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/delay.h>
  40#include <linux/kthread.h>
  41#include <linux/raid/pq.h>
  42#include <linux/async_tx.h>
  43#include <linux/module.h>
  44#include <linux/async.h>
  45#include <linux/seq_file.h>
  46#include <linux/cpu.h>
  47#include <linux/slab.h>
  48#include <linux/ratelimit.h>
  49#include <linux/nodemask.h>
  50
  51#include <trace/events/block.h>
  52#include <linux/list_sort.h>
  53
  54#include "md.h"
  55#include "raid5.h"
  56#include "raid0.h"
  57#include "md-bitmap.h"
  58#include "raid5-log.h"
  59
  60#define UNSUPPORTED_MDDEV_FLAGS	(1L << MD_FAILFAST_SUPPORTED)
  61
  62#define cpu_to_group(cpu) cpu_to_node(cpu)
  63#define ANY_GROUP NUMA_NO_NODE
  64
  65#define RAID5_MAX_REQ_STRIPES 256
  66
  67static bool devices_handle_discard_safely = false;
  68module_param(devices_handle_discard_safely, bool, 0644);
  69MODULE_PARM_DESC(devices_handle_discard_safely,
  70		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  71static struct workqueue_struct *raid5_wq;
 
 
 
 
 
 
 
 
 
 
 
 
 
  72
  73static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  74{
  75	int hash = (sect >> RAID5_STRIPE_SHIFT(conf)) & HASH_MASK;
  76	return &conf->stripe_hashtbl[hash];
  77}
  78
  79static inline int stripe_hash_locks_hash(struct r5conf *conf, sector_t sect)
  80{
  81	return (sect >> RAID5_STRIPE_SHIFT(conf)) & STRIPE_HASH_LOCKS_MASK;
  82}
  83
  84static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  85	__acquires(&conf->device_lock)
  86{
  87	spin_lock_irq(conf->hash_locks + hash);
  88	spin_lock(&conf->device_lock);
  89}
  90
  91static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  92	__releases(&conf->device_lock)
  93{
  94	spin_unlock(&conf->device_lock);
  95	spin_unlock_irq(conf->hash_locks + hash);
  96}
  97
  98static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
  99	__acquires(&conf->device_lock)
 100{
 101	int i;
 102	spin_lock_irq(conf->hash_locks);
 
 103	for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 104		spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 105	spin_lock(&conf->device_lock);
 106}
 107
 108static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 109	__releases(&conf->device_lock)
 110{
 111	int i;
 112	spin_unlock(&conf->device_lock);
 113	for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 114		spin_unlock(conf->hash_locks + i);
 115	spin_unlock_irq(conf->hash_locks);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 116}
 117
 118/* Find first data disk in a raid6 stripe */
 119static inline int raid6_d0(struct stripe_head *sh)
 120{
 121	if (sh->ddf_layout)
 122		/* ddf always start from first device */
 123		return 0;
 124	/* md starts just after Q block */
 125	if (sh->qd_idx == sh->disks - 1)
 126		return 0;
 127	else
 128		return sh->qd_idx + 1;
 129}
 130static inline int raid6_next_disk(int disk, int raid_disks)
 131{
 132	disk++;
 133	return (disk < raid_disks) ? disk : 0;
 134}
 135
 136/* When walking through the disks in a raid5, starting at raid6_d0,
 137 * We need to map each disk to a 'slot', where the data disks are slot
 138 * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 139 * is raid_disks-1.  This help does that mapping.
 140 */
 141static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 142			     int *count, int syndrome_disks)
 143{
 144	int slot = *count;
 145
 146	if (sh->ddf_layout)
 147		(*count)++;
 148	if (idx == sh->pd_idx)
 149		return syndrome_disks;
 150	if (idx == sh->qd_idx)
 151		return syndrome_disks + 1;
 152	if (!sh->ddf_layout)
 153		(*count)++;
 154	return slot;
 155}
 156
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 157static void print_raid5_conf (struct r5conf *conf);
 158
 159static int stripe_operations_active(struct stripe_head *sh)
 160{
 161	return sh->check_state || sh->reconstruct_state ||
 162	       test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 163	       test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 164}
 165
 166static bool stripe_is_lowprio(struct stripe_head *sh)
 167{
 168	return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 169		test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 170	       !test_bit(STRIPE_R5C_CACHING, &sh->state);
 171}
 172
 173static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 174	__must_hold(&sh->raid_conf->device_lock)
 175{
 176	struct r5conf *conf = sh->raid_conf;
 177	struct r5worker_group *group;
 178	int thread_cnt;
 179	int i, cpu = sh->cpu;
 180
 181	if (!cpu_online(cpu)) {
 182		cpu = cpumask_any(cpu_online_mask);
 183		sh->cpu = cpu;
 184	}
 185
 186	if (list_empty(&sh->lru)) {
 187		struct r5worker_group *group;
 188		group = conf->worker_groups + cpu_to_group(cpu);
 189		if (stripe_is_lowprio(sh))
 190			list_add_tail(&sh->lru, &group->loprio_list);
 191		else
 192			list_add_tail(&sh->lru, &group->handle_list);
 193		group->stripes_cnt++;
 194		sh->group = group;
 195	}
 196
 197	if (conf->worker_cnt_per_group == 0) {
 198		md_wakeup_thread(conf->mddev->thread);
 199		return;
 200	}
 201
 202	group = conf->worker_groups + cpu_to_group(sh->cpu);
 203
 204	group->workers[0].working = true;
 205	/* at least one worker should run to avoid race */
 206	queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 207
 208	thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 209	/* wakeup more workers */
 210	for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 211		if (group->workers[i].working == false) {
 212			group->workers[i].working = true;
 213			queue_work_on(sh->cpu, raid5_wq,
 214				      &group->workers[i].work);
 215			thread_cnt--;
 216		}
 217	}
 218}
 219
 220static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 221			      struct list_head *temp_inactive_list)
 222	__must_hold(&conf->device_lock)
 223{
 224	int i;
 225	int injournal = 0;	/* number of date pages with R5_InJournal */
 226
 227	BUG_ON(!list_empty(&sh->lru));
 228	BUG_ON(atomic_read(&conf->active_stripes)==0);
 229
 230	if (r5c_is_writeback(conf->log))
 231		for (i = sh->disks; i--; )
 232			if (test_bit(R5_InJournal, &sh->dev[i].flags))
 233				injournal++;
 234	/*
 235	 * In the following cases, the stripe cannot be released to cached
 236	 * lists. Therefore, we make the stripe write out and set
 237	 * STRIPE_HANDLE:
 238	 *   1. when quiesce in r5c write back;
 239	 *   2. when resync is requested fot the stripe.
 240	 */
 241	if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 242	    (conf->quiesce && r5c_is_writeback(conf->log) &&
 243	     !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 244		if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 245			r5c_make_stripe_write_out(sh);
 246		set_bit(STRIPE_HANDLE, &sh->state);
 247	}
 248
 249	if (test_bit(STRIPE_HANDLE, &sh->state)) {
 250		if (test_bit(STRIPE_DELAYED, &sh->state) &&
 251		    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 252			list_add_tail(&sh->lru, &conf->delayed_list);
 253		else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 254			   sh->bm_seq - conf->seq_write > 0)
 255			list_add_tail(&sh->lru, &conf->bitmap_list);
 256		else {
 257			clear_bit(STRIPE_DELAYED, &sh->state);
 258			clear_bit(STRIPE_BIT_DELAY, &sh->state);
 259			if (conf->worker_cnt_per_group == 0) {
 260				if (stripe_is_lowprio(sh))
 261					list_add_tail(&sh->lru,
 262							&conf->loprio_list);
 263				else
 264					list_add_tail(&sh->lru,
 265							&conf->handle_list);
 266			} else {
 267				raid5_wakeup_stripe_thread(sh);
 268				return;
 269			}
 270		}
 271		md_wakeup_thread(conf->mddev->thread);
 272	} else {
 273		BUG_ON(stripe_operations_active(sh));
 274		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 275			if (atomic_dec_return(&conf->preread_active_stripes)
 276			    < IO_THRESHOLD)
 277				md_wakeup_thread(conf->mddev->thread);
 278		atomic_dec(&conf->active_stripes);
 279		if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 280			if (!r5c_is_writeback(conf->log))
 281				list_add_tail(&sh->lru, temp_inactive_list);
 282			else {
 283				WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 284				if (injournal == 0)
 285					list_add_tail(&sh->lru, temp_inactive_list);
 286				else if (injournal == conf->raid_disks - conf->max_degraded) {
 287					/* full stripe */
 288					if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 289						atomic_inc(&conf->r5c_cached_full_stripes);
 290					if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 291						atomic_dec(&conf->r5c_cached_partial_stripes);
 292					list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 293					r5c_check_cached_full_stripe(conf);
 294				} else
 295					/*
 296					 * STRIPE_R5C_PARTIAL_STRIPE is set in
 297					 * r5c_try_caching_write(). No need to
 298					 * set it again.
 299					 */
 300					list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 301			}
 302		}
 303	}
 304}
 305
 306static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 307			     struct list_head *temp_inactive_list)
 308	__must_hold(&conf->device_lock)
 309{
 310	if (atomic_dec_and_test(&sh->count))
 311		do_release_stripe(conf, sh, temp_inactive_list);
 312}
 313
 314/*
 315 * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 316 *
 317 * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 318 * given time. Adding stripes only takes device lock, while deleting stripes
 319 * only takes hash lock.
 320 */
 321static void release_inactive_stripe_list(struct r5conf *conf,
 322					 struct list_head *temp_inactive_list,
 323					 int hash)
 324{
 325	int size;
 326	bool do_wakeup = false;
 327	unsigned long flags;
 328
 329	if (hash == NR_STRIPE_HASH_LOCKS) {
 330		size = NR_STRIPE_HASH_LOCKS;
 331		hash = NR_STRIPE_HASH_LOCKS - 1;
 332	} else
 333		size = 1;
 334	while (size) {
 335		struct list_head *list = &temp_inactive_list[size - 1];
 336
 337		/*
 338		 * We don't hold any lock here yet, raid5_get_active_stripe() might
 339		 * remove stripes from the list
 340		 */
 341		if (!list_empty_careful(list)) {
 342			spin_lock_irqsave(conf->hash_locks + hash, flags);
 343			if (list_empty(conf->inactive_list + hash) &&
 344			    !list_empty(list))
 345				atomic_dec(&conf->empty_inactive_list_nr);
 346			list_splice_tail_init(list, conf->inactive_list + hash);
 347			do_wakeup = true;
 348			spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 349		}
 350		size--;
 351		hash--;
 352	}
 353
 354	if (do_wakeup) {
 355		wake_up(&conf->wait_for_stripe);
 356		if (atomic_read(&conf->active_stripes) == 0)
 357			wake_up(&conf->wait_for_quiescent);
 358		if (conf->retry_read_aligned)
 359			md_wakeup_thread(conf->mddev->thread);
 360	}
 361}
 362
 
 363static int release_stripe_list(struct r5conf *conf,
 364			       struct list_head *temp_inactive_list)
 365	__must_hold(&conf->device_lock)
 366{
 367	struct stripe_head *sh, *t;
 368	int count = 0;
 369	struct llist_node *head;
 370
 371	head = llist_del_all(&conf->released_stripes);
 372	head = llist_reverse_order(head);
 373	llist_for_each_entry_safe(sh, t, head, release_list) {
 374		int hash;
 375
 
 
 376		/* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 377		smp_mb();
 378		clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 379		/*
 380		 * Don't worry the bit is set here, because if the bit is set
 381		 * again, the count is always > 1. This is true for
 382		 * STRIPE_ON_UNPLUG_LIST bit too.
 383		 */
 384		hash = sh->hash_lock_index;
 385		__release_stripe(conf, sh, &temp_inactive_list[hash]);
 386		count++;
 387	}
 388
 389	return count;
 390}
 391
 392void raid5_release_stripe(struct stripe_head *sh)
 393{
 394	struct r5conf *conf = sh->raid_conf;
 395	unsigned long flags;
 396	struct list_head list;
 397	int hash;
 398	bool wakeup;
 399
 400	/* Avoid release_list until the last reference.
 401	 */
 402	if (atomic_add_unless(&sh->count, -1, 1))
 403		return;
 404
 405	if (unlikely(!conf->mddev->thread) ||
 406		test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 407		goto slow_path;
 408	wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 409	if (wakeup)
 410		md_wakeup_thread(conf->mddev->thread);
 411	return;
 412slow_path:
 
 413	/* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 414	if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
 415		INIT_LIST_HEAD(&list);
 416		hash = sh->hash_lock_index;
 417		do_release_stripe(conf, sh, &list);
 418		spin_unlock_irqrestore(&conf->device_lock, flags);
 419		release_inactive_stripe_list(conf, &list, hash);
 420	}
 
 421}
 422
 423static inline void remove_hash(struct stripe_head *sh)
 424{
 425	pr_debug("remove_hash(), stripe %llu\n",
 426		(unsigned long long)sh->sector);
 427
 428	hlist_del_init(&sh->hash);
 429}
 430
 431static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 432{
 433	struct hlist_head *hp = stripe_hash(conf, sh->sector);
 434
 435	pr_debug("insert_hash(), stripe %llu\n",
 436		(unsigned long long)sh->sector);
 437
 438	hlist_add_head(&sh->hash, hp);
 439}
 440
 
 441/* find an idle stripe, make sure it is unhashed, and return it. */
 442static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 443{
 444	struct stripe_head *sh = NULL;
 445	struct list_head *first;
 446
 447	if (list_empty(conf->inactive_list + hash))
 448		goto out;
 449	first = (conf->inactive_list + hash)->next;
 450	sh = list_entry(first, struct stripe_head, lru);
 451	list_del_init(first);
 452	remove_hash(sh);
 453	atomic_inc(&conf->active_stripes);
 454	BUG_ON(hash != sh->hash_lock_index);
 455	if (list_empty(conf->inactive_list + hash))
 456		atomic_inc(&conf->empty_inactive_list_nr);
 457out:
 458	return sh;
 459}
 460
 461#if PAGE_SIZE != DEFAULT_STRIPE_SIZE
 462static void free_stripe_pages(struct stripe_head *sh)
 463{
 464	int i;
 465	struct page *p;
 466
 467	/* Have not allocate page pool */
 468	if (!sh->pages)
 469		return;
 470
 471	for (i = 0; i < sh->nr_pages; i++) {
 472		p = sh->pages[i];
 473		if (p)
 474			put_page(p);
 475		sh->pages[i] = NULL;
 476	}
 477}
 478
 479static int alloc_stripe_pages(struct stripe_head *sh, gfp_t gfp)
 480{
 481	int i;
 482	struct page *p;
 483
 484	for (i = 0; i < sh->nr_pages; i++) {
 485		/* The page have allocated. */
 486		if (sh->pages[i])
 487			continue;
 488
 489		p = alloc_page(gfp);
 490		if (!p) {
 491			free_stripe_pages(sh);
 492			return -ENOMEM;
 493		}
 494		sh->pages[i] = p;
 495	}
 496	return 0;
 497}
 498
 499static int
 500init_stripe_shared_pages(struct stripe_head *sh, struct r5conf *conf, int disks)
 501{
 502	int nr_pages, cnt;
 503
 504	if (sh->pages)
 505		return 0;
 506
 507	/* Each of the sh->dev[i] need one conf->stripe_size */
 508	cnt = PAGE_SIZE / conf->stripe_size;
 509	nr_pages = (disks + cnt - 1) / cnt;
 510
 511	sh->pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
 512	if (!sh->pages)
 513		return -ENOMEM;
 514	sh->nr_pages = nr_pages;
 515	sh->stripes_per_page = cnt;
 516	return 0;
 517}
 518#endif
 519
 520static void shrink_buffers(struct stripe_head *sh)
 521{
 
 522	int i;
 523	int num = sh->raid_conf->pool_size;
 524
 525#if PAGE_SIZE == DEFAULT_STRIPE_SIZE
 526	for (i = 0; i < num ; i++) {
 527		struct page *p;
 528
 529		WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 530		p = sh->dev[i].page;
 531		if (!p)
 532			continue;
 533		sh->dev[i].page = NULL;
 534		put_page(p);
 535	}
 536#else
 537	for (i = 0; i < num; i++)
 538		sh->dev[i].page = NULL;
 539	free_stripe_pages(sh); /* Free pages */
 540#endif
 541}
 542
 543static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 544{
 545	int i;
 546	int num = sh->raid_conf->pool_size;
 547
 548#if PAGE_SIZE == DEFAULT_STRIPE_SIZE
 549	for (i = 0; i < num; i++) {
 550		struct page *page;
 551
 552		if (!(page = alloc_page(gfp))) {
 553			return 1;
 554		}
 555		sh->dev[i].page = page;
 556		sh->dev[i].orig_page = page;
 557		sh->dev[i].offset = 0;
 558	}
 559#else
 560	if (alloc_stripe_pages(sh, gfp))
 561		return -ENOMEM;
 562
 563	for (i = 0; i < num; i++) {
 564		sh->dev[i].page = raid5_get_dev_page(sh, i);
 565		sh->dev[i].orig_page = sh->dev[i].page;
 566		sh->dev[i].offset = raid5_get_page_offset(sh, i);
 567	}
 568#endif
 569	return 0;
 570}
 571
 
 572static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 573			    struct stripe_head *sh);
 574
 575static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 576{
 577	struct r5conf *conf = sh->raid_conf;
 578	int i, seq;
 579
 580	BUG_ON(atomic_read(&sh->count) != 0);
 581	BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 582	BUG_ON(stripe_operations_active(sh));
 583	BUG_ON(sh->batch_head);
 584
 585	pr_debug("init_stripe called, stripe %llu\n",
 586		(unsigned long long)sector);
 
 
 587retry:
 588	seq = read_seqcount_begin(&conf->gen_lock);
 589	sh->generation = conf->generation - previous;
 590	sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 591	sh->sector = sector;
 592	stripe_set_idx(sector, conf, previous, sh);
 593	sh->state = 0;
 594
 
 595	for (i = sh->disks; i--; ) {
 596		struct r5dev *dev = &sh->dev[i];
 597
 598		if (dev->toread || dev->read || dev->towrite || dev->written ||
 599		    test_bit(R5_LOCKED, &dev->flags)) {
 600			pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 601			       (unsigned long long)sh->sector, i, dev->toread,
 602			       dev->read, dev->towrite, dev->written,
 603			       test_bit(R5_LOCKED, &dev->flags));
 604			WARN_ON(1);
 605		}
 606		dev->flags = 0;
 607		dev->sector = raid5_compute_blocknr(sh, i, previous);
 608	}
 609	if (read_seqcount_retry(&conf->gen_lock, seq))
 610		goto retry;
 611	sh->overwrite_disks = 0;
 612	insert_hash(conf, sh);
 613	sh->cpu = smp_processor_id();
 614	set_bit(STRIPE_BATCH_READY, &sh->state);
 615}
 616
 617static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 618					 short generation)
 619{
 620	struct stripe_head *sh;
 621
 622	pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 623	hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 624		if (sh->sector == sector && sh->generation == generation)
 625			return sh;
 626	pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 627	return NULL;
 628}
 629
 630static struct stripe_head *find_get_stripe(struct r5conf *conf,
 631		sector_t sector, short generation, int hash)
 632{
 633	int inc_empty_inactive_list_flag;
 634	struct stripe_head *sh;
 635
 636	sh = __find_stripe(conf, sector, generation);
 637	if (!sh)
 638		return NULL;
 639
 640	if (atomic_inc_not_zero(&sh->count))
 641		return sh;
 642
 643	/*
 644	 * Slow path. The reference count is zero which means the stripe must
 645	 * be on a list (sh->lru). Must remove the stripe from the list that
 646	 * references it with the device_lock held.
 647	 */
 648
 649	spin_lock(&conf->device_lock);
 650	if (!atomic_read(&sh->count)) {
 651		if (!test_bit(STRIPE_HANDLE, &sh->state))
 652			atomic_inc(&conf->active_stripes);
 653		BUG_ON(list_empty(&sh->lru) &&
 654		       !test_bit(STRIPE_EXPANDING, &sh->state));
 655		inc_empty_inactive_list_flag = 0;
 656		if (!list_empty(conf->inactive_list + hash))
 657			inc_empty_inactive_list_flag = 1;
 658		list_del_init(&sh->lru);
 659		if (list_empty(conf->inactive_list + hash) &&
 660		    inc_empty_inactive_list_flag)
 661			atomic_inc(&conf->empty_inactive_list_nr);
 662		if (sh->group) {
 663			sh->group->stripes_cnt--;
 664			sh->group = NULL;
 665		}
 666	}
 667	atomic_inc(&sh->count);
 668	spin_unlock(&conf->device_lock);
 669
 670	return sh;
 671}
 672
 673/*
 674 * Need to check if array has failed when deciding whether to:
 675 *  - start an array
 676 *  - remove non-faulty devices
 677 *  - add a spare
 678 *  - allow a reshape
 679 * This determination is simple when no reshape is happening.
 680 * However if there is a reshape, we need to carefully check
 681 * both the before and after sections.
 682 * This is because some failed devices may only affect one
 683 * of the two sections, and some non-in_sync devices may
 684 * be insync in the section most affected by failed devices.
 685 *
 686 * Most calls to this function hold &conf->device_lock. Calls
 687 * in raid5_run() do not require the lock as no other threads
 688 * have been started yet.
 689 */
 690int raid5_calc_degraded(struct r5conf *conf)
 691{
 692	int degraded, degraded2;
 693	int i;
 694
 695	rcu_read_lock();
 696	degraded = 0;
 697	for (i = 0; i < conf->previous_raid_disks; i++) {
 698		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 699		if (rdev && test_bit(Faulty, &rdev->flags))
 700			rdev = rcu_dereference(conf->disks[i].replacement);
 701		if (!rdev || test_bit(Faulty, &rdev->flags))
 702			degraded++;
 703		else if (test_bit(In_sync, &rdev->flags))
 704			;
 705		else
 706			/* not in-sync or faulty.
 707			 * If the reshape increases the number of devices,
 708			 * this is being recovered by the reshape, so
 709			 * this 'previous' section is not in_sync.
 710			 * If the number of devices is being reduced however,
 711			 * the device can only be part of the array if
 712			 * we are reverting a reshape, so this section will
 713			 * be in-sync.
 714			 */
 715			if (conf->raid_disks >= conf->previous_raid_disks)
 716				degraded++;
 717	}
 718	rcu_read_unlock();
 719	if (conf->raid_disks == conf->previous_raid_disks)
 720		return degraded;
 721	rcu_read_lock();
 722	degraded2 = 0;
 723	for (i = 0; i < conf->raid_disks; i++) {
 724		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 725		if (rdev && test_bit(Faulty, &rdev->flags))
 726			rdev = rcu_dereference(conf->disks[i].replacement);
 727		if (!rdev || test_bit(Faulty, &rdev->flags))
 728			degraded2++;
 729		else if (test_bit(In_sync, &rdev->flags))
 730			;
 731		else
 732			/* not in-sync or faulty.
 733			 * If reshape increases the number of devices, this
 734			 * section has already been recovered, else it
 735			 * almost certainly hasn't.
 736			 */
 737			if (conf->raid_disks <= conf->previous_raid_disks)
 738				degraded2++;
 739	}
 740	rcu_read_unlock();
 741	if (degraded2 > degraded)
 742		return degraded2;
 743	return degraded;
 744}
 745
 746static bool has_failed(struct r5conf *conf)
 747{
 748	int degraded = conf->mddev->degraded;
 749
 750	if (test_bit(MD_BROKEN, &conf->mddev->flags))
 751		return true;
 752
 753	if (conf->mddev->reshape_position != MaxSector)
 754		degraded = raid5_calc_degraded(conf);
 755
 756	return degraded > conf->max_degraded;
 757}
 758
 759enum stripe_result {
 760	STRIPE_SUCCESS = 0,
 761	STRIPE_RETRY,
 762	STRIPE_SCHEDULE_AND_RETRY,
 763	STRIPE_FAIL,
 764};
 765
 766struct stripe_request_ctx {
 767	/* a reference to the last stripe_head for batching */
 768	struct stripe_head *batch_last;
 769
 770	/* first sector in the request */
 771	sector_t first_sector;
 772
 773	/* last sector in the request */
 774	sector_t last_sector;
 775
 776	/*
 777	 * bitmap to track stripe sectors that have been added to stripes
 778	 * add one to account for unaligned requests
 779	 */
 780	DECLARE_BITMAP(sectors_to_do, RAID5_MAX_REQ_STRIPES + 1);
 781
 782	/* the request had REQ_PREFLUSH, cleared after the first stripe_head */
 783	bool do_flush;
 784};
 785
 786/*
 787 * Block until another thread clears R5_INACTIVE_BLOCKED or
 788 * there are fewer than 3/4 the maximum number of active stripes
 789 * and there is an inactive stripe available.
 790 */
 791static bool is_inactive_blocked(struct r5conf *conf, int hash)
 792{
 793	if (list_empty(conf->inactive_list + hash))
 794		return false;
 795
 796	if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
 797		return true;
 798
 799	return (atomic_read(&conf->active_stripes) <
 800		(conf->max_nr_stripes * 3 / 4));
 801}
 802
 803struct stripe_head *raid5_get_active_stripe(struct r5conf *conf,
 804		struct stripe_request_ctx *ctx, sector_t sector,
 805		unsigned int flags)
 806{
 807	struct stripe_head *sh;
 808	int hash = stripe_hash_locks_hash(conf, sector);
 809	int previous = !!(flags & R5_GAS_PREVIOUS);
 810
 811	pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 812
 813	spin_lock_irq(conf->hash_locks + hash);
 814
 815	for (;;) {
 816		if (!(flags & R5_GAS_NOQUIESCE) && conf->quiesce) {
 817			/*
 818			 * Must release the reference to batch_last before
 819			 * waiting, on quiesce, otherwise the batch_last will
 820			 * hold a reference to a stripe and raid5_quiesce()
 821			 * will deadlock waiting for active_stripes to go to
 822			 * zero.
 823			 */
 824			if (ctx && ctx->batch_last) {
 825				raid5_release_stripe(ctx->batch_last);
 826				ctx->batch_last = NULL;
 827			}
 828
 829			wait_event_lock_irq(conf->wait_for_quiescent,
 830					    !conf->quiesce,
 831					    *(conf->hash_locks + hash));
 832		}
 833
 834		sh = find_get_stripe(conf, sector, conf->generation - previous,
 835				     hash);
 836		if (sh)
 837			break;
 838
 839		if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 840			sh = get_free_stripe(conf, hash);
 841			if (sh) {
 842				r5c_check_stripe_cache_usage(conf);
 843				init_stripe(sh, sector, previous);
 844				atomic_inc(&sh->count);
 845				break;
 846			}
 847
 848			if (!test_bit(R5_DID_ALLOC, &conf->cache_state))
 849				set_bit(R5_ALLOC_MORE, &conf->cache_state);
 
 
 
 
 
 
 
 
 
 
 
