherwise check/repair might fail to detect
3680		 * a real inconsistency.
3681		 */
3682
3683		if ((s->uptodate == disks - 1) &&
3684		    ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3685		    (s->failed && (disk_idx == s->failed_num[0] ||
3686				   disk_idx == s->failed_num[1])))) {
3687			/* have disk failed, and we're requested to fetch it;
3688			 * do compute it
3689			 */
3690			pr_debug("Computing stripe %llu block %d\n",
3691			       (unsigned long long)sh->sector, disk_idx);
3692			set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3693			set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3694			set_bit(R5_Wantcompute, &dev->flags);
3695			sh->ops.target = disk_idx;
3696			sh->ops.target2 = -1; /* no 2nd target */
3697			s->req_compute = 1;
3698			/* Careful: from this point on 'uptodate' is in the eye
3699			 * of raid_run_ops which services 'compute' operations
3700			 * before writes. R5_Wantcompute flags a block that will
3701			 * be R5_UPTODATE by the time it is needed for a
3702			 * subsequent operation.
3703			 */
3704			s->uptodate++;
3705			return 1;
3706		} else if (s->uptodate == disks-2 && s->failed >= 2) {
3707			/* Computing 2-failure is *very* expensive; only
3708			 * do it if failed >= 2
3709			 */
3710			int other;
3711			for (other = disks; other--; ) {
3712				if (other == disk_idx)
3713					continue;
3714				if (!test_bit(R5_UPTODATE,
3715				      &sh->dev[other].flags))
3716					break;
3717			}
3718			BUG_ON(other < 0);
3719			pr_debug("Computing stripe %llu blocks %d,%d\n",
3720			       (unsigned long long)sh->sector,
3721			       disk_idx, other);
3722			set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3723			set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3724			set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3725			set_bit(R5_Wantcompute, &sh->dev[other].flags);
3726			sh->ops.target = disk_idx;
3727			sh->ops.target2 = other;
3728			s->uptodate += 2;
3729			s->req_compute = 1;
3730			return 1;
3731		} else if (test_bit(R5_Insync, &dev->flags)) {
3732			set_bit(R5_LOCKED, &dev->flags);
3733			set_bit(R5_Wantread, &dev->flags);
3734			s->locked++;
3735			pr_debug("Reading block %d (sync=%d)\n",
3736				disk_idx, s->syncing);
3737		}
3738	}
3739
3740	return 0;
3741}
3742
3743/*
3744 * handle_stripe_fill - read or compute data to satisfy pending requests.
3745 */
3746static void handle_stripe_fill(struct stripe_head *sh,
3747			       struct stripe_head_state *s,
3748			       int disks)
3749{
3750	int i;
3751
3752	/* look for blocks to read/compute, skip this if a compute
3753	 * is already in flight, or if the stripe contents are in the
3754	 * midst of changing due to a write
3755	 */
3756	if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3757	    !sh->reconstruct_state) {
3758
3759		/*
3760		 * For degraded stripe with data in journal, do not handle
3761		 * read requests yet, instead, flush the stripe to raid
3762		 * disks first, this avoids handling complex rmw of write
3763		 * back cache (prexor with orig_page, and then xor with
3764		 * page) in the read path
3765		 */
3766		if (s->injournal && s->failed) {
3767			if (test_bit(STRIPE_R5C_CACHING, &sh->state))
3768				r5c_make_stripe_write_out(sh);
3769			goto out;
3770		}
3771
3772		for (i = disks; i--; )
3773			if (fetch_block(sh, s, i, disks))
3774				break;
3775	}
3776out:
3777	set_bit(STRIPE_HANDLE, &sh->state);
3778}
3779
3780static void break_stripe_batch_list(struct stripe_head *head_sh,
3781				    unsigned long handle_flags);
3782/* handle_stripe_clean_event
3783 * any written block on an uptodate or failed drive can be returned.
3784 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
3785 * never LOCKED, so we don't need to test 'failed' directly.
3786 */
3787static void handle_stripe_clean_event(struct r5conf *conf,
3788	struct stripe_head *sh, int disks)
3789{
3790	int i;
3791	struct r5dev *dev;
3792	int discard_pending = 0;
3793	struct stripe_head *head_sh = sh;
3794	bool do_endio = false;
3795
3796	for (i = disks; i--; )
3797		if (sh->dev[i].written) {
3798			dev = &sh->dev[i];
3799			if (!test_bit(R5_LOCKED, &dev->flags) &&
3800			    (test_bit(R5_UPTODATE, &dev->flags) ||
3801			     test_bit(R5_Discard, &dev->flags) ||
3802			     test_bit(R5_SkipCopy, &dev->flags))) {
3803				/* We can return any write requests */
3804				struct bio *wbi, *wbi2;
 
3805				pr_debug("Return write for disc %d\n", i);
3806				if (test_and_clear_bit(R5_Discard, &dev->flags))
3807					clear_bit(R5_UPTODATE, &dev->flags);
3808				if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
3809					WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
3810				}
3811				do_endio = true;
3812
3813returnbi:
3814				dev->page = dev->orig_page;
3815				wbi = dev->written;
3816				dev->written = NULL;
3817				while (wbi && wbi->bi_iter.bi_sector <
3818					dev->sector + RAID5_STRIPE_SECTORS(conf)) {
3819					wbi2 = r5_next_bio(conf, wbi, dev->sector);
3820					md_write_end(conf->mddev);
3821					bio_endio(wbi);
3822					wbi = wbi2;
3823				}
3824				md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3825						   RAID5_STRIPE_SECTORS(conf),
3826						   !test_bit(STRIPE_DEGRADED, &sh->state),
3827						   0);
3828				if (head_sh->batch_head) {
3829					sh = list_first_entry(&sh->batch_list,
3830							      struct stripe_head,
3831							      batch_list);
3832					if (sh != head_sh) {
3833						dev = &sh->dev[i];
3834						goto returnbi;
3835					}
 
3836				}
3837				sh = head_sh;
3838				dev = &sh->dev[i];
3839			} else if (test_bit(R5_Discard, &dev->flags))
3840				discard_pending = 1;
3841		}
3842
3843	log_stripe_write_finished(sh);
3844
3845	if (!discard_pending &&
3846	    test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
3847		int hash;
3848		clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
3849		clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
3850		if (sh->qd_idx >= 0) {
3851			clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
3852			clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
3853		}
3854		/* now that discard is done we can proceed with any sync */
3855		clear_bit(STRIPE_DISCARD, &sh->state);
3856		/*
3857		 * SCSI discard will change some bio fields and the stripe has
3858		 * no updated data, so remove it from hash list and the stripe
3859		 * will be reinitialized
3860		 */
3861unhash:
3862		hash = sh->hash_lock_index;
3863		spin_lock_irq(conf->hash_locks + hash);
3864		remove_hash(sh);
3865		spin_unlock_irq(conf->hash_locks + hash);
3866		if (head_sh->batch_head) {
3867			sh = list_first_entry(&sh->batch_list,
3868					      struct stripe_head, batch_list);
3869			if (sh != head_sh)
3870					goto unhash;
3871		}
3872		sh = head_sh;
3873
3874		if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
3875			set_bit(STRIPE_HANDLE, &sh->state);
3876
3877	}
3878
3879	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3880		if (atomic_dec_and_test(&conf->pending_full_writes))
3881			md_wakeup_thread(conf->mddev->thread);
3882
3883	if (head_sh->batch_head && do_endio)
3884		break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
3885}
3886
3887/*
3888 * For RMW in write back cache, we need extra page in prexor to store the
3889 * old data. This page is stored in dev->orig_page.
3890 *
3891 * This function checks whether we have data for prexor. The exact logic
3892 * is:
3893 *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
3894 */
3895static inline bool uptodate_for_rmw(struct r5dev *dev)
3896{
3897	return (test_bit(R5_UPTODATE, &dev->flags)) &&
3898		(!test_bit(R5_InJournal, &dev->flags) ||
3899		 test_bit(R5_OrigPageUPTDODATE, &dev->flags));
3900}
3901
3902static int handle_stripe_dirtying(struct r5conf *conf,
3903				  struct stripe_head *sh,
3904				  struct stripe_head_state *s,
3905				  int disks)
3906{
3907	int rmw = 0, rcw = 0, i;
3908	sector_t recovery_cp = conf->mddev->recovery_cp;
3909
3910	/* Check whether resync is now happening or should start.
3911	 * If yes, then the array is dirty (after unclean shutdown or
3912	 * initial creation), so parity in some stripes might be inconsistent.
3913	 * In this case, we need to always do reconstruct-write, to ensure
3914	 * that in case of drive failure or read-error correction, we
3915	 * generate correct data from the parity.
3916	 */
3917	if (conf->rmw_level == PARITY_DISABLE_RMW ||
3918	    (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
3919	     s->failed == 0)) {
3920		/* Calculate the real rcw later - for now make it
3921		 * look like rcw is cheaper
3922		 */
3923		rcw = 1; rmw = 2;
3924		pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
3925			 conf->rmw_level, (unsigned long long)recovery_cp,
3926			 (unsigned long long)sh->sector);
3927	} else for (i = disks; i--; ) {
3928		/* would I have to read this buffer for read_modify_write */
3929		struct r5dev *dev = &sh->dev[i];
3930		if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3931		     i == sh->pd_idx || i == sh->qd_idx ||
3932		     test_bit(R5_InJournal, &dev->flags)) &&
3933		    !test_bit(R5_LOCKED, &dev->flags) &&
3934		    !(uptodate_for_rmw(dev) ||
3935		      test_bit(R5_Wantcompute, &dev->flags))) {
3936			if (test_bit(R5_Insync, &dev->flags))
3937				rmw++;
3938			else
3939				rmw += 2*disks;  /* cannot read it */
3940		}
3941		/* Would I have to read this buffer for reconstruct_write */
3942		if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3943		    i != sh->pd_idx && i != sh->qd_idx &&
3944		    !test_bit(R5_LOCKED, &dev->flags) &&
3945		    !(test_bit(R5_UPTODATE, &dev->flags) ||
3946		      test_bit(R5_Wantcompute, &dev->flags))) {
3947			if (test_bit(R5_Insync, &dev->flags))
3948				rcw++;
3949			else
3950				rcw += 2*disks;
3951		}
3952	}
3953
3954	pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
3955		 (unsigned long long)sh->sector, sh->state, rmw, rcw);
3956	set_bit(STRIPE_HANDLE, &sh->state);
3957	if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
3958		/* prefer read-modify-write, but need to get some data */
3959		if (conf->mddev->queue)
3960			blk_add_trace_msg(conf->mddev->queue,
3961					  "raid5 rmw %llu %d",
3962					  (unsigned long long)sh->sector, rmw);
3963		for (i = disks; i--; ) {
3964			struct r5dev *dev = &sh->dev[i];
3965			if (test_bit(R5_InJournal, &dev->flags) &&
3966			    dev->page == dev->orig_page &&
3967			    !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
3968				/* alloc page for prexor */
3969				struct page *p = alloc_page(GFP_NOIO);
3970
3971				if (p) {
3972					dev->orig_page = p;
3973					continue;
3974				}
3975
3976				/*
3977				 * alloc_page() failed, try use
3978				 * disk_info->extra_page
3979				 */
3980				if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
3981						      &conf->cache_state)) {
3982					r5c_use_extra_page(sh);
3983					break;
3984				}
3985
3986				/* extra_page in use, add to delayed_list */
3987				set_bit(STRIPE_DELAYED, &sh->state);
3988				s->waiting_extra_page = 1;
3989				return -EAGAIN;
3990			}
3991		}
3992
3993		for (i = disks; i--; ) {
3994			struct r5dev *dev = &sh->dev[i];
3995			if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3996			     i == sh->pd_idx || i == sh->qd_idx ||
3997			     test_bit(R5_InJournal, &dev->flags)) &&
3998			    !test_bit(R5_LOCKED, &dev->flags) &&
3999			    !(uptodate_for_rmw(dev) ||
4000			      test_bit(R5_Wantcompute, &dev->flags)) &&
4001			    test_bit(R5_Insync, &dev->flags)) {
4002				if (test_bit(STRIPE_PREREAD_ACTIVE,
4003					     &sh->state)) {
4004					pr_debug("Read_old block %d for r-m-w\n",
4005						 i);
4006					set_bit(R5_LOCKED, &dev->flags);
4007					set_bit(R5_Wantread, &dev->flags);
4008					s->locked++;
4009				} else
4010					set_bit(STRIPE_DELAYED, &sh->state);
 
 
4011			}
4012		}
4013	}
4014	if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
4015		/* want reconstruct write, but need to get some data */
4016		int qread =0;
4017		rcw = 0;
4018		for (i = disks; i--; ) {
4019			struct r5dev *dev = &sh->dev[i];
4020			if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4021			    i != sh->pd_idx && i != sh->qd_idx &&
4022			    !test_bit(R5_LOCKED, &dev->flags) &&
4023			    !(test_bit(R5_UPTODATE, &dev->flags) ||
4024			      test_bit(R5_Wantcompute, &dev->flags))) {
4025				rcw++;
4026				if (test_bit(R5_Insync, &dev->flags) &&
4027				    test_bit(STRIPE_PREREAD_ACTIVE,
4028					     &sh->state)) {
 
4029					pr_debug("Read_old block "
4030						"%d for Reconstruct\n", i);
4031					set_bit(R5_LOCKED, &dev->flags);
4032					set_bit(R5_Wantread, &dev->flags);
4033					s->locked++;
4034					qread++;
4035				} else
4036					set_bit(STRIPE_DELAYED, &sh->state);
 
 
4037			}
4038		}
4039		if (rcw && conf->mddev->queue)
4040			blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
4041					  (unsigned long long)sh->sector,
4042					  rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
4043	}
4044
4045	if (rcw > disks && rmw > disks &&
4046	    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4047		set_bit(STRIPE_DELAYED, &sh->state);
4048
4049	/* now if nothing is locked, and if we have enough data,
4050	 * we can start a write request
4051	 */
4052	/* since handle_stripe can be called at any time we need to handle the
4053	 * case where a compute block operation has been submitted and then a
4054	 * subsequent call wants to start a write request.  raid_run_ops only
4055	 * handles the case where compute block and reconstruct are requested
4056	 * simultaneously.  If this is not the case then new writes need to be
4057	 * held off until the compute completes.
4058	 */
4059	if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4060	    (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4061	     !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4062		schedule_reconstruction(sh, s, rcw == 0, 0);
4063	return 0;
4064}
4065
4066static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4067				struct stripe_head_state *s, int disks)
4068{
4069	struct r5dev *dev = NULL;
4070
4071	BUG_ON(sh->batch_head);
4072	set_bit(STRIPE_HANDLE, &sh->state);
4073
4074	switch (sh->check_state) {
4075	case check_state_idle:
4076		/* start a new check operation if there are no failures */
4077		if (s->failed == 0) {
4078			BUG_ON(s->uptodate != disks);
4079			sh->check_state = check_state_run;
4080			set_bit(STRIPE_OP_CHECK, &s->ops_request);
4081			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4082			s->uptodate--;
4083			break;
4084		}
4085		dev = &sh->dev[s->failed_num[0]];
4086		fallthrough;
4087	case check_state_compute_result:
4088		sh->check_state = check_state_idle;
4089		if (!dev)
4090			dev = &sh->dev[sh->pd_idx];
4091
4092		/* check that a write has not made the stripe insync */
4093		if (test_bit(STRIPE_INSYNC, &sh->state))
4094			break;
4095
4096		/* either failed parity check, or recovery is happening */
4097		BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4098		BUG_ON(s->uptodate != disks);
4099
4100		set_bit(R5_LOCKED, &dev->flags);
4101		s->locked++;
4102		set_bit(R5_Wantwrite, &dev->flags);
4103
4104		clear_bit(STRIPE_DEGRADED, &sh->state);
4105		set_bit(STRIPE_INSYNC, &sh->state);
4106		break;
4107	case check_state_run:
4108		break; /* we will be called again upon completion */
4109	case check_state_check_result:
4110		sh->check_state = check_state_idle;
4111
4112		/* if a failure occurred during the check operation, leave
4113		 * STRIPE_INSYNC not set and let the stripe be handled again
4114		 */
4115		if (s->failed)
4116			break;
4117
4118		/* handle a successful check operation, if parity is correct
4119		 * we are done.  Otherwise update the mismatch count and repair
4120		 * parity if !MD_RECOVERY_CHECK
4121		 */
4122		if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4123			/* parity is correct (on disc,
4124			 * not in buffer any more)
4125			 */
4126			set_bit(STRIPE_INSYNC, &sh->state);
4127		else {
4128			atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4129			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4130				/* don't try to repair!! */
4131				set_bit(STRIPE_INSYNC, &sh->state);
4132				pr_warn_ratelimited("%s: mismatch sector in range "
4133						    "%llu-%llu\n", mdname(conf->mddev),
4134						    (unsigned long long) sh->sector,
4135						    (unsigned long long) sh->sector +
4136						    RAID5_STRIPE_SECTORS(conf));
4137			} else {
4138				sh->check_state = check_state_compute_run;
4139				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4140				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4141				set_bit(R5_Wantcompute,
4142					&sh->dev[sh->pd_idx].flags);
4143				sh->ops.target = sh->pd_idx;
4144				sh->ops.target2 = -1;
4145				s->uptodate++;
4146			}
4147		}
4148		break;
4149	case check_state_compute_run:
4150		break;
4151	default:
4152		pr_err("%s: unknown check_state: %d sector: %llu\n",
4153		       __func__, sh->check_state,
4154		       (unsigned long long) sh->sector);
4155		BUG();
4156	}
4157}
4158
 
4159static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4160				  struct stripe_head_state *s,
4161				  int disks)
4162{
4163	int pd_idx = sh->pd_idx;
4164	int qd_idx = sh->qd_idx;
4165	struct r5dev *dev;
4166
4167	BUG_ON(sh->batch_head);
4168	set_bit(STRIPE_HANDLE, &sh->state);
4169
4170	BUG_ON(s->failed > 2);
4171
4172	/* Want to check and possibly repair P and Q.
4173	 * However there could be one 'failed' device, in which
4174	 * case we can only check one of them, possibly using the
4175	 * other to generate missing data
4176	 */
4177
4178	switch (sh->check_state) {
4179	case check_state_idle:
4180		/* start a new check operation if there are < 2 failures */
4181		if (s->failed == s->q_failed) {
4182			/* The only possible failed device holds Q, so it
4183			 * makes sense to check P (If anything else were failed,
4184			 * we would have used P to recreate it).
4185			 */
4186			sh->check_state = check_state_run;
4187		}
4188		if (!s->q_failed && s->failed < 2) {
4189			/* Q is not failed, and we didn't use it to generate
4190			 * anything, so it makes sense to check it
4191			 */
4192			if (sh->check_state == check_state_run)
4193				sh->check_state = check_state_run_pq;
4194			else
4195				sh->check_state = check_state_run_q;
4196		}
4197
4198		/* discard potentially stale zero_sum_result */
4199		sh->ops.zero_sum_result = 0;
4200
4201		if (sh->check_state == check_state_run) {
4202			/* async_xor_zero_sum destroys the contents of P */
4203			clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4204			s->uptodate--;
4205		}
4206		if (sh->check_state >= check_state_run &&
4207		    sh->check_state <= check_state_run_pq) {
4208			/* async_syndrome_zero_sum preserves P and Q, so
4209			 * no need to mark them !uptodate here
4210			 */
4211			set_bit(STRIPE_OP_CHECK, &s->ops_request);
4212			break;
4213		}
4214
4215		/* we have 2-disk failure */
4216		BUG_ON(s->failed != 2);
4217		fallthrough;
4218	case check_state_compute_result:
4219		sh->check_state = check_state_idle;
4220
4221		/* check that a write has not made the stripe insync */
4222		if (test_bit(STRIPE_INSYNC, &sh->state))
4223			break;
4224
4225		/* now write out any block on a failed drive,
4226		 * or P or Q if they were recomputed
4227		 */
4228		dev = NULL;
4229		if (s->failed == 2) {
4230			dev = &sh->dev[s->failed_num[1]];
4231			s->locked++;
4232			set_bit(R5_LOCKED, &dev->flags);
4233			set_bit(R5_Wantwrite, &dev->flags);
4234		}
4235		if (s->failed >= 1) {
4236			dev = &sh->dev[s->failed_num[0]];
4237			s->locked++;
4238			set_bit(R5_LOCKED, &dev->flags);
4239			set_bit(R5_Wantwrite, &dev->flags);
4240		}
4241		if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4242			dev = &sh->dev[pd_idx];
4243			s->locked++;
4244			set_bit(R5_LOCKED, &dev->flags);
4245			set_bit(R5_Wantwrite, &dev->flags);
4246		}
4247		if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4248			dev = &sh->dev[qd_idx];
4249			s->locked++;
4250			set_bit(R5_LOCKED, &dev->flags);
4251			set_bit(R5_Wantwrite, &dev->flags);
4252		}
4253		if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4254			      "%s: disk%td not up to date\n",
4255			      mdname(conf->mddev),
4256			      dev - (struct r5dev *) &sh->dev)) {
4257			clear_bit(R5_LOCKED, &dev->flags);
4258			clear_bit(R5_Wantwrite, &dev->flags);
4259			s->locked--;
4260		}
4261		clear_bit(STRIPE_DEGRADED, &sh->state);
4262
4263		set_bit(STRIPE_INSYNC, &sh->state);
4264		break;
4265	case check_state_run:
4266	case check_state_run_q:
4267	case check_state_run_pq:
4268		break; /* we will be called again upon completion */
4269	case check_state_check_result:
4270		sh->check_state = check_state_idle;
4271
4272		/* handle a successful check operation, if parity is correct
4273		 * we are done.  Otherwise update the mismatch count and repair
4274		 * parity if !MD_RECOVERY_CHECK
4275		 */
4276		if (sh->ops.zero_sum_result == 0) {
4277			/* both parities are correct */
4278			if (!s->failed)
4279				set_bit(STRIPE_INSYNC, &sh->state);
4280			else {
4281				/* in contrast to the raid5 case we can validate
4282				 * parity, but still have a failure to write
4283				 * back
4284				 */
4285				sh->check_state = check_state_compute_result;
4286				/* Returning at this point means that we may go
4287				 * off and bring p and/or q uptodate again so
4288				 * we make sure to check zero_sum_result again
4289				 * to verify if p or q need writeback
4290				 */
4291			}
4292		} else {
4293			atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4294			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4295				/* don't try to repair!! */
4296				set_bit(STRIPE_INSYNC, &sh->state);
4297				pr_warn_ratelimited("%s: mismatch sector in range "
4298						    "%llu-%llu\n", mdname(conf->mddev),
4299						    (unsigned long long) sh->sector,
4300						    (unsigned long long) sh->sector +
4301						    RAID5_STRIPE_SECTORS(conf));
4302			} else {
4303				int *target = &sh->ops.target;
4304
4305				sh->ops.target = -1;
4306				sh->ops.target2 = -1;
4307				sh->check_state = check_state_compute_run;
4308				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4309				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4310				if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4311					set_bit(R5_Wantcompute,
4312						&sh->dev[pd_idx].flags);
4313					*target = pd_idx;
4314					target = &sh->ops.target2;
4315					s->uptodate++;
4316				}
4317				if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4318					set_bit(R5_Wantcompute,
4319						&sh->dev[qd_idx].flags);
4320					*target = qd_idx;
4321					s->uptodate++;
4322				}
4323			}
4324		}
4325		break;
4326	case check_state_compute_run:
4327		break;
4328	default:
4329		pr_warn("%s: unknown check_state: %d sector: %llu\n",
4330			__func__, sh->check_state,
4331			(unsigned long long) sh->sector);
4332		BUG();
4333	}
4334}
4335
4336static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4337{
4338	int i;
4339
4340	/* We have read all the blocks in this stripe and now we need to
4341	 * copy some of them into a target stripe for expand.
4342	 */
4343	struct dma_async_tx_descriptor *tx = NULL;
4344	BUG_ON(sh->batch_head);
4345	clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4346	for (i = 0; i < sh->disks; i++)
4347		if (i != sh->pd_idx && i != sh->qd_idx) {
4348			int dd_idx, j;
4349			struct stripe_head *sh2;
4350			struct async_submit_ctl submit;
4351
4352			sector_t bn = raid5_compute_blocknr(sh, i, 1);
4353			sector_t s = raid5_compute_sector(conf, bn, 0,
4354							  &dd_idx, NULL);
4355			sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4356			if (sh2 == NULL)
4357				/* so far only the early blocks of this stripe
4358				 * have been requested.  When later blocks
4359				 * get requested, we will try again
4360				 */
4361				continue;
4362			if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4363			   test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4364				/* must have already done this block */
4365				raid5_release_stripe(sh2);
4366				continue;
4367			}
4368
4369			/* place all the copies on one channel */
4370			init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4371			tx = async_memcpy(sh2->dev[dd_idx].page,
4372					  sh->dev[i].page, 0, 0, RAID5_STRIPE_SIZE(conf),
4373					  &submit);
4374
4375			set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4376			set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4377			for (j = 0; j < conf->raid_disks; j++)
4378				if (j != sh2->pd_idx &&
4379				    j != sh2->qd_idx &&
4380				    !test_bit(R5_Expanded, &sh2->dev[j].flags))
4381					break;
4382			if (j == conf->raid_disks) {
4383				set_bit(STRIPE_EXPAND_READY, &sh2->state);
4384				set_bit(STRIPE_HANDLE, &sh2->state);
4385			}
4386			raid5_release_stripe(sh2);
4387
4388		}
4389	/* done submitting copies, wait for them to complete */
4390	async_tx_quiesce(&tx);
 