 
 850		}
 851
 852		if (flags & R5_GAS_NOBLOCK)
 853			break;
 854
 855		set_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
 856		r5l_wake_reclaim(conf->log, 0);
 857		wait_event_lock_irq(conf->wait_for_stripe,
 858				    is_inactive_blocked(conf, hash),
 859				    *(conf->hash_locks + hash));
 860		clear_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
 861	}
 862
 863	spin_unlock_irq(conf->hash_locks + hash);
 864	return sh;
 865}
 866
 867static bool is_full_stripe_write(struct stripe_head *sh)
 868{
 869	BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 870	return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 871}
 872
 873static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 874		__acquires(&sh1->stripe_lock)
 875		__acquires(&sh2->stripe_lock)
 876{
 877	if (sh1 > sh2) {
 878		spin_lock_irq(&sh2->stripe_lock);
 879		spin_lock_nested(&sh1->stripe_lock, 1);
 880	} else {
 881		spin_lock_irq(&sh1->stripe_lock);
 882		spin_lock_nested(&sh2->stripe_lock, 1);
 883	}
 884}
 885
 886static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 887		__releases(&sh1->stripe_lock)
 888		__releases(&sh2->stripe_lock)
 889{
 890	spin_unlock(&sh1->stripe_lock);
 891	spin_unlock_irq(&sh2->stripe_lock);
 892}
 893
 894/* Only freshly new full stripe normal write stripe can be added to a batch list */
 895static bool stripe_can_batch(struct stripe_head *sh)
 896{
 897	struct r5conf *conf = sh->raid_conf;
 898
 899	if (raid5_has_log(conf) || raid5_has_ppl(conf))
 900		return false;
 901	return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 902		!test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 903		is_full_stripe_write(sh);
 904}
 905
 906/* we only do back search */
 907static void stripe_add_to_batch_list(struct r5conf *conf,
 908		struct stripe_head *sh, struct stripe_head *last_sh)
 909{
 910	struct stripe_head *head;
 911	sector_t head_sector, tmp_sec;
 912	int hash;
 913	int dd_idx;
 914
 915	/* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 916	tmp_sec = sh->sector;
 917	if (!sector_div(tmp_sec, conf->chunk_sectors))
 918		return;
 919	head_sector = sh->sector - RAID5_STRIPE_SECTORS(conf);
 920
 921	if (last_sh && head_sector == last_sh->sector) {
 922		head = last_sh;
 923		atomic_inc(&head->count);
 924	} else {
 925		hash = stripe_hash_locks_hash(conf, head_sector);
 926		spin_lock_irq(conf->hash_locks + hash);
 927		head = find_get_stripe(conf, head_sector, conf->generation,
 928				       hash);
 929		spin_unlock_irq(conf->hash_locks + hash);
 930		if (!head)
 931			return;
 932		if (!stripe_can_batch(head))
 933			goto out;
 934	}
 935
 936	lock_two_stripes(head, sh);
 937	/* clear_batch_ready clear the flag */
 938	if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 939		goto unlock_out;
 940
 941	if (sh->batch_head)
 942		goto unlock_out;
 943
 944	dd_idx = 0;
 945	while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 946		dd_idx++;
 947	if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 948	    bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 949		goto unlock_out;
 950
 951	if (head->batch_head) {
 952		spin_lock(&head->batch_head->batch_lock);
 953		/* This batch list is already running */
 954		if (!stripe_can_batch(head)) {
 955			spin_unlock(&head->batch_head->batch_lock);
 956			goto unlock_out;
 957		}
 958		/*
 959		 * We must assign batch_head of this stripe within the
 960		 * batch_lock, otherwise clear_batch_ready of batch head
 961		 * stripe could clear BATCH_READY bit of this stripe and
 962		 * this stripe->batch_head doesn't get assigned, which
 963		 * could confuse clear_batch_ready for this stripe
 964		 */
 965		sh->batch_head = head->batch_head;
 966
 967		/*
 968		 * at this point, head's BATCH_READY could be cleared, but we
 969		 * can still add the stripe to batch list
 970		 */
 971		list_add(&sh->batch_list, &head->batch_list);
 972		spin_unlock(&head->batch_head->batch_lock);
 973	} else {
 974		head->batch_head = head;
 975		sh->batch_head = head->batch_head;
 976		spin_lock(&head->batch_lock);
 977		list_add_tail(&sh->batch_list, &head->batch_list);
 978		spin_unlock(&head->batch_lock);
 979	}
 980
 981	if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 982		if (atomic_dec_return(&conf->preread_active_stripes)
 983		    < IO_THRESHOLD)
 984			md_wakeup_thread(conf->mddev->thread);
 985
 986	if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 987		int seq = sh->bm_seq;
 988		if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 989		    sh->batch_head->bm_seq > seq)
 990			seq = sh->batch_head->bm_seq;
 991		set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 992		sh->batch_head->bm_seq = seq;
 993	}
 994
 995	atomic_inc(&sh->count);
 996unlock_out:
 997	unlock_two_stripes(head, sh);
 998out:
 999	raid5_release_stripe(head);
1000}
1001
1002/* Determine if 'data_offset' or 'new_data_offset' should be used
1003 * in this stripe_head.
1004 */
1005static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
1006{
1007	sector_t progress = conf->reshape_progress;
1008	/* Need a memory barrier to make sure we see the value
1009	 * of conf->generation, or ->data_offset that was set before
1010	 * reshape_progress was updated.
1011	 */
1012	smp_rmb();
1013	if (progress == MaxSector)
1014		return 0;
1015	if (sh->generation == conf->generation - 1)
1016		return 0;
1017	/* We are in a reshape, and this is a new-generation stripe,
1018	 * so use new_data_offset.
1019	 */
1020	return 1;
1021}
1022
1023static void dispatch_bio_list(struct bio_list *tmp)
1024{
1025	struct bio *bio;
1026
1027	while ((bio = bio_list_pop(tmp)))
1028		submit_bio_noacct(bio);
1029}
1030
1031static int cmp_stripe(void *priv, const struct list_head *a,
1032		      const struct list_head *b)
1033{
1034	const struct r5pending_data *da = list_entry(a,
1035				struct r5pending_data, sibling);
1036	const struct r5pending_data *db = list_entry(b,
1037				struct r5pending_data, sibling);
1038	if (da->sector > db->sector)
1039		return 1;
1040	if (da->sector < db->sector)
1041		return -1;
1042	return 0;
1043}
1044
1045static void dispatch_defer_bios(struct r5conf *conf, int target,
1046				struct bio_list *list)
1047{
1048	struct r5pending_data *data;
1049	struct list_head *first, *next = NULL;
1050	int cnt = 0;
1051
1052	if (conf->pending_data_cnt == 0)
1053		return;
1054
1055	list_sort(NULL, &conf->pending_list, cmp_stripe);
1056
1057	first = conf->pending_list.next;
1058
1059	/* temporarily move the head */
1060	if (conf->next_pending_data)
1061		list_move_tail(&conf->pending_list,
1062				&conf->next_pending_data->sibling);
1063
1064	while (!list_empty(&conf->pending_list)) {
1065		data = list_first_entry(&conf->pending_list,
1066			struct r5pending_data, sibling);
1067		if (&data->sibling == first)
1068			first = data->sibling.next;
1069		next = data->sibling.next;
1070
1071		bio_list_merge(list, &data->bios);
1072		list_move(&data->sibling, &conf->free_list);
1073		cnt++;
1074		if (cnt >= target)
1075			break;
1076	}
1077	conf->pending_data_cnt -= cnt;
1078	BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
1079
1080	if (next != &conf->pending_list)
1081		conf->next_pending_data = list_entry(next,
1082				struct r5pending_data, sibling);
1083	else
1084		conf->next_pending_data = NULL;
1085	/* list isn't empty */
1086	if (first != &conf->pending_list)
1087		list_move_tail(&conf->pending_list, first);
1088}
1089
1090static void flush_deferred_bios(struct r5conf *conf)
1091{
1092	struct bio_list tmp = BIO_EMPTY_LIST;
1093
1094	if (conf->pending_data_cnt == 0)
1095		return;
1096
1097	spin_lock(&conf->pending_bios_lock);
1098	dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
1099	BUG_ON(conf->pending_data_cnt != 0);
1100	spin_unlock(&conf->pending_bios_lock);
1101
1102	dispatch_bio_list(&tmp);
1103}
1104
1105static void defer_issue_bios(struct r5conf *conf, sector_t sector,
1106				struct bio_list *bios)
1107{
1108	struct bio_list tmp = BIO_EMPTY_LIST;
1109	struct r5pending_data *ent;
1110
1111	spin_lock(&conf->pending_bios_lock);
1112	ent = list_first_entry(&conf->free_list, struct r5pending_data,
1113							sibling);
1114	list_move_tail(&ent->sibling, &conf->pending_list);
1115	ent->sector = sector;
1116	bio_list_init(&ent->bios);
1117	bio_list_merge(&ent->bios, bios);
1118	conf->pending_data_cnt++;
1119	if (conf->pending_data_cnt >= PENDING_IO_MAX)
1120		dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
1121
1122	spin_unlock(&conf->pending_bios_lock);
1123
1124	dispatch_bio_list(&tmp);
1125}
1126
1127static void
1128raid5_end_read_request(struct bio *bi);
1129static void
1130raid5_end_write_request(struct bio *bi);
1131
1132static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
1133{
1134	struct r5conf *conf = sh->raid_conf;
1135	int i, disks = sh->disks;
1136	struct stripe_head *head_sh = sh;
1137	struct bio_list pending_bios = BIO_EMPTY_LIST;
1138	struct r5dev *dev;
1139	bool should_defer;
1140
1141	might_sleep();
1142
1143	if (log_stripe(sh, s) == 0)
1144		return;
1145
1146	should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1147
1148	for (i = disks; i--; ) {
1149		enum req_op op;
1150		blk_opf_t op_flags = 0;
1151		int replace_only = 0;
1152		struct bio *bi, *rbi;
1153		struct md_rdev *rdev, *rrdev = NULL;
1154
1155		sh = head_sh;
1156		if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1157			op = REQ_OP_WRITE;
1158			if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1159				op_flags = REQ_FUA;
 
 
1160			if (test_bit(R5_Discard, &sh->dev[i].flags))
1161				op = REQ_OP_DISCARD;
1162		} else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1163			op = REQ_OP_READ;
1164		else if (test_and_clear_bit(R5_WantReplace,
1165					    &sh->dev[i].flags)) {
1166			op = REQ_OP_WRITE;
1167			replace_only = 1;
1168		} else
1169			continue;
1170		if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1171			op_flags |= REQ_SYNC;
1172
1173again:
1174		dev = &sh->dev[i];
1175		bi = &dev->req;
1176		rbi = &dev->rreq; /* For writing to replacement */
1177
1178		rcu_read_lock();
1179		rrdev = rcu_dereference(conf->disks[i].replacement);
1180		smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1181		rdev = rcu_dereference(conf->disks[i].rdev);
1182		if (!rdev) {
1183			rdev = rrdev;
1184			rrdev = NULL;
1185		}
1186		if (op_is_write(op)) {
1187			if (replace_only)
1188				rdev = NULL;
1189			if (rdev == rrdev)
1190				/* We raced and saw duplicates */
1191				rrdev = NULL;
1192		} else {
1193			if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1194				rdev = rrdev;
1195			rrdev = NULL;
1196		}
1197
1198		if (rdev && test_bit(Faulty, &rdev->flags))
1199			rdev = NULL;
1200		if (rdev)
1201			atomic_inc(&rdev->nr_pending);
1202		if (rrdev && test_bit(Faulty, &rrdev->flags))
1203			rrdev = NULL;
1204		if (rrdev)
1205			atomic_inc(&rrdev->nr_pending);
1206		rcu_read_unlock();
1207
1208		/* We have already checked bad blocks for reads.  Now
1209		 * need to check for writes.  We never accept write errors
1210		 * on the replacement, so we don't to check rrdev.
1211		 */
1212		while (op_is_write(op) && rdev &&
1213		       test_bit(WriteErrorSeen, &rdev->flags)) {
1214			sector_t first_bad;
1215			int bad_sectors;
1216			int bad = is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
1217					      &first_bad, &bad_sectors);
1218			if (!bad)
1219				break;
1220
1221			if (bad < 0) {
1222				set_bit(BlockedBadBlocks, &rdev->flags);
1223				if (!conf->mddev->external &&
1224				    conf->mddev->sb_flags) {
1225					/* It is very unlikely, but we might
1226					 * still need to write out the
1227					 * bad block log - better give it
1228					 * a chance*/
1229					md_check_recovery(conf->mddev);
1230				}
1231				/*
1232				 * Because md_wait_for_blocked_rdev
1233				 * will dec nr_pending, we must
1234				 * increment it first.
1235				 */
1236				atomic_inc(&rdev->nr_pending);
1237				md_wait_for_blocked_rdev(rdev, conf->mddev);
1238			} else {
1239				/* Acknowledged bad block - skip the write */
1240				rdev_dec_pending(rdev, conf->mddev);
1241				rdev = NULL;
1242			}
1243		}
1244
1245		if (rdev) {
1246			if (s->syncing || s->expanding || s->expanded
1247			    || s->replacing)
1248				md_sync_acct(rdev->bdev, RAID5_STRIPE_SECTORS(conf));
1249
1250			set_bit(STRIPE_IO_STARTED, &sh->state);
1251
1252			bio_init(bi, rdev->bdev, &dev->vec, 1, op | op_flags);
1253			bi->bi_end_io = op_is_write(op)
 
 
1254				? raid5_end_write_request
1255				: raid5_end_read_request;
1256			bi->bi_private = sh;
1257
1258			pr_debug("%s: for %llu schedule op %d on disc %d\n",
1259				__func__, (unsigned long long)sh->sector,
1260				bi->bi_opf, i);
1261			atomic_inc(&sh->count);
1262			if (sh != head_sh)
1263				atomic_inc(&head_sh->count);
1264			if (use_new_offset(conf, sh))
1265				bi->bi_iter.bi_sector = (sh->sector
1266						 + rdev->new_data_offset);
1267			else
1268				bi->bi_iter.bi_sector = (sh->sector
1269						 + rdev->data_offset);
1270			if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1271				bi->bi_opf |= REQ_NOMERGE;
1272
1273			if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1274				WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1275
1276			if (!op_is_write(op) &&
1277			    test_bit(R5_InJournal, &sh->dev[i].flags))
1278				/*
1279				 * issuing read for a page in journal, this
1280				 * must be preparing for prexor in rmw; read
1281				 * the data into orig_page
1282				 */
1283				sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1284			else
1285				sh->dev[i].vec.bv_page = sh->dev[i].page;
1286			bi->bi_vcnt = 1;
1287			bi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1288			bi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1289			bi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1290			/*
1291			 * If this is discard request, set bi_vcnt 0. We don't
1292			 * want to confuse SCSI because SCSI will replace payload
1293			 */
1294			if (op == REQ_OP_DISCARD)
1295				bi->bi_vcnt = 0;
1296			if (rrdev)
1297				set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1298
1299			if (conf->mddev->gendisk)
1300				trace_block_bio_remap(bi,
1301						disk_devt(conf->mddev->gendisk),
1302						sh->dev[i].sector);
1303			if (should_defer && op_is_write(op))
1304				bio_list_add(&pending_bios, bi);
1305			else
1306				submit_bio_noacct(bi);
1307		}
1308		if (rrdev) {
1309			if (s->syncing || s->expanding || s->expanded
1310			    || s->replacing)
1311				md_sync_acct(rrdev->bdev, RAID5_STRIPE_SECTORS(conf));
1312
1313			set_bit(STRIPE_IO_STARTED, &sh->state);
1314
1315			bio_init(rbi, rrdev->bdev, &dev->rvec, 1, op | op_flags);
1316			BUG_ON(!op_is_write(op));
 
 
1317			rbi->bi_end_io = raid5_end_write_request;
1318			rbi->bi_private = sh;
1319
1320			pr_debug("%s: for %llu schedule op %d on "
1321				 "replacement disc %d\n",
1322				__func__, (unsigned long long)sh->sector,
1323				rbi->bi_opf, i);
1324			atomic_inc(&sh->count);
1325			if (sh != head_sh)
1326				atomic_inc(&head_sh->count);
1327			if (use_new_offset(conf, sh))
1328				rbi->bi_iter.bi_sector = (sh->sector
1329						  + rrdev->new_data_offset);
1330			else
1331				rbi->bi_iter.bi_sector = (sh->sector
1332						  + rrdev->data_offset);
1333			if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1334				WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1335			sh->dev[i].rvec.bv_page = sh->dev[i].page;
1336			rbi->bi_vcnt = 1;
1337			rbi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1338			rbi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1339			rbi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1340			/*
1341			 * If this is discard request, set bi_vcnt 0. We don't
1342			 * want to confuse SCSI because SCSI will replace payload
1343			 */
1344			if (op == REQ_OP_DISCARD)
1345				rbi->bi_vcnt = 0;
1346			if (conf->mddev->gendisk)
1347				trace_block_bio_remap(rbi,
1348						disk_devt(conf->mddev->gendisk),
1349						sh->dev[i].sector);
1350			if (should_defer && op_is_write(op))
1351				bio_list_add(&pending_bios, rbi);
1352			else
1353				submit_bio_noacct(rbi);
1354		}
1355		if (!rdev && !rrdev) {
1356			if (op_is_write(op))
1357				set_bit(STRIPE_DEGRADED, &sh->state);
1358			pr_debug("skip op %d on disc %d for sector %llu\n",
1359				bi->bi_opf, i, (unsigned long long)sh->sector);
1360			clear_bit(R5_LOCKED, &sh->dev[i].flags);
1361			set_bit(STRIPE_HANDLE, &sh->state);
1362		}
1363
1364		if (!head_sh->batch_head)
1365			continue;
1366		sh = list_first_entry(&sh->batch_list, struct stripe_head,
1367				      batch_list);
1368		if (sh != head_sh)
1369			goto again;
1370	}
1371
1372	if (should_defer && !bio_list_empty(&pending_bios))
1373		defer_issue_bios(conf, head_sh->sector, &pending_bios);
1374}
1375
1376static struct dma_async_tx_descriptor *
1377async_copy_data(int frombio, struct bio *bio, struct page **page,
1378	unsigned int poff, sector_t sector, struct dma_async_tx_descriptor *tx,
1379	struct stripe_head *sh, int no_skipcopy)
1380{
1381	struct bio_vec bvl;
1382	struct bvec_iter iter;
1383	struct page *bio_page;
1384	int page_offset;
1385	struct async_submit_ctl submit;
1386	enum async_tx_flags flags = 0;
1387	struct r5conf *conf = sh->raid_conf;
1388
1389	if (bio->bi_iter.bi_sector >= sector)
1390		page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1391	else
1392		page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1393
1394	if (frombio)
1395		flags |= ASYNC_TX_FENCE;
1396	init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1397
1398	bio_for_each_segment(bvl, bio, iter) {
1399		int len = bvl.bv_len;
1400		int clen;
1401		int b_offset = 0;
1402
1403		if (page_offset < 0) {
1404			b_offset = -page_offset;
1405			page_offset += b_offset;
1406			len -= b_offset;
1407		}
1408
1409		if (len > 0 && page_offset + len > RAID5_STRIPE_SIZE(conf))
1410			clen = RAID5_STRIPE_SIZE(conf) - page_offset;
1411		else
1412			clen = len;
1413
1414		if (clen > 0) {
1415			b_offset += bvl.bv_offset;
1416			bio_page = bvl.bv_page;
1417			if (frombio) {
1418				if (conf->skip_copy &&
1419				    b_offset == 0 && page_offset == 0 &&
1420				    clen == RAID5_STRIPE_SIZE(conf) &&
1421				    !no_skipcopy)
1422					*page = bio_page;
1423				else
1424					tx = async_memcpy(*page, bio_page, page_offset + poff,
1425						  b_offset, clen, &submit);
1426			} else
1427				tx = async_memcpy(bio_page, *page, b_offset,
1428						  page_offset + poff, clen, &submit);
1429		}
1430		/* chain the operations */
1431		submit.depend_tx = tx;
1432
1433		if (clen < len) /* hit end of page */
1434			break;
1435		page_offset +=  len;
1436	}
1437
1438	return tx;
1439}
1440
1441static void ops_complete_biofill(void *stripe_head_ref)
1442{
1443	struct stripe_head *sh = stripe_head_ref;
 
1444	int i;
1445	struct r5conf *conf = sh->raid_conf;
1446
1447	pr_debug("%s: stripe %llu\n", __func__,
1448		(unsigned long long)sh->sector);
1449
1450	/* clear completed biofills */
1451	for (i = sh->disks; i--; ) {
1452		struct r5dev *dev = &sh->dev[i];
1453
1454		/* acknowledge completion of a biofill operation */
1455		/* and check if we need to reply to a read request,
1456		 * new R5_Wantfill requests are held off until
1457		 * !STRIPE_BIOFILL_RUN
1458		 */
1459		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1460			struct bio *rbi, *rbi2;
1461
1462			BUG_ON(!dev->read);
1463			rbi = dev->read;
1464			dev->read = NULL;
1465			while (rbi && rbi->bi_iter.bi_sector <
1466				dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1467				rbi2 = r5_next_bio(conf, rbi, dev->sector);
1468				bio_endio(rbi);
 
 
 
1469				rbi = rbi2;
1470			}
1471		}
1472	}
1473	clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1474
 
 
1475	set_bit(STRIPE_HANDLE, &sh->state);
1476	raid5_release_stripe(sh);
1477}
1478
1479static void ops_run_biofill(struct stripe_head *sh)
1480{
1481	struct dma_async_tx_descriptor *tx = NULL;
1482	struct async_submit_ctl submit;
1483	int i;
1484	struct r5conf *conf = sh->raid_conf;
1485
1486	BUG_ON(sh->batch_head);
1487	pr_debug("%s: stripe %llu\n", __func__,
1488		(unsigned long long)sh->sector);
1489
1490	for (i = sh->disks; i--; ) {
1491		struct r5dev *dev = &sh->dev[i];
1492		if (test_bit(R5_Wantfill, &dev->flags)) {
1493			struct bio *rbi;
1494			spin_lock_irq(&sh->stripe_lock);
1495			dev->read = rbi = dev->toread;
1496			dev->toread = NULL;
1497			spin_unlock_irq(&sh->stripe_lock);
1498			while (rbi && rbi->bi_iter.bi_sector <
1499				dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1500				tx = async_copy_data(0, rbi, &dev->page,
1501						     dev->offset,
1502						     dev->sector, tx, sh, 0);
1503				rbi = r5_next_bio(conf, rbi, dev->sector);
1504			}
1505		}
1506	}
1507
1508	atomic_inc(&sh->count);
1509	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1510	async_trigger_callback(&submit);
1511}
1512
1513static void mark_target_uptodate(struct stripe_head *sh, int target)
1514{
1515	struct r5dev *tgt;
1516
1517	if (target < 0)
1518		return;
1519
1520	tgt = &sh->dev[target];
1521	set_bit(R5_UPTODATE, &tgt->flags);
1522	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1523	clear_bit(R5_Wantcompute, &tgt->flags);
1524}
1525
1526static void ops_complete_compute(void *stripe_head_ref)
1527{
1528	struct stripe_head *sh = stripe_head_ref;
1529
1530	pr_debug("%s: stripe %llu\n", __func__,
1531		(unsigned long long)sh->sector);
1532
1533	/* mark the computed target(s) as uptodate */
1534	mark_target_uptodate(sh, sh->ops.target);
1535	mark_target_uptodate(sh, sh->ops.target2);
1536
1537	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1538	if (sh->check_state == check_state_compute_run)
1539		sh->check_state = check_state_compute_result;
1540	set_bit(STRIPE_HANDLE, &sh->state);
1541	raid5_release_stripe(sh);
1542}
1543
1544/* return a pointer to the address conversion region of the scribble buffer */
1545static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1546{
1547	return percpu->scribble + i * percpu->scribble_obj_size;
1548}
1549
1550/* return a pointer to the address conversion region of the scribble buffer */
1551static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1552				 struct raid5_percpu *percpu, int i)
1553{
1554	return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
1555}
1556
1557/*
1558 * Return a pointer to record offset address.
1559 */
1560static unsigned int *
1561to_addr_offs(struct stripe_head *sh, struct raid5_percpu *percpu)
1562{
1563	return (unsigned int *) (to_addr_conv(sh, percpu, 0) + sh->disks + 2);
1564}
1565
1566static struct dma_async_tx_descriptor *
1567ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1568{
1569	int disks = sh->disks;
1570	struct page **xor_srcs = to_addr_page(percpu, 0);
1571	unsigned int *off_srcs = to_addr_offs(sh, percpu);
1572	int target = sh->ops.target;
1573	struct r5dev *tgt = &sh->dev[target];
1574	struct page *xor_dest = tgt->page;
1575	unsigned int off_dest = tgt->offset;
1576	int count = 0;
1577	struct dma_async_tx_descriptor *tx;
1578	struct async_submit_ctl submit;
1579	int i;
1580
1581	BUG_ON(sh->batch_head);
1582
1583	pr_debug("%s: stripe %llu block: %d\n",
1584		__func__, (unsigned long long)sh->sector, target);
1585	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1586
1587	for (i = disks; i--; ) {
1588		if (i != target) {
1589			off_srcs[count] = sh->dev[i].offset;
1590			xor_srcs[count++] = sh->dev[i].page;
1591		}
1592	}
1593
1594	atomic_inc(&sh->count);
1595
1596	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1597			  ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1598	if (unlikely(count == 1))
1599		tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
1600				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1601	else
1602		tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1603				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1604
1605	return tx;
1606}
1607
1608/* set_syndrome_sources - populate source buffers for gen_syndrome
1609 * @srcs - (struct page *) array of size sh->disks
1610 * @offs - (unsigned int) array of offset for each page
1611 * @sh - stripe_head to parse
1612 *
1613 * Populates srcs in proper layout order for the stripe and returns the
1614 * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1615 * destination buffer is recorded in srcs[count] and the Q destination
1616 * is recorded in srcs[count+1]].
1617 */
1618static int set_syndrome_sources(struct page **srcs,
1619				unsigned int *offs,
1620				struct stripe_head *sh,
1621				int srctype)
1622{
1623	int disks = sh->disks;
1624	int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1625	int d0_idx = raid6_d0(sh);
1626	int count;
1627	int i;
1628
1629	for (i = 0; i < disks; i++)
1630		srcs[i] = NULL;
1631
1632	count = 0;
1633	i = d0_idx;
1634	do {
1635		int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1636		struct r5dev *dev = &sh->dev[i];
1637
1638		if (i == sh->qd_idx || i == sh->pd_idx ||
1639		    (srctype == SYNDROME_SRC_ALL) ||
1640		    (srctype == SYNDROME_SRC_WANT_DRAIN &&
1641		     (test_bit(R5_Wantdrain, &dev->flags) ||
1642		      test_bit(R5_InJournal, &dev->flags))) ||
1643		    (srctype == SYNDROME_SRC_WRITTEN &&
1644		     (dev->written ||
1645		      test_bit(R5_InJournal, &dev->flags)))) {
1646			if (test_bit(R5_InJournal, &dev->flags))
1647				srcs[slot] = sh->dev[i].orig_page;
1648			else
1649				srcs[slot] = sh->dev[i].page;
1650			/*
1651			 * For R5_InJournal, PAGE_SIZE must be 4KB and will
1652			 * not shared page. In that case, dev[i].offset
1653			 * is 0.
1654			 */
1655			offs[slot] = sh->dev[i].offset;
1656		}
1657		i = raid6_next_disk(i, disks);
1658	} while (i != d0_idx);
1659
1660	return syndrome_disks;
1661}
1662
1663static struct dma_async_tx_descriptor *
1664ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1665{
1666	int disks = sh->disks;
1667	struct page **blocks = to_addr_page(percpu, 0);
1668	unsigned int *offs = to_addr_offs(sh, percpu);
1669	int target;
1670	int qd_idx = sh->qd_idx;
1671	struct dma_async_tx_descriptor *tx;
1672	struct async_submit_ctl submit;
1673	struct r5dev *tgt;
1674	struct page *dest;
1675	unsigned int dest_off;
1676	int i;
1677	int count;
1678
1679	BUG_ON(sh->batch_head);
1680	if (sh->ops.target < 0)
1681		target = sh->ops.target2;
1682	else if (sh->ops.target2 < 0)
1683		target = sh->ops.target;
1684	else
1685		/* we should only have one valid target */
1686		BUG();
1687	BUG_ON(target < 0);
1688	pr_debug("%s: stripe %llu block: %d\n",
1689		__func__, (unsigned long long)sh->sector, target);
1690
1691	tgt = &sh->dev[target];
1692	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1693	dest = tgt->page;
1694	dest_off = tgt->offset;
1695
1696	atomic_inc(&sh->count);
1697
1698	if (target == qd_idx) {
1699		count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1700		blocks[count] = NULL; /* regenerating p is not necessary */
1701		BUG_ON(blocks[count+1] != dest); /* q should already be set */
1702		init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1703				  ops_complete_compute, sh,
1704				  to_addr_conv(sh, percpu, 0));
1705		tx = async_gen_syndrome(blocks, offs, count+2,
1706				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1707	} else {
1708		/* Compute any data- or p-drive using XOR */
1709		count = 0;
1710		for (i = disks; i-- ; ) {
1711			if (i == target || i == qd_idx)
1712				continue;
1713			offs[count] = sh->dev[i].offset;
1714			blocks[count++] = sh->dev[i].page;
1715		}
1716
1717		init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1718				  NULL, ops_complete_compute, sh,
1719				  to_addr_conv(sh, percpu, 0));
1720		tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1721				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1722	}
1723
1724	return tx;
1725}
1726
1727static struct dma_async_tx_descriptor *
1728ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1729{
1730	int i, count, disks = sh->disks;
1731	int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1732	int d0_idx = raid6_d0(sh);
1733	int faila = -1, failb = -1;
1734	int target = sh->ops.target;
1735	int target2 = sh->ops.target2;
1736	struct r5dev *tgt = &sh->dev[target];
1737	struct r5dev *tgt2 = &sh->dev[target2];
1738	struct dma_async_tx_descriptor *tx;
1739	struct page **blocks = to_addr_page(percpu, 0);
1740	unsigned int *offs = to_addr_offs(sh, percpu);
1741	struct async_submit_ctl submit;
1742
1743	BUG_ON(sh->batch_head);
1744	pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1745		 __func__, (unsigned long long)sh->sector, target, target2);
1746	BUG_ON(target < 0 || target2 < 0);
1747	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1748	BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1749
1750	/* we need to open-code set_syndrome_sources to handle the
1751	 * slot number conversion for 'faila' and 'failb'
1752	 */
1753	for (i = 0; i < disks ; i++) {
1754		offs[i] = 0;
1755		blocks[i] = NULL;
1756	}
1757	count = 0;
1758	i = d0_idx;
1759	do {
1760		int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1761
1762		offs[slot] = sh->dev[i].offset;
1763		blocks[slot] = sh->dev[i].page;
1764
1765		if (i == target)
1766			faila = slot;
1767		if (i == target2)
1768			failb = slot;
1769		i = raid6_next_disk(i, disks);
1770	} while (i != d0_idx);
1771
1772	BUG_ON(faila == failb);
1773	if (failb < faila)
1774		swap(faila, failb);
1775	pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1776		 __func__, (unsigned long long)sh->sector, faila, failb);
1777
1778	atomic_inc(&sh->count);
1779
1780	if (failb == syndrome_disks+1) {
1781		/* Q disk is one of the missing disks */
1782		if (faila == syndrome_disks) {
1783			/* Missing P+Q, just recompute */
1784			init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1785					  ops_complete_compute, sh,
1786					  to_addr_conv(sh, percpu, 0));
1787			return async_gen_syndrome(blocks, offs, syndrome_disks+2,
1788						  RAID5_STRIPE_SIZE(sh->raid_conf),
1789						  &submit);
1790		} else {
1791			struct page *dest;
1792			unsigned int dest_off;
1793			int data_target;
1794			int qd_idx = sh->qd_idx;
1795
1796			/* Missing D+Q: recompute D from P, then recompute Q */
1797			if (target == qd_idx)
1798				data_target = target2;
1799			else
1800				data_target = target;
1801
1802			count = 0;
1803			for (i = disks; i-- ; ) {
1804				if (i == data_target || i == qd_idx)
1805					continue;
1806				offs[count] = sh->dev[i].offset;
1807				blocks[count++] = sh->dev[i].page;
1808			}
1809			dest = sh->dev[data_target].page;
1810			dest_off = sh->dev[data_target].offset;
1811			init_async_submit(&submit,
1812					  ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1813					  NULL, NULL, NULL,
1814					  to_addr_conv(sh, percpu, 0));
1815			tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1816				       RAID5_STRIPE_SIZE(sh->raid_conf),
1817				       &submit);
1818
1819			count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1820			init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1821					  ops_complete_compute, sh,
1822					  to_addr_conv(sh, percpu, 0));
1823			return async_gen_syndrome(blocks, offs, count+2,
1824						  RAID5_STRIPE_SIZE(sh->raid_conf),
1825						  &submit);
1826		}
1827	} else {
1828		init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1829				  ops_complete_compute, sh,
1830				  to_addr_conv(sh, percpu, 0));
1831		if (failb == syndrome_disks) {
1832			/* We're missing D+P. */
1833			return async_raid6_datap_recov(syndrome_disks+2,
1834						RAID5_STRIPE_SIZE(sh->raid_conf),
1835						faila,
1836						blocks, offs, &submit);
1837		} else {
1838			/* We're missing D+D. */
1839			return async_raid6_2data_recov(syndrome_disks+2,
1840						RAID5_STRIPE_SIZE(sh->raid_conf),
1841						faila, failb,
1842						blocks, offs, &submit);
1843		}
1844	}
1845}
1846
 