 
 
4391}
4392
4393/*
4394 * handle_stripe - do things to a stripe.
4395 *
4396 * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4397 * state of various bits to see what needs to be done.
4398 * Possible results:
4399 *    return some read requests which now have data
4400 *    return some write requests which are safely on storage
4401 *    schedule a read on some buffers
4402 *    schedule a write of some buffers
4403 *    return confirmation of parity correctness
4404 *
4405 */
4406
4407static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4408{
4409	struct r5conf *conf = sh->raid_conf;
4410	int disks = sh->disks;
4411	struct r5dev *dev;
4412	int i;
4413	int do_recovery = 0;
4414
4415	memset(s, 0, sizeof(*s));
4416
4417	s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4418	s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4419	s->failed_num[0] = -1;
4420	s->failed_num[1] = -1;
4421	s->log_failed = r5l_log_disk_error(conf);
4422
4423	/* Now to look around and see what can be done */
4424	rcu_read_lock();
 
4425	for (i=disks; i--; ) {
4426		struct md_rdev *rdev;
4427		sector_t first_bad;
4428		int bad_sectors;
4429		int is_bad = 0;
4430
4431		dev = &sh->dev[i];
4432
4433		pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4434			 i, dev->flags,
4435			 dev->toread, dev->towrite, dev->written);
4436		/* maybe we can reply to a read
4437		 *
4438		 * new wantfill requests are only permitted while
4439		 * ops_complete_biofill is guaranteed to be inactive
4440		 */
4441		if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4442		    !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4443			set_bit(R5_Wantfill, &dev->flags);
4444
4445		/* now count some things */
4446		if (test_bit(R5_LOCKED, &dev->flags))
4447			s->locked++;
4448		if (test_bit(R5_UPTODATE, &dev->flags))
4449			s->uptodate++;
4450		if (test_bit(R5_Wantcompute, &dev->flags)) {
4451			s->compute++;
4452			BUG_ON(s->compute > 2);
4453		}
4454
4455		if (test_bit(R5_Wantfill, &dev->flags))
4456			s->to_fill++;
4457		else if (dev->toread)
4458			s->to_read++;
4459		if (dev->towrite) {
4460			s->to_write++;
4461			if (!test_bit(R5_OVERWRITE, &dev->flags))
4462				s->non_overwrite++;
4463		}
4464		if (dev->written)
4465			s->written++;
4466		/* Prefer to use the replacement for reads, but only
4467		 * if it is recovered enough and has no bad blocks.
4468		 */
4469		rdev = rcu_dereference(conf->disks[i].replacement);
4470		if (rdev && !test_bit(Faulty, &rdev->flags) &&
4471		    rdev->recovery_offset >= sh->sector + RAID5_STRIPE_SECTORS(conf) &&
4472		    !is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
4473				 &first_bad, &bad_sectors))
4474			set_bit(R5_ReadRepl, &dev->flags);
4475		else {
4476			if (rdev && !test_bit(Faulty, &rdev->flags))
4477				set_bit(R5_NeedReplace, &dev->flags);
4478			else
4479				clear_bit(R5_NeedReplace, &dev->flags);
4480			rdev = rcu_dereference(conf->disks[i].rdev);
4481			clear_bit(R5_ReadRepl, &dev->flags);
4482		}
4483		if (rdev && test_bit(Faulty, &rdev->flags))
4484			rdev = NULL;
4485		if (rdev) {
4486			is_bad = is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
4487					     &first_bad, &bad_sectors);
4488			if (s->blocked_rdev == NULL
4489			    && (test_bit(Blocked, &rdev->flags)
4490				|| is_bad < 0)) {
4491				if (is_bad < 0)
4492					set_bit(BlockedBadBlocks,
4493						&rdev->flags);
4494				s->blocked_rdev = rdev;
4495				atomic_inc(&rdev->nr_pending);
4496			}
4497		}
4498		clear_bit(R5_Insync, &dev->flags);
4499		if (!rdev)
4500			/* Not in-sync */;
4501		else if (is_bad) {
4502			/* also not in-sync */
4503			if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4504			    test_bit(R5_UPTODATE, &dev->flags)) {
4505				/* treat as in-sync, but with a read error
4506				 * which we can now try to correct
4507				 */
4508				set_bit(R5_Insync, &dev->flags);
4509				set_bit(R5_ReadError, &dev->flags);
4510			}
4511		} else if (test_bit(In_sync, &rdev->flags))
4512			set_bit(R5_Insync, &dev->flags);
4513		else if (sh->sector + RAID5_STRIPE_SECTORS(conf) <= rdev->recovery_offset)
4514			/* in sync if before recovery_offset */
4515			set_bit(R5_Insync, &dev->flags);
4516		else if (test_bit(R5_UPTODATE, &dev->flags) &&
4517			 test_bit(R5_Expanded, &dev->flags))
4518			/* If we've reshaped into here, we assume it is Insync.
4519			 * We will shortly update recovery_offset to make
4520			 * it official.
4521			 */
4522			set_bit(R5_Insync, &dev->flags);
4523
4524		if (test_bit(R5_WriteError, &dev->flags)) {
4525			/* This flag does not apply to '.replacement'
4526			 * only to .rdev, so make sure to check that*/
4527			struct md_rdev *rdev2 = rcu_dereference(
4528				conf->disks[i].rdev);
4529			if (rdev2 == rdev)
4530				clear_bit(R5_Insync, &dev->flags);
4531			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4532				s->handle_bad_blocks = 1;
4533				atomic_inc(&rdev2->nr_pending);
4534			} else
4535				clear_bit(R5_WriteError, &dev->flags);
4536		}
4537		if (test_bit(R5_MadeGood, &dev->flags)) {
4538			/* This flag does not apply to '.replacement'
4539			 * only to .rdev, so make sure to check that*/
4540			struct md_rdev *rdev2 = rcu_dereference(
4541				conf->disks[i].rdev);
4542			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4543				s->handle_bad_blocks = 1;
4544				atomic_inc(&rdev2->nr_pending);
4545			} else
4546				clear_bit(R5_MadeGood, &dev->flags);
4547		}
4548		if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4549			struct md_rdev *rdev2 = rcu_dereference(
4550				conf->disks[i].replacement);
4551			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4552				s->handle_bad_blocks = 1;
4553				atomic_inc(&rdev2->nr_pending);
4554			} else
4555				clear_bit(R5_MadeGoodRepl, &dev->flags);
4556		}
4557		if (!test_bit(R5_Insync, &dev->flags)) {
4558			/* The ReadError flag will just be confusing now */
4559			clear_bit(R5_ReadError, &dev->flags);
4560			clear_bit(R5_ReWrite, &dev->flags);
4561		}
4562		if (test_bit(R5_ReadError, &dev->flags))
4563			clear_bit(R5_Insync, &dev->flags);
4564		if (!test_bit(R5_Insync, &dev->flags)) {
4565			if (s->failed < 2)
4566				s->failed_num[s->failed] = i;
4567			s->failed++;
4568			if (rdev && !test_bit(Faulty, &rdev->flags))
4569				do_recovery = 1;
4570			else if (!rdev) {
4571				rdev = rcu_dereference(
4572				    conf->disks[i].replacement);
4573				if (rdev && !test_bit(Faulty, &rdev->flags))
4574					do_recovery = 1;
4575			}
4576		}
4577
4578		if (test_bit(R5_InJournal, &dev->flags))
4579			s->injournal++;
4580		if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4581			s->just_cached++;
4582	}
 
4583	if (test_bit(STRIPE_SYNCING, &sh->state)) {
4584		/* If there is a failed device being replaced,
4585		 *     we must be recovering.
4586		 * else if we are after recovery_cp, we must be syncing
4587		 * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4588		 * else we can only be replacing
4589		 * sync and recovery both need to read all devices, and so
4590		 * use the same flag.
4591		 */
4592		if (do_recovery ||
4593		    sh->sector >= conf->mddev->recovery_cp ||
4594		    test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4595			s->syncing = 1;
4596		else
4597			s->replacing = 1;
4598	}
4599	rcu_read_unlock();
4600}
4601
4602/*
4603 * Return '1' if this is a member of batch, or '0' if it is a lone stripe or
4604 * a head which can now be handled.
4605 */
4606static int clear_batch_ready(struct stripe_head *sh)
4607{
4608	struct stripe_head *tmp;
4609	if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4610		return (sh->batch_head && sh->batch_head != sh);
4611	spin_lock(&sh->stripe_lock);
4612	if (!sh->batch_head) {
4613		spin_unlock(&sh->stripe_lock);
4614		return 0;
4615	}
4616
4617	/*
4618	 * this stripe could be added to a batch list before we check
4619	 * BATCH_READY, skips it
4620	 */
4621	if (sh->batch_head != sh) {
4622		spin_unlock(&sh->stripe_lock);
4623		return 1;
4624	}
4625	spin_lock(&sh->batch_lock);
4626	list_for_each_entry(tmp, &sh->batch_list, batch_list)
4627		clear_bit(STRIPE_BATCH_READY, &tmp->state);
4628	spin_unlock(&sh->batch_lock);
4629	spin_unlock(&sh->stripe_lock);
4630
4631	/*
4632	 * BATCH_READY is cleared, no new stripes can be added.
4633	 * batch_list can be accessed without lock
4634	 */
4635	return 0;
4636}
4637
4638static void break_stripe_batch_list(struct stripe_head *head_sh,
4639				    unsigned long handle_flags)
4640{
4641	struct stripe_head *sh, *next;
4642	int i;
4643	int do_wakeup = 0;
4644
4645	list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4646
4647		list_del_init(&sh->batch_list);
4648
4649		WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4650					  (1 << STRIPE_SYNCING) |
4651					  (1 << STRIPE_REPLACED) |
4652					  (1 << STRIPE_DELAYED) |
4653					  (1 << STRIPE_BIT_DELAY) |
4654					  (1 << STRIPE_FULL_WRITE) |
4655					  (1 << STRIPE_BIOFILL_RUN) |
4656					  (1 << STRIPE_COMPUTE_RUN)  |
4657					  (1 << STRIPE_DISCARD) |
4658					  (1 << STRIPE_BATCH_READY) |
4659					  (1 << STRIPE_BATCH_ERR) |
4660					  (1 << STRIPE_BITMAP_PENDING)),
4661			"stripe state: %lx\n", sh->state);
4662		WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4663					      (1 << STRIPE_REPLACED)),
4664			"head stripe state: %lx\n", head_sh->state);
4665
4666		set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4667					    (1 << STRIPE_PREREAD_ACTIVE) |
4668					    (1 << STRIPE_DEGRADED) |
4669					    (1 << STRIPE_ON_UNPLUG_LIST)),
4670			      head_sh->state & (1 << STRIPE_INSYNC));
4671
4672		sh->check_state = head_sh->check_state;
4673		sh->reconstruct_state = head_sh->reconstruct_state;
4674		spin_lock_irq(&sh->stripe_lock);
4675		sh->batch_head = NULL;
4676		spin_unlock_irq(&sh->stripe_lock);
4677		for (i = 0; i < sh->disks; i++) {
4678			if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4679				do_wakeup = 1;
4680			sh->dev[i].flags = head_sh->dev[i].flags &
4681				(~((1 << R5_WriteError) | (1 << R5_Overlap)));
4682		}
4683		if (handle_flags == 0 ||
4684		    sh->state & handle_flags)
4685			set_bit(STRIPE_HANDLE, &sh->state);
4686		raid5_release_stripe(sh);
4687	}
4688	spin_lock_irq(&head_sh->stripe_lock);
4689	head_sh->batch_head = NULL;
4690	spin_unlock_irq(&head_sh->stripe_lock);
4691	for (i = 0; i < head_sh->disks; i++)
4692		if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4693			do_wakeup = 1;
4694	if (head_sh->state & handle_flags)
4695		set_bit(STRIPE_HANDLE, &head_sh->state);
4696
4697	if (do_wakeup)
4698		wake_up(&head_sh->raid_conf->wait_for_overlap);
4699}
4700
4701static void handle_stripe(struct stripe_head *sh)
4702{
4703	struct stripe_head_state s;
4704	struct r5conf *conf = sh->raid_conf;
4705	int i;
4706	int prexor;
4707	int disks = sh->disks;
4708	struct r5dev *pdev, *qdev;
4709
4710	clear_bit(STRIPE_HANDLE, &sh->state);
4711
4712	/*
4713	 * handle_stripe should not continue handle the batched stripe, only
4714	 * the head of batch list or lone stripe can continue. Otherwise we
4715	 * could see break_stripe_batch_list warns about the STRIPE_ACTIVE
4716	 * is set for the batched stripe.
4717	 */
4718	if (clear_batch_ready(sh))
4719		return;
4720
4721	if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4722		/* already being handled, ensure it gets handled
4723		 * again when current action finishes */
4724		set_bit(STRIPE_HANDLE, &sh->state);
4725		return;
4726	}
4727
4728	if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4729		break_stripe_batch_list(sh, 0);
4730
4731	if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4732		spin_lock(&sh->stripe_lock);
4733		/*
4734		 * Cannot process 'sync' concurrently with 'discard'.
4735		 * Flush data in r5cache before 'sync'.
4736		 */
4737		if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
4738		    !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
4739		    !test_bit(STRIPE_DISCARD, &sh->state) &&
4740		    test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4741			set_bit(STRIPE_SYNCING, &sh->state);
4742			clear_bit(STRIPE_INSYNC, &sh->state);
4743			clear_bit(STRIPE_REPLACED, &sh->state);
4744		}
4745		spin_unlock(&sh->stripe_lock);
4746	}
4747	clear_bit(STRIPE_DELAYED, &sh->state);
4748
4749	pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4750		"pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4751	       (unsigned long long)sh->sector, sh->state,
4752	       atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4753	       sh->check_state, sh->reconstruct_state);
4754
4755	analyse_stripe(sh, &s);
4756
4757	if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4758		goto finish;
4759
4760	if (s.handle_bad_blocks ||
4761	    test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4762		set_bit(STRIPE_HANDLE, &sh->state);
4763		goto finish;
4764	}
4765
4766	if (unlikely(s.blocked_rdev)) {
4767		if (s.syncing || s.expanding || s.expanded ||
4768		    s.replacing || s.to_write || s.written) {
4769			set_bit(STRIPE_HANDLE, &sh->state);
4770			goto finish;
4771		}
4772		/* There is nothing for the blocked_rdev to block */
4773		rdev_dec_pending(s.blocked_rdev, conf->mddev);
4774		s.blocked_rdev = NULL;
4775	}
4776
4777	if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
4778		set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
4779		set_bit(STRIPE_BIOFILL_RUN, &sh->state);
4780	}
4781
4782	pr_debug("locked=%d uptodate=%d to_read=%d"
4783	       " to_write=%d failed=%d failed_num=%d,%d\n",
4784	       s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
4785	       s.failed_num[0], s.failed_num[1]);
4786	/*
4787	 * check if the array has lost more than max_degraded devices and,
4788	 * if so, some requests might need to be failed.
4789	 *
4790	 * When journal device failed (log_failed), we will only process
4791	 * the stripe if there is data need write to raid disks
4792	 */
4793	if (s.failed > conf->max_degraded ||
4794	    (s.log_failed && s.injournal == 0)) {
4795		sh->check_state = 0;
4796		sh->reconstruct_state = 0;
4797		break_stripe_batch_list(sh, 0);
4798		if (s.to_read+s.to_write+s.written)
4799			handle_failed_stripe(conf, sh, &s, disks);
4800		if (s.syncing + s.replacing)
4801			handle_failed_sync(conf, sh, &s);
4802	}
4803
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4804	/* Now we check to see if any write operations have recently
4805	 * completed
4806	 */
4807	prexor = 0;
4808	if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
4809		prexor = 1;
4810	if (sh->reconstruct_state == reconstruct_state_drain_result ||
4811	    sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
4812		sh->reconstruct_state = reconstruct_state_idle;
4813
4814		/* All the 'written' buffers and the parity block are ready to
4815		 * be written back to disk
4816		 */
4817		BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
4818		       !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
4819		BUG_ON(sh->qd_idx >= 0 &&
4820		       !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
4821		       !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
4822		for (i = disks; i--; ) {
4823			struct r5dev *dev = &sh->dev[i];
4824			if (test_bit(R5_LOCKED, &dev->flags) &&
4825				(i == sh->pd_idx || i == sh->qd_idx ||
4826				 dev->written || test_bit(R5_InJournal,
4827							  &dev->flags))) {
4828				pr_debug("Writing block %d\n", i);
4829				set_bit(R5_Wantwrite, &dev->flags);
4830				if (prexor)
4831					continue;
4832				if (s.failed > 1)
4833					continue;
4834				if (!test_bit(R5_Insync, &dev->flags) ||
4835				    ((i == sh->pd_idx || i == sh->qd_idx)  &&
4836				     s.failed == 0))
4837					set_bit(STRIPE_INSYNC, &sh->state);
4838			}
4839		}
4840		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4841			s.dec_preread_active = 1;
4842	}
4843
4844	/*
4845	 * might be able to return some write requests if the parity blocks
4846	 * are safe, or on a failed drive
4847	 */
4848	pdev = &sh->dev[sh->pd_idx];
4849	s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
4850		|| (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
4851	qdev = &sh->dev[sh->qd_idx];
4852	s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
4853		|| (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
4854		|| conf->level < 6;
4855
4856	if (s.written &&
4857	    (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
4858			     && !test_bit(R5_LOCKED, &pdev->flags)
4859			     && (test_bit(R5_UPTODATE, &pdev->flags) ||
4860				 test_bit(R5_Discard, &pdev->flags))))) &&
4861	    (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
4862			     && !test_bit(R5_LOCKED, &qdev->flags)
4863			     && (test_bit(R5_UPTODATE, &qdev->flags) ||
4864				 test_bit(R5_Discard, &qdev->flags))))))
4865		handle_stripe_clean_event(conf, sh, disks);
4866
4867	if (s.just_cached)
4868		r5c_handle_cached_data_endio(conf, sh, disks);
4869	log_stripe_write_finished(sh);
4870
4871	/* Now we might consider reading some blocks, either to check/generate
4872	 * parity, or to satisfy requests
4873	 * or to load a block that is being partially written.
4874	 */
4875	if (s.to_read || s.non_overwrite
4876	    || (s.to_write && s.failed)
4877	    || (s.syncing && (s.uptodate + s.compute < disks))
4878	    || s.replacing
4879	    || s.expanding)
4880		handle_stripe_fill(sh, &s, disks);
4881
4882	/*
4883	 * When the stripe finishes full journal write cycle (write to journal
4884	 * and raid disk), this is the clean up procedure so it is ready for
4885	 * next operation.
4886	 */
4887	r5c_finish_stripe_write_out(conf, sh, &s);
4888
4889	/*
4890	 * Now to consider new write requests, cache write back and what else,
4891	 * if anything should be read.  We do not handle new writes when:
4892	 * 1/ A 'write' operation (copy+xor) is already in flight.
4893	 * 2/ A 'check' operation is in flight, as it may clobber the parity
4894	 *    block.
4895	 * 3/ A r5c cache log write is in flight.
4896	 */
4897
4898	if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
4899		if (!r5c_is_writeback(conf->log)) {
4900			if (s.to_write)
4901				handle_stripe_dirtying(conf, sh, &s, disks);
4902		} else { /* write back cache */
4903			int ret = 0;
4904
4905			/* First, try handle writes in caching phase */
4906			if (s.to_write)
4907				ret = r5c_try_caching_write(conf, sh, &s,
4908							    disks);
4909			/*
4910			 * If caching phase failed: ret == -EAGAIN
4911			 *    OR
4912			 * stripe under reclaim: !caching && injournal
4913			 *
4914			 * fall back to handle_stripe_dirtying()
4915			 */
4916			if (ret == -EAGAIN ||
4917			    /* stripe under reclaim: !caching && injournal */
4918			    (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
4919			     s.injournal > 0)) {
4920				ret = handle_stripe_dirtying(conf, sh, &s,
4921							     disks);
4922				if (ret == -EAGAIN)
4923					goto finish;
4924			}
4925		}
4926	}
4927
4928	/* maybe we need to check and possibly fix the parity for this stripe
4929	 * Any reads will already have been scheduled, so we just see if enough
4930	 * data is available.  The parity check is held off while parity
4931	 * dependent operations are in flight.
4932	 */
4933	if (sh->check_state ||
4934	    (s.syncing && s.locked == 0 &&
4935	     !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4936	     !test_bit(STRIPE_INSYNC, &sh->state))) {
4937		if (conf->level == 6)
4938			handle_parity_checks6(conf, sh, &s, disks);
4939		else
4940			handle_parity_checks5(conf, sh, &s, disks);
4941	}
4942
4943	if ((s.replacing || s.syncing) && s.locked == 0
4944	    && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
4945	    && !test_bit(STRIPE_REPLACED, &sh->state)) {
4946		/* Write out to replacement devices where possible */
4947		for (i = 0; i < conf->raid_disks; i++)
4948			if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
4949				WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
4950				set_bit(R5_WantReplace, &sh->dev[i].flags);
4951				set_bit(R5_LOCKED, &sh->dev[i].flags);
4952				s.locked++;
4953			}
4954		if (s.replacing)
4955			set_bit(STRIPE_INSYNC, &sh->state);
4956		set_bit(STRIPE_REPLACED, &sh->state);
4957	}
4958	if ((s.syncing || s.replacing) && s.locked == 0 &&
4959	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4960	    test_bit(STRIPE_INSYNC, &sh->state)) {
4961		md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
4962		clear_bit(STRIPE_SYNCING, &sh->state);
4963		if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
4964			wake_up(&conf->wait_for_overlap);
4965	}
4966
4967	/* If the failed drives are just a ReadError, then we might need
4968	 * to progress the repair/check process
4969	 */
4970	if (s.failed <= conf->max_degraded && !conf->mddev->ro)
4971		for (i = 0; i < s.failed; i++) {
4972			struct r5dev *dev = &sh->dev[s.failed_num[i]];
4973			if (test_bit(R5_ReadError, &dev->flags)
4974			    && !test_bit(R5_LOCKED, &dev->flags)
4975			    && test_bit(R5_UPTODATE, &dev->flags)
4976				) {
4977				if (!test_bit(R5_ReWrite, &dev->flags)) {
4978					set_bit(R5_Wantwrite, &dev->flags);
4979					set_bit(R5_ReWrite, &dev->flags);
4980				} else
 
 
4981					/* let's read it back */
4982					set_bit(R5_Wantread, &dev->flags);
4983				set_bit(R5_LOCKED, &dev->flags);
4984				s.locked++;
 
4985			}
4986		}
4987
 
4988	/* Finish reconstruct operations initiated by the expansion process */
4989	if (sh->reconstruct_state == reconstruct_state_result) {
4990		struct stripe_head *sh_src
4991			= raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
4992		if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
4993			/* sh cannot be written until sh_src has been read.
4994			 * so arrange for sh to be delayed a little
4995			 */
4996			set_bit(STRIPE_DELAYED, &sh->state);
4997			set_bit(STRIPE_HANDLE, &sh->state);
4998			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
4999					      &sh_src->state))
5000				atomic_inc(&conf->preread_active_stripes);
5001			raid5_release_stripe(sh_src);
5002			goto finish;
5003		}
5004		if (sh_src)
5005			raid5_release_stripe(sh_src);
5006
5007		sh->reconstruct_state = reconstruct_state_idle;
5008		clear_bit(STRIPE_EXPANDING, &sh->state);
5009		for (i = conf->raid_disks; i--; ) {
5010			set_bit(R5_Wantwrite, &sh->dev[i].flags);
5011			set_bit(R5_LOCKED, &sh->dev[i].flags);
5012			s.locked++;
5013		}
5014	}
5015
5016	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
5017	    !sh->reconstruct_state) {
5018		/* Need to write out all blocks after computing parity */
5019		sh->disks = conf->raid_disks;
5020		stripe_set_idx(sh->sector, conf, 0, sh);
5021		schedule_reconstruction(sh, &s, 1, 1);
5022	} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
5023		clear_bit(STRIPE_EXPAND_READY, &sh->state);
5024		atomic_dec(&conf->reshape_stripes);
5025		wake_up(&conf->wait_for_overlap);
5026		md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5027	}
5028
5029	if (s.expanding && s.locked == 0 &&
5030	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
5031		handle_stripe_expansion(conf, sh);
5032
5033finish:
5034	/* wait for this device to become unblocked */
5035	if (unlikely(s.blocked_rdev)) {
5036		if (conf->mddev->external)
5037			md_wait_for_blocked_rdev(s.blocked_rdev,
5038						 conf->mddev);
5039		else
5040			/* Internal metadata will immediately
5041			 * be written by raid5d, so we don't
5042			 * need to wait here.
5043			 */
5044			rdev_dec_pending(s.blocked_rdev,
5045					 conf->mddev);
5046	}
5047
5048	if (s.handle_bad_blocks)
5049		for (i = disks; i--; ) {
5050			struct md_rdev *rdev;
5051			struct r5dev *dev = &sh->dev[i];
5052			if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5053				/* We own a safe reference to the rdev */
5054				rdev = conf->disks[i].rdev;
5055				if (!rdev_set_badblocks(rdev, sh->sector,
5056							RAID5_STRIPE_SECTORS(conf), 0))
5057					md_error(conf->mddev, rdev);
5058				rdev_dec_pending(rdev, conf->mddev);
5059			}
5060			if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5061				rdev = conf->disks[i].rdev;
5062				rdev_clear_badblocks(rdev, sh->sector,
5063						     RAID5_STRIPE_SECTORS(conf), 0);
5064				rdev_dec_pending(rdev, conf->mddev);
5065			}
5066			if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5067				rdev = conf->disks[i].replacement;
5068				if (!rdev)
5069					/* rdev have been moved down */
5070					rdev = conf->disks[i].rdev;
5071				rdev_clear_badblocks(rdev, sh->sector,
5072						     RAID5_STRIPE_SECTORS(conf), 0);
5073				rdev_dec_pending(rdev, conf->mddev);
5074			}
5075		}
5076
5077	if (s.ops_request)
5078		raid_run_ops(sh, s.ops_request);
5079
5080	ops_run_io(sh, &s);
5081
5082	if (s.dec_preread_active) {
5083		/* We delay this until after ops_run_io so that if make_request
5084		 * is waiting on a flush, it won't continue until the writes
5085		 * have actually been submitted.
5086		 */
5087		atomic_dec(&conf->preread_active_stripes);
5088		if (atomic_read(&conf->preread_active_stripes) <
5089		    IO_THRESHOLD)
5090			md_wakeup_thread(conf->mddev->thread);
5091	}
5092
 
 
5093	clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5094}
5095
5096static void raid5_activate_delayed(struct r5conf *conf)
5097{
5098	if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5099		while (!list_empty(&conf->delayed_list)) {
5100			struct list_head *l = conf->delayed_list.next;
5101			struct stripe_head *sh;
5102			sh = list_entry(l, struct stripe_head, lru);
5103			list_del_init(l);
5104			clear_bit(STRIPE_DELAYED, &sh->state);
5105			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5106				atomic_inc(&conf->preread_active_stripes);
5107			list_add_tail(&sh->lru, &conf->hold_list);
5108			raid5_wakeup_stripe_thread(sh);
5109		}
5110	}
5111}
5112
5113static void activate_bit_delay(struct r5conf *conf,
5114	struct list_head *temp_inactive_list)
5115{
5116	/* device_lock is held */
5117	struct list_head head;
5118	list_add(&head, &conf->bitmap_list);
5119	list_del_init(&conf->bitmap_list);
5120	while (!list_empty(&head)) {
5121		struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5122		int hash;
5123		list_del_init(&sh->lru);
5124		atomic_inc(&sh->count);
5125		hash = sh->hash_lock_index;
5126		__release_stripe(conf, sh, &temp_inactive_list[hash]);
5127	}
5128}
5129
5130static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5131{
5132	struct r5conf *conf = mddev->private;
5133	sector_t sector = bio->bi_iter.bi_sector;
5134	unsigned int chunk_sectors;
5135	unsigned int bio_sectors = bio_sectors(bio);
5136
5137	WARN_ON_ONCE(bio->bi_partno);
 
 
5138
5139	chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5140	return  chunk_sectors >=
5141		((sector & (chunk_sectors - 1)) + bio_sectors);
5142}
5143
5144/*
5145 *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5146 *  later sampled by raid5d.
5147 */
5148static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5149{
5150	unsigned long flags;
5151
5152	spin_lock_irqsave(&conf->device_lock, flags);
5153
5154	bi->bi_next = conf->retry_read_aligned_list;
5155	conf->retry_read_aligned_list = bi;
5156
5157	spin_unlock_irqrestore(&conf->device_lock, flags);
5158	md_wakeup_thread(conf->mddev->thread);
5159}
5160
5161static struct bio *remove_bio_from_retry(struct r5conf *conf,
5162					 unsigned int *offset)
5163{
5164	struct bio *bi;
5165
5166	bi = conf->retry_read_aligned;
5167	if (bi) {
5168		*offset = conf->retry_read_offset;
5169		conf->retry_read_aligned = NULL;
5170		return bi;
5171	}
5172	bi = conf->retry_read_aligned_list;
5173	if(bi) {
5174		conf->retry_read_aligned_list = bi->bi_next;
5175		bi->bi_next = NULL;
5176		*offset = 0;
 
 
 
 
5177	}
5178
5179	return bi;
5180}
5181
 
5182/*
5183 *  The "raid5_align_endio" should check if the read succeeded and if it
5184 *  did, call bio_endio on the original bio (having bio_put the new bio
5185 *  first).
5186 *  If the read failed..
5187 */
5188static void raid5_align_endio(struct bio *bi)
5189{
5190	struct bio* raid_bi  = bi->bi_private;
5191	struct mddev *mddev;
5192	struct r5conf *conf;
 
5193	struct md_rdev *rdev;
5194	blk_status_t error = bi->bi_status;
5195
5196	bio_put(bi);
5197
5198	rdev = (void*)raid_bi->bi_next;
5199	raid_bi->bi_next = NULL;
5200	mddev = rdev->mddev;
5201	conf = mddev->private;
5202
5203	rdev_dec_pending(rdev, conf->mddev);
5204
5205	if (!error) {
5206		bio_endio(raid_bi);
5207		if (atomic_dec_and_test(&conf->active_aligned_reads))
5208			wake_up(&conf->wait_for_quiescent);
5209		return;
5210	}
5211
 
5212	pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5213
5214	add_bio_to_retry(raid_bi, conf);
5215}
5216
5217static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5218{
5219	struct r5conf *conf = mddev->private;
5220	int dd_idx;
5221	struct bio* align_bi;
5222	struct md_rdev *rdev;
5223	sector_t end_sector;
5224
5225	if (!in_chunk_boundary(mddev, raid_bio)) {
5226		pr_debug("%s: non aligned\n", __func__);
5227		return 0;
5228	}
5229	/*
5230	 * use bio_clone_fast to make a copy of the bio
5231	 */
5232	align_bi = bio_clone_fast(raid_bio, GFP_NOIO, &mddev->bio_set);
5233	if (!align_bi)
5234		return 0;
5235	/*
5236	 *   set bi_end_io to a new function, and set bi_private to the
5237	 *     original bio.
5238	 */
5239	align_bi->bi_end_io  = raid5_align_endio;
5240	align_bi->bi_private = raid_bio;
5241	/*
5242	 *	compute position
5243	 */
5244	align_bi->bi_iter.bi_sector =
5245		raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
5246				     0, &dd_idx, NULL);
5247
5248	end_sector = bio_end_sector(align_bi);
5249	rcu_read_lock();
5250	rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5251	if (!rdev || test_bit(Faulty, &rdev->flags) ||
5252	    rdev->recovery_offset < end_sector) {
5253		rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5254		if (rdev &&
5255		    (test_bit(Faulty, &rdev->flags) ||
5256		    !(test_bit(In_sync, &rdev->flags) ||
5257		      rdev->recovery_offset >= end_sector)))
5258			rdev = NULL;
5259	}
5260
5261	if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
5262		rcu_read_unlock();
5263		bio_put(align_bi);
5264		return 0;
5265	}
5266
5267	if (rdev) {
5268		sector_t first_bad;
5269		int bad_sectors;
5270
5271		atomic_inc(&rdev->nr_pending);
5272		rcu_read_unlock();
5273		raid_bio->bi_next = (void*)rdev;
5274		bio_set_dev(align_bi, rdev->bdev);
 
5275
5276		if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
5277				bio_sectors(align_bi),
5278				&first_bad, &bad_sectors)) {
 
5279			bio_put(align_bi);
5280			rdev_dec_pending(rdev, mddev);
5281			return 0;
5282		}
5283
5284		/* No reshape active, so we can trust rdev->data_offset */
5285		align_bi->bi_iter.bi_sector += rdev->data_offset;
5286
5287		spin_lock_irq(&conf->device_lock);
5288		wait_event_lock_irq(conf->wait_for_quiescent,
5289				    conf->quiesce == 0,
5290				    conf->device_lock);
5291		atomic_inc(&conf->active_aligned_reads);
5292		spin_unlock_irq(&conf->device_lock);
5293
5294		if (mddev->gendisk)
5295			trace_block_bio_remap(align_bi->bi_disk->queue,
5296					      align_bi, disk_devt(mddev->gendisk),
5297					      raid_bio->bi_iter.bi_sector);
5298		submit_bio_noacct(align_bi);
5299		return 1;
5300	} else {
5301		rcu_read_unlock();
5302		bio_put(align_bi);
5303		return 0;
5304	}
5305}
5306
5307static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5308{
5309	struct bio *split;
5310	sector_t sector = raid_bio->bi_iter.bi_sector;
5311	unsigned chunk_sects = mddev->chunk_sectors;
5312	unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5313
5314	if (sectors < bio_sectors(raid_bio)) {
5315		struct r5conf *conf = mddev->private;
5316		split = bio_split(raid_bio, sectors, GFP_NOIO, &conf->bio_split);
5317		bio_chain(split, raid_bio);
5318		submit_bio_noacct(raid_bio);
5319		raid_bio = split;
5320	}
5321
5322	if (!raid5_read_one_chunk(mddev, raid_bio))
5323		return raid_bio;
5324
5325	return NULL;
5326}
5327
5328/* __get_priority_stripe - get the next stripe to process
5329 *
5330 * Full stripe writes are allowed to pass preread active stripes up until
5331 * the bypass_threshold is exceeded.  In general the bypass_count
5332 * increments when the handle_list is handled before the hold_list; however, it
5333 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5334 * stripe with in flight i/o.  The bypass_count will be reset when the
5335 * head of the hold_list has changed, i.e. the head was promoted to the
5336 * handle_list.
5337 */
5338static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5339{
5340	struct stripe_head *sh, *tmp;
5341	struct list_head *handle_list = NULL;
5342	struct r5worker_group *wg;
5343	bool second_try = !r5c_is_writeback(conf->log) &&
5344		!r5l_log_disk_error(conf);
5345	bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5346		r5l_log_disk_error(conf);
5347
5348again:
5349	wg = NULL;
5350	sh = NULL;
5351	if (conf->worker_cnt_per_group == 0) {
5352		handle_list = try_loprio ? &conf->loprio_list :
5353					&conf->handle_list;
5354	} else if (group != ANY_GROUP) {
5355		handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5356				&conf->worker_groups[group].handle_list;
5357		wg = &conf->worker_groups[group];
5358	} else {
5359		int i;
5360		for (i = 0; i < conf->group_cnt; i++) {
5361			handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5362				&conf->worker_groups[i].handle_list;
5363			wg = &conf->worker_groups[i];
5364			if (!list_empty(handle_list))
5365				break;
5366		}
5367	}
5368
5369	pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5370		  __func__,
5371		  list_empty(handle_list) ? "empty" : "busy",
5372		  list_empty(&conf->hold_list) ? "empty" : "busy",
5373		  atomic_read(&conf->pending_full_writes), conf->bypass_count);
5374
5375	if (!list_empty(handle_list)) {
5376		sh = list_entry(handle_list->next, typeof(*sh), lru);
5377
5378		if (list_empty(&conf->hold_list))
5379			conf->bypass_count = 0;
5380		else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5381			if (conf->hold_list.next == conf->last_hold)
5382				conf->bypass_count++;
5383			else {
5384				conf->last_hold = conf->hold_list.next;
5385				conf->bypass_count -= conf->bypass_threshold;
5386				if (conf->bypass_count < 0)
5387					conf->bypass_count = 0;
5388			}
5389		}
5390	} else if (!list_empty(&conf->hold_list) &&
5391		   ((conf->bypass_threshold &&
5392		     conf->bypass_count > conf->bypass_threshold) ||
5393		    atomic_read(&conf->pending_full_writes) == 0)) {
 
 
 
 
 
 
 
5394
5395		list_for_each_entry(tmp, &conf->hold_list,  lru) {
5396			if (conf->worker_cnt_per_group == 0 ||
5397			    group == ANY_GROUP ||
5398			    !cpu_online(tmp->cpu) ||
5399			    cpu_to_group(tmp->cpu) == group) {
5400				sh = tmp;
5401				break;
5402			}
5403		}
5404
5405		if (sh) {
5406			conf->bypass_count -= conf->bypass_threshold;
5407			if (conf->bypass_count < 0)
5408				conf->bypass_count = 0;
5409		}
5410		wg = NULL;
5411	}
5412
5413	if (!sh) {
5414		if (second_try)
5415			return NULL;
5416		second_try = true;
5417		try_loprio = !try_loprio;
5418		goto again;
5419	}
5420
5421	if (wg) {
5422		wg->stripes_cnt--;
5423		sh->group = NULL;
5424	}
5425	list_del_init(&sh->lru);
5426	BUG_ON(atomic_inc_return(&sh->count) != 1);
 