1847static void ops_complete_prexor(void *stripe_head_ref)
1848{
1849	struct stripe_head *sh = stripe_head_ref;
1850
1851	pr_debug("%s: stripe %llu\n", __func__,
1852		(unsigned long long)sh->sector);
1853
1854	if (r5c_is_writeback(sh->raid_conf->log))
1855		/*
1856		 * raid5-cache write back uses orig_page during prexor.
1857		 * After prexor, it is time to free orig_page
1858		 */
1859		r5c_release_extra_page(sh);
1860}
1861
1862static struct dma_async_tx_descriptor *
1863ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1864		struct dma_async_tx_descriptor *tx)
1865{
1866	int disks = sh->disks;
1867	struct page **xor_srcs = to_addr_page(percpu, 0);
1868	unsigned int *off_srcs = to_addr_offs(sh, percpu);
1869	int count = 0, pd_idx = sh->pd_idx, i;
1870	struct async_submit_ctl submit;
1871
1872	/* existing parity data subtracted */
1873	unsigned int off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
1874	struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1875
1876	BUG_ON(sh->batch_head);
1877	pr_debug("%s: stripe %llu\n", __func__,
1878		(unsigned long long)sh->sector);
1879
1880	for (i = disks; i--; ) {
1881		struct r5dev *dev = &sh->dev[i];
1882		/* Only process blocks that are known to be uptodate */
1883		if (test_bit(R5_InJournal, &dev->flags)) {
1884			/*
1885			 * For this case, PAGE_SIZE must be equal to 4KB and
1886			 * page offset is zero.
1887			 */
1888			off_srcs[count] = dev->offset;
1889			xor_srcs[count++] = dev->orig_page;
1890		} else if (test_bit(R5_Wantdrain, &dev->flags)) {
1891			off_srcs[count] = dev->offset;
1892			xor_srcs[count++] = dev->page;
1893		}
1894	}
1895
1896	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1897			  ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1898	tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1899			RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1900
1901	return tx;
1902}
1903
1904static struct dma_async_tx_descriptor *
1905ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1906		struct dma_async_tx_descriptor *tx)
1907{
1908	struct page **blocks = to_addr_page(percpu, 0);
1909	unsigned int *offs = to_addr_offs(sh, percpu);
1910	int count;
1911	struct async_submit_ctl submit;
1912
1913	pr_debug("%s: stripe %llu\n", __func__,
1914		(unsigned long long)sh->sector);
1915
1916	count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_WANT_DRAIN);
1917
1918	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1919			  ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1920	tx = async_gen_syndrome(blocks, offs, count+2,
1921			RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1922
1923	return tx;
1924}
1925
1926static struct dma_async_tx_descriptor *
1927ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1928{
1929	struct r5conf *conf = sh->raid_conf;
1930	int disks = sh->disks;
1931	int i;
1932	struct stripe_head *head_sh = sh;
1933
1934	pr_debug("%s: stripe %llu\n", __func__,
1935		(unsigned long long)sh->sector);
1936
1937	for (i = disks; i--; ) {
1938		struct r5dev *dev;
1939		struct bio *chosen;
1940
1941		sh = head_sh;
1942		if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1943			struct bio *wbi;
1944
1945again:
1946			dev = &sh->dev[i];
1947			/*
1948			 * clear R5_InJournal, so when rewriting a page in
1949			 * journal, it is not skipped by r5l_log_stripe()
1950			 */
1951			clear_bit(R5_InJournal, &dev->flags);
1952			spin_lock_irq(&sh->stripe_lock);
1953			chosen = dev->towrite;
1954			dev->towrite = NULL;
1955			sh->overwrite_disks = 0;
1956			BUG_ON(dev->written);
1957			wbi = dev->written = chosen;
1958			spin_unlock_irq(&sh->stripe_lock);
1959			WARN_ON(dev->page != dev->orig_page);
1960
1961			while (wbi && wbi->bi_iter.bi_sector <
1962				dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1963				if (wbi->bi_opf & REQ_FUA)
1964					set_bit(R5_WantFUA, &dev->flags);
1965				if (wbi->bi_opf & REQ_SYNC)
1966					set_bit(R5_SyncIO, &dev->flags);
1967				if (bio_op(wbi) == REQ_OP_DISCARD)
1968					set_bit(R5_Discard, &dev->flags);
1969				else {
1970					tx = async_copy_data(1, wbi, &dev->page,
1971							     dev->offset,
1972							     dev->sector, tx, sh,
1973							     r5c_is_writeback(conf->log));
1974					if (dev->page != dev->orig_page &&
1975					    !r5c_is_writeback(conf->log)) {
1976						set_bit(R5_SkipCopy, &dev->flags);
1977						clear_bit(R5_UPTODATE, &dev->flags);
1978						clear_bit(R5_OVERWRITE, &dev->flags);
1979					}
1980				}
1981				wbi = r5_next_bio(conf, wbi, dev->sector);
1982			}
1983
1984			if (head_sh->batch_head) {
1985				sh = list_first_entry(&sh->batch_list,
1986						      struct stripe_head,
1987						      batch_list);
1988				if (sh == head_sh)
1989					continue;
1990				goto again;
1991			}
1992		}
1993	}
1994
1995	return tx;
1996}
1997
1998static void ops_complete_reconstruct(void *stripe_head_ref)
1999{
2000	struct stripe_head *sh = stripe_head_ref;
2001	int disks = sh->disks;
2002	int pd_idx = sh->pd_idx;
2003	int qd_idx = sh->qd_idx;
2004	int i;
2005	bool fua = false, sync = false, discard = false;
2006
2007	pr_debug("%s: stripe %llu\n", __func__,
2008		(unsigned long long)sh->sector);
2009
2010	for (i = disks; i--; ) {
2011		fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
2012		sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
2013		discard |= test_bit(R5_Discard, &sh->dev[i].flags);
2014	}
2015
2016	for (i = disks; i--; ) {
2017		struct r5dev *dev = &sh->dev[i];
2018
2019		if (dev->written || i == pd_idx || i == qd_idx) {
2020			if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
2021				set_bit(R5_UPTODATE, &dev->flags);
2022				if (test_bit(STRIPE_EXPAND_READY, &sh->state))
2023					set_bit(R5_Expanded, &dev->flags);
2024			}
2025			if (fua)
2026				set_bit(R5_WantFUA, &dev->flags);
2027			if (sync)
2028				set_bit(R5_SyncIO, &dev->flags);
2029		}
2030	}
2031
2032	if (sh->reconstruct_state == reconstruct_state_drain_run)
2033		sh->reconstruct_state = reconstruct_state_drain_result;
2034	else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
2035		sh->reconstruct_state = reconstruct_state_prexor_drain_result;
2036	else {
2037		BUG_ON(sh->reconstruct_state != reconstruct_state_run);
2038		sh->reconstruct_state = reconstruct_state_result;
2039	}
2040
2041	set_bit(STRIPE_HANDLE, &sh->state);
2042	raid5_release_stripe(sh);
2043}
2044
2045static void
2046ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
2047		     struct dma_async_tx_descriptor *tx)
2048{
2049	int disks = sh->disks;
2050	struct page **xor_srcs;
2051	unsigned int *off_srcs;
2052	struct async_submit_ctl submit;
2053	int count, pd_idx = sh->pd_idx, i;
2054	struct page *xor_dest;
2055	unsigned int off_dest;
2056	int prexor = 0;
2057	unsigned long flags;
2058	int j = 0;
2059	struct stripe_head *head_sh = sh;
2060	int last_stripe;
2061
2062	pr_debug("%s: stripe %llu\n", __func__,
2063		(unsigned long long)sh->sector);
2064
2065	for (i = 0; i < sh->disks; i++) {
2066		if (pd_idx == i)
2067			continue;
2068		if (!test_bit(R5_Discard, &sh->dev[i].flags))
2069			break;
2070	}
2071	if (i >= sh->disks) {
2072		atomic_inc(&sh->count);
2073		set_bit(R5_Discard, &sh->dev[pd_idx].flags);
2074		ops_complete_reconstruct(sh);
2075		return;
2076	}
2077again:
2078	count = 0;
2079	xor_srcs = to_addr_page(percpu, j);
2080	off_srcs = to_addr_offs(sh, percpu);
2081	/* check if prexor is active which means only process blocks
2082	 * that are part of a read-modify-write (written)
2083	 */
2084	if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2085		prexor = 1;
2086		off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
2087		xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
2088		for (i = disks; i--; ) {
2089			struct r5dev *dev = &sh->dev[i];
2090			if (head_sh->dev[i].written ||
2091			    test_bit(R5_InJournal, &head_sh->dev[i].flags)) {
2092				off_srcs[count] = dev->offset;
2093				xor_srcs[count++] = dev->page;
2094			}
2095		}
2096	} else {
2097		xor_dest = sh->dev[pd_idx].page;
2098		off_dest = sh->dev[pd_idx].offset;
2099		for (i = disks; i--; ) {
2100			struct r5dev *dev = &sh->dev[i];
2101			if (i != pd_idx) {
2102				off_srcs[count] = dev->offset;
2103				xor_srcs[count++] = dev->page;
2104			}
2105		}
2106	}
2107
2108	/* 1/ if we prexor'd then the dest is reused as a source
2109	 * 2/ if we did not prexor then we are redoing the parity
2110	 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
2111	 * for the synchronous xor case
2112	 */
2113	last_stripe = !head_sh->batch_head ||
2114		list_first_entry(&sh->batch_list,
2115				 struct stripe_head, batch_list) == head_sh;
2116	if (last_stripe) {
2117		flags = ASYNC_TX_ACK |
2118			(prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
2119
2120		atomic_inc(&head_sh->count);
2121		init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
2122				  to_addr_conv(sh, percpu, j));
2123	} else {
2124		flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
2125		init_async_submit(&submit, flags, tx, NULL, NULL,
2126				  to_addr_conv(sh, percpu, j));
2127	}
2128
 
 
2129	if (unlikely(count == 1))
2130		tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
2131				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2132	else
2133		tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2134				RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2135	if (!last_stripe) {
2136		j++;
2137		sh = list_first_entry(&sh->batch_list, struct stripe_head,
2138				      batch_list);
2139		goto again;
2140	}
2141}
2142
2143static void
2144ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
2145		     struct dma_async_tx_descriptor *tx)
2146{
2147	struct async_submit_ctl submit;
2148	struct page **blocks;
2149	unsigned int *offs;
2150	int count, i, j = 0;
2151	struct stripe_head *head_sh = sh;
2152	int last_stripe;
2153	int synflags;
2154	unsigned long txflags;
2155
2156	pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
2157
2158	for (i = 0; i < sh->disks; i++) {
2159		if (sh->pd_idx == i || sh->qd_idx == i)
2160			continue;
2161		if (!test_bit(R5_Discard, &sh->dev[i].flags))
2162			break;
2163	}
2164	if (i >= sh->disks) {
2165		atomic_inc(&sh->count);
2166		set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
2167		set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
2168		ops_complete_reconstruct(sh);
2169		return;
2170	}
2171
2172again:
2173	blocks = to_addr_page(percpu, j);
2174	offs = to_addr_offs(sh, percpu);
2175
2176	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2177		synflags = SYNDROME_SRC_WRITTEN;
2178		txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
2179	} else {
2180		synflags = SYNDROME_SRC_ALL;
2181		txflags = ASYNC_TX_ACK;
2182	}
2183
2184	count = set_syndrome_sources(blocks, offs, sh, synflags);
2185	last_stripe = !head_sh->batch_head ||
2186		list_first_entry(&sh->batch_list,
2187				 struct stripe_head, batch_list) == head_sh;
2188
2189	if (last_stripe) {
2190		atomic_inc(&head_sh->count);
2191		init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
2192				  head_sh, to_addr_conv(sh, percpu, j));
2193	} else
2194		init_async_submit(&submit, 0, tx, NULL, NULL,
2195				  to_addr_conv(sh, percpu, j));
2196	tx = async_gen_syndrome(blocks, offs, count+2,
2197			RAID5_STRIPE_SIZE(sh->raid_conf),  &submit);
2198	if (!last_stripe) {
2199		j++;
2200		sh = list_first_entry(&sh->batch_list, struct stripe_head,
2201				      batch_list);
2202		goto again;
2203	}
2204}
2205
2206static void ops_complete_check(void *stripe_head_ref)
2207{
2208	struct stripe_head *sh = stripe_head_ref;
2209
2210	pr_debug("%s: stripe %llu\n", __func__,
2211		(unsigned long long)sh->sector);
2212
2213	sh->check_state = check_state_check_result;
2214	set_bit(STRIPE_HANDLE, &sh->state);
2215	raid5_release_stripe(sh);
2216}
2217
2218static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2219{
2220	int disks = sh->disks;
2221	int pd_idx = sh->pd_idx;
2222	int qd_idx = sh->qd_idx;
2223	struct page *xor_dest;
2224	unsigned int off_dest;
2225	struct page **xor_srcs = to_addr_page(percpu, 0);
2226	unsigned int *off_srcs = to_addr_offs(sh, percpu);
2227	struct dma_async_tx_descriptor *tx;
2228	struct async_submit_ctl submit;
2229	int count;
2230	int i;
2231
2232	pr_debug("%s: stripe %llu\n", __func__,
2233		(unsigned long long)sh->sector);
2234
2235	BUG_ON(sh->batch_head);
2236	count = 0;
2237	xor_dest = sh->dev[pd_idx].page;
2238	off_dest = sh->dev[pd_idx].offset;
2239	off_srcs[count] = off_dest;
2240	xor_srcs[count++] = xor_dest;
2241	for (i = disks; i--; ) {
2242		if (i == pd_idx || i == qd_idx)
2243			continue;
2244		off_srcs[count] = sh->dev[i].offset;
2245		xor_srcs[count++] = sh->dev[i].page;
2246	}
2247
2248	init_async_submit(&submit, 0, NULL, NULL, NULL,
2249			  to_addr_conv(sh, percpu, 0));
2250	tx = async_xor_val_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2251			   RAID5_STRIPE_SIZE(sh->raid_conf),
2252			   &sh->ops.zero_sum_result, &submit);
2253
2254	atomic_inc(&sh->count);
2255	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2256	tx = async_trigger_callback(&submit);
2257}
2258
2259static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2260{
2261	struct page **srcs = to_addr_page(percpu, 0);
2262	unsigned int *offs = to_addr_offs(sh, percpu);
2263	struct async_submit_ctl submit;
2264	int count;
2265
2266	pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2267		(unsigned long long)sh->sector, checkp);
2268
2269	BUG_ON(sh->batch_head);
2270	count = set_syndrome_sources(srcs, offs, sh, SYNDROME_SRC_ALL);
2271	if (!checkp)
2272		srcs[count] = NULL;
2273
2274	atomic_inc(&sh->count);
2275	init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2276			  sh, to_addr_conv(sh, percpu, 0));
2277	async_syndrome_val(srcs, offs, count+2,
2278			   RAID5_STRIPE_SIZE(sh->raid_conf),
2279			   &sh->ops.zero_sum_result, percpu->spare_page, 0, &submit);
2280}
2281
2282static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2283{
2284	int overlap_clear = 0, i, disks = sh->disks;
2285	struct dma_async_tx_descriptor *tx = NULL;
2286	struct r5conf *conf = sh->raid_conf;
2287	int level = conf->level;
2288	struct raid5_percpu *percpu;
 
2289
2290	local_lock(&conf->percpu->lock);
2291	percpu = this_cpu_ptr(conf->percpu);
2292	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2293		ops_run_biofill(sh);
2294		overlap_clear++;
2295	}
2296
2297	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2298		if (level < 6)
2299			tx = ops_run_compute5(sh, percpu);
2300		else {
2301			if (sh->ops.target2 < 0 || sh->ops.target < 0)
2302				tx = ops_run_compute6_1(sh, percpu);
2303			else
2304				tx = ops_run_compute6_2(sh, percpu);
2305		}
2306		/* terminate the chain if reconstruct is not set to be run */
2307		if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2308			async_tx_ack(tx);
2309	}
2310
2311	if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2312		if (level < 6)
2313			tx = ops_run_prexor5(sh, percpu, tx);
2314		else
2315			tx = ops_run_prexor6(sh, percpu, tx);
2316	}
2317
2318	if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2319		tx = ops_run_partial_parity(sh, percpu, tx);
2320
2321	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2322		tx = ops_run_biodrain(sh, tx);
2323		overlap_clear++;
2324	}
2325
2326	if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2327		if (level < 6)
2328			ops_run_reconstruct5(sh, percpu, tx);
2329		else
2330			ops_run_reconstruct6(sh, percpu, tx);
2331	}
2332
2333	if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2334		if (sh->check_state == check_state_run)
2335			ops_run_check_p(sh, percpu);
2336		else if (sh->check_state == check_state_run_q)
2337			ops_run_check_pq(sh, percpu, 0);
2338		else if (sh->check_state == check_state_run_pq)
2339			ops_run_check_pq(sh, percpu, 1);
2340		else
2341			BUG();
2342	}
2343
2344	if (overlap_clear && !sh->batch_head) {
2345		for (i = disks; i--; ) {
2346			struct r5dev *dev = &sh->dev[i];
2347			if (test_and_clear_bit(R5_Overlap, &dev->flags))
2348				wake_up(&sh->raid_conf->wait_for_overlap);
2349		}
2350	}
2351	local_unlock(&conf->percpu->lock);
2352}
2353
2354static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2355{
2356#if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2357	kfree(sh->pages);
2358#endif
2359	if (sh->ppl_page)
2360		__free_page(sh->ppl_page);
2361	kmem_cache_free(sc, sh);
2362}
2363
2364static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2365	int disks, struct r5conf *conf)
2366{
2367	struct stripe_head *sh;
2368
2369	sh = kmem_cache_zalloc(sc, gfp);
2370	if (sh) {
2371		spin_lock_init(&sh->stripe_lock);
2372		spin_lock_init(&sh->batch_lock);
2373		INIT_LIST_HEAD(&sh->batch_list);
2374		INIT_LIST_HEAD(&sh->lru);
2375		INIT_LIST_HEAD(&sh->r5c);
2376		INIT_LIST_HEAD(&sh->log_list);
2377		atomic_set(&sh->count, 1);
2378		sh->raid_conf = conf;
2379		sh->log_start = MaxSector;
2380
2381		if (raid5_has_ppl(conf)) {
2382			sh->ppl_page = alloc_page(gfp);
2383			if (!sh->ppl_page) {
2384				free_stripe(sc, sh);
2385				return NULL;
2386			}
2387		}
2388#if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2389		if (init_stripe_shared_pages(sh, conf, disks)) {
2390			free_stripe(sc, sh);
2391			return NULL;
2392		}
2393#endif
2394	}
2395	return sh;
2396}
2397static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2398{
2399	struct stripe_head *sh;
2400
2401	sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2402	if (!sh)
2403		return 0;
2404
2405	if (grow_buffers(sh, gfp)) {
 
 
 
 
2406		shrink_buffers(sh);
2407		free_stripe(conf->slab_cache, sh);
2408		return 0;
2409	}
2410	sh->hash_lock_index =
2411		conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2412	/* we just created an active stripe so... */
 
2413	atomic_inc(&conf->active_stripes);
2414
2415	raid5_release_stripe(sh);
2416	conf->max_nr_stripes++;
2417	return 1;
2418}
2419
2420static int grow_stripes(struct r5conf *conf, int num)
2421{
2422	struct kmem_cache *sc;
2423	size_t namelen = sizeof(conf->cache_name[0]);
2424	int devs = max(conf->raid_disks, conf->previous_raid_disks);
 
2425
2426	if (conf->mddev->gendisk)
2427		snprintf(conf->cache_name[0], namelen,
2428			"raid%d-%s", conf->level, mdname(conf->mddev));
2429	else
2430		snprintf(conf->cache_name[0], namelen,
2431			"raid%d-%p", conf->level, conf->mddev);
2432	snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2433
2434	conf->active_name = 0;
2435	sc = kmem_cache_create(conf->cache_name[conf->active_name],
2436			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2437			       0, 0, NULL);
2438	if (!sc)
2439		return 1;
2440	conf->slab_cache = sc;
2441	conf->pool_size = devs;
2442	while (num--)
2443		if (!grow_one_stripe(conf, GFP_KERNEL))
 
2444			return 1;
2445
 
 
2446	return 0;
2447}
2448
2449/**
2450 * scribble_alloc - allocate percpu scribble buffer for required size
2451 *		    of the scribble region
2452 * @percpu: from for_each_present_cpu() of the caller
2453 * @num: total number of disks in the array
2454 * @cnt: scribble objs count for required size of the scribble region
2455 *
2456 * The scribble buffer size must be enough to contain:
2457 * 1/ a struct page pointer for each device in the array +2
2458 * 2/ room to convert each entry in (1) to its corresponding dma
2459 *    (dma_map_page()) or page (page_address()) address.
2460 *
2461 * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2462 * calculate over all devices (not just the data blocks), using zeros in place
2463 * of the P and Q blocks.
2464 */
2465static int scribble_alloc(struct raid5_percpu *percpu,
2466			  int num, int cnt)
2467{
2468	size_t obj_size =
2469		sizeof(struct page *) * (num + 2) +
2470		sizeof(addr_conv_t) * (num + 2) +
2471		sizeof(unsigned int) * (num + 2);
2472	void *scribble;
2473
2474	/*
2475	 * If here is in raid array suspend context, it is in memalloc noio
2476	 * context as well, there is no potential recursive memory reclaim
2477	 * I/Os with the GFP_KERNEL flag.
2478	 */
2479	scribble = kvmalloc_array(cnt, obj_size, GFP_KERNEL);
2480	if (!scribble)
2481		return -ENOMEM;
2482
2483	kvfree(percpu->scribble);
2484
2485	percpu->scribble = scribble;
2486	percpu->scribble_obj_size = obj_size;
2487	return 0;
2488}
2489
2490static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2491{
2492	unsigned long cpu;
2493	int err = 0;
2494
2495	/*
2496	 * Never shrink. And mddev_suspend() could deadlock if this is called
2497	 * from raid5d. In that case, scribble_disks and scribble_sectors
2498	 * should equal to new_disks and new_sectors
2499	 */
2500	if (conf->scribble_disks >= new_disks &&
2501	    conf->scribble_sectors >= new_sectors)
2502		return 0;
2503	mddev_suspend(conf->mddev);
2504	cpus_read_lock();
2505
2506	for_each_present_cpu(cpu) {
2507		struct raid5_percpu *percpu;
2508
2509		percpu = per_cpu_ptr(conf->percpu, cpu);
2510		err = scribble_alloc(percpu, new_disks,
2511				     new_sectors / RAID5_STRIPE_SECTORS(conf));
2512		if (err)
2513			break;
2514	}
2515
2516	cpus_read_unlock();
2517	mddev_resume(conf->mddev);
2518	if (!err) {
2519		conf->scribble_disks = new_disks;
2520		conf->scribble_sectors = new_sectors;
2521	}
2522	return err;
2523}
2524
2525static int resize_stripes(struct r5conf *conf, int newsize)
2526{
2527	/* Make all the stripes able to hold 'newsize' devices.
2528	 * New slots in each stripe get 'page' set to a new page.
2529	 *
2530	 * This happens in stages:
2531	 * 1/ create a new kmem_cache and allocate the required number of
2532	 *    stripe_heads.
2533	 * 2/ gather all the old stripe_heads and transfer the pages across
2534	 *    to the new stripe_heads.  This will have the side effect of
2535	 *    freezing the array as once all stripe_heads have been collected,
2536	 *    no IO will be possible.  Old stripe heads are freed once their
2537	 *    pages have been transferred over, and the old kmem_cache is
2538	 *    freed when all stripes are done.
2539	 * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2540	 *    we simple return a failure status - no need to clean anything up.
2541	 * 4/ allocate new pages for the new slots in the new stripe_heads.
2542	 *    If this fails, we don't bother trying the shrink the
2543	 *    stripe_heads down again, we just leave them as they are.
2544	 *    As each stripe_head is processed the new one is released into
2545	 *    active service.
2546	 *
2547	 * Once step2 is started, we cannot afford to wait for a write,
2548	 * so we use GFP_NOIO allocations.
2549	 */
2550	struct stripe_head *osh, *nsh;
2551	LIST_HEAD(newstripes);
2552	struct disk_info *ndisks;
2553	int err = 0;
 
2554	struct kmem_cache *sc;
2555	int i;
2556	int hash, cnt;
2557
2558	md_allow_write(conf->mddev);
 
 
 
 
 
2559
2560	/* Step 1 */
2561	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2562			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2563			       0, 0, NULL);
2564	if (!sc)
2565		return -ENOMEM;
2566
2567	/* Need to ensure auto-resizing doesn't interfere */
2568	mutex_lock(&conf->cache_size_mutex);
2569
2570	for (i = conf->max_nr_stripes; i; i--) {
2571		nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2572		if (!nsh)
2573			break;
2574
 
 
 
2575		list_add(&nsh->lru, &newstripes);
2576	}
2577	if (i) {
2578		/* didn't get enough, give up */
2579		while (!list_empty(&newstripes)) {
2580			nsh = list_entry(newstripes.next, struct stripe_head, lru);
2581			list_del(&nsh->lru);
2582			free_stripe(sc, nsh);
2583		}
2584		kmem_cache_destroy(sc);
2585		mutex_unlock(&conf->cache_size_mutex);
2586		return -ENOMEM;
2587	}
2588	/* Step 2 - Must use GFP_NOIO now.
2589	 * OK, we have enough stripes, start collecting inactive
2590	 * stripes and copying them over
2591	 */
2592	hash = 0;
2593	cnt = 0;
2594	list_for_each_entry(nsh, &newstripes, lru) {
2595		lock_device_hash_lock(conf, hash);
2596		wait_event_cmd(conf->wait_for_stripe,
2597				    !list_empty(conf->inactive_list + hash),
2598				    unlock_device_hash_lock(conf, hash),
2599				    lock_device_hash_lock(conf, hash));
2600		osh = get_free_stripe(conf, hash);
2601		unlock_device_hash_lock(conf, hash);
2602
2603#if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2604	for (i = 0; i < osh->nr_pages; i++) {
2605		nsh->pages[i] = osh->pages[i];
2606		osh->pages[i] = NULL;
2607	}
2608#endif
2609		for(i=0; i<conf->pool_size; i++) {
2610			nsh->dev[i].page = osh->dev[i].page;
2611			nsh->dev[i].orig_page = osh->dev[i].page;
2612			nsh->dev[i].offset = osh->dev[i].offset;
2613		}
2614		nsh->hash_lock_index = hash;
2615		free_stripe(conf->slab_cache, osh);
2616		cnt++;
2617		if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2618		    !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2619			hash++;
2620			cnt = 0;
2621		}
2622	}
2623	kmem_cache_destroy(conf->slab_cache);
2624
2625	/* Step 3.
2626	 * At this point, we are holding all the stripes so the array
2627	 * is completely stalled, so now is a good time to resize
2628	 * conf->disks and the scribble region
2629	 */
2630	ndisks = kcalloc(newsize, sizeof(struct disk_info), GFP_NOIO);
2631	if (ndisks) {
2632		for (i = 0; i < conf->pool_size; i++)
2633			ndisks[i] = conf->disks[i];
 