5427	return sh;
5428}
5429
5430struct raid5_plug_cb {
5431	struct blk_plug_cb	cb;
5432	struct list_head	list;
5433	struct list_head	temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5434};
5435
5436static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5437{
5438	struct raid5_plug_cb *cb = container_of(
5439		blk_cb, struct raid5_plug_cb, cb);
5440	struct stripe_head *sh;
5441	struct mddev *mddev = cb->cb.data;
5442	struct r5conf *conf = mddev->private;
5443	int cnt = 0;
5444	int hash;
5445
5446	if (cb->list.next && !list_empty(&cb->list)) {
5447		spin_lock_irq(&conf->device_lock);
5448		while (!list_empty(&cb->list)) {
5449			sh = list_first_entry(&cb->list, struct stripe_head, lru);
5450			list_del_init(&sh->lru);
5451			/*
5452			 * avoid race release_stripe_plug() sees
5453			 * STRIPE_ON_UNPLUG_LIST clear but the stripe
5454			 * is still in our list
5455			 */
5456			smp_mb__before_atomic();
5457			clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5458			/*
5459			 * STRIPE_ON_RELEASE_LIST could be set here. In that
5460			 * case, the count is always > 1 here
5461			 */
5462			hash = sh->hash_lock_index;
5463			__release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5464			cnt++;
5465		}
5466		spin_unlock_irq(&conf->device_lock);
5467	}
5468	release_inactive_stripe_list(conf, cb->temp_inactive_list,
5469				     NR_STRIPE_HASH_LOCKS);
5470	if (mddev->queue)
5471		trace_block_unplug(mddev->queue, cnt, !from_schedule);
5472	kfree(cb);
5473}
5474
5475static void release_stripe_plug(struct mddev *mddev,
5476				struct stripe_head *sh)
5477{
5478	struct blk_plug_cb *blk_cb = blk_check_plugged(
5479		raid5_unplug, mddev,
5480		sizeof(struct raid5_plug_cb));
5481	struct raid5_plug_cb *cb;
5482
5483	if (!blk_cb) {
5484		raid5_release_stripe(sh);
5485		return;
5486	}
5487
5488	cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5489
5490	if (cb->list.next == NULL) {
5491		int i;
5492		INIT_LIST_HEAD(&cb->list);
5493		for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5494			INIT_LIST_HEAD(cb->temp_inactive_list + i);
5495	}
5496
5497	if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5498		list_add_tail(&sh->lru, &cb->list);
5499	else
5500		raid5_release_stripe(sh);
5501}
5502
5503static void make_discard_request(struct mddev *mddev, struct bio *bi)
5504{
5505	struct r5conf *conf = mddev->private;
5506	sector_t logical_sector, last_sector;
5507	struct stripe_head *sh;
5508	int stripe_sectors;
5509
5510	if (mddev->reshape_position != MaxSector)
5511		/* Skip discard while reshape is happening */
5512		return;
5513
5514	logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
5515	last_sector = bio_end_sector(bi);
5516
5517	bi->bi_next = NULL;
5518
5519	stripe_sectors = conf->chunk_sectors *
5520		(conf->raid_disks - conf->max_degraded);
5521	logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5522					       stripe_sectors);
5523	sector_div(last_sector, stripe_sectors);
5524
5525	logical_sector *= conf->chunk_sectors;
5526	last_sector *= conf->chunk_sectors;
5527
5528	for (; logical_sector < last_sector;
5529	     logical_sector += RAID5_STRIPE_SECTORS(conf)) {
5530		DEFINE_WAIT(w);
5531		int d;
5532	again:
5533		sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5534		prepare_to_wait(&conf->wait_for_overlap, &w,
5535				TASK_UNINTERRUPTIBLE);
5536		set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5537		if (test_bit(STRIPE_SYNCING, &sh->state)) {
5538			raid5_release_stripe(sh);
5539			schedule();
5540			goto again;
5541		}
5542		clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5543		spin_lock_irq(&sh->stripe_lock);
5544		for (d = 0; d < conf->raid_disks; d++) {
5545			if (d == sh->pd_idx || d == sh->qd_idx)
5546				continue;
5547			if (sh->dev[d].towrite || sh->dev[d].toread) {
5548				set_bit(R5_Overlap, &sh->dev[d].flags);
5549				spin_unlock_irq(&sh->stripe_lock);
5550				raid5_release_stripe(sh);
5551				schedule();
5552				goto again;
5553			}
5554		}
5555		set_bit(STRIPE_DISCARD, &sh->state);
5556		finish_wait(&conf->wait_for_overlap, &w);
5557		sh->overwrite_disks = 0;
5558		for (d = 0; d < conf->raid_disks; d++) {
5559			if (d == sh->pd_idx || d == sh->qd_idx)
5560				continue;
5561			sh->dev[d].towrite = bi;
5562			set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5563			bio_inc_remaining(bi);
5564			md_write_inc(mddev, bi);
5565			sh->overwrite_disks++;
5566		}
5567		spin_unlock_irq(&sh->stripe_lock);
5568		if (conf->mddev->bitmap) {
5569			for (d = 0;
5570			     d < conf->raid_disks - conf->max_degraded;
5571			     d++)
5572				md_bitmap_startwrite(mddev->bitmap,
5573						     sh->sector,
5574						     RAID5_STRIPE_SECTORS(conf),
5575						     0);
5576			sh->bm_seq = conf->seq_flush + 1;
5577			set_bit(STRIPE_BIT_DELAY, &sh->state);
5578		}
5579
5580		set_bit(STRIPE_HANDLE, &sh->state);
5581		clear_bit(STRIPE_DELAYED, &sh->state);
5582		if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5583			atomic_inc(&conf->preread_active_stripes);
5584		release_stripe_plug(mddev, sh);
5585	}
5586
5587	bio_endio(bi);
5588}
5589
5590static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
5591{
5592	struct r5conf *conf = mddev->private;
5593	int dd_idx;
5594	sector_t new_sector;
5595	sector_t logical_sector, last_sector;
5596	struct stripe_head *sh;
5597	const int rw = bio_data_dir(bi);
5598	DEFINE_WAIT(w);
5599	bool do_prepare;
5600	bool do_flush = false;
5601
5602	if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
5603		int ret = log_handle_flush_request(conf, bi);
5604
5605		if (ret == 0)
5606			return true;
5607		if (ret == -ENODEV) {
5608			if (md_flush_request(mddev, bi))
5609				return true;
5610		}
5611		/* ret == -EAGAIN, fallback */
5612		/*
5613		 * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
5614		 * we need to flush journal device
5615		 */
5616		do_flush = bi->bi_opf & REQ_PREFLUSH;
5617	}
5618
5619	if (!md_write_start(mddev, bi))
5620		return false;
5621	/*
5622	 * If array is degraded, better not do chunk aligned read because
5623	 * later we might have to read it again in order to reconstruct
5624	 * data on failed drives.
5625	 */
5626	if (rw == READ && mddev->degraded == 0 &&
5627	    mddev->reshape_position == MaxSector) {
5628		bi = chunk_aligned_read(mddev, bi);
5629		if (!bi)
5630			return true;
5631	}
5632
5633	if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
5634		make_discard_request(mddev, bi);
5635		md_write_end(mddev);
5636		return true;
5637	}
5638
5639	logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
5640	last_sector = bio_end_sector(bi);
 
 
 
 
 
5641	bi->bi_next = NULL;
 
5642
5643	prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
5644	for (; logical_sector < last_sector; logical_sector += RAID5_STRIPE_SECTORS(conf)) {
5645		int previous;
5646		int seq;
5647
5648		do_prepare = false;
5649	retry:
5650		seq = read_seqcount_begin(&conf->gen_lock);
5651		previous = 0;
5652		if (do_prepare)
5653			prepare_to_wait(&conf->wait_for_overlap, &w,
5654				TASK_UNINTERRUPTIBLE);
5655		if (unlikely(conf->reshape_progress != MaxSector)) {
5656			/* spinlock is needed as reshape_progress may be
5657			 * 64bit on a 32bit platform, and so it might be
5658			 * possible to see a half-updated value
5659			 * Of course reshape_progress could change after
5660			 * the lock is dropped, so once we get a reference
5661			 * to the stripe that we think it is, we will have
5662			 * to check again.
5663			 */
5664			spin_lock_irq(&conf->device_lock);
5665			if (mddev->reshape_backwards
5666			    ? logical_sector < conf->reshape_progress
5667			    : logical_sector >= conf->reshape_progress) {
5668				previous = 1;
5669			} else {
5670				if (mddev->reshape_backwards
5671				    ? logical_sector < conf->reshape_safe
5672				    : logical_sector >= conf->reshape_safe) {
5673					spin_unlock_irq(&conf->device_lock);
5674					schedule();
5675					do_prepare = true;
5676					goto retry;
5677				}
5678			}
5679			spin_unlock_irq(&conf->device_lock);
5680		}
5681
5682		new_sector = raid5_compute_sector(conf, logical_sector,
5683						  previous,
5684						  &dd_idx, NULL);
5685		pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
5686			(unsigned long long)new_sector,
5687			(unsigned long long)logical_sector);
5688
5689		sh = raid5_get_active_stripe(conf, new_sector, previous,
5690				       (bi->bi_opf & REQ_RAHEAD), 0);
5691		if (sh) {
5692			if (unlikely(previous)) {
5693				/* expansion might have moved on while waiting for a
5694				 * stripe, so we must do the range check again.
5695				 * Expansion could still move past after this
5696				 * test, but as we are holding a reference to
5697				 * 'sh', we know that if that happens,
5698				 *  STRIPE_EXPANDING will get set and the expansion
5699				 * won't proceed until we finish with the stripe.
5700				 */
5701				int must_retry = 0;
5702				spin_lock_irq(&conf->device_lock);
5703				if (mddev->reshape_backwards
5704				    ? logical_sector >= conf->reshape_progress
5705				    : logical_sector < conf->reshape_progress)
5706					/* mismatch, need to try again */
5707					must_retry = 1;
5708				spin_unlock_irq(&conf->device_lock);
5709				if (must_retry) {
5710					raid5_release_stripe(sh);
5711					schedule();
5712					do_prepare = true;
5713					goto retry;
5714				}
5715			}
5716			if (read_seqcount_retry(&conf->gen_lock, seq)) {
5717				/* Might have got the wrong stripe_head
5718				 * by accident
 
 
 
 
 
5719				 */
5720				raid5_release_stripe(sh);
 
 
 
 
 
5721				goto retry;
5722			}
5723
5724			if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5725			    !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
5726				/* Stripe is busy expanding or
5727				 * add failed due to overlap.  Flush everything
5728				 * and wait a while
5729				 */
5730				md_wakeup_thread(mddev->thread);
5731				raid5_release_stripe(sh);
5732				schedule();
5733				do_prepare = true;
5734				goto retry;
5735			}
5736			if (do_flush) {
5737				set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5738				/* we only need flush for one stripe */
5739				do_flush = false;
5740			}
5741
5742			set_bit(STRIPE_HANDLE, &sh->state);
5743			clear_bit(STRIPE_DELAYED, &sh->state);
5744			if ((!sh->batch_head || sh == sh->batch_head) &&
5745			    (bi->bi_opf & REQ_SYNC) &&
5746			    !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5747				atomic_inc(&conf->preread_active_stripes);
5748			release_stripe_plug(mddev, sh);
 
5749		} else {
5750			/* cannot get stripe for read-ahead, just give-up */
5751			bi->bi_status = BLK_STS_IOERR;
 
5752			break;
5753		}
5754	}
5755	finish_wait(&conf->wait_for_overlap, &w);
5756
5757	if (rw == WRITE)
5758		md_write_end(mddev);
5759	bio_endio(bi);
5760	return true;
 
 
 
 
 
 
5761}
5762
5763static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
5764
5765static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
5766{
5767	/* reshaping is quite different to recovery/resync so it is
5768	 * handled quite separately ... here.
5769	 *
5770	 * On each call to sync_request, we gather one chunk worth of
5771	 * destination stripes and flag them as expanding.
5772	 * Then we find all the source stripes and request reads.
5773	 * As the reads complete, handle_stripe will copy the data
5774	 * into the destination stripe and release that stripe.
5775	 */
5776	struct r5conf *conf = mddev->private;
5777	struct stripe_head *sh;
5778	struct md_rdev *rdev;
5779	sector_t first_sector, last_sector;
5780	int raid_disks = conf->previous_raid_disks;
5781	int data_disks = raid_disks - conf->max_degraded;
5782	int new_data_disks = conf->raid_disks - conf->max_degraded;
5783	int i;
5784	int dd_idx;
5785	sector_t writepos, readpos, safepos;
5786	sector_t stripe_addr;
5787	int reshape_sectors;
5788	struct list_head stripes;
5789	sector_t retn;
5790
5791	if (sector_nr == 0) {
5792		/* If restarting in the middle, skip the initial sectors */
5793		if (mddev->reshape_backwards &&
5794		    conf->reshape_progress < raid5_size(mddev, 0, 0)) {
5795			sector_nr = raid5_size(mddev, 0, 0)
5796				- conf->reshape_progress;
5797		} else if (mddev->reshape_backwards &&
5798			   conf->reshape_progress == MaxSector) {
5799			/* shouldn't happen, but just in case, finish up.*/
5800			sector_nr = MaxSector;
5801		} else if (!mddev->reshape_backwards &&
5802			   conf->reshape_progress > 0)
5803			sector_nr = conf->reshape_progress;
5804		sector_div(sector_nr, new_data_disks);
5805		if (sector_nr) {
5806			mddev->curr_resync_completed = sector_nr;
5807			sysfs_notify_dirent_safe(mddev->sysfs_completed);
5808			*skipped = 1;
5809			retn = sector_nr;
5810			goto finish;
5811		}
5812	}
5813
5814	/* We need to process a full chunk at a time.
5815	 * If old and new chunk sizes differ, we need to process the
5816	 * largest of these
5817	 */
5818
5819	reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
 
 
5820
5821	/* We update the metadata at least every 10 seconds, or when
5822	 * the data about to be copied would over-write the source of
5823	 * the data at the front of the range.  i.e. one new_stripe
5824	 * along from reshape_progress new_maps to after where
5825	 * reshape_safe old_maps to
5826	 */
5827	writepos = conf->reshape_progress;
5828	sector_div(writepos, new_data_disks);
5829	readpos = conf->reshape_progress;
5830	sector_div(readpos, data_disks);
5831	safepos = conf->reshape_safe;
5832	sector_div(safepos, data_disks);
5833	if (mddev->reshape_backwards) {
5834		BUG_ON(writepos < reshape_sectors);
5835		writepos -= reshape_sectors;
5836		readpos += reshape_sectors;
5837		safepos += reshape_sectors;
5838	} else {
5839		writepos += reshape_sectors;
5840		/* readpos and safepos are worst-case calculations.
5841		 * A negative number is overly pessimistic, and causes
5842		 * obvious problems for unsigned storage.  So clip to 0.
5843		 */
5844		readpos -= min_t(sector_t, reshape_sectors, readpos);
5845		safepos -= min_t(sector_t, reshape_sectors, safepos);
5846	}
5847
5848	/* Having calculated the 'writepos' possibly use it
5849	 * to set 'stripe_addr' which is where we will write to.
5850	 */
5851	if (mddev->reshape_backwards) {
5852		BUG_ON(conf->reshape_progress == 0);
5853		stripe_addr = writepos;
5854		BUG_ON((mddev->dev_sectors &
5855			~((sector_t)reshape_sectors - 1))
5856		       - reshape_sectors - stripe_addr
5857		       != sector_nr);
5858	} else {
5859		BUG_ON(writepos != sector_nr + reshape_sectors);
5860		stripe_addr = sector_nr;
5861	}
5862
5863	/* 'writepos' is the most advanced device address we might write.
5864	 * 'readpos' is the least advanced device address we might read.
5865	 * 'safepos' is the least address recorded in the metadata as having
5866	 *     been reshaped.
5867	 * If there is a min_offset_diff, these are adjusted either by
5868	 * increasing the safepos/readpos if diff is negative, or
5869	 * increasing writepos if diff is positive.
5870	 * If 'readpos' is then behind 'writepos', there is no way that we can
5871	 * ensure safety in the face of a crash - that must be done by userspace
5872	 * making a backup of the data.  So in that case there is no particular
5873	 * rush to update metadata.
5874	 * Otherwise if 'safepos' is behind 'writepos', then we really need to
5875	 * update the metadata to advance 'safepos' to match 'readpos' so that
5876	 * we can be safe in the event of a crash.
5877	 * So we insist on updating metadata if safepos is behind writepos and
5878	 * readpos is beyond writepos.
5879	 * In any case, update the metadata every 10 seconds.
5880	 * Maybe that number should be configurable, but I'm not sure it is
5881	 * worth it.... maybe it could be a multiple of safemode_delay???
5882	 */
5883	if (conf->min_offset_diff < 0) {
5884		safepos += -conf->min_offset_diff;
5885		readpos += -conf->min_offset_diff;
5886	} else
5887		writepos += conf->min_offset_diff;
5888
5889	if ((mddev->reshape_backwards
5890	     ? (safepos > writepos && readpos < writepos)
5891	     : (safepos < writepos && readpos > writepos)) ||
5892	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
5893		/* Cannot proceed until we've updated the superblock... */
5894		wait_event(conf->wait_for_overlap,
5895			   atomic_read(&conf->reshape_stripes)==0
5896			   || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5897		if (atomic_read(&conf->reshape_stripes) != 0)
5898			return 0;
5899		mddev->reshape_position = conf->reshape_progress;
5900		mddev->curr_resync_completed = sector_nr;
5901		if (!mddev->reshape_backwards)
5902			/* Can update recovery_offset */
5903			rdev_for_each(rdev, mddev)
5904				if (rdev->raid_disk >= 0 &&
5905				    !test_bit(Journal, &rdev->flags) &&
5906				    !test_bit(In_sync, &rdev->flags) &&
5907				    rdev->recovery_offset < sector_nr)
5908					rdev->recovery_offset = sector_nr;
5909
5910		conf->reshape_checkpoint = jiffies;
5911		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5912		md_wakeup_thread(mddev->thread);
5913		wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
5914			   test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5915		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5916			return 0;
5917		spin_lock_irq(&conf->device_lock);
5918		conf->reshape_safe = mddev->reshape_position;
5919		spin_unlock_irq(&conf->device_lock);
5920		wake_up(&conf->wait_for_overlap);
5921		sysfs_notify_dirent_safe(mddev->sysfs_completed);
5922	}
5923
5924	INIT_LIST_HEAD(&stripes);
5925	for (i = 0; i < reshape_sectors; i += RAID5_STRIPE_SECTORS(conf)) {
5926		int j;
5927		int skipped_disk = 0;
5928		sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
5929		set_bit(STRIPE_EXPANDING, &sh->state);
5930		atomic_inc(&conf->reshape_stripes);
5931		/* If any of this stripe is beyond the end of the old
5932		 * array, then we need to zero those blocks
5933		 */
5934		for (j=sh->disks; j--;) {
5935			sector_t s;
5936			if (j == sh->pd_idx)
5937				continue;
5938			if (conf->level == 6 &&
5939			    j == sh->qd_idx)
5940				continue;
5941			s = raid5_compute_blocknr(sh, j, 0);
5942			if (s < raid5_size(mddev, 0, 0)) {
5943				skipped_disk = 1;
5944				continue;
5945			}
5946			memset(page_address(sh->dev[j].page), 0, RAID5_STRIPE_SIZE(conf));
5947			set_bit(R5_Expanded, &sh->dev[j].flags);
5948			set_bit(R5_UPTODATE, &sh->dev[j].flags);
5949		}
5950		if (!skipped_disk) {
5951			set_bit(STRIPE_EXPAND_READY, &sh->state);
5952			set_bit(STRIPE_HANDLE, &sh->state);
5953		}
5954		list_add(&sh->lru, &stripes);
5955	}
5956	spin_lock_irq(&conf->device_lock);
5957	if (mddev->reshape_backwards)
5958		conf->reshape_progress -= reshape_sectors * new_data_disks;
5959	else
5960		conf->reshape_progress += reshape_sectors * new_data_disks;
5961	spin_unlock_irq(&conf->device_lock);
5962	/* Ok, those stripe are ready. We can start scheduling
5963	 * reads on the source stripes.
5964	 * The source stripes are determined by mapping the first and last
5965	 * block on the destination stripes.
5966	 */
5967	first_sector =
5968		raid5_compute_sector(conf, stripe_addr*(new_data_disks),
5969				     1, &dd_idx, NULL);
5970	last_sector =
5971		raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
5972					    * new_data_disks - 1),
5973				     1, &dd_idx, NULL);
5974	if (last_sector >= mddev->dev_sectors)
5975		last_sector = mddev->dev_sectors - 1;
5976	while (first_sector <= last_sector) {
5977		sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
5978		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
5979		set_bit(STRIPE_HANDLE, &sh->state);
5980		raid5_release_stripe(sh);
5981		first_sector += RAID5_STRIPE_SECTORS(conf);
5982	}
5983	/* Now that the sources are clearly marked, we can release
5984	 * the destination stripes
5985	 */
5986	while (!list_empty(&stripes)) {
5987		sh = list_entry(stripes.next, struct stripe_head, lru);
5988		list_del_init(&sh->lru);
5989		raid5_release_stripe(sh);
5990	}
5991	/* If this takes us to the resync_max point where we have to pause,
5992	 * then we need to write out the superblock.
5993	 */
5994	sector_nr += reshape_sectors;
5995	retn = reshape_sectors;
5996finish:
5997	if (mddev->curr_resync_completed > mddev->resync_max ||
5998	    (sector_nr - mddev->curr_resync_completed) * 2
5999	    >= mddev->resync_max - mddev->curr_resync_completed) {
6000		/* Cannot proceed until we've updated the superblock... */
6001		wait_event(conf->wait_for_overlap,
6002			   atomic_read(&conf->reshape_stripes) == 0
6003			   || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6004		if (atomic_read(&conf->reshape_stripes) != 0)
6005			goto ret;
6006		mddev->reshape_position = conf->reshape_progress;
6007		mddev->curr_resync_completed = sector_nr;
6008		if (!mddev->reshape_backwards)
6009			/* Can update recovery_offset */
6010			rdev_for_each(rdev, mddev)
6011				if (rdev->raid_disk >= 0 &&
6012				    !test_bit(Journal, &rdev->flags) &&
6013				    !test_bit(In_sync, &rdev->flags) &&
6014				    rdev->recovery_offset < sector_nr)
6015					rdev->recovery_offset = sector_nr;
6016		conf->reshape_checkpoint = jiffies;
6017		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6018		md_wakeup_thread(mddev->thread);
6019		wait_event(mddev->sb_wait,
6020			   !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6021			   || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6022		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6023			goto ret;
6024		spin_lock_irq(&conf->device_lock);
6025		conf->reshape_safe = mddev->reshape_position;
6026		spin_unlock_irq(&conf->device_lock);
6027		wake_up(&conf->wait_for_overlap);
6028		sysfs_notify_dirent_safe(mddev->sysfs_completed);
6029	}
6030ret:
6031	return retn;
6032}
6033
6034static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6035					  int *skipped)
6036{
6037	struct r5conf *conf = mddev->private;
6038	struct stripe_head *sh;
6039	sector_t max_sector = mddev->dev_sectors;
6040	sector_t sync_blocks;
6041	int still_degraded = 0;
6042	int i;
6043
6044	if (sector_nr >= max_sector) {
6045		/* just being told to finish up .. nothing much to do */
6046
6047		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6048			end_reshape(conf);
6049			return 0;
6050		}
6051
6052		if (mddev->curr_resync < max_sector) /* aborted */
6053			md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6054					   &sync_blocks, 1);
6055		else /* completed sync */
6056			conf->fullsync = 0;
6057		md_bitmap_close_sync(mddev->bitmap);
6058
6059		return 0;
6060	}
6061
6062	/* Allow raid5_quiesce to complete */
6063	wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6064
6065	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6066		return reshape_request(mddev, sector_nr, skipped);
6067
6068	/* No need to check resync_max as we never do more than one
6069	 * stripe, and as resync_max will always be on a chunk boundary,
6070	 * if the check in md_do_sync didn't fire, there is no chance
6071	 * of overstepping resync_max here
6072	 */
6073
6074	/* if there is too many failed drives and we are trying
6075	 * to resync, then assert that we are finished, because there is
6076	 * nothing we can do.
6077	 */
6078	if (mddev->degraded >= conf->max_degraded &&
6079	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6080		sector_t rv = mddev->dev_sectors - sector_nr;
6081		*skipped = 1;
6082		return rv;
6083	}
6084	if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6085	    !conf->fullsync &&
6086	    !md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6087	    sync_blocks >= RAID5_STRIPE_SECTORS(conf)) {
6088		/* we can skip this block, and probably more */
6089		do_div(sync_blocks, RAID5_STRIPE_SECTORS(conf));
6090		*skipped = 1;
6091		/* keep things rounded to whole stripes */
6092		return sync_blocks * RAID5_STRIPE_SECTORS(conf);
6093	}
6094
6095	md_bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6096
6097	sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6098	if (sh == NULL) {
6099		sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6100		/* make sure we don't swamp the stripe cache if someone else
6101		 * is trying to get access
6102		 */
6103		schedule_timeout_uninterruptible(1);
6104	}
6105	/* Need to check if array will still be degraded after recovery/resync
6106	 * Note in case of > 1 drive failures it's possible we're rebuilding
6107	 * one drive while leaving another faulty drive in array.
6108	 */
6109	rcu_read_lock();
6110	for (i = 0; i < conf->raid_disks; i++) {
6111		struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
6112
6113		if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6114			still_degraded = 1;
6115	}
6116	rcu_read_unlock();
6117
6118	md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6119
6120	set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6121	set_bit(STRIPE_HANDLE, &sh->state);
6122
6123	raid5_release_stripe(sh);
 
6124
6125	return RAID5_STRIPE_SECTORS(conf);
6126}
6127
6128static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6129			       unsigned int offset)
6130{
6131	/* We may not be able to submit a whole bio at once as there
6132	 * may not be enough stripe_heads available.
6133	 * We cannot pre-allocate enough stripe_heads as we may need
6134	 * more than exist in the cache (if we allow ever large chunks).
6135	 * So we do one stripe head at a time and record in
6136	 * ->bi_hw_segments how many have been done.
6137	 *
6138	 * We *know* that this entire raid_bio is in one chunk, so
6139	 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6140	 */
6141	struct stripe_head *sh;
6142	int dd_idx;
6143	sector_t sector, logical_sector, last_sector;
6144	int scnt = 0;
 
6145	int handled = 0;
6146
6147	logical_sector = raid_bio->bi_iter.bi_sector &
6148		~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6149	sector = raid5_compute_sector(conf, logical_sector,
6150				      0, &dd_idx, NULL);
6151	last_sector = bio_end_sector(raid_bio);
6152
6153	for (; logical_sector < last_sector;
6154	     logical_sector += RAID5_STRIPE_SECTORS(conf),
6155		     sector += RAID5_STRIPE_SECTORS(conf),
6156		     scnt++) {
6157
6158		if (scnt < offset)
6159			/* already done this stripe */
6160			continue;
6161
6162		sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6163
6164		if (!sh) {
6165			/* failed to get a stripe - must wait */
 
6166			conf->retry_read_aligned = raid_bio;
6167			conf->retry_read_offset = scnt;
6168			return handled;
6169		}
6170
6171		if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6172			raid5_release_stripe(sh);
 
6173			conf->retry_read_aligned = raid_bio;
6174			conf->retry_read_offset = scnt;
6175			return handled;
6176		}
6177
6178		set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6179		handle_stripe(sh);
6180		raid5_release_stripe(sh);
6181		handled++;
6182	}
6183
6184	bio_endio(raid_bio);
6185
 
 
6186	if (atomic_dec_and_test(&conf->active_aligned_reads))
6187		wake_up(&conf->wait_for_quiescent);
6188	return handled;
6189}
6190
6191static int handle_active_stripes(struct r5conf *conf, int group,
6192				 struct r5worker *worker,
6193				 struct list_head *temp_inactive_list)
6194		__releases(&conf->device_lock)
6195		__acquires(&conf->device_lock)
6196{
6197	struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6198	int i, batch_size = 0, hash;
6199	bool release_inactive = false;
6200
6201	while (batch_size < MAX_STRIPE_BATCH &&
6202			(sh = __get_priority_stripe(conf, group)) != NULL)
6203		batch[batch_size++] = sh;
6204
6205	if (batch_size == 0) {
6206		for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6207			if (!list_empty(temp_inactive_list + i))
6208				break;
6209		if (i == NR_STRIPE_HASH_LOCKS) {
6210			spin_unlock_irq(&conf->device_lock);
6211			log_flush_stripe_to_raid(conf);
6212			spin_lock_irq(&conf->device_lock);
6213			return batch_size;
6214		}
6215		release_inactive = true;
6216	}
6217	spin_unlock_irq(&conf->device_lock);
6218
6219	release_inactive_stripe_list(conf, temp_inactive_list,
6220				     NR_STRIPE_HASH_LOCKS);
6221
6222	r5l_flush_stripe_to_raid(conf->log);
6223	if (release_inactive) {
6224		spin_lock_irq(&conf->device_lock);
6225		return 0;
6226	}
6227
6228	for (i = 0; i < batch_size; i++)
6229		handle_stripe(batch[i]);
6230	log_write_stripe_run(conf);
6231
6232	cond_resched();
6233
6234	spin_lock_irq(&conf->device_lock);
6235	for (i = 0; i < batch_size; i++) {
6236		hash = batch[i]->hash_lock_index;
6237		__release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6238	}
6239	return batch_size;
6240}
6241
6242static void raid5_do_work(struct work_struct *work)
6243{
6244	struct r5worker *worker = container_of(work, struct r5worker, work);
6245	struct r5worker_group *group = worker->group;
6246	struct r5conf *conf = group->conf;
6247	struct mddev *mddev = conf->mddev;
6248	int group_id = group - conf->worker_groups;
6249	int handled;
6250	struct blk_plug plug;
6251
6252	pr_debug("+++ raid5worker active\n");
6253
6254	blk_start_plug(&plug);
6255	handled = 0;
6256	spin_lock_irq(&conf->device_lock);
6257	while (1) {
6258		int batch_size, released;
6259
6260		released = release_stripe_list(conf, worker->temp_inactive_list);
6261
6262		batch_size = handle_active_stripes(conf, group_id, worker,
6263						   worker->temp_inactive_list);
6264		worker->working = false;
6265		if (!batch_size && !released)
6266			break;
6267		handled += batch_size;
6268		wait_event_lock_irq(mddev->sb_wait,
6269			!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6270			conf->device_lock);
6271	}
6272	pr_debug("%d stripes handled\n", handled);
6273
6274	spin_unlock_irq(&conf->device_lock);
6275
6276	flush_deferred_bios(conf);
6277
6278	r5l_flush_stripe_to_raid(conf->log);
6279
6280	async_tx_issue_pending_all();
6281	blk_finish_plug(&plug);
6282
6283	pr_debug("--- raid5worker inactive\n");
6284}
6285
6286/*
6287 * This is our raid5 kernel thread.
6288 *
6289 * We scan the hash table for stripes which can be handled now.
6290 * During the scan, completed stripes are saved for us by the interrupt
6291 * handler, so that they will not have to wait for our next wakeup.
6292 */
6293static void raid5d(struct md_thread *thread)
6294{
6295	struct mddev *mddev = thread->mddev;
6296	struct r5conf *conf = mddev->private;
6297	int handled;
6298	struct blk_plug plug;
6299
6300	pr_debug("+++ raid5d active\n");
6301
6302	md_check_recovery(mddev);
6303
6304	blk_start_plug(&plug);
6305	handled = 0;
6306	spin_lock_irq(&conf->device_lock);
6307	while (1) {
6308		struct bio *bio;
6309		int batch_size, released;
6310		unsigned int offset;
6311
6312		released = release_stripe_list(conf, conf->temp_inactive_list);
6313		if (released)
6314			clear_bit(R5_DID_ALLOC, &conf->cache_state);
6315
6316		if (
6317		    !list_empty(&conf->bitmap_list)) {
6318			/* Now is a good time to flush some bitmap updates */
6319			conf->seq_flush++;
6320			spin_unlock_irq(&conf->device_lock);
6321			md_bitmap_unplug(mddev->bitmap);
6322			spin_lock_irq(&conf->device_lock);
6323			conf->seq_write = conf->seq_flush;
6324			activate_bit_delay(conf, conf->temp_inactive_list);
6325		}
6326		raid5_activate_delayed(conf);
 
6327
6328		while ((bio = remove_bio_from_retry(conf, &offset))) {
6329			int ok;
6330			spin_unlock_irq(&conf->device_lock);
6331			ok = retry_aligned_read(conf, bio, offset);
6332			spin_lock_irq(&conf->device_lock);
6333			if (!ok)
6334				break;
6335			handled++;
6336		}
6337
6338		batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6339						   conf->temp_inactive_list);
6340		if (!batch_size && !released)
6341			break;
6342		handled += batch_size;
 
 
 
 
 
6343
6344		if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6345			spin_unlock_irq(&conf->device_lock);
6346			md_check_recovery(mddev);
6347			spin_lock_irq(&conf->device_lock);
6348		}
6349	}
6350	pr_debug("%d stripes handled\n", handled);
6351
6352	spin_unlock_irq(&conf->device_lock);
6353	if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6354	    mutex_trylock(&conf->cache_size_mutex)) {
6355		grow_one_stripe(conf, __GFP_NOWARN);
6356		/* Set flag even if allocation failed.  This helps
6357		 * slow down allocation requests when mem is short
6358		 */
6359		set_bit(R5_DID_ALLOC, &conf->cache_state);
6360		mutex_unlock(&conf->cache_size_mutex);
6361	}
6362
6363	flush_deferred_bios(conf);
6364
6365	r5l_flush_stripe_to_raid(conf->log);
6366
6367	async_tx_issue_pending_all();
6368	blk_finish_plug(&plug);
6369
6370	pr_debug("--- raid5d inactive\n");
6371}
6372
6373static ssize_t
6374raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6375{
6376	struct r5conf *conf;
6377	int ret = 0;
6378	spin_lock(&mddev->lock);
6379	conf = mddev->private;
6380	if (conf)
6381		ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6382	spin_unlock(&mddev->lock);
6383	return ret;
6384}
6385
6386int
6387raid5_set_cache_size(struct mddev *mddev, int size)
6388{
6389	int result = 0;
6390	struct r5conf *conf = mddev->private;
 
6391
6392	if (size <= 16 || size > 32768)
6393		return -EINVAL;
6394
6395	conf->min_nr_stripes = size;
6396	mutex_lock(&conf->cache_size_mutex);
6397	while (size < conf->max_nr_stripes &&
6398	       drop_one_stripe(conf))
6399		;
6400	mutex_unlock(&conf->cache_size_mutex);
6401
6402	md_allow_write(mddev);
6403
6404	mutex_lock(&conf->cache_size_mutex);
6405	while (size > conf->max_nr_stripes)
6406		if (!grow_one_stripe(conf, GFP_KERNEL)) {
6407			conf->min_nr_stripes = conf->max_nr_stripes;
6408			result = -ENOMEM;
6409			break;
6410		}
6411	mutex_unlock(&conf->cache_size_mutex);
6412
6413	return result;
 
 
 
 
 
 
6414}
6415EXPORT_SYMBOL(raid5_set_cache_size);
6416
6417static ssize_t
6418raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6419{
6420	struct r5conf *conf;
6421	unsigned long new;
6422	int err;
6423
6424	if (len >= PAGE_SIZE)
6425		return -EINVAL;
6426	if (kstrtoul(page, 10, &new))
 
 
 
6427		return -EINVAL;
6428	err = mddev_lock(mddev);
6429	if (err)
6430		return err;
6431	conf = mddev->private;
6432	if (!conf)
6433		err = -ENODEV;
6434	else
6435		err = raid5_set_cache_size(mddev, new);
6436	mddev_unlock(mddev);
6437
6438	return err ?: len;
6439}
6440
6441static struct md_sysfs_entry
6442raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6443				raid5_show_stripe_cache_size,
6444				raid5_store_stripe_cache_size);
6445
6446static ssize_t
6447raid5_show_rmw_level(struct mddev  *mddev, char *page)
6448{
6449	struct r5conf *conf = mddev->private;
6450	if (conf)
6451		return sprintf(page, "%d\n", conf->rmw_level);
6452	else
6453		return 0;
6454}
6455
6456static ssize_t
6457raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6458{
6459	struct r5conf *conf = mddev->private;
6460	unsigned long new;
6461
6462	if (!conf)
6463		return -ENODEV;
6464
6465	if (len >= PAGE_SIZE)
6466		return -EINVAL;
 
 
6467
6468	if (kstrtoul(page, 10, &new))
6469		return -EINVAL;
6470
6471	if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6472		return -EINVAL;
6473
6474	if (new != PARITY_DISABLE_RMW &&
6475	    new != PARITY_ENABLE_RMW &&
6476	    new != PARITY_PREFER_RMW)
6477		return -EINVAL;
6478
6479	conf->rmw_level = new;
6480	return len;
6481}
6482
6483static struct md_sysfs_entry
6484raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6485			 raid5_show_rmw_level,
6486			 raid5_store_rmw_level);
6487
6488static ssize_t
6489raid5_show_stripe_size(struct mddev  *mddev, char *page)
6490{
6491	struct r5conf *conf;
6492	int ret = 0;
6493
6494	spin_lock(&mddev->lock);
6495	conf = mddev->private;
6496	if (conf)
6497		ret = sprintf(page, "%lu\n", RAID5_STRIPE_SIZE(conf));
6498	spin_unlock(&mddev->lock);
6499	return ret;
6500}
6501
6502#if PAGE_SIZE != DEFAULT_STRIPE_SIZE
6503static ssize_t
6504raid5_store_stripe_size(struct mddev  *mddev, const char *page, size_t len)
6505{
6506	struct r5conf *conf;
6507	unsigned long new;
6508	int err;
6509
6510	if (len >= PAGE_SIZE)
6511		return -EINVAL;
6512	if (kstrtoul(page, 10, &new))
6513		return -EINVAL;
6514
6515	/*
6516	 * The value should not be bigger than PAGE_SIZE. It requires to
6517	 * be multiple of DEFAULT_STRIPE_SIZE and the value should be power
6518	 * of two.
6519	 */
6520	if (new % DEFAULT_STRIPE_SIZE != 0 ||
6521			new > PAGE_SIZE || new == 0 ||
6522			new != roundup_pow_of_two(new))
6523		return -EINVAL;
6524
6525	err = mddev_lock(mddev);
6526	if (err)
6527		return err;
6528
6529	conf = mddev->private;
6530	if (!conf) {
6531		err = -ENODEV;
6532		goto out_unlock;
6533	}
6534
6535	if (new == conf->stripe_size)
6536		goto out_unlock;
6537
6538	pr_debug("md/raid: change stripe_size from %lu to %lu\n",
6539			conf->stripe_size, new);
6540
6541	mddev_suspend(mddev);
6542	conf->stripe_size = new;
6543	conf->stripe_shift = ilog2(new) - 9;
6544	conf->stripe_sectors = new >> 9;
6545	mddev_resume(mddev);
6546
6547out_unlock:
6548	mddev_unlock(mddev);
6549	return err ?: len;
6550}
6551
6552static struct md_sysfs_entry
6553raid5_stripe_size = __ATTR(stripe_size, 0644,
6554			 raid5_show_stripe_size,
6555			 raid5_store_stripe_size);
6556#else
6557static struct md_sysfs_entry
6558raid5_stripe_size = __ATTR(stripe_size, 0444,
6559			 raid5_show_stripe_size,
6560			 NULL);
6561#endif
6562
6563static ssize_t
6564raid5_show_preread_threshold(struct mddev *mddev, char *page)
6565{
6566	struct r5conf *conf;
6567	int ret = 0;
6568	spin_lock(&mddev->lock);
6569	conf = mddev->private;
6570	if (conf)
6571		ret = sprintf(page, "%d\n", conf->bypass_threshold);
6572	spin_unlock(&mddev->lock);
6573	return ret;
6574}
6575
6576static ssize_t
6577raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
6578{
6579	struct r5conf *conf;
6580	unsigned long new;
6581	int err;
6582
6583	if (len >= PAGE_SIZE)
6584		return -EINVAL;
6585	if (kstrtoul(page, 10, &new))
6586		return -EINVAL;
6587
6588	err = mddev_lock(mddev);
6589	if (err)
6590		return err;
6591	conf = mddev->private;
6592	if (!conf)
6593		err = -ENODEV;
6594	else if (new > conf->min_nr_stripes)
6595		err = -EINVAL;
6596	else
6597		conf->bypass_threshold = new;
6598	mddev_unlock(mddev);
6599	return err ?: len;
6600}
6601
6602static struct md_sysfs_entry
6603raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
6604					S_IRUGO | S_IWUSR,
6605					raid5_show_preread_threshold,
6606					raid5_store_preread_threshold);
6607
6608static ssize_t
6609raid5_show_skip_copy(struct mddev *mddev, char *page)
6610{
6611	struct r5conf *conf;
6612	int ret = 0;
6613	spin_lock(&mddev->lock);
6614	conf = mddev->private;
6615	if (conf)
6616		ret = sprintf(page, "%d\n", conf->skip_copy);
6617	spin_unlock(&mddev->lock);
6618	return ret;
6619}
6620
6621static ssize_t
6622raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
6623{
6624	struct r5conf *conf;
6625	unsigned long new;
6626	int err;
6627
6628	if (len >= PAGE_SIZE)
6629		return -EINVAL;
6630	if (kstrtoul(page, 10, &new))
6631		return -EINVAL;
6632	new = !!new;
6633
6634	err = mddev_lock(mddev);
6635	if (err)
6636		return err;
6637	conf = mddev->private;
6638	if (!conf)
6639		err = -ENODEV;
6640	else if (new != conf->skip_copy) {
6641		mddev_suspend(mddev);
6642		conf->skip_copy = new;
6643		if (new)
6644			mddev->queue->backing_dev_info->capabilities |=
6645				BDI_CAP_STABLE_WRITES;
6646		else
6647			mddev->queue->backing_dev_info->capabilities &=
6648				~BDI_CAP_STABLE_WRITES;
6649		mddev_resume(mddev);
6650	}
6651	mddev_unlock(mddev);
6652	return err ?: len;
6653}
6654
6655static struct md_sysfs_entry
6656raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
6657					raid5_show_skip_copy,
6658					raid5_store_skip_copy);
6659
6660static ssize_t
6661stripe_cache_active_show(struct mddev *mddev, char *page)
6662{
6663	struct r5conf *conf = mddev->private;
6664	if (conf)
6665		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
6666	else
6667		return 0;
6668}
6669
6670static struct md_sysfs_entry
6671raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
6672
6673static ssize_t
6674raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
6675{
6676	struct r5conf *conf;
6677	int ret = 0;
6678	spin_lock(&mddev->lock);
6679	conf = mddev->private;
6680	if (conf)
6681		ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
6682	spin_unlock(&mddev->lock);
6683	return ret;
6684}
6685
6686static int alloc_thread_groups(struct r5conf *conf, int cnt,
6687			       int *group_cnt,
6688			       struct r5worker_group **worker_groups);
6689static ssize_t
6690raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
6691{
6692	struct r5conf *conf;
6693	unsigned int new;
6694	int err;
6695	struct r5worker_group *new_groups, *old_groups;
6696	int group_cnt;
6697
6698	if (len >= PAGE_SIZE)
6699		return -EINVAL;
6700	if (kstrtouint(page, 10, &new))
6701		return -EINVAL;
6702	/* 8192 should be big enough */
6703	if (new > 8192)
6704		return -EINVAL;
6705
6706	err = mddev_lock(mddev);
6707	if (err)
6708		return err;
6709	conf = mddev->private;
6710	if (!conf)
6711		err = -ENODEV;
6712	else if (new != conf->worker_cnt_per_group) {
6713		mddev_suspend(mddev);
6714
6715		old_groups = conf->worker_groups;
6716		if (old_groups)
6717			flush_workqueue(raid5_wq);
6718
6719		err = alloc_thread_groups(conf, new, &group_cnt, &new_groups);
6720		if (!err) {
6721			spin_lock_irq(&conf->device_lock);
6722			conf->group_cnt = group_cnt;
6723			conf->worker_cnt_per_group = new;
6724			conf->worker_groups = new_groups;
6725			spin_unlock_irq(&conf->device_lock);
6726
6727			if (old_groups)
6728				kfree(old_groups[0].workers);
6729			kfree(old_groups);
6730		}
6731		mddev_resume(mddev);
6732	}
6733	mddev_unlock(mddev);
6734
6735	return err ?: len;
6736}
6737
6738static struct md_sysfs_entry
6739raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
6740				raid5_show_group_thread_cnt,
6741				raid5_store_group_thread_cnt);
6742
6743static struct attribute *raid5_attrs[] =  {
6744	&raid5_stripecache_size.attr,
6745	&raid5_stripecache_active.attr,
6746	&raid5_preread_bypass_threshold.attr,
6747	&raid5_group_thread_cnt.attr,
6748	&raid5_skip_copy.attr,
6749	&raid5_rmw_level.attr,
6750	&raid5_stripe_size.attr,
6751	&r5c_journal_mode.attr,
6752	&ppl_write_hint.attr,
6753	NULL,
6754};
6755static struct attribute_group raid5_attrs_group = {
6756	.name = NULL,
6757	.attrs = raid5_attrs,
6758};
6759
6760static int alloc_thread_groups(struct r5conf *conf, int cnt, int *group_cnt,
6761			       struct r5worker_group **worker_groups)
6762{
6763	int i, j, k;
6764	ssize_t size;
6765	struct r5worker *workers;
6766
6767	if (cnt == 0) {
6768		*group_cnt = 0;
6769		*worker_groups = NULL;
6770		return 0;
6771	}
6772	*group_cnt = num_possible_nodes();
6773	size = sizeof(struct r5worker) * cnt;
6774	workers = kcalloc(size, *group_cnt, GFP_NOIO);
6775	*worker_groups = kcalloc(*group_cnt, sizeof(struct r5worker_group),
6776				 GFP_NOIO);
6777	if (!*worker_groups || !workers) {
6778		kfree(workers);
6779		kfree(*worker_groups);
6780		return -ENOMEM;
6781	}
6782
6783	for (i = 0; i < *group_cnt; i++) {
6784		struct r5worker_group *group;
6785
6786		group = &(*worker_groups)[i];
6787		INIT_LIST_HEAD(&group->handle_list);
6788		INIT_LIST_HEAD(&group->loprio_list);
6789		group->conf = conf;
6790		group->workers = workers + i * cnt;
6791
6792		for (j = 0; j < cnt; j++) {
6793			struct r5worker *worker = group->workers + j;
6794			worker->group = group;
6795			INIT_WORK(&worker->work, raid5_do_work);
6796
6797			for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
6798				INIT_LIST_HEAD(worker->temp_inactive_list + k);
6799		}
6800	}
6801
6802	return 0;
6803}
6804
6805static void free_thread_groups(struct r5conf *conf)
6806{
6807	if (conf->worker_groups)
6808		kfree(conf->worker_groups[0].workers);
6809	kfree(conf->worker_groups);
6810	conf->worker_groups = NULL;
6811}
6812
6813static sector_t
6814raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
6815{
6816	struct r5conf *conf = mddev->private;
6817
6818	if (!sectors)
6819		sectors = mddev->dev_sectors;
6820	if (!raid_disks)
6821		/* size is defined by the smallest of previous and new size */
6822		raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
6823
6824	sectors &= ~((sector_t)conf->chunk_sectors - 1);
6825	sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
6826	return sectors * (raid_disks - conf->max_degraded);
6827}
6828
6829static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6830{
6831	safe_put_page(percpu->spare_page);
6832	percpu->spare_page = NULL;
6833	kvfree(percpu->scribble);
6834	percpu->scribble = NULL;
6835}
6836
6837static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6838{
6839	if (conf->level == 6 && !percpu->spare_page) {
6840		percpu->spare_page = alloc_page(GFP_KERNEL);
6841		if (!percpu->spare_page)
6842			return -ENOMEM;
6843	}
6844
6845	if (scribble_alloc(percpu,
6846			   max(conf->raid_disks,
6847			       conf->previous_raid_disks),
6848			   max(conf->chunk_sectors,
6849			       conf->prev_chunk_sectors)
6850			   / RAID5_STRIPE_SECTORS(conf))) {
6851		free_scratch_buffer(conf, percpu);
6852		return -ENOMEM;
6853	}
6854
6855	return 0;
6856}
6857
6858static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
6859{
6860	struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6861
6862	free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
6863	return 0;
6864}
6865
6866static void raid5_free_percpu(struct r5conf *conf)
6867{
 