 
 
 
2634
2635		for (i = conf->pool_size; i < newsize; i++) {
2636			ndisks[i].extra_page = alloc_page(GFP_NOIO);
2637			if (!ndisks[i].extra_page)
2638				err = -ENOMEM;
2639		}
2640
2641		if (err) {
2642			for (i = conf->pool_size; i < newsize; i++)
2643				if (ndisks[i].extra_page)
2644					put_page(ndisks[i].extra_page);
2645			kfree(ndisks);
 
2646		} else {
2647			kfree(conf->disks);
2648			conf->disks = ndisks;
2649		}
2650	} else
2651		err = -ENOMEM;
2652
2653	conf->slab_cache = sc;
2654	conf->active_name = 1-conf->active_name;
2655
2656	/* Step 4, return new stripes to service */
2657	while(!list_empty(&newstripes)) {
2658		nsh = list_entry(newstripes.next, struct stripe_head, lru);
2659		list_del_init(&nsh->lru);
2660
2661#if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2662		for (i = 0; i < nsh->nr_pages; i++) {
2663			if (nsh->pages[i])
2664				continue;
2665			nsh->pages[i] = alloc_page(GFP_NOIO);
2666			if (!nsh->pages[i])
2667				err = -ENOMEM;
2668		}
2669
2670		for (i = conf->raid_disks; i < newsize; i++) {
2671			if (nsh->dev[i].page)
2672				continue;
2673			nsh->dev[i].page = raid5_get_dev_page(nsh, i);
2674			nsh->dev[i].orig_page = nsh->dev[i].page;
2675			nsh->dev[i].offset = raid5_get_page_offset(nsh, i);
2676		}
2677#else
2678		for (i=conf->raid_disks; i < newsize; i++)
2679			if (nsh->dev[i].page == NULL) {
2680				struct page *p = alloc_page(GFP_NOIO);
2681				nsh->dev[i].page = p;
2682				nsh->dev[i].orig_page = p;
2683				nsh->dev[i].offset = 0;
2684				if (!p)
2685					err = -ENOMEM;
2686			}
2687#endif
2688		raid5_release_stripe(nsh);
2689	}
2690	/* critical section pass, GFP_NOIO no longer needed */
2691
2692	if (!err)
2693		conf->pool_size = newsize;
2694	mutex_unlock(&conf->cache_size_mutex);
2695
2696	return err;
2697}
2698
2699static int drop_one_stripe(struct r5conf *conf)
2700{
2701	struct stripe_head *sh;
2702	int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2703
2704	spin_lock_irq(conf->hash_locks + hash);
2705	sh = get_free_stripe(conf, hash);
2706	spin_unlock_irq(conf->hash_locks + hash);
2707	if (!sh)
2708		return 0;
2709	BUG_ON(atomic_read(&sh->count));
2710	shrink_buffers(sh);
2711	free_stripe(conf->slab_cache, sh);
2712	atomic_dec(&conf->active_stripes);
2713	conf->max_nr_stripes--;
2714	return 1;
2715}
2716
2717static void shrink_stripes(struct r5conf *conf)
2718{
2719	while (conf->max_nr_stripes &&
2720	       drop_one_stripe(conf))
2721		;
 
2722
2723	kmem_cache_destroy(conf->slab_cache);
 
2724	conf->slab_cache = NULL;
2725}
2726
2727/*
2728 * This helper wraps rcu_dereference_protected() and can be used when
2729 * it is known that the nr_pending of the rdev is elevated.
2730 */
2731static struct md_rdev *rdev_pend_deref(struct md_rdev __rcu *rdev)
2732{
2733	return rcu_dereference_protected(rdev,
2734			atomic_read(&rcu_access_pointer(rdev)->nr_pending));
2735}
2736
2737/*
2738 * This helper wraps rcu_dereference_protected() and should be used
2739 * when it is known that the mddev_lock() is held. This is safe
2740 * seeing raid5_remove_disk() has the same lock held.
2741 */
2742static struct md_rdev *rdev_mdlock_deref(struct mddev *mddev,
2743					 struct md_rdev __rcu *rdev)
2744{
2745	return rcu_dereference_protected(rdev,
2746			lockdep_is_held(&mddev->reconfig_mutex));
2747}
2748
2749static void raid5_end_read_request(struct bio * bi)
2750{
2751	struct stripe_head *sh = bi->bi_private;
2752	struct r5conf *conf = sh->raid_conf;
2753	int disks = sh->disks, i;
 
 
2754	struct md_rdev *rdev = NULL;
2755	sector_t s;
2756
2757	for (i=0 ; i<disks; i++)
2758		if (bi == &sh->dev[i].req)
2759			break;
2760
2761	pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2762		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
2763		bi->bi_status);
2764	if (i == disks) {
2765		BUG();
2766		return;
2767	}
2768	if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2769		/* If replacement finished while this request was outstanding,
2770		 * 'replacement' might be NULL already.
2771		 * In that case it moved down to 'rdev'.
2772		 * rdev is not removed until all requests are finished.
2773		 */
2774		rdev = rdev_pend_deref(conf->disks[i].replacement);
2775	if (!rdev)
2776		rdev = rdev_pend_deref(conf->disks[i].rdev);
2777
2778	if (use_new_offset(conf, sh))
2779		s = sh->sector + rdev->new_data_offset;
2780	else
2781		s = sh->sector + rdev->data_offset;
2782	if (!bi->bi_status) {
2783		set_bit(R5_UPTODATE, &sh->dev[i].flags);
2784		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2785			/* Note that this cannot happen on a
2786			 * replacement device.  We just fail those on
2787			 * any error
2788			 */
2789			pr_info_ratelimited(
2790				"md/raid:%s: read error corrected (%lu sectors at %llu on %pg)\n",
2791				mdname(conf->mddev), RAID5_STRIPE_SECTORS(conf),
 
 
2792				(unsigned long long)s,
2793				rdev->bdev);
2794			atomic_add(RAID5_STRIPE_SECTORS(conf), &rdev->corrected_errors);
2795			clear_bit(R5_ReadError, &sh->dev[i].flags);
2796			clear_bit(R5_ReWrite, &sh->dev[i].flags);
2797		} else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2798			clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2799
2800		if (test_bit(R5_InJournal, &sh->dev[i].flags))
2801			/*
2802			 * end read for a page in journal, this
2803			 * must be preparing for prexor in rmw
2804			 */
2805			set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2806
2807		if (atomic_read(&rdev->read_errors))
2808			atomic_set(&rdev->read_errors, 0);
2809	} else {
 
2810		int retry = 0;
2811		int set_bad = 0;
2812
2813		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2814		if (!(bi->bi_status == BLK_STS_PROTECTION))
2815			atomic_inc(&rdev->read_errors);
2816		if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2817			pr_warn_ratelimited(
2818				"md/raid:%s: read error on replacement device (sector %llu on %pg).\n",
 
 
2819				mdname(conf->mddev),
2820				(unsigned long long)s,
2821				rdev->bdev);
2822		else if (conf->mddev->degraded >= conf->max_degraded) {
2823			set_bad = 1;
2824			pr_warn_ratelimited(
2825				"md/raid:%s: read error not correctable (sector %llu on %pg).\n",
 
 
2826				mdname(conf->mddev),
2827				(unsigned long long)s,
2828				rdev->bdev);
2829		} else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2830			/* Oh, no!!! */
2831			set_bad = 1;
2832			pr_warn_ratelimited(
2833				"md/raid:%s: read error NOT corrected!! (sector %llu on %pg).\n",
 
 
2834				mdname(conf->mddev),
2835				(unsigned long long)s,
2836				rdev->bdev);
2837		} else if (atomic_read(&rdev->read_errors)
2838			 > conf->max_nr_stripes) {
2839			if (!test_bit(Faulty, &rdev->flags)) {
2840				pr_warn("md/raid:%s: %d read_errors > %d stripes\n",
2841				    mdname(conf->mddev),
2842				    atomic_read(&rdev->read_errors),
2843				    conf->max_nr_stripes);
2844				pr_warn("md/raid:%s: Too many read errors, failing device %pg.\n",
2845				    mdname(conf->mddev), rdev->bdev);
2846			}
2847		} else
2848			retry = 1;
2849		if (set_bad && test_bit(In_sync, &rdev->flags)
2850		    && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2851			retry = 1;
2852		if (retry)
2853			if (sh->qd_idx >= 0 && sh->pd_idx == i)
2854				set_bit(R5_ReadError, &sh->dev[i].flags);
2855			else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2856				set_bit(R5_ReadError, &sh->dev[i].flags);
2857				clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2858			} else
2859				set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2860		else {
2861			clear_bit(R5_ReadError, &sh->dev[i].flags);
2862			clear_bit(R5_ReWrite, &sh->dev[i].flags);
2863			if (!(set_bad
2864			      && test_bit(In_sync, &rdev->flags)
2865			      && rdev_set_badblocks(
2866				      rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0)))
2867				md_error(conf->mddev, rdev);
2868		}
2869	}
2870	rdev_dec_pending(rdev, conf->mddev);
2871	bio_uninit(bi);
2872	clear_bit(R5_LOCKED, &sh->dev[i].flags);
2873	set_bit(STRIPE_HANDLE, &sh->state);
2874	raid5_release_stripe(sh);
2875}
2876
2877static void raid5_end_write_request(struct bio *bi)
2878{
2879	struct stripe_head *sh = bi->bi_private;
2880	struct r5conf *conf = sh->raid_conf;
2881	int disks = sh->disks, i;
2882	struct md_rdev *rdev;
 
2883	sector_t first_bad;
2884	int bad_sectors;
2885	int replacement = 0;
2886
2887	for (i = 0 ; i < disks; i++) {
2888		if (bi == &sh->dev[i].req) {
2889			rdev = rdev_pend_deref(conf->disks[i].rdev);
2890			break;
2891		}
2892		if (bi == &sh->dev[i].rreq) {
2893			rdev = rdev_pend_deref(conf->disks[i].replacement);
2894			if (rdev)
2895				replacement = 1;
2896			else
2897				/* rdev was removed and 'replacement'
2898				 * replaced it.  rdev is not removed
2899				 * until all requests are finished.
2900				 */
2901				rdev = rdev_pend_deref(conf->disks[i].rdev);
2902			break;
2903		}
2904	}
2905	pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2906		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
2907		bi->bi_status);
2908	if (i == disks) {
2909		BUG();
2910		return;
2911	}
2912
2913	if (replacement) {
2914		if (bi->bi_status)
2915			md_error(conf->mddev, rdev);
2916		else if (is_badblock(rdev, sh->sector,
2917				     RAID5_STRIPE_SECTORS(conf),
2918				     &first_bad, &bad_sectors))
2919			set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2920	} else {
2921		if (bi->bi_status) {
2922			set_bit(STRIPE_DEGRADED, &sh->state);
2923			set_bit(WriteErrorSeen, &rdev->flags);
2924			set_bit(R5_WriteError, &sh->dev[i].flags);
2925			if (!test_and_set_bit(WantReplacement, &rdev->flags))
2926				set_bit(MD_RECOVERY_NEEDED,
2927					&rdev->mddev->recovery);
2928		} else if (is_badblock(rdev, sh->sector,
2929				       RAID5_STRIPE_SECTORS(conf),
2930				       &first_bad, &bad_sectors)) {
2931			set_bit(R5_MadeGood, &sh->dev[i].flags);
2932			if (test_bit(R5_ReadError, &sh->dev[i].flags))
2933				/* That was a successful write so make
2934				 * sure it looks like we already did
2935				 * a re-write.
2936				 */
2937				set_bit(R5_ReWrite, &sh->dev[i].flags);
2938		}
2939	}
2940	rdev_dec_pending(rdev, conf->mddev);
2941
2942	if (sh->batch_head && bi->bi_status && !replacement)
2943		set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2944
2945	bio_uninit(bi);
2946	if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2947		clear_bit(R5_LOCKED, &sh->dev[i].flags);
2948	set_bit(STRIPE_HANDLE, &sh->state);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2949
2950	if (sh->batch_head && sh != sh->batch_head)
2951		raid5_release_stripe(sh->batch_head);
2952	raid5_release_stripe(sh);
 
 
 
 
 
 
2953}
2954
2955static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2956{
 
2957	struct r5conf *conf = mddev->private;
2958	unsigned long flags;
2959	pr_debug("raid456: error called\n");
2960
2961	pr_crit("md/raid:%s: Disk failure on %pg, disabling device.\n",
2962		mdname(mddev), rdev->bdev);
2963
2964	spin_lock_irqsave(&conf->device_lock, flags);
2965	set_bit(Faulty, &rdev->flags);
2966	clear_bit(In_sync, &rdev->flags);
2967	mddev->degraded = raid5_calc_degraded(conf);
2968
2969	if (has_failed(conf)) {
2970		set_bit(MD_BROKEN, &conf->mddev->flags);
2971		conf->recovery_disabled = mddev->recovery_disabled;
2972
2973		pr_crit("md/raid:%s: Cannot continue operation (%d/%d failed).\n",
2974			mdname(mddev), mddev->degraded, conf->raid_disks);
2975	} else {
2976		pr_crit("md/raid:%s: Operation continuing on %d devices.\n",
2977			mdname(mddev), conf->raid_disks - mddev->degraded);
2978	}
2979
2980	spin_unlock_irqrestore(&conf->device_lock, flags);
2981	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2982
2983	set_bit(Blocked, &rdev->flags);
2984	set_mask_bits(&mddev->sb_flags, 0,
2985		      BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2986	r5c_update_on_rdev_error(mddev, rdev);
 
 
 
 
 
 
2987}
2988
2989/*
2990 * Input: a 'big' sector number,
2991 * Output: index of the data and parity disk, and the sector # in them.
2992 */
2993sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2994			      int previous, int *dd_idx,
2995			      struct stripe_head *sh)
2996{
2997	sector_t stripe, stripe2;
2998	sector_t chunk_number;
2999	unsigned int chunk_offset;
3000	int pd_idx, qd_idx;
3001	int ddf_layout = 0;
3002	sector_t new_sector;
3003	int algorithm = previous ? conf->prev_algo
3004				 : conf->algorithm;
3005	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
3006					 : conf->chunk_sectors;
3007	int raid_disks = previous ? conf->previous_raid_disks
3008				  : conf->raid_disks;
3009	int data_disks = raid_disks - conf->max_degraded;
3010
3011	/* First compute the information on this sector */
3012
3013	/*
3014	 * Compute the chunk number and the sector offset inside the chunk
3015	 */
3016	chunk_offset = sector_div(r_sector, sectors_per_chunk);
3017	chunk_number = r_sector;
3018
3019	/*
3020	 * Compute the stripe number
3021	 */
3022	stripe = chunk_number;
3023	*dd_idx = sector_div(stripe, data_disks);
3024	stripe2 = stripe;
3025	/*
3026	 * Select the parity disk based on the user selected algorithm.
3027	 */
3028	pd_idx = qd_idx = -1;
3029	switch(conf->level) {
3030	case 4:
3031		pd_idx = data_disks;
3032		break;
3033	case 5:
3034		switch (algorithm) {
3035		case ALGORITHM_LEFT_ASYMMETRIC:
3036			pd_idx = data_disks - sector_div(stripe2, raid_disks);
3037			if (*dd_idx >= pd_idx)
3038				(*dd_idx)++;
3039			break;
3040		case ALGORITHM_RIGHT_ASYMMETRIC:
3041			pd_idx = sector_div(stripe2, raid_disks);
3042			if (*dd_idx >= pd_idx)
3043				(*dd_idx)++;
3044			break;
3045		case ALGORITHM_LEFT_SYMMETRIC:
3046			pd_idx = data_disks - sector_div(stripe2, raid_disks);
3047			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3048			break;
3049		case ALGORITHM_RIGHT_SYMMETRIC:
3050			pd_idx = sector_div(stripe2, raid_disks);
3051			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3052			break;
3053		case ALGORITHM_PARITY_0:
3054			pd_idx = 0;
3055			(*dd_idx)++;
3056			break;
3057		case ALGORITHM_PARITY_N:
3058			pd_idx = data_disks;
3059			break;
3060		default:
3061			BUG();
3062		}
3063		break;
3064	case 6:
3065
3066		switch (algorithm) {
3067		case ALGORITHM_LEFT_ASYMMETRIC:
3068			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3069			qd_idx = pd_idx + 1;
3070			if (pd_idx == raid_disks-1) {
3071				(*dd_idx)++;	/* Q D D D P */
3072				qd_idx = 0;
3073			} else if (*dd_idx >= pd_idx)
3074				(*dd_idx) += 2; /* D D P Q D */
3075			break;
3076		case ALGORITHM_RIGHT_ASYMMETRIC:
3077			pd_idx = sector_div(stripe2, raid_disks);
3078			qd_idx = pd_idx + 1;
3079			if (pd_idx == raid_disks-1) {
3080				(*dd_idx)++;	/* Q D D D P */
3081				qd_idx = 0;
3082			} else if (*dd_idx >= pd_idx)
3083				(*dd_idx) += 2; /* D D P Q D */
3084			break;
3085		case ALGORITHM_LEFT_SYMMETRIC:
3086			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3087			qd_idx = (pd_idx + 1) % raid_disks;
3088			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3089			break;
3090		case ALGORITHM_RIGHT_SYMMETRIC:
3091			pd_idx = sector_div(stripe2, raid_disks);
3092			qd_idx = (pd_idx + 1) % raid_disks;
3093			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3094			break;
3095
3096		case ALGORITHM_PARITY_0:
3097			pd_idx = 0;
3098			qd_idx = 1;
3099			(*dd_idx) += 2;
3100			break;
3101		case ALGORITHM_PARITY_N:
3102			pd_idx = data_disks;
3103			qd_idx = data_disks + 1;
3104			break;
3105
3106		case ALGORITHM_ROTATING_ZERO_RESTART:
3107			/* Exactly the same as RIGHT_ASYMMETRIC, but or
3108			 * of blocks for computing Q is different.
3109			 */
3110			pd_idx = sector_div(stripe2, raid_disks);
3111			qd_idx = pd_idx + 1;
3112			if (pd_idx == raid_disks-1) {
3113				(*dd_idx)++;	/* Q D D D P */
3114				qd_idx = 0;
3115			} else if (*dd_idx >= pd_idx)
3116				(*dd_idx) += 2; /* D D P Q D */
3117			ddf_layout = 1;
3118			break;
3119
3120		case ALGORITHM_ROTATING_N_RESTART:
3121			/* Same a left_asymmetric, by first stripe is
3122			 * D D D P Q  rather than
3123			 * Q D D D P
3124			 */
3125			stripe2 += 1;
3126			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3127			qd_idx = pd_idx + 1;
3128			if (pd_idx == raid_disks-1) {
3129				(*dd_idx)++;	/* Q D D D P */
3130				qd_idx = 0;
3131			} else if (*dd_idx >= pd_idx)
3132				(*dd_idx) += 2; /* D D P Q D */
3133			ddf_layout = 1;
3134			break;
3135
3136		case ALGORITHM_ROTATING_N_CONTINUE:
3137			/* Same as left_symmetric but Q is before P */
3138			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3139			qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
3140			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3141			ddf_layout = 1;
3142			break;
3143
3144		case ALGORITHM_LEFT_ASYMMETRIC_6:
3145			/* RAID5 left_asymmetric, with Q on last device */
3146			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3147			if (*dd_idx >= pd_idx)
3148				(*dd_idx)++;
3149			qd_idx = raid_disks - 1;
3150			break;
3151
3152		case ALGORITHM_RIGHT_ASYMMETRIC_6:
3153			pd_idx = sector_div(stripe2, raid_disks-1);
3154			if (*dd_idx >= pd_idx)
3155				(*dd_idx)++;
3156			qd_idx = raid_disks - 1;
3157			break;
3158
3159		case ALGORITHM_LEFT_SYMMETRIC_6:
3160			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3161			*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3162			qd_idx = raid_disks - 1;
3163			break;
3164
3165		case ALGORITHM_RIGHT_SYMMETRIC_6:
3166			pd_idx = sector_div(stripe2, raid_disks-1);
3167			*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3168			qd_idx = raid_disks - 1;
3169			break;
3170
3171		case ALGORITHM_PARITY_0_6:
3172			pd_idx = 0;
3173			(*dd_idx)++;
3174			qd_idx = raid_disks - 1;
3175			break;
3176
3177		default:
3178			BUG();
3179		}
3180		break;
3181	}
3182
3183	if (sh) {
3184		sh->pd_idx = pd_idx;
3185		sh->qd_idx = qd_idx;
3186		sh->ddf_layout = ddf_layout;
3187	}
3188	/*
3189	 * Finally, compute the new sector number
3190	 */
3191	new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
3192	return new_sector;
3193}
3194
3195sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
 
3196{
3197	struct r5conf *conf = sh->raid_conf;
3198	int raid_disks = sh->disks;
3199	int data_disks = raid_disks - conf->max_degraded;
3200	sector_t new_sector = sh->sector, check;
3201	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
3202					 : conf->chunk_sectors;
3203	int algorithm = previous ? conf->prev_algo
3204				 : conf->algorithm;
3205	sector_t stripe;
3206	int chunk_offset;
3207	sector_t chunk_number;
3208	int dummy1, dd_idx = i;
3209	sector_t r_sector;
3210	struct stripe_head sh2;
3211
 
3212	chunk_offset = sector_div(new_sector, sectors_per_chunk);
3213	stripe = new_sector;
3214
3215	if (i == sh->pd_idx)
3216		return 0;
3217	switch(conf->level) {
3218	case 4: break;
3219	case 5:
3220		switch (algorithm) {
3221		case ALGORITHM_LEFT_ASYMMETRIC:
3222		case ALGORITHM_RIGHT_ASYMMETRIC:
3223			if (i > sh->pd_idx)
3224				i--;
3225			break;
3226		case ALGORITHM_LEFT_SYMMETRIC:
3227		case ALGORITHM_RIGHT_SYMMETRIC:
3228			if (i < sh->pd_idx)
3229				i += raid_disks;
3230			i -= (sh->pd_idx + 1);
3231			break;
3232		case ALGORITHM_PARITY_0:
3233			i -= 1;
3234			break;
3235		case ALGORITHM_PARITY_N:
3236			break;
3237		default:
3238			BUG();
3239		}
3240		break;
3241	case 6:
3242		if (i == sh->qd_idx)
3243			return 0; /* It is the Q disk */
3244		switch (algorithm) {
3245		case ALGORITHM_LEFT_ASYMMETRIC:
3246		case ALGORITHM_RIGHT_ASYMMETRIC:
3247		case ALGORITHM_ROTATING_ZERO_RESTART:
3248		case ALGORITHM_ROTATING_N_RESTART:
3249			if (sh->pd_idx == raid_disks-1)
3250				i--;	/* Q D D D P */
3251			else if (i > sh->pd_idx)
3252				i -= 2; /* D D P Q D */
3253			break;
3254		case ALGORITHM_LEFT_SYMMETRIC:
3255		case ALGORITHM_RIGHT_SYMMETRIC:
3256			if (sh->pd_idx == raid_disks-1)
3257				i--; /* Q D D D P */
3258			else {
3259				/* D D P Q D */
3260				if (i < sh->pd_idx)
3261					i += raid_disks;
3262				i -= (sh->pd_idx + 2);
3263			}
3264			break;
3265		case ALGORITHM_PARITY_0:
3266			i -= 2;
3267			break;
3268		case ALGORITHM_PARITY_N:
3269			break;
3270		case ALGORITHM_ROTATING_N_CONTINUE:
3271			/* Like left_symmetric, but P is before Q */
3272			if (sh->pd_idx == 0)
3273				i--;	/* P D D D Q */
3274			else {
3275				/* D D Q P D */
3276				if (i < sh->pd_idx)
3277					i += raid_disks;
3278				i -= (sh->pd_idx + 1);
3279			}
3280			break;
3281		case ALGORITHM_LEFT_ASYMMETRIC_6:
3282		case ALGORITHM_RIGHT_ASYMMETRIC_6:
3283			if (i > sh->pd_idx)
3284				i--;
3285			break;
3286		case ALGORITHM_LEFT_SYMMETRIC_6:
3287		case ALGORITHM_RIGHT_SYMMETRIC_6:
3288			if (i < sh->pd_idx)
3289				i += data_disks + 1;
3290			i -= (sh->pd_idx + 1);
3291			break;
3292		case ALGORITHM_PARITY_0_6:
3293			i -= 1;
3294			break;
3295		default:
3296			BUG();
3297		}
3298		break;
3299	}
3300
3301	chunk_number = stripe * data_disks + i;
3302	r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3303
3304	check = raid5_compute_sector(conf, r_sector,
3305				     previous, &dummy1, &sh2);
3306	if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3307		|| sh2.qd_idx != sh->qd_idx) {
3308		pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3309			mdname(conf->mddev));
3310		return 0;
3311	}
3312	return r_sector;
3313}
3314
3315/*
3316 * There are cases where we want handle_stripe_dirtying() and
3317 * schedule_reconstruction() to delay towrite to some dev of a stripe.
3318 *
3319 * This function checks whether we want to delay the towrite. Specifically,
3320 * we delay the towrite when:
3321 *
3322 *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3323 *      stripe has data in journal (for other devices).
3324 *
3325 *      In this case, when reading data for the non-overwrite dev, it is
3326 *      necessary to handle complex rmw of write back cache (prexor with
3327 *      orig_page, and xor with page). To keep read path simple, we would
3328 *      like to flush data in journal to RAID disks first, so complex rmw
3329 *      is handled in the write patch (handle_stripe_dirtying).
3330 *
3331 *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3332 *
3333 *      It is important to be able to flush all stripes in raid5-cache.
3334 *      Therefore, we need reserve some space on the journal device for
3335 *      these flushes. If flush operation includes pending writes to the
3336 *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3337 *      for the flush out. If we exclude these pending writes from flush
3338 *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3339 *      Therefore, excluding pending writes in these cases enables more
3340 *      efficient use of the journal device.
3341 *
3342 *      Note: To make sure the stripe makes progress, we only delay
3343 *      towrite for stripes with data already in journal (injournal > 0).
3344 *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3345 *      no_space_stripes list.
3346 *
3347 *   3. during journal failure
3348 *      In journal failure, we try to flush all cached data to raid disks
3349 *      based on data in stripe cache. The array is read-only to upper
3350 *      layers, so we would skip all pending writes.
3351 *
3352 */
3353static inline bool delay_towrite(struct r5conf *conf,
3354				 struct r5dev *dev,
3355				 struct stripe_head_state *s)
3356{
3357	/* case 1 above */
3358	if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3359	    !test_bit(R5_Insync, &dev->flags) && s->injournal)
3360		return true;
3361	/* case 2 above */
3362	if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3363	    s->injournal > 0)
3364		return true;
3365	/* case 3 above */
3366	if (s->log_failed && s->injournal)
3367		return true;
3368	return false;
3369}
3370
3371static void
3372schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3373			 int rcw, int expand)
3374{
3375	int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3376	struct r5conf *conf = sh->raid_conf;
3377	int level = conf->level;
3378
3379	if (rcw) {
3380		/*
3381		 * In some cases, handle_stripe_dirtying initially decided to
3382		 * run rmw and allocates extra page for prexor. However, rcw is
3383		 * cheaper later on. We need to free the extra page now,
3384		 * because we won't be able to do that in ops_complete_prexor().
3385		 */
3386		r5c_release_extra_page(sh);
3387
3388		for (i = disks; i--; ) {
3389			struct r5dev *dev = &sh->dev[i];
3390
3391			if (dev->towrite && !delay_towrite(conf, dev, s)) {
3392				set_bit(R5_LOCKED, &dev->flags);
3393				set_bit(R5_Wantdrain, &dev->flags);
3394				if (!expand)
3395					clear_bit(R5_UPTODATE, &dev->flags);
3396				s->locked++;
3397			} else if (test_bit(R5_InJournal, &dev->flags)) {
3398				set_bit(R5_LOCKED, &dev->flags);
3399				s->locked++;
3400			}
3401		}
3402		/* if we are not expanding this is a proper write request, and
3403		 * there will be bios with new data to be drained into the
3404		 * stripe cache
3405		 */
3406		if (!expand) {
3407			if (!s->locked)
3408				/* False alarm, nothing to do */
3409				return;
3410			sh->reconstruct_state = reconstruct_state_drain_run;
3411			set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3412		} else
3413			sh->reconstruct_state = reconstruct_state_run;
3414
3415		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3416
3417		if (s->locked + conf->max_degraded == disks)
3418			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3419				atomic_inc(&conf->pending_full_writes);
3420	} else {
 