 
 
6868	if (!conf->percpu)
6869		return;
6870
6871	cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
 
 
 
 
 
 
 
 
 
 
6872	free_percpu(conf->percpu);
6873}
6874
6875static void free_conf(struct r5conf *conf)
6876{
6877	int i;
6878
6879	log_exit(conf);
6880
6881	unregister_shrinker(&conf->shrinker);
6882	free_thread_groups(conf);
6883	shrink_stripes(conf);
6884	raid5_free_percpu(conf);
6885	for (i = 0; i < conf->pool_size; i++)
6886		if (conf->disks[i].extra_page)
6887			put_page(conf->disks[i].extra_page);
6888	kfree(conf->disks);
6889	bioset_exit(&conf->bio_split);
6890	kfree(conf->stripe_hashtbl);
6891	kfree(conf->pending_data);
6892	kfree(conf);
6893}
6894
6895static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
 
 
6896{
6897	struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
 
6898	struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
6899
6900	if (alloc_scratch_buffer(conf, percpu)) {
6901		pr_warn("%s: failed memory allocation for cpu%u\n",
6902			__func__, cpu);
6903		return -ENOMEM;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6904	}
6905	return 0;
6906}
 
6907
6908static int raid5_alloc_percpu(struct r5conf *conf)
6909{
6910	int err = 0;
 
 
 
 
6911
6912	conf->percpu = alloc_percpu(struct raid5_percpu);
6913	if (!conf->percpu)
6914		return -ENOMEM;
 
6915
6916	err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6917	if (!err) {
6918		conf->scribble_disks = max(conf->raid_disks,
6919			conf->previous_raid_disks);
6920		conf->scribble_sectors = max(conf->chunk_sectors,
6921			conf->prev_chunk_sectors);
6922	}
6923	return err;
6924}
6925
6926static unsigned long raid5_cache_scan(struct shrinker *shrink,
6927				      struct shrink_control *sc)
6928{
6929	struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6930	unsigned long ret = SHRINK_STOP;
6931
6932	if (mutex_trylock(&conf->cache_size_mutex)) {
6933		ret= 0;
6934		while (ret < sc->nr_to_scan &&
6935		       conf->max_nr_stripes > conf->min_nr_stripes) {
6936			if (drop_one_stripe(conf) == 0) {
6937				ret = SHRINK_STOP;
6938				break;
6939			}
6940			ret++;
 
 
 
 
 
6941		}
6942		mutex_unlock(&conf->cache_size_mutex);
6943	}
6944	return ret;
6945}
6946
6947static unsigned long raid5_cache_count(struct shrinker *shrink,
6948				       struct shrink_control *sc)
6949{
6950	struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6951
6952	if (conf->max_nr_stripes < conf->min_nr_stripes)
6953		/* unlikely, but not impossible */
6954		return 0;
6955	return conf->max_nr_stripes - conf->min_nr_stripes;
6956}
6957
6958static struct r5conf *setup_conf(struct mddev *mddev)
6959{
6960	struct r5conf *conf;
6961	int raid_disk, memory, max_disks;
6962	struct md_rdev *rdev;
6963	struct disk_info *disk;
6964	char pers_name[6];
6965	int i;
6966	int group_cnt;
6967	struct r5worker_group *new_group;
6968	int ret;
6969
6970	if (mddev->new_level != 5
6971	    && mddev->new_level != 4
6972	    && mddev->new_level != 6) {
6973		pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
6974			mdname(mddev), mddev->new_level);
6975		return ERR_PTR(-EIO);
6976	}
6977	if ((mddev->new_level == 5
6978	     && !algorithm_valid_raid5(mddev->new_layout)) ||
6979	    (mddev->new_level == 6
6980	     && !algorithm_valid_raid6(mddev->new_layout))) {
6981		pr_warn("md/raid:%s: layout %d not supported\n",
6982			mdname(mddev), mddev->new_layout);
6983		return ERR_PTR(-EIO);
6984	}
6985	if (mddev->new_level == 6 && mddev->raid_disks < 4) {
6986		pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
6987			mdname(mddev), mddev->raid_disks);
6988		return ERR_PTR(-EINVAL);
6989	}
6990
6991	if (!mddev->new_chunk_sectors ||
6992	    (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
6993	    !is_power_of_2(mddev->new_chunk_sectors)) {
6994		pr_warn("md/raid:%s: invalid chunk size %d\n",
6995			mdname(mddev), mddev->new_chunk_sectors << 9);
6996		return ERR_PTR(-EINVAL);
6997	}
6998
6999	conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
7000	if (conf == NULL)
7001		goto abort;
7002
7003#if PAGE_SIZE != DEFAULT_STRIPE_SIZE
7004	conf->stripe_size = DEFAULT_STRIPE_SIZE;
7005	conf->stripe_shift = ilog2(DEFAULT_STRIPE_SIZE) - 9;
7006	conf->stripe_sectors = DEFAULT_STRIPE_SIZE >> 9;
7007#endif
7008	INIT_LIST_HEAD(&conf->free_list);
7009	INIT_LIST_HEAD(&conf->pending_list);
7010	conf->pending_data = kcalloc(PENDING_IO_MAX,
7011				     sizeof(struct r5pending_data),
7012				     GFP_KERNEL);
7013	if (!conf->pending_data)
7014		goto abort;
7015	for (i = 0; i < PENDING_IO_MAX; i++)
7016		list_add(&conf->pending_data[i].sibling, &conf->free_list);
7017	/* Don't enable multi-threading by default*/
7018	if (!alloc_thread_groups(conf, 0, &group_cnt, &new_group)) {
7019		conf->group_cnt = group_cnt;
7020		conf->worker_cnt_per_group = 0;
7021		conf->worker_groups = new_group;
7022	} else
7023		goto abort;
7024	spin_lock_init(&conf->device_lock);
7025	seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock);
7026	mutex_init(&conf->cache_size_mutex);
7027	init_waitqueue_head(&conf->wait_for_quiescent);
7028	init_waitqueue_head(&conf->wait_for_stripe);
7029	init_waitqueue_head(&conf->wait_for_overlap);
7030	INIT_LIST_HEAD(&conf->handle_list);
7031	INIT_LIST_HEAD(&conf->loprio_list);
7032	INIT_LIST_HEAD(&conf->hold_list);
7033	INIT_LIST_HEAD(&conf->delayed_list);
7034	INIT_LIST_HEAD(&conf->bitmap_list);
7035	init_llist_head(&conf->released_stripes);
7036	atomic_set(&conf->active_stripes, 0);
7037	atomic_set(&conf->preread_active_stripes, 0);
7038	atomic_set(&conf->active_aligned_reads, 0);
7039	spin_lock_init(&conf->pending_bios_lock);
7040	conf->batch_bio_dispatch = true;
7041	rdev_for_each(rdev, mddev) {
7042		if (test_bit(Journal, &rdev->flags))
7043			continue;
7044		if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
7045			conf->batch_bio_dispatch = false;
7046			break;
7047		}
7048	}
7049
7050	conf->bypass_threshold = BYPASS_THRESHOLD;
7051	conf->recovery_disabled = mddev->recovery_disabled - 1;
7052
7053	conf->raid_disks = mddev->raid_disks;
7054	if (mddev->reshape_position == MaxSector)
7055		conf->previous_raid_disks = mddev->raid_disks;
7056	else
7057		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
7058	max_disks = max(conf->raid_disks, conf->previous_raid_disks);
 
7059
7060	conf->disks = kcalloc(max_disks, sizeof(struct disk_info),
7061			      GFP_KERNEL);
7062
7063	if (!conf->disks)
7064		goto abort;
7065
7066	for (i = 0; i < max_disks; i++) {
7067		conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
7068		if (!conf->disks[i].extra_page)
7069			goto abort;
7070	}
7071
7072	ret = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
7073	if (ret)
7074		goto abort;
7075	conf->mddev = mddev;
7076
7077	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
7078		goto abort;
7079
7080	/* We init hash_locks[0] separately to that it can be used
7081	 * as the reference lock in the spin_lock_nest_lock() call
7082	 * in lock_all_device_hash_locks_irq in order to convince
7083	 * lockdep that we know what we are doing.
7084	 */
7085	spin_lock_init(conf->hash_locks);
7086	for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
7087		spin_lock_init(conf->hash_locks + i);
7088
7089	for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7090		INIT_LIST_HEAD(conf->inactive_list + i);
7091
7092	for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7093		INIT_LIST_HEAD(conf->temp_inactive_list + i);
7094
7095	atomic_set(&conf->r5c_cached_full_stripes, 0);
7096	INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7097	atomic_set(&conf->r5c_cached_partial_stripes, 0);
7098	INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7099	atomic_set(&conf->r5c_flushing_full_stripes, 0);
7100	atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7101
7102	conf->level = mddev->new_level;
7103	conf->chunk_sectors = mddev->new_chunk_sectors;
7104	if (raid5_alloc_percpu(conf) != 0)
7105		goto abort;
7106
7107	pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7108
7109	rdev_for_each(rdev, mddev) {
7110		raid_disk = rdev->raid_disk;
7111		if (raid_disk >= max_disks
7112		    || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7113			continue;
7114		disk = conf->disks + raid_disk;
7115
7116		if (test_bit(Replacement, &rdev->flags)) {
7117			if (disk->replacement)
7118				goto abort;
7119			disk->replacement = rdev;
7120		} else {
7121			if (disk->rdev)
7122				goto abort;
7123			disk->rdev = rdev;
7124		}
7125
7126		if (test_bit(In_sync, &rdev->flags)) {
7127			char b[BDEVNAME_SIZE];
7128			pr_info("md/raid:%s: device %s operational as raid disk %d\n",
7129				mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
 
7130		} else if (rdev->saved_raid_disk != raid_disk)
7131			/* Cannot rely on bitmap to complete recovery */
7132			conf->fullsync = 1;
7133	}
7134
 
7135	conf->level = mddev->new_level;
7136	if (conf->level == 6) {
7137		conf->max_degraded = 2;
7138		if (raid6_call.xor_syndrome)
7139			conf->rmw_level = PARITY_ENABLE_RMW;
7140		else
7141			conf->rmw_level = PARITY_DISABLE_RMW;
7142	} else {
7143		conf->max_degraded = 1;
7144		conf->rmw_level = PARITY_ENABLE_RMW;
7145	}
7146	conf->algorithm = mddev->new_layout;
 
7147	conf->reshape_progress = mddev->reshape_position;
7148	if (conf->reshape_progress != MaxSector) {
7149		conf->prev_chunk_sectors = mddev->chunk_sectors;
7150		conf->prev_algo = mddev->layout;
7151	} else {
7152		conf->prev_chunk_sectors = conf->chunk_sectors;
7153		conf->prev_algo = conf->algorithm;
7154	}
7155
7156	conf->min_nr_stripes = NR_STRIPES;
7157	if (mddev->reshape_position != MaxSector) {
7158		int stripes = max_t(int,
7159			((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4,
7160			((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4);
7161		conf->min_nr_stripes = max(NR_STRIPES, stripes);
7162		if (conf->min_nr_stripes != NR_STRIPES)
7163			pr_info("md/raid:%s: force stripe size %d for reshape\n",
7164				mdname(mddev), conf->min_nr_stripes);
7165	}
7166	memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7167		 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7168	atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7169	if (grow_stripes(conf, conf->min_nr_stripes)) {
7170		pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7171			mdname(mddev), memory);
7172		goto abort;
7173	} else
7174		pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7175	/*
7176	 * Losing a stripe head costs more than the time to refill it,
7177	 * it reduces the queue depth and so can hurt throughput.
7178	 * So set it rather large, scaled by number of devices.
7179	 */
7180	conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7181	conf->shrinker.scan_objects = raid5_cache_scan;
7182	conf->shrinker.count_objects = raid5_cache_count;
7183	conf->shrinker.batch = 128;
7184	conf->shrinker.flags = 0;
7185	if (register_shrinker(&conf->shrinker)) {
7186		pr_warn("md/raid:%s: couldn't register shrinker.\n",
7187			mdname(mddev));
7188		goto abort;
7189	}
7190
7191	sprintf(pers_name, "raid%d", mddev->new_level);
7192	conf->thread = md_register_thread(raid5d, mddev, pers_name);
7193	if (!conf->thread) {
7194		pr_warn("md/raid:%s: couldn't allocate thread.\n",
7195			mdname(mddev));
 
7196		goto abort;
7197	}
7198
7199	return conf;
7200
7201 abort:
7202	if (conf) {
7203		free_conf(conf);
7204		return ERR_PTR(-EIO);
7205	} else
7206		return ERR_PTR(-ENOMEM);
7207}
7208
 
7209static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7210{
7211	switch (algo) {
7212	case ALGORITHM_PARITY_0:
7213		if (raid_disk < max_degraded)
7214			return 1;
7215		break;
7216	case ALGORITHM_PARITY_N:
7217		if (raid_disk >= raid_disks - max_degraded)
7218			return 1;
7219		break;
7220	case ALGORITHM_PARITY_0_6:
7221		if (raid_disk == 0 ||
7222		    raid_disk == raid_disks - 1)
7223			return 1;
7224		break;
7225	case ALGORITHM_LEFT_ASYMMETRIC_6:
7226	case ALGORITHM_RIGHT_ASYMMETRIC_6:
7227	case ALGORITHM_LEFT_SYMMETRIC_6:
7228	case ALGORITHM_RIGHT_SYMMETRIC_6:
7229		if (raid_disk == raid_disks - 1)
7230			return 1;
7231	}
7232	return 0;
7233}
7234
7235static int raid5_run(struct mddev *mddev)
7236{
7237	struct r5conf *conf;
7238	int working_disks = 0;
7239	int dirty_parity_disks = 0;
7240	struct md_rdev *rdev;
7241	struct md_rdev *journal_dev = NULL;
7242	sector_t reshape_offset = 0;
7243	int i;
7244	long long min_offset_diff = 0;
7245	int first = 1;
7246
7247	if (mddev_init_writes_pending(mddev) < 0)
7248		return -ENOMEM;
7249
7250	if (mddev->recovery_cp != MaxSector)
7251		pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7252			  mdname(mddev));
 
7253
7254	rdev_for_each(rdev, mddev) {
7255		long long diff;
7256
7257		if (test_bit(Journal, &rdev->flags)) {
7258			journal_dev = rdev;
7259			continue;
7260		}
7261		if (rdev->raid_disk < 0)
7262			continue;
7263		diff = (rdev->new_data_offset - rdev->data_offset);
7264		if (first) {
7265			min_offset_diff = diff;
7266			first = 0;
7267		} else if (mddev->reshape_backwards &&
7268			 diff < min_offset_diff)
7269			min_offset_diff = diff;
7270		else if (!mddev->reshape_backwards &&
7271			 diff > min_offset_diff)
7272			min_offset_diff = diff;
7273	}
7274
7275	if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7276	    (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7277		pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7278			  mdname(mddev));
7279		return -EINVAL;
7280	}
7281
7282	if (mddev->reshape_position != MaxSector) {
7283		/* Check that we can continue the reshape.
7284		 * Difficulties arise if the stripe we would write to
7285		 * next is at or after the stripe we would read from next.
7286		 * For a reshape that changes the number of devices, this
7287		 * is only possible for a very short time, and mdadm makes
7288		 * sure that time appears to have past before assembling
7289		 * the array.  So we fail if that time hasn't passed.
7290		 * For a reshape that keeps the number of devices the same
7291		 * mdadm must be monitoring the reshape can keeping the
7292		 * critical areas read-only and backed up.  It will start
7293		 * the array in read-only mode, so we check for that.
7294		 */
7295		sector_t here_new, here_old;
7296		int old_disks;
7297		int max_degraded = (mddev->level == 6 ? 2 : 1);
7298		int chunk_sectors;
7299		int new_data_disks;
7300
7301		if (journal_dev) {
7302			pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7303				mdname(mddev));
7304			return -EINVAL;
7305		}
7306
7307		if (mddev->new_level != mddev->level) {
7308			pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7309				mdname(mddev));
 
7310			return -EINVAL;
7311		}
7312		old_disks = mddev->raid_disks - mddev->delta_disks;
7313		/* reshape_position must be on a new-stripe boundary, and one
7314		 * further up in new geometry must map after here in old
7315		 * geometry.
7316		 * If the chunk sizes are different, then as we perform reshape
7317		 * in units of the largest of the two, reshape_position needs
7318		 * be a multiple of the largest chunk size times new data disks.
7319		 */
7320		here_new = mddev->reshape_position;
7321		chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7322		new_data_disks = mddev->raid_disks - max_degraded;
7323		if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7324			pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7325				mdname(mddev));
7326			return -EINVAL;
7327		}
7328		reshape_offset = here_new * chunk_sectors;
7329		/* here_new is the stripe we will write to */
7330		here_old = mddev->reshape_position;
7331		sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
 
7332		/* here_old is the first stripe that we might need to read
7333		 * from */
7334		if (mddev->delta_disks == 0) {
 
 
 
 
 
 
7335			/* We cannot be sure it is safe to start an in-place
7336			 * reshape.  It is only safe if user-space is monitoring
7337			 * and taking constant backups.
7338			 * mdadm always starts a situation like this in
7339			 * readonly mode so it can take control before
7340			 * allowing any writes.  So just check for that.
7341			 */
7342			if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7343			    abs(min_offset_diff) >= mddev->new_chunk_sectors)
7344				/* not really in-place - so OK */;
7345			else if (mddev->ro == 0) {
7346				pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7347					mdname(mddev));
 
 
7348				return -EINVAL;
7349			}
7350		} else if (mddev->reshape_backwards
7351		    ? (here_new * chunk_sectors + min_offset_diff <=
7352		       here_old * chunk_sectors)
7353		    : (here_new * chunk_sectors >=
7354		       here_old * chunk_sectors + (-min_offset_diff))) {
7355			/* Reading from the same stripe as writing to - bad */
7356			pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7357				mdname(mddev));
 
7358			return -EINVAL;
7359		}
7360		pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
 