3421		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3422			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3423		BUG_ON(level == 6 &&
3424			(!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3425			   test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3426
3427		for (i = disks; i--; ) {
3428			struct r5dev *dev = &sh->dev[i];
3429			if (i == pd_idx || i == qd_idx)
3430				continue;
3431
3432			if (dev->towrite &&
3433			    (test_bit(R5_UPTODATE, &dev->flags) ||
3434			     test_bit(R5_Wantcompute, &dev->flags))) {
3435				set_bit(R5_Wantdrain, &dev->flags);
3436				set_bit(R5_LOCKED, &dev->flags);
3437				clear_bit(R5_UPTODATE, &dev->flags);
3438				s->locked++;
3439			} else if (test_bit(R5_InJournal, &dev->flags)) {
3440				set_bit(R5_LOCKED, &dev->flags);
3441				s->locked++;
3442			}
3443		}
3444		if (!s->locked)
3445			/* False alarm - nothing to do */
3446			return;
3447		sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3448		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3449		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3450		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3451	}
3452
3453	/* keep the parity disk(s) locked while asynchronous operations
3454	 * are in flight
3455	 */
3456	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3457	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3458	s->locked++;
3459
3460	if (level == 6) {
3461		int qd_idx = sh->qd_idx;
3462		struct r5dev *dev = &sh->dev[qd_idx];
3463
3464		set_bit(R5_LOCKED, &dev->flags);
3465		clear_bit(R5_UPTODATE, &dev->flags);
3466		s->locked++;
3467	}
3468
3469	if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3470	    test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3471	    !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3472	    test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3473		set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3474
3475	pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3476		__func__, (unsigned long long)sh->sector,
3477		s->locked, s->ops_request);
3478}
3479
3480static bool stripe_bio_overlaps(struct stripe_head *sh, struct bio *bi,
3481				int dd_idx, int forwrite)
 
 
 
 
3482{
3483	struct r5conf *conf = sh->raid_conf;
3484	struct bio **bip;
 
 
3485
3486	pr_debug("checking bi b#%llu to stripe s#%llu\n",
3487		 bi->bi_iter.bi_sector, sh->sector);
3488
3489	/* Don't allow new IO added to stripes in batch list */
3490	if (sh->batch_head)
3491		return true;
3492
3493	if (forwrite)
 
 
 
 
 
 
 
 
 
3494		bip = &sh->dev[dd_idx].towrite;
3495	else
 
 
3496		bip = &sh->dev[dd_idx].toread;
3497
3498	while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3499		if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3500			return true;
3501		bip = &(*bip)->bi_next;
3502	}
3503
3504	if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3505		return true;
3506
3507	if (forwrite && raid5_has_ppl(conf)) {
3508		/*
3509		 * With PPL only writes to consecutive data chunks within a
3510		 * stripe are allowed because for a single stripe_head we can
3511		 * only have one PPL entry at a time, which describes one data
3512		 * range. Not really an overlap, but wait_for_overlap can be
3513		 * used to handle this.
3514		 */
3515		sector_t sector;
3516		sector_t first = 0;
3517		sector_t last = 0;
3518		int count = 0;
3519		int i;
3520
3521		for (i = 0; i < sh->disks; i++) {
3522			if (i != sh->pd_idx &&
3523			    (i == dd_idx || sh->dev[i].towrite)) {
3524				sector = sh->dev[i].sector;
3525				if (count == 0 || sector < first)
3526					first = sector;
3527				if (sector > last)
3528					last = sector;
3529				count++;
3530			}
3531		}
3532
3533		if (first + conf->chunk_sectors * (count - 1) != last)
3534			return true;
3535	}
3536
3537	return false;
3538}
3539
3540static void __add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3541			     int dd_idx, int forwrite, int previous)
3542{
3543	struct r5conf *conf = sh->raid_conf;
3544	struct bio **bip;
3545	int firstwrite = 0;
3546
3547	if (forwrite) {
3548		bip = &sh->dev[dd_idx].towrite;
3549		if (!*bip)
3550			firstwrite = 1;
3551	} else {
3552		bip = &sh->dev[dd_idx].toread;
3553	}
3554
3555	while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector)
3556		bip = &(*bip)->bi_next;
3557
3558	if (!forwrite || previous)
3559		clear_bit(STRIPE_BATCH_READY, &sh->state);
3560
3561	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3562	if (*bip)
3563		bi->bi_next = *bip;
3564	*bip = bi;
3565	bio_inc_remaining(bi);
3566	md_write_inc(conf->mddev, bi);
3567
3568	if (forwrite) {
3569		/* check if page is covered */
3570		sector_t sector = sh->dev[dd_idx].sector;
3571		for (bi=sh->dev[dd_idx].towrite;
3572		     sector < sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf) &&
3573			     bi && bi->bi_iter.bi_sector <= sector;
3574		     bi = r5_next_bio(conf, bi, sh->dev[dd_idx].sector)) {
3575			if (bio_end_sector(bi) >= sector)
3576				sector = bio_end_sector(bi);
3577		}
3578		if (sector >= sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf))
3579			if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3580				sh->overwrite_disks++;
3581	}
3582
3583	pr_debug("added bi b#%llu to stripe s#%llu, disk %d, logical %llu\n",
3584		 (*bip)->bi_iter.bi_sector, sh->sector, dd_idx,
3585		 sh->dev[dd_idx].sector);
 
3586
3587	if (conf->mddev->bitmap && firstwrite) {
3588		/* Cannot hold spinlock over bitmap_startwrite,
3589		 * but must ensure this isn't added to a batch until
3590		 * we have added to the bitmap and set bm_seq.
3591		 * So set STRIPE_BITMAP_PENDING to prevent
3592		 * batching.
3593		 * If multiple __add_stripe_bio() calls race here they
3594		 * much all set STRIPE_BITMAP_PENDING.  So only the first one
3595		 * to complete "bitmap_startwrite" gets to set
3596		 * STRIPE_BIT_DELAY.  This is important as once a stripe
3597		 * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3598		 * any more.
3599		 */
3600		set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3601		spin_unlock_irq(&sh->stripe_lock);
3602		md_bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3603				     RAID5_STRIPE_SECTORS(conf), 0);
3604		spin_lock_irq(&sh->stripe_lock);
3605		clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3606		if (!sh->batch_head) {
3607			sh->bm_seq = conf->seq_flush+1;
3608			set_bit(STRIPE_BIT_DELAY, &sh->state);
3609		}
3610	}
3611}
3612
3613/*
3614 * Each stripe/dev can have one or more bios attached.
3615 * toread/towrite point to the first in a chain.
3616 * The bi_next chain must be in order.
3617 */
3618static bool add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3619			   int dd_idx, int forwrite, int previous)
3620{
3621	spin_lock_irq(&sh->stripe_lock);
3622
3623	if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
3624		set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3625		spin_unlock_irq(&sh->stripe_lock);
3626		return false;
3627	}
 
3628
3629	__add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
 
3630	spin_unlock_irq(&sh->stripe_lock);
3631	return true;
3632}
3633
3634static void end_reshape(struct r5conf *conf);
3635
3636static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3637			    struct stripe_head *sh)
3638{
3639	int sectors_per_chunk =
3640		previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3641	int dd_idx;
3642	int chunk_offset = sector_div(stripe, sectors_per_chunk);
3643	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3644
3645	raid5_compute_sector(conf,
3646			     stripe * (disks - conf->max_degraded)
3647			     *sectors_per_chunk + chunk_offset,
3648			     previous,
3649			     &dd_idx, sh);
3650}
3651
3652static void
3653handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3654		     struct stripe_head_state *s, int disks)
 
3655{
3656	int i;
3657	BUG_ON(sh->batch_head);
3658	for (i = disks; i--; ) {
3659		struct bio *bi;
3660		int bitmap_end = 0;
3661
3662		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3663			struct md_rdev *rdev;
3664			rcu_read_lock();
3665			rdev = rcu_dereference(conf->disks[i].rdev);
3666			if (rdev && test_bit(In_sync, &rdev->flags) &&
3667			    !test_bit(Faulty, &rdev->flags))
3668				atomic_inc(&rdev->nr_pending);
3669			else
3670				rdev = NULL;
3671			rcu_read_unlock();
3672			if (rdev) {
3673				if (!rdev_set_badblocks(
3674					    rdev,
3675					    sh->sector,
3676					    RAID5_STRIPE_SECTORS(conf), 0))
3677					md_error(conf->mddev, rdev);
3678				rdev_dec_pending(rdev, conf->mddev);
3679			}
3680		}
3681		spin_lock_irq(&sh->stripe_lock);
3682		/* fail all writes first */
3683		bi = sh->dev[i].towrite;
3684		sh->dev[i].towrite = NULL;
3685		sh->overwrite_disks = 0;
3686		spin_unlock_irq(&sh->stripe_lock);
3687		if (bi)
3688			bitmap_end = 1;
3689
3690		log_stripe_write_finished(sh);
3691
3692		if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3693			wake_up(&conf->wait_for_overlap);
3694
3695		while (bi && bi->bi_iter.bi_sector <
3696			sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3697			struct bio *nextbi = r5_next_bio(conf, bi, sh->dev[i].sector);
3698
3699			md_write_end(conf->mddev);
3700			bio_io_error(bi);
 
 
 
3701			bi = nextbi;
3702		}
3703		if (bitmap_end)
3704			md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3705					   RAID5_STRIPE_SECTORS(conf), 0, 0);
3706		bitmap_end = 0;
3707		/* and fail all 'written' */
3708		bi = sh->dev[i].written;
3709		sh->dev[i].written = NULL;
3710		if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3711			WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3712			sh->dev[i].page = sh->dev[i].orig_page;
3713		}
3714
3715		if (bi) bitmap_end = 1;
3716		while (bi && bi->bi_iter.bi_sector <
3717		       sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3718			struct bio *bi2 = r5_next_bio(conf, bi, sh->dev[i].sector);
3719
3720			md_write_end(conf->mddev);
3721			bio_io_error(bi);
 
 
 
3722			bi = bi2;
3723		}
3724
3725		/* fail any reads if this device is non-operational and
3726		 * the data has not reached the cache yet.
3727		 */
3728		if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3729		    s->failed > conf->max_degraded &&
3730		    (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3731		      test_bit(R5_ReadError, &sh->dev[i].flags))) {
3732			spin_lock_irq(&sh->stripe_lock);
3733			bi = sh->dev[i].toread;
3734			sh->dev[i].toread = NULL;
3735			spin_unlock_irq(&sh->stripe_lock);
3736			if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3737				wake_up(&conf->wait_for_overlap);
3738			if (bi)
3739				s->to_read--;
3740			while (bi && bi->bi_iter.bi_sector <
3741			       sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3742				struct bio *nextbi =
3743					r5_next_bio(conf, bi, sh->dev[i].sector);
3744
3745				bio_io_error(bi);
 
 
 
3746				bi = nextbi;
3747			}
3748		}
3749		if (bitmap_end)
3750			md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3751					   RAID5_STRIPE_SECTORS(conf), 0, 0);
3752		/* If we were in the middle of a write the parity block might
3753		 * still be locked - so just clear all R5_LOCKED flags
3754		 */
3755		clear_bit(R5_LOCKED, &sh->dev[i].flags);
3756	}
3757	s->to_write = 0;
3758	s->written = 0;
3759
3760	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3761		if (atomic_dec_and_test(&conf->pending_full_writes))
3762			md_wakeup_thread(conf->mddev->thread);
3763}
3764
3765static void
3766handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3767		   struct stripe_head_state *s)
3768{
3769	int abort = 0;
3770	int i;
3771
3772	BUG_ON(sh->batch_head);
3773	clear_bit(STRIPE_SYNCING, &sh->state);
3774	if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3775		wake_up(&conf->wait_for_overlap);
3776	s->syncing = 0;
3777	s->replacing = 0;
3778	/* There is nothing more to do for sync/check/repair.
3779	 * Don't even need to abort as that is handled elsewhere
3780	 * if needed, and not always wanted e.g. if there is a known
3781	 * bad block here.
3782	 * For recover/replace we need to record a bad block on all
3783	 * non-sync devices, or abort the recovery
3784	 */
3785	if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3786		/* During recovery devices cannot be removed, so
3787		 * locking and refcounting of rdevs is not needed
3788		 */
3789		rcu_read_lock();
3790		for (i = 0; i < conf->raid_disks; i++) {
3791			struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3792			if (rdev
3793			    && !test_bit(Faulty, &rdev->flags)
3794			    && !test_bit(In_sync, &rdev->flags)
3795			    && !rdev_set_badblocks(rdev, sh->sector,
3796						   RAID5_STRIPE_SECTORS(conf), 0))
3797				abort = 1;
3798			rdev = rcu_dereference(conf->disks[i].replacement);
3799			if (rdev
3800			    && !test_bit(Faulty, &rdev->flags)
3801			    && !test_bit(In_sync, &rdev->flags)
3802			    && !rdev_set_badblocks(rdev, sh->sector,
3803						   RAID5_STRIPE_SECTORS(conf), 0))
3804				abort = 1;
3805		}
3806		rcu_read_unlock();
3807		if (abort)
3808			conf->recovery_disabled =
3809				conf->mddev->recovery_disabled;
3810	}
3811	md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), !abort);
3812}
3813
3814static int want_replace(struct stripe_head *sh, int disk_idx)
3815{
3816	struct md_rdev *rdev;
3817	int rv = 0;
3818
3819	rcu_read_lock();
3820	rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3821	if (rdev
3822	    && !test_bit(Faulty, &rdev->flags)
3823	    && !test_bit(In_sync, &rdev->flags)
3824	    && (rdev->recovery_offset <= sh->sector
3825		|| rdev->mddev->recovery_cp <= sh->sector))
3826		rv = 1;
3827	rcu_read_unlock();
3828	return rv;
3829}
3830
3831static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3832			   int disk_idx, int disks)
3833{
3834	struct r5dev *dev = &sh->dev[disk_idx];
3835	struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3836				  &sh->dev[s->failed_num[1]] };
3837	int i;
3838	bool force_rcw = (sh->raid_conf->rmw_level == PARITY_DISABLE_RMW);
3839
3840
3841	if (test_bit(R5_LOCKED, &dev->flags) ||
3842	    test_bit(R5_UPTODATE, &dev->flags))
3843		/* No point reading this as we already have it or have
3844		 * decided to get it.
3845		 */
3846		return 0;
3847
3848	if (dev->toread ||
3849	    (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3850		/* We need this block to directly satisfy a request */
3851		return 1;
3852
3853	if (s->syncing || s->expanding ||
3854	    (s->replacing && want_replace(sh, disk_idx)))
3855		/* When syncing, or expanding we read everything.
3856		 * When replacing, we need the replaced block.
3857		 */
3858		return 1;
3859
3860	if ((s->failed >= 1 && fdev[0]->toread) ||
3861	    (s->failed >= 2 && fdev[1]->toread))
3862		/* If we want to read from a failed device, then
3863		 * we need to actually read every other device.
3864		 */
3865		return 1;
3866
3867	/* Sometimes neither read-modify-write nor reconstruct-write
3868	 * cycles can work.  In those cases we read every block we
3869	 * can.  Then the parity-update is certain to have enough to
3870	 * work with.
3871	 * This can only be a problem when we need to write something,
3872	 * and some device has failed.  If either of those tests
3873	 * fail we need look no further.
3874	 */
3875	if (!s->failed || !s->to_write)
3876		return 0;
3877
3878	if (test_bit(R5_Insync, &dev->flags) &&
3879	    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3880		/* Pre-reads at not permitted until after short delay
3881		 * to gather multiple requests.  However if this
3882		 * device is no Insync, the block could only be computed
3883		 * and there is no need to delay that.
3884		 */
3885		return 0;
3886
3887	for (i = 0; i < s->failed && i < 2; i++) {
3888		if (fdev[i]->towrite &&
3889		    !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3890		    !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3891			/* If we have a partial write to a failed
3892			 * device, then we will need to reconstruct
3893			 * the content of that device, so all other
3894			 * devices must be read.
3895			 */
3896			return 1;
3897
3898		if (s->failed >= 2 &&
3899		    (fdev[i]->towrite ||
3900		     s->failed_num[i] == sh->pd_idx ||
3901		     s->failed_num[i] == sh->qd_idx) &&
3902		    !test_bit(R5_UPTODATE, &fdev[i]->flags))
3903			/* In max degraded raid6, If the failed disk is P, Q,
3904			 * or we want to read the failed disk, we need to do
3905			 * reconstruct-write.
3906			 */
3907			force_rcw = true;
3908	}
3909
3910	/* If we are forced to do a reconstruct-write, because parity
3911	 * cannot be trusted and we are currently recovering it, there
3912	 * is extra need to be careful.
3913	 * If one of the devices that we would need to read, because
3914	 * it is not being overwritten (and maybe not written at all)
3915	 * is missing/faulty, then we need to read everything we can.
3916	 */
3917	if (!force_rcw &&
3918	    sh->sector < sh->raid_conf->mddev->recovery_cp)
3919		/* reconstruct-write isn't being forced */
3920		return 0;
3921	for (i = 0; i < s->failed && i < 2; i++) {
3922		if (s->failed_num[i] != sh->pd_idx &&
3923		    s->failed_num[i] != sh->qd_idx &&
3924		    !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3925		    !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3926			return 1;
3927	}
3928
3929	return 0;
3930}
3931
3932/* fetch_block - checks the given member device to see if its data needs
3933 * to be read or computed to satisfy a request.
3934 *
3935 * Returns 1 when no more member devices need to be checked, otherwise returns
3936 * 0 to tell the loop in handle_stripe_fill to continue
3937 */
3938static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3939		       int disk_idx, int disks)
3940{
3941	struct r5dev *dev = &sh->dev[disk_idx];
 
 
3942
3943	/* is the data in this block needed, and can we get it? */
3944	if (need_this_block(sh, s, disk_idx, disks)) {
 
 
 
 
 
 
 
 
 
 
3945		/* we would like to get this block, possibly by computing it,
3946		 * otherwise read it if the backing disk is insync
3947		 */
3948		BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3949		BUG_ON(test_bit(R5_Wantread, &dev->flags));
3950		BUG_ON(sh->batch_head);
3951
3952		/*
3953		 * In the raid6 case if the only non-uptodate disk is P
3954		 * then we already trusted P to compute the other failed
3955		 * drives. It is safe to compute rather than re-read P.
3956		 * In other cases we only compute blocks from failed
3957		 * devices, otherwise check/repair might fail to detect
3958		 * a real inconsistency.
3959		 */
3960
3961		if ((s->uptodate == disks - 1) &&
3962		    ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3963		    (s->failed && (disk_idx == s->failed_num[0] ||
3964				   disk_idx == s->failed_num[1])))) {
3965			/* have disk failed, and we're requested to fetch it;
3966			 * do compute it
3967			 */
3968			pr_debug("Computing stripe %llu block %d\n",
3969			       (unsigned long long)sh->sector, disk_idx);
3970			set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3971			set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3972			set_bit(R5_Wantcompute, &dev->flags);
3973			sh->ops.target = disk_idx;
3974			sh->ops.target2 = -1; /* no 2nd target */
3975			s->req_compute = 1;
3976			/* Careful: from this point on 'uptodate' is in the eye
3977			 * of raid_run_ops which services 'compute' operations
3978			 * before writes. R5_Wantcompute flags a block that will
3979			 * be R5_UPTODATE by the time it is needed for a
3980			 * subsequent operation.
3981			 */
3982			s->uptodate++;
3983			return 1;
3984		} else if (s->uptodate == disks-2 && s->failed >= 2) {
3985			/* Computing 2-failure is *very* expensive; only
3986			 * do it if failed >= 2
3987			 */
3988			int other;
3989			for (other = disks; other--; ) {
3990				if (other == disk_idx)
3991					continue;
3992				if (!test_bit(R5_UPTODATE,
3993				      &sh->dev[other].flags))
3994					break;
3995			}
3996			BUG_ON(other < 0);
3997			pr_debug("Computing stripe %llu blocks %d,%d\n",
3998			       (unsigned long long)sh->sector,
3999			       disk_idx, other);
4000			set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4001			set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4002			set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
4003			set_bit(R5_Wantcompute, &sh->dev[other].flags);
4004			sh->ops.target = disk_idx;
4005			sh->ops.target2 = other;
4006			s->uptodate += 2;
4007			s->req_compute = 1;
4008			return 1;
4009		} else if (test_bit(R5_Insync, &dev->flags)) {
4010			set_bit(R5_LOCKED, &dev->flags);
4011			set_bit(R5_Wantread, &dev->flags);
4012			s->locked++;
4013			pr_debug("Reading block %d (sync=%d)\n",
4014				disk_idx, s->syncing);
4015		}
4016	}
4017
4018	return 0;
4019}
4020
4021/*
4022 * handle_stripe_fill - read or compute data to satisfy pending requests.
4023 */
4024static void handle_stripe_fill(struct stripe_head *sh,
4025			       struct stripe_head_state *s,
4026			       int disks)
4027{
4028	int i;
4029
4030	/* look for blocks to read/compute, skip this if a compute
4031	 * is already in flight, or if the stripe contents are in the
4032	 * midst of changing due to a write
4033	 */
4034	if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
4035	    !sh->reconstruct_state) {
4036
4037		/*
4038		 * For degraded stripe with data in journal, do not handle
4039		 * read requests yet, instead, flush the stripe to raid
4040		 * disks first, this avoids handling complex rmw of write
4041		 * back cache (prexor with orig_page, and then xor with
4042		 * page) in the read path
4043		 */
4044		if (s->to_read && s->injournal && s->failed) {
4045			if (test_bit(STRIPE_R5C_CACHING, &sh->state))
4046				r5c_make_stripe_write_out(sh);
4047			goto out;
4048		}
4049
4050		for (i = disks; i--; )
4051			if (fetch_block(sh, s, i, disks))
4052				break;
4053	}
4054out:
4055	set_bit(STRIPE_HANDLE, &sh->state);
4056}
4057
4058static void break_stripe_batch_list(struct stripe_head *head_sh,
4059				    unsigned long handle_flags);
4060/* handle_stripe_clean_event
4061 * any written block on an uptodate or failed drive can be returned.
4062 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
4063 * never LOCKED, so we don't need to test 'failed' directly.
4064 */
4065static void handle_stripe_clean_event(struct r5conf *conf,
4066	struct stripe_head *sh, int disks)
4067{
4068	int i;
4069	struct r5dev *dev;
4070	int discard_pending = 0;
4071	struct stripe_head *head_sh = sh;
4072	bool do_endio = false;
4073
4074	for (i = disks; i--; )
4075		if (sh->dev[i].written) {
4076			dev = &sh->dev[i];
4077			if (!test_bit(R5_LOCKED, &dev->flags) &&
4078			    (test_bit(R5_UPTODATE, &dev->flags) ||
4079			     test_bit(R5_Discard, &dev->flags) ||
4080			     test_bit(R5_SkipCopy, &dev->flags))) {
4081				/* We can return any write requests */
4082				struct bio *wbi, *wbi2;
4083				pr_debug("Return write for disc %d\n", i);
4084				if (test_and_clear_bit(R5_Discard, &dev->flags))
4085					clear_bit(R5_UPTODATE, &dev->flags);
4086				if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
4087					WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
4088				}
4089				do_endio = true;
4090
4091returnbi:
4092				dev->page = dev->orig_page;
4093				wbi = dev->written;
4094				dev->written = NULL;
4095				while (wbi && wbi->bi_iter.bi_sector <
4096					dev->sector + RAID5_STRIPE_SECTORS(conf)) {
4097					wbi2 = r5_next_bio(conf, wbi, dev->sector);
4098					md_write_end(conf->mddev);
4099					bio_endio(wbi);
4100					wbi = wbi2;
4101				}
4102				md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
4103						   RAID5_STRIPE_SECTORS(conf),
4104						   !test_bit(STRIPE_DEGRADED, &sh->state),
4105						   0);
4106				if (head_sh->batch_head) {
4107					sh = list_first_entry(&sh->batch_list,
4108							      struct stripe_head,
4109							      batch_list);
4110					if (sh != head_sh) {
4111						dev = &sh->dev[i];
4112						goto returnbi;
4113					}
 
4114				}
4115				sh = head_sh;
4116				dev = &sh->dev[i];
 
 
4117			} else if (test_bit(R5_Discard, &dev->flags))
4118				discard_pending = 1;
4119		}
4120
4121	log_stripe_write_finished(sh);
4122
4123	if (!discard_pending &&
4124	    test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
4125		int hash;
4126		clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
4127		clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4128		if (sh->qd_idx >= 0) {
4129			clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
4130			clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
4131		}
4132		/* now that discard is done we can proceed with any sync */
4133		clear_bit(STRIPE_DISCARD, &sh->state);
4134		/*
4135		 * SCSI discard will change some bio fields and the stripe has
4136		 * no updated data, so remove it from hash list and the stripe
4137		 * will be reinitialized
4138		 */
4139unhash:
4140		hash = sh->hash_lock_index;
4141		spin_lock_irq(conf->hash_locks + hash);
4142		remove_hash(sh);
4143		spin_unlock_irq(conf->hash_locks + hash);
4144		if (head_sh->batch_head) {
4145			sh = list_first_entry(&sh->batch_list,
4146					      struct stripe_head, batch_list);
4147			if (sh != head_sh)
4148					goto unhash;
4149		}
4150		sh = head_sh;
4151
4152		if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
4153			set_bit(STRIPE_HANDLE, &sh->state);
4154
4155	}
4156
4157	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
4158		if (atomic_dec_and_test(&conf->pending_full_writes))
4159			md_wakeup_thread(conf->mddev->thread);
4160
4161	if (head_sh->batch_head && do_endio)
4162		break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
4163}
4164
4165/*
4166 * For RMW in write back cache, we need extra page in prexor to store the
4167 * old data. This page is stored in dev->orig_page.
4168 *
4169 * This function checks whether we have data for prexor. The exact logic
4170 * is:
4171 *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
4172 */
4173static inline bool uptodate_for_rmw(struct r5dev *dev)
4174{
4175	return (test_bit(R5_UPTODATE, &dev->flags)) &&
4176		(!test_bit(R5_InJournal, &dev->flags) ||
4177		 test_bit(R5_OrigPageUPTDODATE, &dev->flags));
4178}
4179
4180static int handle_stripe_dirtying(struct r5conf *conf,
4181				  struct stripe_head *sh,
4182				  struct stripe_head_state *s,
4183				  int disks)
4184{
4185	int rmw = 0, rcw = 0, i;
4186	sector_t recovery_cp = conf->mddev->recovery_cp;
4187
4188	/* Check whether resync is now happening or should start.
 
4189	 * If yes, then the array is dirty (after unclean shutdown or
4190	 * initial creation), so parity in some stripes might be inconsistent.
4191	 * In this case, we need to always do reconstruct-write, to ensure
4192	 * that in case of drive failure or read-error correction, we
4193	 * generate correct data from the parity.
4194	 */
4195	if (conf->rmw_level == PARITY_DISABLE_RMW ||
4196	    (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
4197	     s->failed == 0)) {
4198		/* Calculate the real rcw later - for now make it
4199		 * look like rcw is cheaper
4200		 */
4201		rcw = 1; rmw = 2;
4202		pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
4203			 conf->rmw_level, (unsigned long long)recovery_cp,
4204			 (unsigned long long)sh->sector);
4205	} else for (i = disks; i--; ) {
4206		/* would I have to read this buffer for read_modify_write */
4207		struct r5dev *dev = &sh->dev[i];
4208		if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4209		     i == sh->pd_idx || i == sh->qd_idx ||
4210		     test_bit(R5_InJournal, &dev->flags)) &&
4211		    !test_bit(R5_LOCKED, &dev->flags) &&
4212		    !(uptodate_for_rmw(dev) ||
4213		      test_bit(R5_Wantcompute, &dev->flags))) {
4214			if (test_bit(R5_Insync, &dev->flags))
4215				rmw++;
4216			else
4217				rmw += 2*disks;  /* cannot read it */
4218		}
4219		/* Would I have to read this buffer for reconstruct_write */
4220		if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4221		    i != sh->pd_idx && i != sh->qd_idx &&
4222		    !test_bit(R5_LOCKED, &dev->flags) &&
4223		    !(test_bit(R5_UPTODATE, &dev->flags) ||
4224		      test_bit(R5_Wantcompute, &dev->flags))) {
4225			if (test_bit(R5_Insync, &dev->flags))
4226				rcw++;
4227			else
4228				rcw += 2*disks;
4229		}
4230	}
4231
4232	pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
4233		 (unsigned long long)sh->sector, sh->state, rmw, rcw);
4234	set_bit(STRIPE_HANDLE, &sh->state);
4235	if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
4236		/* prefer read-modify-write, but need to get some data */
4237		if (conf->mddev->queue)
4238			blk_add_trace_msg(conf->mddev->queue,
4239					  "raid5 rmw %llu %d",
4240					  (unsigned long long)sh->sector, rmw);
4241		for (i = disks; i--; ) {
4242			struct r5dev *dev = &sh->dev[i];
4243			if (test_bit(R5_InJournal, &dev->flags) &&
4244			    dev->page == dev->orig_page &&
4245			    !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
4246				/* alloc page for prexor */
4247				struct page *p = alloc_page(GFP_NOIO);
4248
4249				if (p) {
4250					dev->orig_page = p;
4251					continue;
4252				}
4253
4254				/*
4255				 * alloc_page() failed, try use
4256				 * disk_info->extra_page
4257				 */
4258				if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
4259						      &conf->cache_state)) {
4260					r5c_use_extra_page(sh);
4261					break;
4262				}
4263
4264				/* extra_page in use, add to delayed_list */
4265				set_bit(STRIPE_DELAYED, &sh->state);
4266				s->waiting_extra_page = 1;
4267				return -EAGAIN;
4268			}
4269		}
4270
4271		for (i = disks; i--; ) {
4272			struct r5dev *dev = &sh->dev[i];
4273			if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4274			     i == sh->pd_idx || i == sh->qd_idx ||
4275			     test_bit(R5_InJournal, &dev->flags)) &&
4276			    !test_bit(R5_LOCKED, &dev->flags) &&
4277			    !(uptodate_for_rmw(dev) ||
4278			      test_bit(R5_Wantcompute, &dev->flags)) &&
4279			    test_bit(R5_Insync, &dev->flags)) {
4280				if (test_bit(STRIPE_PREREAD_ACTIVE,
4281					     &sh->state)) {
4282					pr_debug("Read_old block %d for r-m-w\n",
4283						 i);
4284					set_bit(R5_LOCKED, &dev->flags);
4285					set_bit(R5_Wantread, &dev->flags);
4286					s->locked++;
4287				} else
4288					set_bit(STRIPE_DELAYED, &sh->state);
 
 
4289			}
4290		}
4291	}
4292	if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
4293		/* want reconstruct write, but need to get some data */
4294		int qread =0;
4295		rcw = 0;
4296		for (i = disks; i--; ) {
4297			struct r5dev *dev = &sh->dev[i];
4298			if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4299			    i != sh->pd_idx && i != sh->qd_idx &&
4300			    !test_bit(R5_LOCKED, &dev->flags) &&
4301			    !(test_bit(R5_UPTODATE, &dev->flags) ||
4302			      test_bit(R5_Wantcompute, &dev->flags))) {
4303				rcw++;
4304				if (test_bit(R5_Insync, &dev->flags) &&
4305				    test_bit(STRIPE_PREREAD_ACTIVE,
4306					     &sh->state)) {
 
4307					pr_debug("Read_old block "
4308						"%d for Reconstruct\n", i);
4309					set_bit(R5_LOCKED, &dev->flags);
4310					set_bit(R5_Wantread, &dev->flags);
4311					s->locked++;
4312					qread++;
4313				} else
4314					set_bit(STRIPE_DELAYED, &sh->state);
 
 
4315			}
4316		}
4317		if (rcw && conf->mddev->queue)
4318			blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
4319					  (unsigned long long)sh->sector,
4320					  rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
4321	}
4322
4323	if (rcw > disks && rmw > disks &&
4324	    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4325		set_bit(STRIPE_DELAYED, &sh->state);
4326
4327	/* now if nothing is locked, and if we have enough data,
4328	 * we can start a write request
4329	 */
4330	/* since handle_stripe can be called at any time we need to handle the
4331	 * case where a compute block operation has been submitted and then a
4332	 * subsequent call wants to start a write request.  raid_run_ops only
4333	 * handles the case where compute block and reconstruct are requested
4334	 * simultaneously.  If this is not the case then new writes need to be
4335	 * held off until the compute completes.
4336	 */
4337	if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4338	    (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4339	     !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4340		schedule_reconstruction(sh, s, rcw == 0, 0);
4341	return 0;
4342}
4343
4344static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4345				struct stripe_head_state *s, int disks)
4346{
4347	struct r5dev *dev = NULL;
4348
4349	BUG_ON(sh->batch_head);
4350	set_bit(STRIPE_HANDLE, &sh->state);
4351
4352	switch (sh->check_state) {
4353	case check_state_idle:
4354		/* start a new check operation if there are no failures */
4355		if (s->failed == 0) {
4356			BUG_ON(s->uptodate != disks);
4357			sh->check_state = check_state_run;
4358			set_bit(STRIPE_OP_CHECK, &s->ops_request);
4359			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4360			s->uptodate--;
4361			break;
4362		}
4363		dev = &sh->dev[s->failed_num[0]];
4364		fallthrough;
4365	case check_state_compute_result:
4366		sh->check_state = check_state_idle;
4367		if (!dev)
4368			dev = &sh->dev[sh->pd_idx];
4369
4370		/* check that a write has not made the stripe insync */
4371		if (test_bit(STRIPE_INSYNC, &sh->state))
4372			break;
4373
4374		/* either failed parity check, or recovery is happening */
4375		BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4376		BUG_ON(s->uptodate != disks);
4377
4378		set_bit(R5_LOCKED, &dev->flags);
4379		s->locked++;
4380		set_bit(R5_Wantwrite, &dev->flags);
4381
4382		clear_bit(STRIPE_DEGRADED, &sh->state);
4383		set_bit(STRIPE_INSYNC, &sh->state);
4384		break;
4385	case check_state_run:
4386		break; /* we will be called again upon completion */
4387	case check_state_check_result:
4388		sh->check_state = check_state_idle;
4389
4390		/* if a failure occurred during the check operation, leave
4391		 * STRIPE_INSYNC not set and let the stripe be handled again
4392		 */
4393		if (s->failed)
4394			break;
4395
4396		/* handle a successful check operation, if parity is correct
4397		 * we are done.  Otherwise update the mismatch count and repair
4398		 * parity if !MD_RECOVERY_CHECK
4399		 */
4400		if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4401			/* parity is correct (on disc,
4402			 * not in buffer any more)
4403			 */
4404			set_bit(STRIPE_INSYNC, &sh->state);
4405		else {
4406			atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4407			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4408				/* don't try to repair!! */
4409				set_bit(STRIPE_INSYNC, &sh->state);
4410				pr_warn_ratelimited("%s: mismatch sector in range "
4411						    "%llu-%llu\n", mdname(conf->mddev),
4412						    (unsigned long long) sh->sector,
4413						    (unsigned long long) sh->sector +
4414						    RAID5_STRIPE_SECTORS(conf));
4415			} else {
4416				sh->check_state = check_state_compute_run;
4417				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4418				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4419				set_bit(R5_Wantcompute,
4420					&sh->dev[sh->pd_idx].flags);
4421				sh->ops.target = sh->pd_idx;
4422				sh->ops.target2 = -1;
4423				s->uptodate++;
4424			}
4425		}
4426		break;
4427	case check_state_compute_run:
4428		break;
4429	default:
4430		pr_err("%s: unknown check_state: %d sector: %llu\n",
4431		       __func__, sh->check_state,
4432		       (unsigned long long) sh->sector);
4433		BUG();
4434	}
4435}
4436
 
4437static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4438				  struct stripe_head_state *s,
4439				  int disks)
4440{
4441	int pd_idx = sh->pd_idx;
4442	int qd_idx = sh->qd_idx;
4443	struct r5dev *dev;
4444
4445	BUG_ON(sh->batch_head);
4446	set_bit(STRIPE_HANDLE, &sh->state);
4447
4448	BUG_ON(s->failed > 2);
4449
4450	/* Want to check and possibly repair P and Q.
4451	 * However there could be one 'failed' device, in which
4452	 * case we can only check one of them, possibly using the
4453	 * other to generate missing data
4454	 */
4455
4456	switch (sh->check_state) {
4457	case check_state_idle:
4458		/* start a new check operation if there are < 2 failures */
4459		if (s->failed == s->q_failed) {
4460			/* The only possible failed device holds Q, so it
4461			 * makes sense to check P (If anything else were failed,
4462			 * we would have used P to recreate it).
4463			 */
4464			sh->check_state = check_state_run;
4465		}
4466		if (!s->q_failed && s->failed < 2) {
4467			/* Q is not failed, and we didn't use it to generate
4468			 * anything, so it makes sense to check it
4469			 */
4470			if (sh->check_state == check_state_run)
4471				sh->check_state = check_state_run_pq;
4472			else
4473				sh->check_state = check_state_run_q;
4474		}
4475
4476		/* discard potentially stale zero_sum_result */
4477		sh->ops.zero_sum_result = 0;
4478
4479		if (sh->check_state == check_state_run) {
4480			/* async_xor_zero_sum destroys the contents of P */
4481			clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4482			s->uptodate--;
4483		}
4484		if (sh->check_state >= check_state_run &&
4485		    sh->check_state <= check_state_run_pq) {
4486			/* async_syndrome_zero_sum preserves P and Q, so
4487			 * no need to mark them !uptodate here
4488			 */
4489			set_bit(STRIPE_OP_CHECK, &s->ops_request);
4490			break;
4491		}
4492
4493		/* we have 2-disk failure */
4494		BUG_ON(s->failed != 2);
4495		fallthrough;
4496	case check_state_compute_result:
4497		sh->check_state = check_state_idle;
4498
4499		/* check that a write has not made the stripe insync */
4500		if (test_bit(STRIPE_INSYNC, &sh->state))
4501			break;
4502
4503		/* now write out any block on a failed drive,
4504		 * or P or Q if they were recomputed
4505		 */
4506		dev = NULL;
4507		if (s->failed == 2) {
4508			dev = &sh->dev[s->failed_num[1]];
4509			s->locked++;
4510			set_bit(R5_LOCKED, &dev->flags);
4511			set_bit(R5_Wantwrite, &dev->flags);
4512		}
4513		if (s->failed >= 1) {
4514			dev = &sh->dev[s->failed_num[0]];
4515			s->locked++;
4516			set_bit(R5_LOCKED, &dev->flags);
4517			set_bit(R5_Wantwrite, &dev->flags);
4518		}
4519		if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4520			dev = &sh->dev[pd_idx];
4521			s->locked++;
4522			set_bit(R5_LOCKED, &dev->flags);
4523			set_bit(R5_Wantwrite, &dev->flags);
4524		}
4525		if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4526			dev = &sh->dev[qd_idx];
4527			s->locked++;
4528			set_bit(R5_LOCKED, &dev->flags);
4529			set_bit(R5_Wantwrite, &dev->flags);
4530		}
4531		if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4532			      "%s: disk%td not up to date\n",
4533			      mdname(conf->mddev),
4534			      dev - (struct r5dev *) &sh->dev)) {
4535			clear_bit(R5_LOCKED, &dev->flags);
4536			clear_bit(R5_Wantwrite, &dev->flags);
4537			s->locked--;
4538		}
4539		clear_bit(STRIPE_DEGRADED, &sh->state);
4540
4541		set_bit(STRIPE_INSYNC, &sh->state);
4542		break;
4543	case check_state_run:
4544	case check_state_run_q:
4545	case check_state_run_pq:
4546		break; /* we will be called again upon completion */
4547	case check_state_check_result:
4548		sh->check_state = check_state_idle;
4549
4550		/* handle a successful check operation, if parity is correct
4551		 * we are done.  Otherwise update the mismatch count and repair
4552		 * parity if !MD_RECOVERY_CHECK
4553		 */
4554		if (sh->ops.zero_sum_result == 0) {
4555			/* both parities are correct */
4556			if (!s->failed)
4557				set_bit(STRIPE_INSYNC, &sh->state);
4558			else {
4559				/* in contrast to the raid5 case we can validate
4560				 * parity, but still have a failure to write
4561				 * back
4562				 */
4563				sh->check_state = check_state_compute_result;
4564				/* Returning at this point means that we may go
4565				 * off and bring p and/or q uptodate again so
4566				 * we make sure to check zero_sum_result again
4567				 * to verify if p or q need writeback
4568				 */
4569			}
4570		} else {
4571			atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4572			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4573				/* don't try to repair!! */
4574				set_bit(STRIPE_INSYNC, &sh->state);
4575				pr_warn_ratelimited("%s: mismatch sector in range "
4576						    "%llu-%llu\n", mdname(conf->mddev),
4577						    (unsigned long long) sh->sector,
4578						    (unsigned long long) sh->sector +
4579						    RAID5_STRIPE_SECTORS(conf));
4580			} else {
4581				int *target = &sh->ops.target;
4582
4583				sh->ops.target = -1;
4584				sh->ops.target2 = -1;
4585				sh->check_state = check_state_compute_run;
4586				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4587				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4588				if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4589					set_bit(R5_Wantcompute,
4590						&sh->dev[pd_idx].flags);
4591					*target = pd_idx;
4592					target = &sh->ops.target2;
4593					s->uptodate++;
4594				}
4595				if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4596					set_bit(R5_Wantcompute,
4597						&sh->dev[qd_idx].flags);
4598					*target = qd_idx;
4599					s->uptodate++;
4600				}
4601			}
4602		}
4603		break;
4604	case check_state_compute_run:
4605		break;
4606	default:
4607		pr_warn("%s: unknown check_state: %d sector: %llu\n",
4608			__func__, sh->check_state,
4609			(unsigned long long) sh->sector);
4610		BUG();
4611	}
4612}
4613
4614static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4615{
4616	int i;
4617
4618	/* We have read all the blocks in this stripe and now we need to
4619	 * copy some of them into a target stripe for expand.
4620	 */
4621	struct dma_async_tx_descriptor *tx = NULL;
4622	BUG_ON(sh->batch_head);
4623	clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4624	for (i = 0; i < sh->disks; i++)
4625		if (i != sh->pd_idx && i != sh->qd_idx) {
4626			int dd_idx, j;
4627			struct stripe_head *sh2;
4628			struct async_submit_ctl submit;
4629
4630			sector_t bn = raid5_compute_blocknr(sh, i, 1);
4631			sector_t s = raid5_compute_sector(conf, bn, 0,
4632							  &dd_idx, NULL);
4633			sh2 = raid5_get_active_stripe(conf, NULL, s,
4634				R5_GAS_NOBLOCK | R5_GAS_NOQUIESCE);
4635			if (sh2 == NULL)
4636				/* so far only the early blocks of this stripe
4637				 * have been requested.  When later blocks
4638				 * get requested, we will try again
4639				 */
4640				continue;
4641			if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4642			   test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4643				/* must have already done this block */
4644				raid5_release_stripe(sh2);
4645				continue;
4646			}
4647
4648			/* place all the copies on one channel */
4649			init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4650			tx = async_memcpy(sh2->dev[dd_idx].page,
4651					  sh->dev[i].page, sh2->dev[dd_idx].offset,
4652					  sh->dev[i].offset, RAID5_STRIPE_SIZE(conf),
4653					  &submit);
4654
4655			set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4656			set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4657			for (j = 0; j < conf->raid_disks; j++)
4658				if (j != sh2->pd_idx &&
4659				    j != sh2->qd_idx &&
4660				    !test_bit(R5_Expanded, &sh2->dev[j].flags))
4661					break;
4662			if (j == conf->raid_disks) {
4663				set_bit(STRIPE_EXPAND_READY, &sh2->state);
4664				set_bit(STRIPE_HANDLE, &sh2->state);
4665			}
4666			raid5_release_stripe(sh2);
4667
4668		}
4669	/* done submitting copies, wait for them to complete */
4670	async_tx_quiesce(&tx);
4671}
4672
4673/*
4674 * handle_stripe - do things to a stripe.
4675 *
4676 * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4677 * state of various bits to see what needs to be done.
4678 * Possible results:
4679 *    return some read requests which now have data
4680 *    return some write requests which are safely on storage
4681 *    schedule a read on some buffers
4682 *    schedule a write of some buffers
4683 *    return confirmation of parity correctness
4684 *
4685 */
4686
4687static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4688{
4689	struct r5conf *conf = sh->raid_conf;
4690	int disks = sh->disks;
4691	struct r5dev *dev;
4692	int i;
4693	int do_recovery = 0;
4694
4695	memset(s, 0, sizeof(*s));
4696
4697	s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4698	s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4699	s->failed_num[0] = -1;
4700	s->failed_num[1] = -1;
4701	s->log_failed = r5l_log_disk_error(conf);
4702
4703	/* Now to look around and see what can be done */
4704	rcu_read_lock();
4705	for (i=disks; i--; ) {
4706		struct md_rdev *rdev;
4707		sector_t first_bad;
4708		int bad_sectors;
4709		int is_bad = 0;
4710
4711		dev = &sh->dev[i];
4712
4713		pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4714			 i, dev->flags,
4715			 dev->toread, dev->towrite, dev->written);
4716		/* maybe we can reply to a read
4717		 *
4718		 * new wantfill requests are only permitted while
4719		 * ops_complete_biofill is guaranteed to be inactive
4720		 */
4721		if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4722		    !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4723			set_bit(R5_Wantfill, &dev->flags);
4724
4725		/* now count some things */
4726		if (test_bit(R5_LOCKED, &dev->flags))
4727			s->locked++;
4728		if (test_bit(R5_UPTODATE, &dev->flags))
4729			s->uptodate++;
4730		if (test_bit(R5_Wantcompute, &dev->flags)) {
4731			s->compute++;
4732			BUG_ON(s->compute > 2);
4733		}
4734
4735		if (test_bit(R5_Wantfill, &dev->flags))
4736			s->to_fill++;
4737		else if (dev->toread)
4738			s->to_read++;
4739		if (dev->towrite) {
4740			s->to_write++;
4741			if (!test_bit(R5_OVERWRITE, &dev->flags))
4742				s->non_overwrite++;
4743		}
4744		if (dev->written)
4745			s->written++;
4746		/* Prefer to use the replacement for reads, but only
4747		 * if it is recovered enough and has no bad blocks.
4748		 */
4749		rdev = rcu_dereference(conf->disks[i].replacement);
4750		if (rdev && !test_bit(Faulty, &rdev->flags) &&
4751		    rdev->recovery_offset >= sh->sector + RAID5_STRIPE_SECTORS(conf) &&
4752		    !is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
4753				 &first_bad, &bad_sectors))
4754			set_bit(R5_ReadRepl, &dev->flags);
4755		else {
4756			if (rdev && !test_bit(Faulty, &rdev->flags))
4757				set_bit(R5_NeedReplace, &dev->flags);
4758			else
4759				clear_bit(R5_NeedReplace, &dev->flags);
4760			rdev = rcu_dereference(conf->disks[i].rdev);
4761			clear_bit(R5_ReadRepl, &dev->flags);
4762		}
4763		if (rdev && test_bit(Faulty, &rdev->flags))
4764			rdev = NULL;
4765		if (rdev) {
4766			is_bad = is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
4767					     &first_bad, &bad_sectors);
4768			if (s->blocked_rdev == NULL
4769			    && (test_bit(Blocked, &rdev->flags)
4770				|| is_bad < 0)) {
4771				if (is_bad < 0)
4772					set_bit(BlockedBadBlocks,
4773						&rdev->flags);
4774				s->blocked_rdev = rdev;
4775				atomic_inc(&rdev->nr_pending);
4776			}
4777		}
4778		clear_bit(R5_Insync, &dev->flags);
4779		if (!rdev)
4780			/* Not in-sync */;
4781		else if (is_bad) {
4782			/* also not in-sync */
4783			if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4784			    test_bit(R5_UPTODATE, &dev->flags)) {
4785				/* treat as in-sync, but with a read error
4786				 * which we can now try to correct
4787				 */
4788				set_bit(R5_Insync, &dev->flags);
4789				set_bit(R5_ReadError, &dev->flags);
4790			}
4791		} else if (test_bit(In_sync, &rdev->flags))
4792			set_bit(R5_Insync, &dev->flags);
4793		else if (sh->sector + RAID5_STRIPE_SECTORS(conf) <= rdev->recovery_offset)
4794			/* in sync if before recovery_offset */
4795			set_bit(R5_Insync, &dev->flags);
4796		else if (test_bit(R5_UPTODATE, &dev->flags) &&
4797			 test_bit(R5_Expanded, &dev->flags))
4798			/* If we've reshaped into here, we assume it is Insync.
4799			 * We will shortly update recovery_offset to make
4800			 * it official.
4801			 */
4802			set_bit(R5_Insync, &dev->flags);
4803
4804		if (test_bit(R5_WriteError, &dev->flags)) {
4805			/* This flag does not apply to '.replacement'
4806			 * only to .rdev, so make sure to check that*/
4807			struct md_rdev *rdev2 = rcu_dereference(
4808				conf->disks[i].rdev);
4809			if (rdev2 == rdev)
4810				clear_bit(R5_Insync, &dev->flags);
4811			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4812				s->handle_bad_blocks = 1;
4813				atomic_inc(&rdev2->nr_pending);
4814			} else
4815				clear_bit(R5_WriteError, &dev->flags);
4816		}
4817		if (test_bit(R5_MadeGood, &dev->flags)) {
4818			/* This flag does not apply to '.replacement'
4819			 * only to .rdev, so make sure to check that*/
4820			struct md_rdev *rdev2 = rcu_dereference(
4821				conf->disks[i].rdev);
4822			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4823				s->handle_bad_blocks = 1;
4824				atomic_inc(&rdev2->nr_pending);
4825			} else
4826				clear_bit(R5_MadeGood, &dev->flags);
4827		}
4828		if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4829			struct md_rdev *rdev2 = rcu_dereference(
4830				conf->disks[i].replacement);
4831			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4832				s->handle_bad_blocks = 1;
4833				atomic_inc(&rdev2->nr_pending);
4834			} else
4835				clear_bit(R5_MadeGoodRepl, &dev->flags);
4836		}
4837		if (!test_bit(R5_Insync, &dev->flags)) {
4838			/* The ReadError flag will just be confusing now */
4839			clear_bit(R5_ReadError, &dev->flags);
4840			clear_bit(R5_ReWrite, &dev->flags);
4841		}
4842		if (test_bit(R5_ReadError, &dev->flags))
4843			clear_bit(R5_Insync, &dev->flags);
4844		if (!test_bit(R5_Insync, &dev->flags)) {
4845			if (s->failed < 2)
4846				s->failed_num[s->failed] = i;
4847			s->failed++;
4848			if (rdev && !test_bit(Faulty, &rdev->flags))
4849				do_recovery = 1;
4850			else if (!rdev) {
4851				rdev = rcu_dereference(
4852				    conf->disks[i].replacement);
4853				if (rdev && !test_bit(Faulty, &rdev->flags))
4854					do_recovery = 1;
4855			}
4856		}
4857
4858		if (test_bit(R5_InJournal, &dev->flags))
4859			s->injournal++;
4860		if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4861			s->just_cached++;
4862	}
4863	if (test_bit(STRIPE_SYNCING, &sh->state)) {
4864		/* If there is a failed device being replaced,
4865		 *     we must be recovering.
4866		 * else if we are after recovery_cp, we must be syncing
4867		 * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4868		 * else we can only be replacing
4869		 * sync and recovery both need to read all devices, and so
4870		 * use the same flag.
4871		 */
4872		if (do_recovery ||
4873		    sh->sector >= conf->mddev->recovery_cp ||
4874		    test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4875			s->syncing = 1;
4876		else
4877			s->replacing = 1;
4878	}
4879	rcu_read_unlock();
4880}
4881
4882/*
4883 * Return '1' if this is a member of batch, or '0' if it is a lone stripe or
4884 * a head which can now be handled.
4885 */
4886static int clear_batch_ready(struct stripe_head *sh)
4887{
4888	struct stripe_head *tmp;
4889	if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4890		return (sh->batch_head && sh->batch_head != sh);
4891	spin_lock(&sh->stripe_lock);
4892	if (!sh->batch_head) {
4893		spin_unlock(&sh->stripe_lock);
4894		return 0;
4895	}
4896
4897	/*
4898	 * this stripe could be added to a batch list before we check
4899	 * BATCH_READY, skips it
4900	 */
4901	if (sh->batch_head != sh) {
4902		spin_unlock(&sh->stripe_lock);
4903		return 1;
4904	}
4905	spin_lock(&sh->batch_lock);
4906	list_for_each_entry(tmp, &sh->batch_list, batch_list)
4907		clear_bit(STRIPE_BATCH_READY, &tmp->state);
4908	spin_unlock(&sh->batch_lock);
4909	spin_unlock(&sh->stripe_lock);
4910
4911	/*
4912	 * BATCH_READY is cleared, no new stripes can be added.
4913	 * batch_list can be accessed without lock
4914	 */
4915	return 0;
4916}
4917
4918static void break_stripe_batch_list(struct stripe_head *head_sh,
4919				    unsigned long handle_flags)
4920{
4921	struct stripe_head *sh, *next;
4922	int i;
4923	int do_wakeup = 0;
4924
4925	list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4926
4927		list_del_init(&sh->batch_list);
4928
4929		WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4930					  (1 << STRIPE_SYNCING) |
4931					  (1 << STRIPE_REPLACED) |
4932					  (1 << STRIPE_DELAYED) |
4933					  (1 << STRIPE_BIT_DELAY) |
4934					  (1 << STRIPE_FULL_WRITE) |
4935					  (1 << STRIPE_BIOFILL_RUN) |
4936					  (1 << STRIPE_COMPUTE_RUN)  |
4937					  (1 << STRIPE_DISCARD) |
4938					  (1 << STRIPE_BATCH_READY) |
4939					  (1 << STRIPE_BATCH_ERR) |
4940					  (1 << STRIPE_BITMAP_PENDING)),
4941			"stripe state: %lx\n", sh->state);
4942		WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4943					      (1 << STRIPE_REPLACED)),
4944			"head stripe state: %lx\n", head_sh->state);
4945
4946		set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4947					    (1 << STRIPE_PREREAD_ACTIVE) |
4948					    (1 << STRIPE_DEGRADED) |
4949					    (1 << STRIPE_ON_UNPLUG_LIST)),
4950			      head_sh->state & (1 << STRIPE_INSYNC));
4951
4952		sh->check_state = head_sh->check_state;
4953		sh->reconstruct_state = head_sh->reconstruct_state;
4954		spin_lock_irq(&sh->stripe_lock);
4955		sh->batch_head = NULL;
4956		spin_unlock_irq(&sh->stripe_lock);
4957		for (i = 0; i < sh->disks; i++) {
4958			if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4959				do_wakeup = 1;
4960			sh->dev[i].flags = head_sh->dev[i].flags &
4961				(~((1 << R5_WriteError) | (1 << R5_Overlap)));
4962		}
4963		if (handle_flags == 0 ||
4964		    sh->state & handle_flags)
4965			set_bit(STRIPE_HANDLE, &sh->state);
4966		raid5_release_stripe(sh);
4967	}
4968	spin_lock_irq(&head_sh->stripe_lock);
4969	head_sh->batch_head = NULL;
4970	spin_unlock_irq(&head_sh->stripe_lock);
4971	for (i = 0; i < head_sh->disks; i++)
4972		if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4973			do_wakeup = 1;
4974	if (head_sh->state & handle_flags)
4975		set_bit(STRIPE_HANDLE, &head_sh->state);
4976
4977	if (do_wakeup)
4978		wake_up(&head_sh->raid_conf->wait_for_overlap);
4979}
4980
4981static void handle_stripe(struct stripe_head *sh)
4982{
4983	struct stripe_head_state s;
4984	struct r5conf *conf = sh->raid_conf;
4985	int i;
4986	int prexor;
4987	int disks = sh->disks;
4988	struct r5dev *pdev, *qdev;
4989
4990	clear_bit(STRIPE_HANDLE, &sh->state);
4991
4992	/*
4993	 * handle_stripe should not continue handle the batched stripe, only
4994	 * the head of batch list or lone stripe can continue. Otherwise we
4995	 * could see break_stripe_batch_list warns about the STRIPE_ACTIVE
4996	 * is set for the batched stripe.
4997	 */
4998	if (clear_batch_ready(sh))
4999		return;
5000
5001	if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
5002		/* already being handled, ensure it gets handled
5003		 * again when current action finishes */
5004		set_bit(STRIPE_HANDLE, &sh->state);
5005		return;
5006	}
5007
5008	if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
5009		break_stripe_batch_list(sh, 0);
5010
5011	if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
5012		spin_lock(&sh->stripe_lock);
5013		/*
5014		 * Cannot process 'sync' concurrently with 'discard'.
5015		 * Flush data in r5cache before 'sync'.
5016		 */
5017		if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
5018		    !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
5019		    !test_bit(STRIPE_DISCARD, &sh->state) &&
5020		    test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
5021			set_bit(STRIPE_SYNCING, &sh->state);
5022			clear_bit(STRIPE_INSYNC, &sh->state);
5023			clear_bit(STRIPE_REPLACED, &sh->state);
5024		}
5025		spin_unlock(&sh->stripe_lock);
5026	}
5027	clear_bit(STRIPE_DELAYED, &sh->state);
5028
5029	pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
5030		"pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
5031	       (unsigned long long)sh->sector, sh->state,
5032	       atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
5033	       sh->check_state, sh->reconstruct_state);
5034
5035	analyse_stripe(sh, &s);
5036
5037	if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
5038		goto finish;
5039
5040	if (s.handle_bad_blocks ||
5041	    test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
5042		set_bit(STRIPE_HANDLE, &sh->state);
5043		goto finish;
5044	}
5045
5046	if (unlikely(s.blocked_rdev)) {
5047		if (s.syncing || s.expanding || s.expanded ||
5048		    s.replacing || s.to_write || s.written) {
5049			set_bit(STRIPE_HANDLE, &sh->state);
5050			goto finish;
5051		}
5052		/* There is nothing for the blocked_rdev to block */
5053		rdev_dec_pending(s.blocked_rdev, conf->mddev);
5054		s.blocked_rdev = NULL;
5055	}
5056
5057	if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
5058		set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
5059		set_bit(STRIPE_BIOFILL_RUN, &sh->state);
5060	}
5061
5062	pr_debug("locked=%d uptodate=%d to_read=%d"
5063	       " to_write=%d failed=%d failed_num=%d,%d\n",
5064	       s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
5065	       s.failed_num[0], s.failed_num[1]);
5066	/*
5067	 * check if the array has lost more than max_degraded devices and,
5068	 * if so, some requests might need to be failed.
5069	 *
5070	 * When journal device failed (log_failed), we will only process
5071	 * the stripe if there is data need write to raid disks
5072	 */
5073	if (s.failed > conf->max_degraded ||
5074	    (s.log_failed && s.injournal == 0)) {
5075		sh->check_state = 0;
5076		sh->reconstruct_state = 0;
5077		break_stripe_batch_list(sh, 0);
5078		if (s.to_read+s.to_write+s.written)
5079			handle_failed_stripe(conf, sh, &s, disks);
5080		if (s.syncing + s.replacing)
5081			handle_failed_sync(conf, sh, &s);
5082	}
5083
5084	/* Now we check to see if any write operations have recently
5085	 * completed
5086	 */
5087	prexor = 0;
5088	if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
5089		prexor = 1;
5090	if (sh->reconstruct_state == reconstruct_state_drain_result ||
5091	    sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
5092		sh->reconstruct_state = reconstruct_state_idle;
5093
5094		/* All the 'written' buffers and the parity block are ready to
5095		 * be written back to disk
5096		 */
5097		BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
5098		       !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
5099		BUG_ON(sh->qd_idx >= 0 &&
5100		       !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
5101		       !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
5102		for (i = disks; i--; ) {
5103			struct r5dev *dev = &sh->dev[i];
5104			if (test_bit(R5_LOCKED, &dev->flags) &&
5105				(i == sh->pd_idx || i == sh->qd_idx ||
5106				 dev->written || test_bit(R5_InJournal,
5107							  &dev->flags))) {
5108				pr_debug("Writing block %d\n", i);
5109				set_bit(R5_Wantwrite, &dev->flags);
5110				if (prexor)
5111					continue;
5112				if (s.failed > 1)
5113					continue;
5114				if (!test_bit(R5_Insync, &dev->flags) ||
5115				    ((i == sh->pd_idx || i == sh->qd_idx)  &&
5116				     s.failed == 0))
5117					set_bit(STRIPE_INSYNC, &sh->state);
5118			}
5119		}
5120		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5121			s.dec_preread_active = 1;
5122	}
5123
5124	/*
5125	 * might be able to return some write requests if the parity blocks
5126	 * are safe, or on a failed drive
5127	 */
5128	pdev = &sh->dev[sh->pd_idx];
5129	s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
5130		|| (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
5131	qdev = &sh->dev[sh->qd_idx];
5132	s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
5133		|| (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
5134		|| conf->level < 6;
5135
5136	if (s.written &&
5137	    (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
5138			     && !test_bit(R5_LOCKED, &pdev->flags)
5139			     && (test_bit(R5_UPTODATE, &pdev->flags) ||
5140				 test_bit(R5_Discard, &pdev->flags))))) &&
5141	    (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
5142			     && !test_bit(R5_LOCKED, &qdev->flags)
5143			     && (test_bit(R5_UPTODATE, &qdev->flags) ||
5144				 test_bit(R5_Discard, &qdev->flags))))))
5145		handle_stripe_clean_event(conf, sh, disks);
5146
5147	if (s.just_cached)
5148		r5c_handle_cached_data_endio(conf, sh, disks);
5149	log_stripe_write_finished(sh);
5150
5151	/* Now we might consider reading some blocks, either to check/generate
5152	 * parity, or to satisfy requests
5153	 * or to load a block that is being partially written.
5154	 */
5155	if (s.to_read || s.non_overwrite
5156	    || (s.to_write && s.failed)
5157	    || (s.syncing && (s.uptodate + s.compute < disks))
5158	    || s.replacing
5159	    || s.expanding)
5160		handle_stripe_fill(sh, &s, disks);
5161
5162	/*
5163	 * When the stripe finishes full journal write cycle (write to journal
5164	 * and raid disk), this is the clean up procedure so it is ready for
5165	 * next operation.
5166	 */
5167	r5c_finish_stripe_write_out(conf, sh, &s);
5168
5169	/*
5170	 * Now to consider new write requests, cache write back and what else,
5171	 * if anything should be read.  We do not handle new writes when:
5172	 * 1/ A 'write' operation (copy+xor) is already in flight.
5173	 * 2/ A 'check' operation is in flight, as it may clobber the parity
5174	 *    block.
5175	 * 3/ A r5c cache log write is in flight.
5176	 */
5177
5178	if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
5179		if (!r5c_is_writeback(conf->log)) {
5180			if (s.to_write)
5181				handle_stripe_dirtying(conf, sh, &s, disks);
5182		} else { /* write back cache */
5183			int ret = 0;
5184
5185			/* First, try handle writes in caching phase */
5186			if (s.to_write)
5187				ret = r5c_try_caching_write(conf, sh, &s,
5188							    disks);
5189			/*
5190			 * If caching phase failed: ret == -EAGAIN
5191			 *    OR
5192			 * stripe under reclaim: !caching && injournal
5193			 *
5194			 * fall back to handle_stripe_dirtying()
5195			 */
5196			if (ret == -EAGAIN ||
5197			    /* stripe under reclaim: !caching && injournal */
5198			    (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
5199			     s.injournal > 0)) {
5200				ret = handle_stripe_dirtying(conf, sh, &s,
5201							     disks);
5202				if (ret == -EAGAIN)
5203					goto finish;
5204			}
5205		}
5206	}
5207
5208	/* maybe we need to check and possibly fix the parity for this stripe
5209	 * Any reads will already have been scheduled, so we just see if enough
5210	 * data is available.  The parity check is held off while parity
5211	 * dependent operations are in flight.
5212	 */
5213	if (sh->check_state ||
5214	    (s.syncing && s.locked == 0 &&
5215	     !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5216	     !test_bit(STRIPE_INSYNC, &sh->state))) {
5217		if (conf->level == 6)
5218			handle_parity_checks6(conf, sh, &s, disks);
5219		else
5220			handle_parity_checks5(conf, sh, &s, disks);
5221	}
5222
5223	if ((s.replacing || s.syncing) && s.locked == 0
5224	    && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
5225	    && !test_bit(STRIPE_REPLACED, &sh->state)) {
5226		/* Write out to replacement devices where possible */
5227		for (i = 0; i < conf->raid_disks; i++)
5228			if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
5229				WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
5230				set_bit(R5_WantReplace, &sh->dev[i].flags);
5231				set_bit(R5_LOCKED, &sh->dev[i].flags);
5232				s.locked++;
5233			}
5234		if (s.replacing)
5235			set_bit(STRIPE_INSYNC, &sh->state);
5236		set_bit(STRIPE_REPLACED, &sh->state);
5237	}
5238	if ((s.syncing || s.replacing) && s.locked == 0 &&
5239	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5240	    test_bit(STRIPE_INSYNC, &sh->state)) {
5241		md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5242		clear_bit(STRIPE_SYNCING, &sh->state);
5243		if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
5244			wake_up(&conf->wait_for_overlap);
5245	}
5246
5247	/* If the failed drives are just a ReadError, then we might need
5248	 * to progress the repair/check process
5249	 */
5250	if (s.failed <= conf->max_degraded && !conf->mddev->ro)
5251		for (i = 0; i < s.failed; i++) {
5252			struct r5dev *dev = &sh->dev[s.failed_num[i]];
5253			if (test_bit(R5_ReadError, &dev->flags)
5254			    && !test_bit(R5_LOCKED, &dev->flags)
5255			    && test_bit(R5_UPTODATE, &dev->flags)
5256				) {
5257				if (!test_bit(R5_ReWrite, &dev->flags)) {
5258					set_bit(R5_Wantwrite, &dev->flags);
5259					set_bit(R5_ReWrite, &dev->flags);
5260				} else
 