7361		/* OK, we should be able to continue; */
7362	} else {
7363		BUG_ON(mddev->level != mddev->new_level);
7364		BUG_ON(mddev->layout != mddev->new_layout);
7365		BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7366		BUG_ON(mddev->delta_disks != 0);
7367	}
7368
7369	if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7370	    test_bit(MD_HAS_PPL, &mddev->flags)) {
7371		pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7372			mdname(mddev));
7373		clear_bit(MD_HAS_PPL, &mddev->flags);
7374		clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7375	}
7376
7377	if (mddev->private == NULL)
7378		conf = setup_conf(mddev);
7379	else
7380		conf = mddev->private;
7381
7382	if (IS_ERR(conf))
7383		return PTR_ERR(conf);
7384
7385	if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7386		if (!journal_dev) {
7387			pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7388				mdname(mddev));
7389			mddev->ro = 1;
7390			set_disk_ro(mddev->gendisk, 1);
7391		} else if (mddev->recovery_cp == MaxSector)
7392			set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7393	}
7394
7395	conf->min_offset_diff = min_offset_diff;
7396	mddev->thread = conf->thread;
7397	conf->thread = NULL;
7398	mddev->private = conf;
7399
7400	for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7401	     i++) {
7402		rdev = conf->disks[i].rdev;
7403		if (!rdev && conf->disks[i].replacement) {
7404			/* The replacement is all we have yet */
7405			rdev = conf->disks[i].replacement;
7406			conf->disks[i].replacement = NULL;
7407			clear_bit(Replacement, &rdev->flags);
7408			conf->disks[i].rdev = rdev;
7409		}
7410		if (!rdev)
7411			continue;
7412		if (conf->disks[i].replacement &&
7413		    conf->reshape_progress != MaxSector) {
7414			/* replacements and reshape simply do not mix. */
7415			pr_warn("md: cannot handle concurrent replacement and reshape.\n");
 
7416			goto abort;
7417		}
7418		if (test_bit(In_sync, &rdev->flags)) {
7419			working_disks++;
7420			continue;
7421		}
7422		/* This disc is not fully in-sync.  However if it
7423		 * just stored parity (beyond the recovery_offset),
7424		 * when we don't need to be concerned about the
7425		 * array being dirty.
7426		 * When reshape goes 'backwards', we never have
7427		 * partially completed devices, so we only need
7428		 * to worry about reshape going forwards.
7429		 */
7430		/* Hack because v0.91 doesn't store recovery_offset properly. */
7431		if (mddev->major_version == 0 &&
7432		    mddev->minor_version > 90)
7433			rdev->recovery_offset = reshape_offset;
7434
7435		if (rdev->recovery_offset < reshape_offset) {
7436			/* We need to check old and new layout */
7437			if (!only_parity(rdev->raid_disk,
7438					 conf->algorithm,
7439					 conf->raid_disks,
7440					 conf->max_degraded))
7441				continue;
7442		}
7443		if (!only_parity(rdev->raid_disk,
7444				 conf->prev_algo,
7445				 conf->previous_raid_disks,
7446				 conf->max_degraded))
7447			continue;
7448		dirty_parity_disks++;
7449	}
7450
7451	/*
7452	 * 0 for a fully functional array, 1 or 2 for a degraded array.
7453	 */
7454	mddev->degraded = raid5_calc_degraded(conf);
7455
7456	if (has_failed(conf)) {
7457		pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
 
7458			mdname(mddev), mddev->degraded, conf->raid_disks);
7459		goto abort;
7460	}
7461
7462	/* device size must be a multiple of chunk size */
7463	mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
7464	mddev->resync_max_sectors = mddev->dev_sectors;
7465
7466	if (mddev->degraded > dirty_parity_disks &&
7467	    mddev->recovery_cp != MaxSector) {
7468		if (test_bit(MD_HAS_PPL, &mddev->flags))
7469			pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7470				mdname(mddev));
7471		else if (mddev->ok_start_degraded)
7472			pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7473				mdname(mddev));
7474		else {
7475			pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7476				mdname(mddev));
 
7477			goto abort;
7478		}
7479	}
7480
7481	pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7482		mdname(mddev), conf->level,
7483		mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7484		mddev->new_layout);
 
 
 
 
 
 
 
7485
7486	print_raid5_conf(conf);
7487
7488	if (conf->reshape_progress != MaxSector) {
7489		conf->reshape_safe = conf->reshape_progress;
7490		atomic_set(&conf->reshape_stripes, 0);
7491		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7492		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7493		set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7494		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7495		mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7496							"reshape");
7497		if (!mddev->sync_thread)
7498			goto abort;
7499	}
7500
 
7501	/* Ok, everything is just fine now */
7502	if (mddev->to_remove == &raid5_attrs_group)
7503		mddev->to_remove = NULL;
7504	else if (mddev->kobj.sd &&
7505	    sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7506		pr_warn("raid5: failed to create sysfs attributes for %s\n",
7507			mdname(mddev));
 
7508	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7509
7510	if (mddev->queue) {
7511		int chunk_size;
7512		/* read-ahead size must cover two whole stripes, which
7513		 * is 2 * (datadisks) * chunksize where 'n' is the
7514		 * number of raid devices
7515		 */
7516		int data_disks = conf->previous_raid_disks - conf->max_degraded;
7517		int stripe = data_disks *
7518			((mddev->chunk_sectors << 9) / PAGE_SIZE);
7519		if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7520			mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
 
 
 
 
 
7521
7522		chunk_size = mddev->chunk_sectors << 9;
7523		blk_queue_io_min(mddev->queue, chunk_size);
7524		blk_queue_io_opt(mddev->queue, chunk_size *
7525				 (conf->raid_disks - conf->max_degraded));
7526		mddev->queue->limits.raid_partial_stripes_expensive = 1;
7527		/*
7528		 * We can only discard a whole stripe. It doesn't make sense to
7529		 * discard data disk but write parity disk
7530		 */
7531		stripe = stripe * PAGE_SIZE;
7532		/* Round up to power of 2, as discard handling
7533		 * currently assumes that */
7534		while ((stripe-1) & stripe)
7535			stripe = (stripe | (stripe-1)) + 1;
7536		mddev->queue->limits.discard_alignment = stripe;
7537		mddev->queue->limits.discard_granularity = stripe;
7538
7539		blk_queue_max_write_same_sectors(mddev->queue, 0);
7540		blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
7541
7542		rdev_for_each(rdev, mddev) {
7543			disk_stack_limits(mddev->gendisk, rdev->bdev,
7544					  rdev->data_offset << 9);
7545			disk_stack_limits(mddev->gendisk, rdev->bdev,
7546					  rdev->new_data_offset << 9);
7547		}
7548
7549		/*
7550		 * zeroing is required, otherwise data
7551		 * could be lost. Consider a scenario: discard a stripe
7552		 * (the stripe could be inconsistent if
7553		 * discard_zeroes_data is 0); write one disk of the
7554		 * stripe (the stripe could be inconsistent again
7555		 * depending on which disks are used to calculate
7556		 * parity); the disk is broken; The stripe data of this
7557		 * disk is lost.
7558		 *
7559		 * We only allow DISCARD if the sysadmin has confirmed that
7560		 * only safe devices are in use by setting a module parameter.
7561		 * A better idea might be to turn DISCARD into WRITE_ZEROES
7562		 * requests, as that is required to be safe.
7563		 */
7564		if (devices_handle_discard_safely &&
7565		    mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
7566		    mddev->queue->limits.discard_granularity >= stripe)
7567			blk_queue_flag_set(QUEUE_FLAG_DISCARD,
7568						mddev->queue);
7569		else
7570			blk_queue_flag_clear(QUEUE_FLAG_DISCARD,
7571						mddev->queue);
7572
7573		blk_queue_max_hw_sectors(mddev->queue, UINT_MAX);
7574	}
7575
7576	if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
7577		goto abort;
7578
7579	return 0;
7580abort:
7581	md_unregister_thread(&mddev->thread);
7582	print_raid5_conf(conf);
7583	free_conf(conf);
7584	mddev->private = NULL;
7585	pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
7586	return -EIO;
7587}
7588
7589static void raid5_free(struct mddev *mddev, void *priv)
7590{
7591	struct r5conf *conf = priv;
7592
 
 
 
7593	free_conf(conf);
 
7594	mddev->to_remove = &raid5_attrs_group;
 
7595}
7596
7597static void raid5_status(struct seq_file *seq, struct mddev *mddev)
7598{
7599	struct r5conf *conf = mddev->private;
7600	int i;
7601
7602	seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
7603		conf->chunk_sectors / 2, mddev->layout);
7604	seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
7605	rcu_read_lock();
7606	for (i = 0; i < conf->raid_disks; i++) {
7607		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
7608		seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
7609	}
7610	rcu_read_unlock();
7611	seq_printf (seq, "]");
7612}
7613
7614static void print_raid5_conf (struct r5conf *conf)
7615{
7616	int i;
7617	struct disk_info *tmp;
7618
7619	pr_debug("RAID conf printout:\n");
7620	if (!conf) {
7621		pr_debug("(conf==NULL)\n");
7622		return;
7623	}
7624	pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
7625	       conf->raid_disks,
7626	       conf->raid_disks - conf->mddev->degraded);
7627
7628	for (i = 0; i < conf->raid_disks; i++) {
7629		char b[BDEVNAME_SIZE];
7630		tmp = conf->disks + i;
7631		if (tmp->rdev)
7632			pr_debug(" disk %d, o:%d, dev:%s\n",
7633			       i, !test_bit(Faulty, &tmp->rdev->flags),
7634			       bdevname(tmp->rdev->bdev, b));
7635	}
7636}
7637
7638static int raid5_spare_active(struct mddev *mddev)
7639{
7640	int i;
7641	struct r5conf *conf = mddev->private;
7642	struct disk_info *tmp;
7643	int count = 0;
7644	unsigned long flags;
7645
7646	for (i = 0; i < conf->raid_disks; i++) {
7647		tmp = conf->disks + i;
7648		if (tmp->replacement
7649		    && tmp->replacement->recovery_offset == MaxSector
7650		    && !test_bit(Faulty, &tmp->replacement->flags)
7651		    && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
7652			/* Replacement has just become active. */
7653			if (!tmp->rdev
7654			    || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
7655				count++;
7656			if (tmp->rdev) {
7657				/* Replaced device not technically faulty,
7658				 * but we need to be sure it gets removed
7659				 * and never re-added.
7660				 */
7661				set_bit(Faulty, &tmp->rdev->flags);
7662				sysfs_notify_dirent_safe(
7663					tmp->rdev->sysfs_state);
7664			}
7665			sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
7666		} else if (tmp->rdev
7667		    && tmp->rdev->recovery_offset == MaxSector
7668		    && !test_bit(Faulty, &tmp->rdev->flags)
7669		    && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
7670			count++;
7671			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
7672		}
7673	}
7674	spin_lock_irqsave(&conf->device_lock, flags);
7675	mddev->degraded = raid5_calc_degraded(conf);
7676	spin_unlock_irqrestore(&conf->device_lock, flags);
7677	print_raid5_conf(conf);
7678	return count;
7679}
7680
7681static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
7682{
7683	struct r5conf *conf = mddev->private;
7684	int err = 0;
7685	int number = rdev->raid_disk;
7686	struct md_rdev **rdevp;
7687	struct disk_info *p = conf->disks + number;
7688
7689	print_raid5_conf(conf);
7690	if (test_bit(Journal, &rdev->flags) && conf->log) {
7691		/*
7692		 * we can't wait pending write here, as this is called in
7693		 * raid5d, wait will deadlock.
7694		 * neilb: there is no locking about new writes here,
7695		 * so this cannot be safe.
7696		 */
7697		if (atomic_read(&conf->active_stripes) ||
7698		    atomic_read(&conf->r5c_cached_full_stripes) ||
7699		    atomic_read(&conf->r5c_cached_partial_stripes)) {
7700			return -EBUSY;
7701		}
7702		log_exit(conf);
7703		return 0;
7704	}
7705	if (rdev == p->rdev)
7706		rdevp = &p->rdev;
7707	else if (rdev == p->replacement)
7708		rdevp = &p->replacement;
7709	else
7710		return 0;
7711
7712	if (number >= conf->raid_disks &&
7713	    conf->reshape_progress == MaxSector)
7714		clear_bit(In_sync, &rdev->flags);
7715
7716	if (test_bit(In_sync, &rdev->flags) ||
7717	    atomic_read(&rdev->nr_pending)) {
7718		err = -EBUSY;
7719		goto abort;
7720	}
7721	/* Only remove non-faulty devices if recovery
7722	 * isn't possible.
7723	 */
7724	if (!test_bit(Faulty, &rdev->flags) &&
7725	    mddev->recovery_disabled != conf->recovery_disabled &&
7726	    !has_failed(conf) &&
7727	    (!p->replacement || p->replacement == rdev) &&
7728	    number < conf->raid_disks) {
7729		err = -EBUSY;
7730		goto abort;
7731	}
7732	*rdevp = NULL;
7733	if (!test_bit(RemoveSynchronized, &rdev->flags)) {
7734		synchronize_rcu();
7735		if (atomic_read(&rdev->nr_pending)) {
7736			/* lost the race, try later */
7737			err = -EBUSY;
7738			*rdevp = rdev;
7739		}
7740	}
7741	if (!err) {
7742		err = log_modify(conf, rdev, false);
7743		if (err)
7744			goto abort;
7745	}
7746	if (p->replacement) {
7747		/* We must have just cleared 'rdev' */
7748		p->rdev = p->replacement;
7749		clear_bit(Replacement, &p->replacement->flags);
7750		smp_mb(); /* Make sure other CPUs may see both as identical
7751			   * but will never see neither - if they are careful
7752			   */
7753		p->replacement = NULL;
7754
7755		if (!err)
7756			err = log_modify(conf, p->rdev, true);
7757	}
7758
7759	clear_bit(WantReplacement, &rdev->flags);
7760abort:
7761
7762	print_raid5_conf(conf);
7763	return err;
7764}
7765
7766static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
7767{
7768	struct r5conf *conf = mddev->private;
7769	int ret, err = -EEXIST;
7770	int disk;
7771	struct disk_info *p;
7772	int first = 0;
7773	int last = conf->raid_disks - 1;
7774
7775	if (test_bit(Journal, &rdev->flags)) {
7776		if (conf->log)
7777			return -EBUSY;
7778
7779		rdev->raid_disk = 0;
7780		/*
7781		 * The array is in readonly mode if journal is missing, so no
7782		 * write requests running. We should be safe
7783		 */
7784		ret = log_init(conf, rdev, false);
7785		if (ret)
7786			return ret;
7787
7788		ret = r5l_start(conf->log);
7789		if (ret)
7790			return ret;
7791
7792		return 0;
7793	}
7794	if (mddev->recovery_disabled == conf->recovery_disabled)
7795		return -EBUSY;
7796
7797	if (rdev->saved_raid_disk < 0 && has_failed(conf))
7798		/* no point adding a device */
7799		return -EINVAL;
7800
7801	if (rdev->raid_disk >= 0)
7802		first = last = rdev->raid_disk;
7803
7804	/*
7805	 * find the disk ... but prefer rdev->saved_raid_disk
7806	 * if possible.
7807	 */
7808	if (rdev->saved_raid_disk >= 0 &&
7809	    rdev->saved_raid_disk >= first &&
7810	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
7811		first = rdev->saved_raid_disk;
7812
7813	for (disk = first; disk <= last; disk++) {
7814		p = conf->disks + disk;
7815		if (p->rdev == NULL) {
7816			clear_bit(In_sync, &rdev->flags);
7817			rdev->raid_disk = disk;
 
7818			if (rdev->saved_raid_disk != disk)
7819				conf->fullsync = 1;
7820			rcu_assign_pointer(p->rdev, rdev);
7821
7822			err = log_modify(conf, rdev, true);
7823
7824			goto out;
7825		}
7826	}
7827	for (disk = first; disk <= last; disk++) {
7828		p = conf->disks + disk;
7829		if (test_bit(WantReplacement, &p->rdev->flags) &&
7830		    p->replacement == NULL) {
7831			clear_bit(In_sync, &rdev->flags);
7832			set_bit(Replacement, &rdev->flags);
7833			rdev->raid_disk = disk;
7834			err = 0;
7835			conf->fullsync = 1;
7836			rcu_assign_pointer(p->replacement, rdev);
7837			break;
7838		}
7839	}
7840out:
7841	print_raid5_conf(conf);
7842	return err;
7843}
7844
7845static int raid5_resize(struct mddev *mddev, sector_t sectors)
7846{
7847	/* no resync is happening, and there is enough space
7848	 * on all devices, so we can resize.
7849	 * We need to make sure resync covers any new space.
7850	 * If the array is shrinking we should possibly wait until
7851	 * any io in the removed space completes, but it hardly seems
7852	 * worth it.
7853	 */
7854	sector_t newsize;
7855	struct r5conf *conf = mddev->private;
7856
7857	if (raid5_has_log(conf) || raid5_has_ppl(conf))
7858		return -EINVAL;
7859	sectors &= ~((sector_t)conf->chunk_sectors - 1);
7860	newsize = raid5_size(mddev, sectors, mddev->raid_disks);
7861	if (mddev->external_size &&
7862	    mddev->array_sectors > newsize)
7863		return -EINVAL;
7864	if (mddev->bitmap) {
7865		int ret = md_bitmap_resize(mddev->bitmap, sectors, 0, 0);
7866		if (ret)
7867			return ret;
7868	}
7869	md_set_array_sectors(mddev, newsize);
 
 
7870	if (sectors > mddev->dev_sectors &&
7871	    mddev->recovery_cp > mddev->dev_sectors) {
7872		mddev->recovery_cp = mddev->dev_sectors;
7873		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7874	}
7875	mddev->dev_sectors = sectors;
7876	mddev->resync_max_sectors = sectors;
7877	return 0;
7878}
7879
7880static int check_stripe_cache(struct mddev *mddev)
7881{
7882	/* Can only proceed if there are plenty of stripe_heads.
7883	 * We need a minimum of one full stripe,, and for sensible progress
7884	 * it is best to have about 4 times that.
7885	 * If we require 4 times, then the default 256 4K stripe_heads will
7886	 * allow for chunk sizes up to 256K, which is probably OK.
7887	 * If the chunk size is greater, user-space should request more
7888	 * stripe_heads first.
7889	 */
7890	struct r5conf *conf = mddev->private;
7891	if (((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
7892	    > conf->min_nr_stripes ||
7893	    ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
7894	    > conf->min_nr_stripes) {
7895		pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
7896			mdname(mddev),
7897			((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
7898			 / RAID5_STRIPE_SIZE(conf))*4);
7899		return 0;
7900	}
7901	return 1;
7902}
7903
7904static int check_reshape(struct mddev *mddev)
7905{
7906	struct r5conf *conf = mddev->private;
7907
7908	if (raid5_has_log(conf) || raid5_has_ppl(conf))
7909		return -EINVAL;
7910	if (mddev->delta_disks == 0 &&
7911	    mddev->new_layout == mddev->layout &&
7912	    mddev->new_chunk_sectors == mddev->chunk_sectors)
7913		return 0; /* nothing to do */
7914	if (has_failed(conf))
7915		return -EINVAL;
7916	if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
7917		/* We might be able to shrink, but the devices must
7918		 * be made bigger first.
7919		 * For raid6, 4 is the minimum size.
7920		 * Otherwise 2 is the minimum
7921		 */
7922		int min = 2;
7923		if (mddev->level == 6)
7924			min = 4;
7925		if (mddev->raid_disks + mddev->delta_disks < min)
7926			return -EINVAL;
7927	}
7928
7929	if (!check_stripe_cache(mddev))
7930		return -ENOSPC;
7931
7932	if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
7933	    mddev->delta_disks > 0)
7934		if (resize_chunks(conf,
7935				  conf->previous_raid_disks
7936				  + max(0, mddev->delta_disks),
7937				  max(mddev->new_chunk_sectors,
7938				      mddev->chunk_sectors)
7939			    ) < 0)
7940			return -ENOMEM;
7941
7942	if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
7943		return 0; /* never bother to shrink */
7944	return resize_stripes(conf, (conf->previous_raid_disks
7945				     + mddev->delta_disks));
7946}
7947
7948static int raid5_start_reshape(struct mddev *mddev)
7949{
7950	struct r5conf *conf = mddev->private;
7951	struct md_rdev *rdev;
7952	int spares = 0;
7953	unsigned long flags;
7954
7955	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
7956		return -EBUSY;
7957
7958	if (!check_stripe_cache(mddev))
7959		return -ENOSPC;
7960
7961	if (has_failed(conf))
7962		return -EINVAL;
7963
7964	rdev_for_each(rdev, mddev) {
7965		if (!test_bit(In_sync, &rdev->flags)
7966		    && !test_bit(Faulty, &rdev->flags))
7967			spares++;
7968	}
7969
7970	if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
7971		/* Not enough devices even to make a degraded array
7972		 * of that size
7973		 */
7974		return -EINVAL;
7975
7976	/* Refuse to reduce size of the array.  Any reductions in
7977	 * array size must be through explicit setting of array_size
7978	 * attribute.
7979	 */
7980	if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
7981	    < mddev->array_sectors) {
7982		pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
7983			mdname(mddev));
7984		return -EINVAL;
7985	}
7986
7987	atomic_set(&conf->reshape_stripes, 0);
7988	spin_lock_irq(&conf->device_lock);
7989	write_seqcount_begin(&conf->gen_lock);
7990	conf->previous_raid_disks = conf->raid_disks;
7991	conf->raid_disks += mddev->delta_disks;
7992	conf->prev_chunk_sectors = conf->chunk_sectors;
7993	conf->chunk_sectors = mddev->new_chunk_sectors;
7994	conf->prev_algo = conf->algorithm;
7995	conf->algorithm = mddev->new_layout;
7996	conf->generation++;
7997	/* Code that selects data_offset needs to see the generation update
7998	 * if reshape_progress has been set - so a memory barrier needed.
7999	 */
8000	smp_mb();
8001	if (mddev->reshape_backwards)
8002		conf->reshape_progress = raid5_size(mddev, 0, 0);
8003	else
8004		conf->reshape_progress = 0;
8005	conf->reshape_safe = conf->reshape_progress;
8006	write_seqcount_end(&conf->gen_lock);
8007	spin_unlock_irq(&conf->device_lock);
8008
8009	/* Now make sure any requests that proceeded on the assumption
8010	 * the reshape wasn't running - like Discard or Read - have
8011	 * completed.
8012	 */
8013	mddev_suspend(mddev);
8014	mddev_resume(mddev);
8015
8016	/* Add some new drives, as many as will fit.
8017	 * We know there are enough to make the newly sized array work.
8018	 * Don't add devices if we are reducing the number of
8019	 * devices in the array.  This is because it is not possible
8020	 * to correctly record the "partially reconstructed" state of
8021	 * such devices during the reshape and confusion could result.
8022	 */
8023	if (mddev->delta_disks >= 0) {
8024		rdev_for_each(rdev, mddev)
8025			if (rdev->raid_disk < 0 &&
8026			    !test_bit(Faulty, &rdev->flags)) {
8027				if (raid5_add_disk(mddev, rdev) == 0) {
8028					if (rdev->raid_disk
8029					    >= conf->previous_raid_disks)
8030						set_bit(In_sync, &rdev->flags);
8031					else
8032						rdev->recovery_offset = 0;
8033
8034					/* Failure here is OK */
8035					sysfs_link_rdev(mddev, rdev);
8036				}
8037			} else if (rdev->raid_disk >= conf->previous_raid_disks
8038				   && !test_bit(Faulty, &rdev->flags)) {
8039				/* This is a spare that was manually added */
8040				set_bit(In_sync, &rdev->flags);
8041			}
8042
8043		/* When a reshape changes the number of devices,
8044		 * ->degraded is measured against the larger of the
8045		 * pre and post number of devices.
8046		 */
8047		spin_lock_irqsave(&conf->device_lock, flags);
8048		mddev->degraded = raid5_calc_degraded(conf);
8049		spin_unlock_irqrestore(&conf->device_lock, flags);
8050	}
8051	mddev->raid_disks = conf->raid_disks;
8052	mddev->reshape_position = conf->reshape_progress;
8053	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8054
8055	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
8056	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
8057	clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
8058	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
8059	set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
8060	mddev->sync_thread = md_register_thread(md_do_sync, mddev,
8061						"reshape");
8062	if (!mddev->sync_thread) {
8063		mddev->recovery = 0;
8064		spin_lock_irq(&conf->device_lock);
8065		write_seqcount_begin(&conf->gen_lock);
8066		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
8067		mddev->new_chunk_sectors =
8068			conf->chunk_sectors = conf->prev_chunk_sectors;
8069		mddev->new_layout = conf->algorithm = conf->prev_algo;
8070		rdev_for_each(rdev, mddev)
8071			rdev->new_data_offset = rdev->data_offset;
8072		smp_wmb();
8073		conf->generation --;
8074		conf->reshape_progress = MaxSector;
8075		mddev->reshape_position = MaxSector;
8076		write_seqcount_end(&conf->gen_lock);
8077		spin_unlock_irq(&conf->device_lock);
8078		return -EAGAIN;
8079	}
8080	conf->reshape_checkpoint = jiffies;
8081	md_wakeup_thread(mddev->sync_thread);
8082	md_new_event(mddev);
8083	return 0;
8084}
8085
8086/* This is called from the reshape thread and should make any
8087 * changes needed in 'conf'
8088 */
8089static void end_reshape(struct r5conf *conf)
8090{
8091
8092	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
8093		struct md_rdev *rdev;
8094
8095		spin_lock_irq(&conf->device_lock);
8096		conf->previous_raid_disks = conf->raid_disks;
8097		md_finish_reshape(conf->mddev);
 