 
5261					/* let's read it back */
5262					set_bit(R5_Wantread, &dev->flags);
5263				set_bit(R5_LOCKED, &dev->flags);
5264				s.locked++;
 
5265			}
5266		}
5267
 
5268	/* Finish reconstruct operations initiated by the expansion process */
5269	if (sh->reconstruct_state == reconstruct_state_result) {
5270		struct stripe_head *sh_src
5271			= raid5_get_active_stripe(conf, NULL, sh->sector,
5272					R5_GAS_PREVIOUS | R5_GAS_NOBLOCK |
5273					R5_GAS_NOQUIESCE);
5274		if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
5275			/* sh cannot be written until sh_src has been read.
5276			 * so arrange for sh to be delayed a little
5277			 */
5278			set_bit(STRIPE_DELAYED, &sh->state);
5279			set_bit(STRIPE_HANDLE, &sh->state);
5280			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
5281					      &sh_src->state))
5282				atomic_inc(&conf->preread_active_stripes);
5283			raid5_release_stripe(sh_src);
5284			goto finish;
5285		}
5286		if (sh_src)
5287			raid5_release_stripe(sh_src);
5288
5289		sh->reconstruct_state = reconstruct_state_idle;
5290		clear_bit(STRIPE_EXPANDING, &sh->state);
5291		for (i = conf->raid_disks; i--; ) {
5292			set_bit(R5_Wantwrite, &sh->dev[i].flags);
5293			set_bit(R5_LOCKED, &sh->dev[i].flags);
5294			s.locked++;
5295		}
5296	}
5297
5298	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
5299	    !sh->reconstruct_state) {
5300		/* Need to write out all blocks after computing parity */
5301		sh->disks = conf->raid_disks;
5302		stripe_set_idx(sh->sector, conf, 0, sh);
5303		schedule_reconstruction(sh, &s, 1, 1);
5304	} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
5305		clear_bit(STRIPE_EXPAND_READY, &sh->state);
5306		atomic_dec(&conf->reshape_stripes);
5307		wake_up(&conf->wait_for_overlap);
5308		md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5309	}
5310
5311	if (s.expanding && s.locked == 0 &&
5312	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
5313		handle_stripe_expansion(conf, sh);
5314
5315finish:
5316	/* wait for this device to become unblocked */
5317	if (unlikely(s.blocked_rdev)) {
5318		if (conf->mddev->external)
5319			md_wait_for_blocked_rdev(s.blocked_rdev,
5320						 conf->mddev);
5321		else
5322			/* Internal metadata will immediately
5323			 * be written by raid5d, so we don't
5324			 * need to wait here.
5325			 */
5326			rdev_dec_pending(s.blocked_rdev,
5327					 conf->mddev);
5328	}
5329
5330	if (s.handle_bad_blocks)
5331		for (i = disks; i--; ) {
5332			struct md_rdev *rdev;
5333			struct r5dev *dev = &sh->dev[i];
5334			if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5335				/* We own a safe reference to the rdev */
5336				rdev = rdev_pend_deref(conf->disks[i].rdev);
5337				if (!rdev_set_badblocks(rdev, sh->sector,
5338							RAID5_STRIPE_SECTORS(conf), 0))
5339					md_error(conf->mddev, rdev);
5340				rdev_dec_pending(rdev, conf->mddev);
5341			}
5342			if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5343				rdev = rdev_pend_deref(conf->disks[i].rdev);
5344				rdev_clear_badblocks(rdev, sh->sector,
5345						     RAID5_STRIPE_SECTORS(conf), 0);
5346				rdev_dec_pending(rdev, conf->mddev);
5347			}
5348			if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5349				rdev = rdev_pend_deref(conf->disks[i].replacement);
5350				if (!rdev)
5351					/* rdev have been moved down */
5352					rdev = rdev_pend_deref(conf->disks[i].rdev);
5353				rdev_clear_badblocks(rdev, sh->sector,
5354						     RAID5_STRIPE_SECTORS(conf), 0);
5355				rdev_dec_pending(rdev, conf->mddev);
5356			}
5357		}
5358
5359	if (s.ops_request)
5360		raid_run_ops(sh, s.ops_request);
5361
5362	ops_run_io(sh, &s);
5363
5364	if (s.dec_preread_active) {
5365		/* We delay this until after ops_run_io so that if make_request
5366		 * is waiting on a flush, it won't continue until the writes
5367		 * have actually been submitted.
5368		 */
5369		atomic_dec(&conf->preread_active_stripes);
5370		if (atomic_read(&conf->preread_active_stripes) <
5371		    IO_THRESHOLD)
5372			md_wakeup_thread(conf->mddev->thread);
5373	}
5374
 
 
5375	clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5376}
5377
5378static void raid5_activate_delayed(struct r5conf *conf)
5379	__must_hold(&conf->device_lock)
5380{
5381	if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5382		while (!list_empty(&conf->delayed_list)) {
5383			struct list_head *l = conf->delayed_list.next;
5384			struct stripe_head *sh;
5385			sh = list_entry(l, struct stripe_head, lru);
5386			list_del_init(l);
5387			clear_bit(STRIPE_DELAYED, &sh->state);
5388			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5389				atomic_inc(&conf->preread_active_stripes);
5390			list_add_tail(&sh->lru, &conf->hold_list);
5391			raid5_wakeup_stripe_thread(sh);
5392		}
5393	}
5394}
5395
5396static void activate_bit_delay(struct r5conf *conf,
5397		struct list_head *temp_inactive_list)
5398	__must_hold(&conf->device_lock)
5399{
 
5400	struct list_head head;
5401	list_add(&head, &conf->bitmap_list);
5402	list_del_init(&conf->bitmap_list);
5403	while (!list_empty(&head)) {
5404		struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5405		int hash;
5406		list_del_init(&sh->lru);
5407		atomic_inc(&sh->count);
5408		hash = sh->hash_lock_index;
5409		__release_stripe(conf, sh, &temp_inactive_list[hash]);
5410	}
5411}
5412
5413static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5414{
5415	struct r5conf *conf = mddev->private;
5416	sector_t sector = bio->bi_iter.bi_sector;
5417	unsigned int chunk_sectors;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5418	unsigned int bio_sectors = bio_sectors(bio);
5419
5420	chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
 
5421	return  chunk_sectors >=
5422		((sector & (chunk_sectors - 1)) + bio_sectors);
5423}
5424
5425/*
5426 *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5427 *  later sampled by raid5d.
5428 */
5429static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5430{
5431	unsigned long flags;
5432
5433	spin_lock_irqsave(&conf->device_lock, flags);
5434
5435	bi->bi_next = conf->retry_read_aligned_list;
5436	conf->retry_read_aligned_list = bi;
5437
5438	spin_unlock_irqrestore(&conf->device_lock, flags);
5439	md_wakeup_thread(conf->mddev->thread);
5440}
5441
5442static struct bio *remove_bio_from_retry(struct r5conf *conf,
5443					 unsigned int *offset)
5444{
5445	struct bio *bi;
5446
5447	bi = conf->retry_read_aligned;
5448	if (bi) {
5449		*offset = conf->retry_read_offset;
5450		conf->retry_read_aligned = NULL;
5451		return bi;
5452	}
5453	bi = conf->retry_read_aligned_list;
5454	if(bi) {
5455		conf->retry_read_aligned_list = bi->bi_next;
5456		bi->bi_next = NULL;
5457		*offset = 0;
 
 
 
 
5458	}
5459
5460	return bi;
5461}
5462
 
5463/*
5464 *  The "raid5_align_endio" should check if the read succeeded and if it
5465 *  did, call bio_endio on the original bio (having bio_put the new bio
5466 *  first).
5467 *  If the read failed..
5468 */
5469static void raid5_align_endio(struct bio *bi)
5470{
5471	struct md_io_acct *md_io_acct = bi->bi_private;
5472	struct bio *raid_bi = md_io_acct->orig_bio;
5473	struct mddev *mddev;
5474	struct r5conf *conf;
 
5475	struct md_rdev *rdev;
5476	blk_status_t error = bi->bi_status;
5477	unsigned long start_time = md_io_acct->start_time;
5478
5479	bio_put(bi);
5480
5481	rdev = (void*)raid_bi->bi_next;
5482	raid_bi->bi_next = NULL;
5483	mddev = rdev->mddev;
5484	conf = mddev->private;
5485
5486	rdev_dec_pending(rdev, conf->mddev);
5487
5488	if (!error) {
5489		if (blk_queue_io_stat(raid_bi->bi_bdev->bd_disk->queue))
5490			bio_end_io_acct(raid_bi, start_time);
5491		bio_endio(raid_bi);
5492		if (atomic_dec_and_test(&conf->active_aligned_reads))
5493			wake_up(&conf->wait_for_quiescent);
5494		return;
5495	}
5496
 
5497	pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5498
5499	add_bio_to_retry(raid_bi, conf);
5500}
5501
5502static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5503{
5504	struct r5conf *conf = mddev->private;
5505	struct bio *align_bio;
 
5506	struct md_rdev *rdev;
5507	sector_t sector, end_sector, first_bad;
5508	int bad_sectors, dd_idx;
5509	struct md_io_acct *md_io_acct;
5510	bool did_inc;
5511
5512	if (!in_chunk_boundary(mddev, raid_bio)) {
5513		pr_debug("%s: non aligned\n", __func__);
5514		return 0;
5515	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5516
5517	sector = raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector, 0,
5518				      &dd_idx, NULL);
5519	end_sector = bio_end_sector(raid_bio);
5520
5521	rcu_read_lock();
5522	if (r5c_big_stripe_cached(conf, sector))
5523		goto out_rcu_unlock;
5524
5525	rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5526	if (!rdev || test_bit(Faulty, &rdev->flags) ||
5527	    rdev->recovery_offset < end_sector) {
5528		rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5529		if (!rdev)
5530			goto out_rcu_unlock;
5531		if (test_bit(Faulty, &rdev->flags) ||
5532		    !(test_bit(In_sync, &rdev->flags) ||
5533		      rdev->recovery_offset >= end_sector))
5534			goto out_rcu_unlock;
5535	}
5536
5537	atomic_inc(&rdev->nr_pending);
5538	rcu_read_unlock();
5539
5540	if (is_badblock(rdev, sector, bio_sectors(raid_bio), &first_bad,
5541			&bad_sectors)) {
5542		rdev_dec_pending(rdev, mddev);
5543		return 0;
5544	}
 
 
 
5545
5546	align_bio = bio_alloc_clone(rdev->bdev, raid_bio, GFP_NOIO,
5547				    &mddev->io_acct_set);
5548	md_io_acct = container_of(align_bio, struct md_io_acct, bio_clone);
5549	raid_bio->bi_next = (void *)rdev;
5550	if (blk_queue_io_stat(raid_bio->bi_bdev->bd_disk->queue))
5551		md_io_acct->start_time = bio_start_io_acct(raid_bio);
5552	md_io_acct->orig_bio = raid_bio;
5553
5554	align_bio->bi_end_io = raid5_align_endio;
5555	align_bio->bi_private = md_io_acct;
5556	align_bio->bi_iter.bi_sector = sector;
 
 
 
 
5557
5558	/* No reshape active, so we can trust rdev->data_offset */
5559	align_bio->bi_iter.bi_sector += rdev->data_offset;
5560
5561	did_inc = false;
5562	if (conf->quiesce == 0) {
5563		atomic_inc(&conf->active_aligned_reads);
5564		did_inc = true;
5565	}
5566	/* need a memory barrier to detect the race with raid5_quiesce() */
5567	if (!did_inc || smp_load_acquire(&conf->quiesce) != 0) {
5568		/* quiesce is in progress, so we need to undo io activation and wait
5569		 * for it to finish
5570		 */
5571		if (did_inc && atomic_dec_and_test(&conf->active_aligned_reads))
5572			wake_up(&conf->wait_for_quiescent);
5573		spin_lock_irq(&conf->device_lock);
5574		wait_event_lock_irq(conf->wait_for_quiescent, conf->quiesce == 0,
 
5575				    conf->device_lock);
5576		atomic_inc(&conf->active_aligned_reads);
5577		spin_unlock_irq(&conf->device_lock);
5578	}
5579
5580	if (mddev->gendisk)
5581		trace_block_bio_remap(align_bio, disk_devt(mddev->gendisk),
5582				      raid_bio->bi_iter.bi_sector);
5583	submit_bio_noacct(align_bio);
5584	return 1;
5585
5586out_rcu_unlock:
5587	rcu_read_unlock();
5588	return 0;
5589}
5590
5591static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5592{
5593	struct bio *split;
5594	sector_t sector = raid_bio->bi_iter.bi_sector;
5595	unsigned chunk_sects = mddev->chunk_sectors;
5596	unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5597
5598	if (sectors < bio_sectors(raid_bio)) {
5599		struct r5conf *conf = mddev->private;
5600		split = bio_split(raid_bio, sectors, GFP_NOIO, &conf->bio_split);
5601		bio_chain(split, raid_bio);
5602		submit_bio_noacct(raid_bio);
5603		raid_bio = split;
5604	}
5605
5606	if (!raid5_read_one_chunk(mddev, raid_bio))
5607		return raid_bio;
5608
5609	return NULL;
5610}
5611
5612/* __get_priority_stripe - get the next stripe to process
5613 *
5614 * Full stripe writes are allowed to pass preread active stripes up until
5615 * the bypass_threshold is exceeded.  In general the bypass_count
5616 * increments when the handle_list is handled before the hold_list; however, it
5617 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5618 * stripe with in flight i/o.  The bypass_count will be reset when the
5619 * head of the hold_list has changed, i.e. the head was promoted to the
5620 * handle_list.
5621 */
5622static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5623	__must_hold(&conf->device_lock)
5624{
5625	struct stripe_head *sh, *tmp;
5626	struct list_head *handle_list = NULL;
5627	struct r5worker_group *wg;
5628	bool second_try = !r5c_is_writeback(conf->log) &&
5629		!r5l_log_disk_error(conf);
5630	bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5631		r5l_log_disk_error(conf);
5632
5633again:
5634	wg = NULL;
5635	sh = NULL;
5636	if (conf->worker_cnt_per_group == 0) {
5637		handle_list = try_loprio ? &conf->loprio_list :
5638					&conf->handle_list;
5639	} else if (group != ANY_GROUP) {
5640		handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5641				&conf->worker_groups[group].handle_list;
5642		wg = &conf->worker_groups[group];
5643	} else {
5644		int i;
5645		for (i = 0; i < conf->group_cnt; i++) {
5646			handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5647				&conf->worker_groups[i].handle_list;
5648			wg = &conf->worker_groups[i];
5649			if (!list_empty(handle_list))
5650				break;
5651		}
5652	}
5653
5654	pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5655		  __func__,
5656		  list_empty(handle_list) ? "empty" : "busy",
5657		  list_empty(&conf->hold_list) ? "empty" : "busy",
5658		  atomic_read(&conf->pending_full_writes), conf->bypass_count);
5659
5660	if (!list_empty(handle_list)) {
5661		sh = list_entry(handle_list->next, typeof(*sh), lru);
5662
5663		if (list_empty(&conf->hold_list))
5664			conf->bypass_count = 0;
5665		else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5666			if (conf->hold_list.next == conf->last_hold)
5667				conf->bypass_count++;
5668			else {
5669				conf->last_hold = conf->hold_list.next;
5670				conf->bypass_count -= conf->bypass_threshold;
5671				if (conf->bypass_count < 0)
5672					conf->bypass_count = 0;
5673			}
5674		}
5675	} else if (!list_empty(&conf->hold_list) &&
5676		   ((conf->bypass_threshold &&
5677		     conf->bypass_count > conf->bypass_threshold) ||
5678		    atomic_read(&conf->pending_full_writes) == 0)) {
5679
5680		list_for_each_entry(tmp, &conf->hold_list,  lru) {
5681			if (conf->worker_cnt_per_group == 0 ||
5682			    group == ANY_GROUP ||
5683			    !cpu_online(tmp->cpu) ||
5684			    cpu_to_group(tmp->cpu) == group) {
5685				sh = tmp;
5686				break;
5687			}
5688		}
5689
5690		if (sh) {
5691			conf->bypass_count -= conf->bypass_threshold;
5692			if (conf->bypass_count < 0)
5693				conf->bypass_count = 0;
5694		}
5695		wg = NULL;
5696	}
5697
5698	if (!sh) {
5699		if (second_try)
5700			return NULL;
5701		second_try = true;
5702		try_loprio = !try_loprio;
5703		goto again;
5704	}
5705
5706	if (wg) {
5707		wg->stripes_cnt--;
5708		sh->group = NULL;
5709	}
5710	list_del_init(&sh->lru);
5711	BUG_ON(atomic_inc_return(&sh->count) != 1);
5712	return sh;
5713}
5714
5715struct raid5_plug_cb {
5716	struct blk_plug_cb	cb;
5717	struct list_head	list;
5718	struct list_head	temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5719};
5720
5721static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5722{
5723	struct raid5_plug_cb *cb = container_of(
5724		blk_cb, struct raid5_plug_cb, cb);
5725	struct stripe_head *sh;
5726	struct mddev *mddev = cb->cb.data;
5727	struct r5conf *conf = mddev->private;
5728	int cnt = 0;
5729	int hash;
5730
5731	if (cb->list.next && !list_empty(&cb->list)) {
5732		spin_lock_irq(&conf->device_lock);
5733		while (!list_empty(&cb->list)) {
5734			sh = list_first_entry(&cb->list, struct stripe_head, lru);
5735			list_del_init(&sh->lru);
5736			/*
5737			 * avoid race release_stripe_plug() sees
5738			 * STRIPE_ON_UNPLUG_LIST clear but the stripe
5739			 * is still in our list
5740			 */
5741			smp_mb__before_atomic();
5742			clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5743			/*
5744			 * STRIPE_ON_RELEASE_LIST could be set here. In that
5745			 * case, the count is always > 1 here
5746			 */
5747			hash = sh->hash_lock_index;
5748			__release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5749			cnt++;
5750		}
5751		spin_unlock_irq(&conf->device_lock);
5752	}
5753	release_inactive_stripe_list(conf, cb->temp_inactive_list,
5754				     NR_STRIPE_HASH_LOCKS);
5755	if (mddev->queue)
5756		trace_block_unplug(mddev->queue, cnt, !from_schedule);
5757	kfree(cb);
5758}
5759
5760static void release_stripe_plug(struct mddev *mddev,
5761				struct stripe_head *sh)
5762{
5763	struct blk_plug_cb *blk_cb = blk_check_plugged(
5764		raid5_unplug, mddev,
5765		sizeof(struct raid5_plug_cb));
5766	struct raid5_plug_cb *cb;
5767
5768	if (!blk_cb) {
5769		raid5_release_stripe(sh);
5770		return;
5771	}
5772
5773	cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5774
5775	if (cb->list.next == NULL) {
5776		int i;
5777		INIT_LIST_HEAD(&cb->list);
5778		for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5779			INIT_LIST_HEAD(cb->temp_inactive_list + i);
5780	}
5781
5782	if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5783		list_add_tail(&sh->lru, &cb->list);
5784	else
5785		raid5_release_stripe(sh);
5786}
5787
5788static void make_discard_request(struct mddev *mddev, struct bio *bi)
5789{
5790	struct r5conf *conf = mddev->private;
5791	sector_t logical_sector, last_sector;
5792	struct stripe_head *sh;
 
5793	int stripe_sectors;
5794
5795	/* We need to handle this when io_uring supports discard/trim */
5796	if (WARN_ON_ONCE(bi->bi_opf & REQ_NOWAIT))
5797		return;
5798
5799	if (mddev->reshape_position != MaxSector)
5800		/* Skip discard while reshape is happening */
5801		return;
5802
5803	logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
5804	last_sector = bio_end_sector(bi);
5805
5806	bi->bi_next = NULL;
 