8098		smp_wmb();
8099		conf->reshape_progress = MaxSector;
8100		conf->mddev->reshape_position = MaxSector;
8101		rdev_for_each(rdev, conf->mddev)
8102			if (rdev->raid_disk >= 0 &&
8103			    !test_bit(Journal, &rdev->flags) &&
8104			    !test_bit(In_sync, &rdev->flags))
8105				rdev->recovery_offset = MaxSector;
8106		spin_unlock_irq(&conf->device_lock);
8107		wake_up(&conf->wait_for_overlap);
8108
8109		/* read-ahead size must cover two whole stripes, which is
8110		 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
8111		 */
8112		if (conf->mddev->queue) {
8113			int data_disks = conf->raid_disks - conf->max_degraded;
8114			int stripe = data_disks * ((conf->chunk_sectors << 9)
8115						   / PAGE_SIZE);
8116			if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
8117				conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
8118		}
8119	}
8120}
8121
8122/* This is called from the raid5d thread with mddev_lock held.
8123 * It makes config changes to the device.
8124 */
8125static void raid5_finish_reshape(struct mddev *mddev)
8126{
8127	struct r5conf *conf = mddev->private;
8128
8129	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8130
8131		if (mddev->delta_disks <= 0) {
 
 
 
 
8132			int d;
8133			spin_lock_irq(&conf->device_lock);
8134			mddev->degraded = raid5_calc_degraded(conf);
8135			spin_unlock_irq(&conf->device_lock);
8136			for (d = conf->raid_disks ;
8137			     d < conf->raid_disks - mddev->delta_disks;
8138			     d++) {
8139				struct md_rdev *rdev = conf->disks[d].rdev;
8140				if (rdev)
8141					clear_bit(In_sync, &rdev->flags);
8142				rdev = conf->disks[d].replacement;
8143				if (rdev)
8144					clear_bit(In_sync, &rdev->flags);
8145			}
8146		}
8147		mddev->layout = conf->algorithm;
8148		mddev->chunk_sectors = conf->chunk_sectors;
8149		mddev->reshape_position = MaxSector;
8150		mddev->delta_disks = 0;
8151		mddev->reshape_backwards = 0;
8152	}
8153}
8154
8155static void raid5_quiesce(struct mddev *mddev, int quiesce)
8156{
8157	struct r5conf *conf = mddev->private;
8158
8159	if (quiesce) {
8160		/* stop all writes */
8161		lock_all_device_hash_locks_irq(conf);
 
 
 
 
8162		/* '2' tells resync/reshape to pause so that all
8163		 * active stripes can drain
8164		 */
8165		r5c_flush_cache(conf, INT_MAX);
8166		conf->quiesce = 2;
8167		wait_event_cmd(conf->wait_for_quiescent,
8168				    atomic_read(&conf->active_stripes) == 0 &&
8169				    atomic_read(&conf->active_aligned_reads) == 0,
8170				    unlock_all_device_hash_locks_irq(conf),
8171				    lock_all_device_hash_locks_irq(conf));
8172		conf->quiesce = 1;
8173		unlock_all_device_hash_locks_irq(conf);
8174		/* allow reshape to continue */
8175		wake_up(&conf->wait_for_overlap);
8176	} else {
8177		/* re-enable writes */
8178		lock_all_device_hash_locks_irq(conf);
 
8179		conf->quiesce = 0;
8180		wake_up(&conf->wait_for_quiescent);
8181		wake_up(&conf->wait_for_overlap);
8182		unlock_all_device_hash_locks_irq(conf);
 
8183	}
8184	log_quiesce(conf, quiesce);
8185}
8186
 
8187static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8188{
8189	struct r0conf *raid0_conf = mddev->private;
8190	sector_t sectors;
8191
8192	/* for raid0 takeover only one zone is supported */
8193	if (raid0_conf->nr_strip_zones > 1) {
8194		pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8195			mdname(mddev));
8196		return ERR_PTR(-EINVAL);
8197	}
8198
8199	sectors = raid0_conf->strip_zone[0].zone_end;
8200	sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8201	mddev->dev_sectors = sectors;
8202	mddev->new_level = level;
8203	mddev->new_layout = ALGORITHM_PARITY_N;
8204	mddev->new_chunk_sectors = mddev->chunk_sectors;
8205	mddev->raid_disks += 1;
8206	mddev->delta_disks = 1;
8207	/* make sure it will be not marked as dirty */
8208	mddev->recovery_cp = MaxSector;
8209
8210	return setup_conf(mddev);
8211}
8212
 
8213static void *raid5_takeover_raid1(struct mddev *mddev)
8214{
8215	int chunksect;
8216	void *ret;
8217
8218	if (mddev->raid_disks != 2 ||
8219	    mddev->degraded > 1)
8220		return ERR_PTR(-EINVAL);
8221
8222	/* Should check if there are write-behind devices? */
8223
8224	chunksect = 64*2; /* 64K by default */
8225
8226	/* The array must be an exact multiple of chunksize */
8227	while (chunksect && (mddev->array_sectors & (chunksect-1)))
8228		chunksect >>= 1;
8229
8230	if ((chunksect<<9) < RAID5_STRIPE_SIZE((struct r5conf *)mddev->private))
8231		/* array size does not allow a suitable chunk size */
8232		return ERR_PTR(-EINVAL);
8233
8234	mddev->new_level = 5;
8235	mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8236	mddev->new_chunk_sectors = chunksect;
8237
8238	ret = setup_conf(mddev);
8239	if (!IS_ERR(ret))
8240		mddev_clear_unsupported_flags(mddev,
8241			UNSUPPORTED_MDDEV_FLAGS);
8242	return ret;
8243}
8244
8245static void *raid5_takeover_raid6(struct mddev *mddev)
8246{
8247	int new_layout;
8248
8249	switch (mddev->layout) {
8250	case ALGORITHM_LEFT_ASYMMETRIC_6:
8251		new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8252		break;
8253	case ALGORITHM_RIGHT_ASYMMETRIC_6:
8254		new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8255		break;
8256	case ALGORITHM_LEFT_SYMMETRIC_6:
8257		new_layout = ALGORITHM_LEFT_SYMMETRIC;
8258		break;
8259	case ALGORITHM_RIGHT_SYMMETRIC_6:
8260		new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8261		break;
8262	case ALGORITHM_PARITY_0_6:
8263		new_layout = ALGORITHM_PARITY_0;
8264		break;
8265	case ALGORITHM_PARITY_N:
8266		new_layout = ALGORITHM_PARITY_N;
8267		break;
8268	default:
8269		return ERR_PTR(-EINVAL);
8270	}
8271	mddev->new_level = 5;
8272	mddev->new_layout = new_layout;
8273	mddev->delta_disks = -1;
8274	mddev->raid_disks -= 1;
8275	return setup_conf(mddev);
8276}
8277
 
8278static int raid5_check_reshape(struct mddev *mddev)
8279{
8280	/* For a 2-drive array, the layout and chunk size can be changed
8281	 * immediately as not restriping is needed.
8282	 * For larger arrays we record the new value - after validation
8283	 * to be used by a reshape pass.
8284	 */
8285	struct r5conf *conf = mddev->private;
8286	int new_chunk = mddev->new_chunk_sectors;
8287
8288	if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8289		return -EINVAL;
8290	if (new_chunk > 0) {
8291		if (!is_power_of_2(new_chunk))
8292			return -EINVAL;
8293		if (new_chunk < (PAGE_SIZE>>9))
8294			return -EINVAL;
8295		if (mddev->array_sectors & (new_chunk-1))
8296			/* not factor of array size */
8297			return -EINVAL;
8298	}
8299
8300	/* They look valid */
8301
8302	if (mddev->raid_disks == 2) {
8303		/* can make the change immediately */
8304		if (mddev->new_layout >= 0) {
8305			conf->algorithm = mddev->new_layout;
8306			mddev->layout = mddev->new_layout;
8307		}
8308		if (new_chunk > 0) {
8309			conf->chunk_sectors = new_chunk ;
8310			mddev->chunk_sectors = new_chunk;
8311		}
8312		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8313		md_wakeup_thread(mddev->thread);
8314	}
8315	return check_reshape(mddev);
8316}
8317
8318static int raid6_check_reshape(struct mddev *mddev)
8319{
8320	int new_chunk = mddev->new_chunk_sectors;
8321
8322	if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8323		return -EINVAL;
8324	if (new_chunk > 0) {
8325		if (!is_power_of_2(new_chunk))
8326			return -EINVAL;
8327		if (new_chunk < (PAGE_SIZE >> 9))
8328			return -EINVAL;
8329		if (mddev->array_sectors & (new_chunk-1))
8330			/* not factor of array size */
8331			return -EINVAL;
8332	}
8333
8334	/* They look valid */
8335	return check_reshape(mddev);
8336}
8337
8338static void *raid5_takeover(struct mddev *mddev)
8339{
8340	/* raid5 can take over:
8341	 *  raid0 - if there is only one strip zone - make it a raid4 layout
8342	 *  raid1 - if there are two drives.  We need to know the chunk size
8343	 *  raid4 - trivial - just use a raid4 layout.
8344	 *  raid6 - Providing it is a *_6 layout
8345	 */
8346	if (mddev->level == 0)
8347		return raid45_takeover_raid0(mddev, 5);
8348	if (mddev->level == 1)
8349		return raid5_takeover_raid1(mddev);
8350	if (mddev->level == 4) {
8351		mddev->new_layout = ALGORITHM_PARITY_N;
8352		mddev->new_level = 5;
8353		return setup_conf(mddev);
8354	}
8355	if (mddev->level == 6)
8356		return raid5_takeover_raid6(mddev);
8357
8358	return ERR_PTR(-EINVAL);
8359}
8360
8361static void *raid4_takeover(struct mddev *mddev)
8362{
8363	/* raid4 can take over:
8364	 *  raid0 - if there is only one strip zone
8365	 *  raid5 - if layout is right
8366	 */
8367	if (mddev->level == 0)
8368		return raid45_takeover_raid0(mddev, 4);
8369	if (mddev->level == 5 &&
8370	    mddev->layout == ALGORITHM_PARITY_N) {
8371		mddev->new_layout = 0;
8372		mddev->new_level = 4;
8373		return setup_conf(mddev);
8374	}
8375	return ERR_PTR(-EINVAL);
8376}
8377
8378static struct md_personality raid5_personality;
8379
8380static void *raid6_takeover(struct mddev *mddev)
8381{
8382	/* Currently can only take over a raid5.  We map the
8383	 * personality to an equivalent raid6 personality
8384	 * with the Q block at the end.
8385	 */
8386	int new_layout;
8387
8388	if (mddev->pers != &raid5_personality)
8389		return ERR_PTR(-EINVAL);
8390	if (mddev->degraded > 1)
8391		return ERR_PTR(-EINVAL);
8392	if (mddev->raid_disks > 253)
8393		return ERR_PTR(-EINVAL);
8394	if (mddev->raid_disks < 3)
8395		return ERR_PTR(-EINVAL);
8396
8397	switch (mddev->layout) {
8398	case ALGORITHM_LEFT_ASYMMETRIC:
8399		new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8400		break;
8401	case ALGORITHM_RIGHT_ASYMMETRIC:
8402		new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8403		break;
8404	case ALGORITHM_LEFT_SYMMETRIC:
8405		new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8406		break;
8407	case ALGORITHM_RIGHT_SYMMETRIC:
8408		new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8409		break;
8410	case ALGORITHM_PARITY_0:
8411		new_layout = ALGORITHM_PARITY_0_6;
8412		break;
8413	case ALGORITHM_PARITY_N:
8414		new_layout = ALGORITHM_PARITY_N;
8415		break;
8416	default:
8417		return ERR_PTR(-EINVAL);
8418	}
8419	mddev->new_level = 6;
8420	mddev->new_layout = new_layout;
8421	mddev->delta_disks = 1;
8422	mddev->raid_disks += 1;
8423	return setup_conf(mddev);
8424}
8425
8426static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8427{
8428	struct r5conf *conf;
8429	int err;
8430
8431	err = mddev_lock(mddev);
8432	if (err)
8433		return err;
8434	conf = mddev->private;
8435	if (!conf) {
8436		mddev_unlock(mddev);
8437		return -ENODEV;
8438	}
8439
8440	if (strncmp(buf, "ppl", 3) == 0) {
8441		/* ppl only works with RAID 5 */
8442		if (!raid5_has_ppl(conf) && conf->level == 5) {
8443			err = log_init(conf, NULL, true);
8444			if (!err) {
8445				err = resize_stripes(conf, conf->pool_size);
8446				if (err)
8447					log_exit(conf);
8448			}
8449		} else
8450			err = -EINVAL;
8451	} else if (strncmp(buf, "resync", 6) == 0) {
8452		if (raid5_has_ppl(conf)) {
8453			mddev_suspend(mddev);
8454			log_exit(conf);
8455			mddev_resume(mddev);
8456			err = resize_stripes(conf, conf->pool_size);
8457		} else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8458			   r5l_log_disk_error(conf)) {
8459			bool journal_dev_exists = false;
8460			struct md_rdev *rdev;
8461
8462			rdev_for_each(rdev, mddev)
8463				if (test_bit(Journal, &rdev->flags)) {
8464					journal_dev_exists = true;
8465					break;
8466				}
8467
8468			if (!journal_dev_exists) {
8469				mddev_suspend(mddev);
8470				clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8471				mddev_resume(mddev);
8472			} else  /* need remove journal device first */
8473				err = -EBUSY;
8474		} else
8475			err = -EINVAL;
8476	} else {
8477		err = -EINVAL;
8478	}
8479
8480	if (!err)
8481		md_update_sb(mddev, 1);
8482
8483	mddev_unlock(mddev);
8484
8485	return err;
8486}
8487
8488static int raid5_start(struct mddev *mddev)
8489{
8490	struct r5conf *conf = mddev->private;
8491
8492	return r5l_start(conf->log);
8493}
8494
8495static struct md_personality raid6_personality =
8496{
8497	.name		= "raid6",
8498	.level		= 6,
8499	.owner		= THIS_MODULE,
8500	.make_request	= raid5_make_request,
8501	.run		= raid5_run,
8502	.start		= raid5_start,
8503	.free		= raid5_free,
8504	.status		= raid5_status,
8505	.error_handler	= raid5_error,
8506	.hot_add_disk	= raid5_add_disk,
8507	.hot_remove_disk= raid5_remove_disk,
8508	.spare_active	= raid5_spare_active,
8509	.sync_request	= raid5_sync_request,
8510	.resize		= raid5_resize,
8511	.size		= raid5_size,
8512	.check_reshape	= raid6_check_reshape,
8513	.start_reshape  = raid5_start_reshape,
8514	.finish_reshape = raid5_finish_reshape,
8515	.quiesce	= raid5_quiesce,
8516	.takeover	= raid6_takeover,
8517	.change_consistency_policy = raid5_change_consistency_policy,
8518};
8519static struct md_personality raid5_personality =
8520{
8521	.name		= "raid5",
8522	.level		= 5,
8523	.owner		= THIS_MODULE,
8524	.make_request	= raid5_make_request,
8525	.run		= raid5_run,
8526	.start		= raid5_start,
8527	.free		= raid5_free,
8528	.status		= raid5_status,
8529	.error_handler	= raid5_error,
8530	.hot_add_disk	= raid5_add_disk,
8531	.hot_remove_disk= raid5_remove_disk,
8532	.spare_active	= raid5_spare_active,
8533	.sync_request	= raid5_sync_request,
8534	.resize		= raid5_resize,
8535	.size		= raid5_size,
8536	.check_reshape	= raid5_check_reshape,
8537	.start_reshape  = raid5_start_reshape,
8538	.finish_reshape = raid5_finish_reshape,
8539	.quiesce	= raid5_quiesce,
8540	.takeover	= raid5_takeover,
8541	.change_consistency_policy = raid5_change_consistency_policy,
8542};
8543
8544static struct md_personality raid4_personality =
8545{
8546	.name		= "raid4",
8547	.level		= 4,
8548	.owner		= THIS_MODULE,
8549	.make_request	= raid5_make_request,
8550	.run		= raid5_run,
8551	.start		= raid5_start,
8552	.free		= raid5_free,
8553	.status		= raid5_status,
8554	.error_handler	= raid5_error,
8555	.hot_add_disk	= raid5_add_disk,
8556	.hot_remove_disk= raid5_remove_disk,
8557	.spare_active	= raid5_spare_active,
8558	.sync_request	= raid5_sync_request,
8559	.resize		= raid5_resize,
8560	.size		= raid5_size,
8561	.check_reshape	= raid5_check_reshape,
8562	.start_reshape  = raid5_start_reshape,
8563	.finish_reshape = raid5_finish_reshape,
8564	.quiesce	= raid5_quiesce,
8565	.takeover	= raid4_takeover,
8566	.change_consistency_policy = raid5_change_consistency_policy,
8567};
8568
8569static int __init raid5_init(void)
8570{
8571	int ret;
8572
8573	raid5_wq = alloc_workqueue("raid5wq",
8574		WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
8575	if (!raid5_wq)
8576		return -ENOMEM;
8577
8578	ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
8579				      "md/raid5:prepare",
8580				      raid456_cpu_up_prepare,
8581				      raid456_cpu_dead);
8582	if (ret) {
8583		destroy_workqueue(raid5_wq);
8584		return ret;
8585	}
8586	register_md_personality(&raid6_personality);
8587	register_md_personality(&raid5_personality);
8588	register_md_personality(&raid4_personality);
8589	return 0;
8590}
8591
8592static void raid5_exit(void)
8593{
8594	unregister_md_personality(&raid6_personality);
8595	unregister_md_personality(&raid5_personality);
8596	unregister_md_personality(&raid4_personality);
8597	cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
8598	destroy_workqueue(raid5_wq);
8599}
8600
8601module_init(raid5_init);
8602module_exit(raid5_exit);
8603MODULE_LICENSE("GPL");
8604MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
8605MODULE_ALIAS("md-personality-4"); /* RAID5 */
8606MODULE_ALIAS("md-raid5");
8607MODULE_ALIAS("md-raid4");
8608MODULE_ALIAS("md-level-5");
8609MODULE_ALIAS("md-level-4");
8610MODULE_ALIAS("md-personality-8"); /* RAID6 */
8611MODULE_ALIAS("md-raid6");
8612MODULE_ALIAS("md-level-6");
8613
8614/* This used to be two separate modules, they were: */
8615MODULE_ALIAS("raid5");
8616MODULE_ALIAS("raid6");