5807
5808	stripe_sectors = conf->chunk_sectors *
5809		(conf->raid_disks - conf->max_degraded);
5810	logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5811					       stripe_sectors);
5812	sector_div(last_sector, stripe_sectors);
5813
5814	logical_sector *= conf->chunk_sectors;
5815	last_sector *= conf->chunk_sectors;
5816
5817	for (; logical_sector < last_sector;
5818	     logical_sector += RAID5_STRIPE_SECTORS(conf)) {
5819		DEFINE_WAIT(w);
5820		int d;
5821	again:
5822		sh = raid5_get_active_stripe(conf, NULL, logical_sector, 0);
5823		prepare_to_wait(&conf->wait_for_overlap, &w,
5824				TASK_UNINTERRUPTIBLE);
5825		set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5826		if (test_bit(STRIPE_SYNCING, &sh->state)) {
5827			raid5_release_stripe(sh);
5828			schedule();
5829			goto again;
5830		}
5831		clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5832		spin_lock_irq(&sh->stripe_lock);
5833		for (d = 0; d < conf->raid_disks; d++) {
5834			if (d == sh->pd_idx || d == sh->qd_idx)
5835				continue;
5836			if (sh->dev[d].towrite || sh->dev[d].toread) {
5837				set_bit(R5_Overlap, &sh->dev[d].flags);
5838				spin_unlock_irq(&sh->stripe_lock);
5839				raid5_release_stripe(sh);
5840				schedule();
5841				goto again;
5842			}
5843		}
5844		set_bit(STRIPE_DISCARD, &sh->state);
5845		finish_wait(&conf->wait_for_overlap, &w);
5846		sh->overwrite_disks = 0;
5847		for (d = 0; d < conf->raid_disks; d++) {
5848			if (d == sh->pd_idx || d == sh->qd_idx)
5849				continue;
5850			sh->dev[d].towrite = bi;
5851			set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5852			bio_inc_remaining(bi);
5853			md_write_inc(mddev, bi);
5854			sh->overwrite_disks++;
5855		}
5856		spin_unlock_irq(&sh->stripe_lock);
5857		if (conf->mddev->bitmap) {
5858			for (d = 0;
5859			     d < conf->raid_disks - conf->max_degraded;
5860			     d++)
5861				md_bitmap_startwrite(mddev->bitmap,
5862						     sh->sector,
5863						     RAID5_STRIPE_SECTORS(conf),
5864						     0);
5865			sh->bm_seq = conf->seq_flush + 1;
5866			set_bit(STRIPE_BIT_DELAY, &sh->state);
5867		}
5868
5869		set_bit(STRIPE_HANDLE, &sh->state);
5870		clear_bit(STRIPE_DELAYED, &sh->state);
5871		if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5872			atomic_inc(&conf->preread_active_stripes);
5873		release_stripe_plug(mddev, sh);
5874	}
5875
5876	bio_endio(bi);
5877}
5878
5879static bool ahead_of_reshape(struct mddev *mddev, sector_t sector,
5880			     sector_t reshape_sector)
5881{
5882	return mddev->reshape_backwards ? sector < reshape_sector :
5883					  sector >= reshape_sector;
5884}
5885
5886static bool range_ahead_of_reshape(struct mddev *mddev, sector_t min,
5887				   sector_t max, sector_t reshape_sector)
5888{
5889	return mddev->reshape_backwards ? max < reshape_sector :
5890					  min >= reshape_sector;
5891}
5892
5893static bool stripe_ahead_of_reshape(struct mddev *mddev, struct r5conf *conf,
5894				    struct stripe_head *sh)
5895{
5896	sector_t max_sector = 0, min_sector = MaxSector;
5897	bool ret = false;
5898	int dd_idx;
5899
5900	for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5901		if (dd_idx == sh->pd_idx)
5902			continue;
5903
5904		min_sector = min(min_sector, sh->dev[dd_idx].sector);
5905		max_sector = min(max_sector, sh->dev[dd_idx].sector);
5906	}
5907
5908	spin_lock_irq(&conf->device_lock);
5909
5910	if (!range_ahead_of_reshape(mddev, min_sector, max_sector,
5911				     conf->reshape_progress))
5912		/* mismatch, need to try again */
5913		ret = true;
5914
5915	spin_unlock_irq(&conf->device_lock);
5916
5917	return ret;
5918}
5919
5920static int add_all_stripe_bios(struct r5conf *conf,
5921		struct stripe_request_ctx *ctx, struct stripe_head *sh,
5922		struct bio *bi, int forwrite, int previous)
5923{
 
5924	int dd_idx;
5925	int ret = 1;
5926
5927	spin_lock_irq(&sh->stripe_lock);
5928
5929	for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5930		struct r5dev *dev = &sh->dev[dd_idx];
5931
5932		if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5933			continue;
5934
5935		if (dev->sector < ctx->first_sector ||
5936		    dev->sector >= ctx->last_sector)
5937			continue;
5938
5939		if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
5940			set_bit(R5_Overlap, &dev->flags);
5941			ret = 0;
5942			continue;
5943		}
5944	}
5945
5946	if (!ret)
5947		goto out;
5948
5949	for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5950		struct r5dev *dev = &sh->dev[dd_idx];
5951
5952		if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5953			continue;
5954
5955		if (dev->sector < ctx->first_sector ||
5956		    dev->sector >= ctx->last_sector)
5957			continue;
 
5958
5959		__add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
5960		clear_bit((dev->sector - ctx->first_sector) >>
5961			  RAID5_STRIPE_SHIFT(conf), ctx->sectors_to_do);
5962	}
5963
5964out:
5965	spin_unlock_irq(&sh->stripe_lock);
5966	return ret;
5967}
5968
5969static enum stripe_result make_stripe_request(struct mddev *mddev,
5970		struct r5conf *conf, struct stripe_request_ctx *ctx,
5971		sector_t logical_sector, struct bio *bi)
5972{
5973	const int rw = bio_data_dir(bi);
5974	enum stripe_result ret;
5975	struct stripe_head *sh;
5976	sector_t new_sector;
5977	int previous = 0, flags = 0;
5978	int seq, dd_idx;
5979
5980	seq = read_seqcount_begin(&conf->gen_lock);
5981
5982	if (unlikely(conf->reshape_progress != MaxSector)) {
5983		/*
5984		 * Spinlock is needed as reshape_progress may be
5985		 * 64bit on a 32bit platform, and so it might be
5986		 * possible to see a half-updated value
5987		 * Of course reshape_progress could change after
5988		 * the lock is dropped, so once we get a reference
5989		 * to the stripe that we think it is, we will have
5990		 * to check again.
5991		 */
5992		spin_lock_irq(&conf->device_lock);
5993		if (ahead_of_reshape(mddev, logical_sector,
5994				     conf->reshape_progress)) {
5995			previous = 1;
5996		} else {
5997			if (ahead_of_reshape(mddev, logical_sector,
5998					     conf->reshape_safe)) {
5999				spin_unlock_irq(&conf->device_lock);
6000				return STRIPE_SCHEDULE_AND_RETRY;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6001			}
 
6002		}
6003		spin_unlock_irq(&conf->device_lock);
6004	}
6005
6006	new_sector = raid5_compute_sector(conf, logical_sector, previous,
6007					  &dd_idx, NULL);
6008	pr_debug("raid456: %s, sector %llu logical %llu\n", __func__,
6009		 new_sector, logical_sector);
6010
6011	if (previous)
6012		flags |= R5_GAS_PREVIOUS;
6013	if (bi->bi_opf & REQ_RAHEAD)
6014		flags |= R5_GAS_NOBLOCK;
6015	sh = raid5_get_active_stripe(conf, ctx, new_sector, flags);
6016	if (unlikely(!sh)) {
6017		/* cannot get stripe, just give-up */
6018		bi->bi_status = BLK_STS_IOERR;
6019		return STRIPE_FAIL;
6020	}
6021
6022	if (unlikely(previous) &&
6023	    stripe_ahead_of_reshape(mddev, conf, sh)) {
6024		/*
6025		 * Expansion moved on while waiting for a stripe.
6026		 * Expansion could still move past after this
6027		 * test, but as we are holding a reference to
6028		 * 'sh', we know that if that happens,
6029		 *  STRIPE_EXPANDING will get set and the expansion
6030		 * won't proceed until we finish with the stripe.
6031		 */
6032		ret = STRIPE_SCHEDULE_AND_RETRY;
6033		goto out_release;
6034	}
6035
6036	if (read_seqcount_retry(&conf->gen_lock, seq)) {
6037		/* Might have got the wrong stripe_head by accident */
6038		ret = STRIPE_RETRY;
6039		goto out_release;
6040	}
6041
6042	if (test_bit(STRIPE_EXPANDING, &sh->state) ||
6043	    !add_all_stripe_bios(conf, ctx, sh, bi, rw, previous)) {
6044		/*
6045		 * Stripe is busy expanding or add failed due to
6046		 * overlap. Flush everything and wait a while.
6047		 */
6048		md_wakeup_thread(mddev->thread);
6049		ret = STRIPE_SCHEDULE_AND_RETRY;
6050		goto out_release;
6051	}
6052
6053	if (stripe_can_batch(sh)) {
6054		stripe_add_to_batch_list(conf, sh, ctx->batch_last);
6055		if (ctx->batch_last)
6056			raid5_release_stripe(ctx->batch_last);
6057		atomic_inc(&sh->count);
6058		ctx->batch_last = sh;
6059	}
6060
6061	if (ctx->do_flush) {
6062		set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
6063		/* we only need flush for one stripe */
6064		ctx->do_flush = false;
6065	}
6066
6067	set_bit(STRIPE_HANDLE, &sh->state);
6068	clear_bit(STRIPE_DELAYED, &sh->state);
6069	if ((!sh->batch_head || sh == sh->batch_head) &&
6070	    (bi->bi_opf & REQ_SYNC) &&
6071	    !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
6072		atomic_inc(&conf->preread_active_stripes);
6073
6074	release_stripe_plug(mddev, sh);
6075	return STRIPE_SUCCESS;
6076
6077out_release:
6078	raid5_release_stripe(sh);
6079	return ret;
6080}
6081
6082static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
6083{
6084	DEFINE_WAIT_FUNC(wait, woken_wake_function);
6085	struct r5conf *conf = mddev->private;
6086	sector_t logical_sector;
6087	struct stripe_request_ctx ctx = {};
6088	const int rw = bio_data_dir(bi);
6089	enum stripe_result res;
6090	int s, stripe_cnt;
6091
6092	if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
6093		int ret = log_handle_flush_request(conf, bi);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6094
6095		if (ret == 0)
6096			return true;
6097		if (ret == -ENODEV) {
6098			if (md_flush_request(mddev, bi))
6099				return true;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6100		}
6101		/* ret == -EAGAIN, fallback */
6102		/*
6103		 * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
6104		 * we need to flush journal device
6105		 */
6106		ctx.do_flush = bi->bi_opf & REQ_PREFLUSH;
6107	}
6108
6109	if (!md_write_start(mddev, bi))
6110		return false;
6111	/*
6112	 * If array is degraded, better not do chunk aligned read because
6113	 * later we might have to read it again in order to reconstruct
6114	 * data on failed drives.
6115	 */
6116	if (rw == READ && mddev->degraded == 0 &&
6117	    mddev->reshape_position == MaxSector) {
6118		bi = chunk_aligned_read(mddev, bi);
6119		if (!bi)
6120			return true;
6121	}
 
6122
6123	if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
6124		make_discard_request(mddev, bi);
6125		md_write_end(mddev);
6126		return true;
6127	}
6128
6129	logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6130	ctx.first_sector = logical_sector;
6131	ctx.last_sector = bio_end_sector(bi);
6132	bi->bi_next = NULL;
6133
6134	stripe_cnt = DIV_ROUND_UP_SECTOR_T(ctx.last_sector - logical_sector,
6135					   RAID5_STRIPE_SECTORS(conf));
6136	bitmap_set(ctx.sectors_to_do, 0, stripe_cnt);
6137
6138	pr_debug("raid456: %s, logical %llu to %llu\n", __func__,
6139		 bi->bi_iter.bi_sector, ctx.last_sector);
6140
6141	/* Bail out if conflicts with reshape and REQ_NOWAIT is set */
6142	if ((bi->bi_opf & REQ_NOWAIT) &&
6143	    (conf->reshape_progress != MaxSector) &&
6144	    !ahead_of_reshape(mddev, logical_sector, conf->reshape_progress) &&
6145	    ahead_of_reshape(mddev, logical_sector, conf->reshape_safe)) {
6146		bio_wouldblock_error(bi);
6147		if (rw == WRITE)
6148			md_write_end(mddev);
6149		return true;
6150	}
6151	md_account_bio(mddev, &bi);
6152
6153	add_wait_queue(&conf->wait_for_overlap, &wait);
6154	while (1) {
6155		res = make_stripe_request(mddev, conf, &ctx, logical_sector,
6156					  bi);
6157		if (res == STRIPE_FAIL)
6158			break;
6159
6160		if (res == STRIPE_RETRY)
6161			continue;
6162
6163		if (res == STRIPE_SCHEDULE_AND_RETRY) {
6164			/*
6165			 * Must release the reference to batch_last before
6166			 * scheduling and waiting for work to be done,
6167			 * otherwise the batch_last stripe head could prevent
6168			 * raid5_activate_delayed() from making progress
6169			 * and thus deadlocking.
6170			 */
6171			if (ctx.batch_last) {
6172				raid5_release_stripe(ctx.batch_last);
6173				ctx.batch_last = NULL;
6174			}
6175
6176			wait_woken(&wait, TASK_UNINTERRUPTIBLE,
6177				   MAX_SCHEDULE_TIMEOUT);
6178			continue;
6179		}
6180
6181		s = find_first_bit(ctx.sectors_to_do, stripe_cnt);
6182		if (s == stripe_cnt)
6183			break;
6184
6185		logical_sector = ctx.first_sector +
6186			(s << RAID5_STRIPE_SHIFT(conf));
 
6187	}
6188	remove_wait_queue(&conf->wait_for_overlap, &wait);
6189
6190	if (ctx.batch_last)
6191		raid5_release_stripe(ctx.batch_last);
6192
6193	if (rw == WRITE)
6194		md_write_end(mddev);
6195	bio_endio(bi);
6196	return true;
6197}
6198
6199static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
6200
6201static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
6202{
6203	/* reshaping is quite different to recovery/resync so it is
6204	 * handled quite separately ... here.
6205	 *
6206	 * On each call to sync_request, we gather one chunk worth of
6207	 * destination stripes and flag them as expanding.
6208	 * Then we find all the source stripes and request reads.
6209	 * As the reads complete, handle_stripe will copy the data
6210	 * into the destination stripe and release that stripe.
6211	 */
6212	struct r5conf *conf = mddev->private;
6213	struct stripe_head *sh;
6214	struct md_rdev *rdev;
6215	sector_t first_sector, last_sector;
6216	int raid_disks = conf->previous_raid_disks;
6217	int data_disks = raid_disks - conf->max_degraded;
6218	int new_data_disks = conf->raid_disks - conf->max_degraded;
6219	int i;
6220	int dd_idx;
6221	sector_t writepos, readpos, safepos;
6222	sector_t stripe_addr;
6223	int reshape_sectors;
6224	struct list_head stripes;
6225	sector_t retn;
6226
6227	if (sector_nr == 0) {
6228		/* If restarting in the middle, skip the initial sectors */
6229		if (mddev->reshape_backwards &&
6230		    conf->reshape_progress < raid5_size(mddev, 0, 0)) {
6231			sector_nr = raid5_size(mddev, 0, 0)
6232				- conf->reshape_progress;
6233		} else if (mddev->reshape_backwards &&
6234			   conf->reshape_progress == MaxSector) {
6235			/* shouldn't happen, but just in case, finish up.*/
6236			sector_nr = MaxSector;
6237		} else if (!mddev->reshape_backwards &&
6238			   conf->reshape_progress > 0)
6239			sector_nr = conf->reshape_progress;
6240		sector_div(sector_nr, new_data_disks);
6241		if (sector_nr) {
6242			mddev->curr_resync_completed = sector_nr;
6243			sysfs_notify_dirent_safe(mddev->sysfs_completed);
6244			*skipped = 1;
6245			retn = sector_nr;
6246			goto finish;
6247		}
6248	}
6249
6250	/* We need to process a full chunk at a time.
6251	 * If old and new chunk sizes differ, we need to process the
6252	 * largest of these
6253	 */
6254
6255	reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
 
 
6256
6257	/* We update the metadata at least every 10 seconds, or when
6258	 * the data about to be copied would over-write the source of
6259	 * the data at the front of the range.  i.e. one new_stripe
6260	 * along from reshape_progress new_maps to after where
6261	 * reshape_safe old_maps to
6262	 */
6263	writepos = conf->reshape_progress;
6264	sector_div(writepos, new_data_disks);
6265	readpos = conf->reshape_progress;
6266	sector_div(readpos, data_disks);
6267	safepos = conf->reshape_safe;
6268	sector_div(safepos, data_disks);
6269	if (mddev->reshape_backwards) {
6270		BUG_ON(writepos < reshape_sectors);
6271		writepos -= reshape_sectors;
6272		readpos += reshape_sectors;
6273		safepos += reshape_sectors;
6274	} else {
6275		writepos += reshape_sectors;
6276		/* readpos and safepos are worst-case calculations.
6277		 * A negative number is overly pessimistic, and causes
6278		 * obvious problems for unsigned storage.  So clip to 0.
6279		 */
6280		readpos -= min_t(sector_t, reshape_sectors, readpos);
6281		safepos -= min_t(sector_t, reshape_sectors, safepos);
6282	}
6283
6284	/* Having calculated the 'writepos' possibly use it
6285	 * to set 'stripe_addr' which is where we will write to.
6286	 */
6287	if (mddev->reshape_backwards) {
6288		BUG_ON(conf->reshape_progress == 0);
6289		stripe_addr = writepos;
6290		BUG_ON((mddev->dev_sectors &
6291			~((sector_t)reshape_sectors - 1))
6292		       - reshape_sectors - stripe_addr
6293		       != sector_nr);
6294	} else {
6295		BUG_ON(writepos != sector_nr + reshape_sectors);
6296		stripe_addr = sector_nr;
6297	}
6298
6299	/* 'writepos' is the most advanced device address we might write.
6300	 * 'readpos' is the least advanced device address we might read.
6301	 * 'safepos' is the least address recorded in the metadata as having
6302	 *     been reshaped.
6303	 * If there is a min_offset_diff, these are adjusted either by
6304	 * increasing the safepos/readpos if diff is negative, or
6305	 * increasing writepos if diff is positive.
6306	 * If 'readpos' is then behind 'writepos', there is no way that we can
6307	 * ensure safety in the face of a crash - that must be done by userspace
6308	 * making a backup of the data.  So in that case there is no particular
6309	 * rush to update metadata.
6310	 * Otherwise if 'safepos' is behind 'writepos', then we really need to
6311	 * update the metadata to advance 'safepos' to match 'readpos' so that
6312	 * we can be safe in the event of a crash.
6313	 * So we insist on updating metadata if safepos is behind writepos and
6314	 * readpos is beyond writepos.
6315	 * In any case, update the metadata every 10 seconds.
6316	 * Maybe that number should be configurable, but I'm not sure it is
6317	 * worth it.... maybe it could be a multiple of safemode_delay???
6318	 */
6319	if (conf->min_offset_diff < 0) {
6320		safepos += -conf->min_offset_diff;
6321		readpos += -conf->min_offset_diff;
6322	} else
6323		writepos += conf->min_offset_diff;
6324
6325	if ((mddev->reshape_backwards
6326	     ? (safepos > writepos && readpos < writepos)
6327	     : (safepos < writepos && readpos > writepos)) ||
6328	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
6329		/* Cannot proceed until we've updated the superblock... */
6330		wait_event(conf->wait_for_overlap,
6331			   atomic_read(&conf->reshape_stripes)==0
6332			   || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6333		if (atomic_read(&conf->reshape_stripes) != 0)
6334			return 0;
6335		mddev->reshape_position = conf->reshape_progress;
6336		mddev->curr_resync_completed = sector_nr;
6337		if (!mddev->reshape_backwards)
6338			/* Can update recovery_offset */
6339			rdev_for_each(rdev, mddev)
6340				if (rdev->raid_disk >= 0 &&
6341				    !test_bit(Journal, &rdev->flags) &&
6342				    !test_bit(In_sync, &rdev->flags) &&
6343				    rdev->recovery_offset < sector_nr)
6344					rdev->recovery_offset = sector_nr;
6345
6346		conf->reshape_checkpoint = jiffies;
6347		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6348		md_wakeup_thread(mddev->thread);
6349		wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
6350			   test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6351		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6352			return 0;
6353		spin_lock_irq(&conf->device_lock);
6354		conf->reshape_safe = mddev->reshape_position;
6355		spin_unlock_irq(&conf->device_lock);
6356		wake_up(&conf->wait_for_overlap);
6357		sysfs_notify_dirent_safe(mddev->sysfs_completed);
6358	}
6359
6360	INIT_LIST_HEAD(&stripes);
6361	for (i = 0; i < reshape_sectors; i += RAID5_STRIPE_SECTORS(conf)) {
6362		int j;
6363		int skipped_disk = 0;
6364		sh = raid5_get_active_stripe(conf, NULL, stripe_addr+i,
6365					     R5_GAS_NOQUIESCE);
6366		set_bit(STRIPE_EXPANDING, &sh->state);
6367		atomic_inc(&conf->reshape_stripes);
6368		/* If any of this stripe is beyond the end of the old
6369		 * array, then we need to zero those blocks
6370		 */
6371		for (j=sh->disks; j--;) {
6372			sector_t s;
6373			if (j == sh->pd_idx)
6374				continue;
6375			if (conf->level == 6 &&
6376			    j == sh->qd_idx)
6377				continue;
6378			s = raid5_compute_blocknr(sh, j, 0);
6379			if (s < raid5_size(mddev, 0, 0)) {
6380				skipped_disk = 1;
6381				continue;
6382			}
6383			memset(page_address(sh->dev[j].page), 0, RAID5_STRIPE_SIZE(conf));
6384			set_bit(R5_Expanded, &sh->dev[j].flags);
6385			set_bit(R5_UPTODATE, &sh->dev[j].flags);
6386		}
6387		if (!skipped_disk) {
6388			set_bit(STRIPE_EXPAND_READY, &sh->state);
6389			set_bit(STRIPE_HANDLE, &sh->state);
6390		}
6391		list_add(&sh->lru, &stripes);
6392	}
6393	spin_lock_irq(&conf->device_lock);
6394	if (mddev->reshape_backwards)
6395		conf->reshape_progress -= reshape_sectors * new_data_disks;
6396	else
6397		conf->reshape_progress += reshape_sectors * new_data_disks;
6398	spin_unlock_irq(&conf->device_lock);
6399	/* Ok, those stripe are ready. We can start scheduling
6400	 * reads on the source stripes.
6401	 * The source stripes are determined by mapping the first and last
6402	 * block on the destination stripes.
6403	 */
6404	first_sector =
6405		raid5_compute_sector(conf, stripe_addr*(new_data_disks),
6406				     1, &dd_idx, NULL);
6407	last_sector =
6408		raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
6409					    * new_data_disks - 1),
6410				     1, &dd_idx, NULL);
6411	if (last_sector >= mddev->dev_sectors)
6412		last_sector = mddev->dev_sectors - 1;
6413	while (first_sector <= last_sector) {
6414		sh = raid5_get_active_stripe(conf, NULL, first_sector,
6415				R5_GAS_PREVIOUS | R5_GAS_NOQUIESCE);
6416		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
6417		set_bit(STRIPE_HANDLE, &sh->state);
6418		raid5_release_stripe(sh);
6419		first_sector += RAID5_STRIPE_SECTORS(conf);
6420	}
6421	/* Now that the sources are clearly marked, we can release
6422	 * the destination stripes
6423	 */
6424	while (!list_empty(&stripes)) {
6425		sh = list_entry(stripes.next, struct stripe_head, lru);
6426		list_del_init(&sh->lru);
6427		raid5_release_stripe(sh);
6428	}
6429	/* If this takes us to the resync_max point where we have to pause,
6430	 * then we need to write out the superblock.
6431	 */
6432	sector_nr += reshape_sectors;
6433	retn = reshape_sectors;
6434finish:
6435	if (mddev->curr_resync_completed > mddev->resync_max ||
6436	    (sector_nr - mddev->curr_resync_completed) * 2
6437	    >= mddev->resync_max - mddev->curr_resync_completed) {
6438		/* Cannot proceed until we've updated the superblock... */
6439		wait_event(conf->wait_for_overlap,
6440			   atomic_read(&conf->reshape_stripes) == 0
6441			   || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6442		if (atomic_read(&conf->reshape_stripes) != 0)
6443			goto ret;
6444		mddev->reshape_position = conf->reshape_progress;
6445		mddev->curr_resync_completed = sector_nr;
6446		if (!mddev->reshape_backwards)
6447			/* Can update recovery_offset */
6448			rdev_for_each(rdev, mddev)
6449				if (rdev->raid_disk >= 0 &&
6450				    !test_bit(Journal, &rdev->flags) &&
6451				    !test_bit(In_sync, &rdev->flags) &&
6452				    rdev->recovery_offset < sector_nr)
6453					rdev->recovery_offset = sector_nr;
6454		conf->reshape_checkpoint = jiffies;
6455		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6456		md_wakeup_thread(mddev->thread);
6457		wait_event(mddev->sb_wait,
6458			   !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6459			   || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6460		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6461			goto ret;
6462		spin_lock_irq(&conf->device_lock);
6463		conf->reshape_safe = mddev->reshape_position;
6464		spin_unlock_irq(&conf->device_lock);
6465		wake_up(&conf->wait_for_overlap);
6466		sysfs_notify_dirent_safe(mddev->sysfs_completed);
6467	}
6468ret:
6469	return retn;
6470}
6471
6472static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6473					  int *skipped)
6474{
6475	struct r5conf *conf = mddev->private;
6476	struct stripe_head *sh;
6477	sector_t max_sector = mddev->dev_sectors;
6478	sector_t sync_blocks;
6479	int still_degraded = 0;
6480	int i;
6481
6482	if (sector_nr >= max_sector) {
6483		/* just being told to finish up .. nothing much to do */
6484
6485		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6486			end_reshape(conf);
6487			return 0;
6488		}
6489
6490		if (mddev->curr_resync < max_sector) /* aborted */
6491			md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6492					   &sync_blocks, 1);
6493		else /* completed sync */
6494			conf->fullsync = 0;
6495		md_bitmap_close_sync(mddev->bitmap);
6496
6497		return 0;
6498	}
6499
6500	/* Allow raid5_quiesce to complete */
6501	wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6502
6503	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6504		return reshape_request(mddev, sector_nr, skipped);
6505
6506	/* No need to check resync_max as we never do more than one
6507	 * stripe, and as resync_max will always be on a chunk boundary,
6508	 * if the check in md_do_sync didn't fire, there is no chance
6509	 * of overstepping resync_max here
6510	 */
6511
6512	/* if there is too many failed drives and we are trying
6513	 * to resync, then assert that we are finished, because there is
6514	 * nothing we can do.
6515	 */
6516	if (mddev->degraded >= conf->max_degraded &&
6517	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6518		sector_t rv = mddev->dev_sectors - sector_nr;
6519		*skipped = 1;
6520		return rv;
6521	}
6522	if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6523	    !conf->fullsync &&
6524	    !md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6525	    sync_blocks >= RAID5_STRIPE_SECTORS(conf)) {
6526		/* we can skip this block, and probably more */
6527		do_div(sync_blocks, RAID5_STRIPE_SECTORS(conf));
6528		*skipped = 1;
6529		/* keep things rounded to whole stripes */
6530		return sync_blocks * RAID5_STRIPE_SECTORS(conf);
6531	}
6532
6533	md_bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6534
6535	sh = raid5_get_active_stripe(conf, NULL, sector_nr,
6536				     R5_GAS_NOBLOCK);
6537	if (sh == NULL) {
6538		sh = raid5_get_active_stripe(conf, NULL, sector_nr, 0);
6539		/* make sure we don't swamp the stripe cache if someone else
6540		 * is trying to get access
6541		 */
6542		schedule_timeout_uninterruptible(1);
6543	}
6544	/* Need to check if array will still be degraded after recovery/resync
6545	 * Note in case of > 1 drive failures it's possible we're rebuilding
6546	 * one drive while leaving another faulty drive in array.
6547	 */
6548	rcu_read_lock();
6549	for (i = 0; i < conf->raid_disks; i++) {
6550		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
6551
6552		if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6553			still_degraded = 1;
6554	}
6555	rcu_read_unlock();
6556
6557	md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6558
6559	set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6560	set_bit(STRIPE_HANDLE, &sh->state);
6561
6562	raid5_release_stripe(sh);
 
6563
6564	return RAID5_STRIPE_SECTORS(conf);
6565}
6566
6567static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6568			       unsigned int offset)
6569{
6570	/* We may not be able to submit a whole bio at once as there
6571	 * may not be enough stripe_heads available.
6572	 * We cannot pre-allocate enough stripe_heads as we may need
6573	 * more than exist in the cache (if we allow ever large chunks).
6574	 * So we do one stripe head at a time and record in
6575	 * ->bi_hw_segments how many have been done.
6576	 *
6577	 * We *know* that this entire raid_bio is in one chunk, so
6578	 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6579	 */
6580	struct stripe_head *sh;
6581	int dd_idx;
6582	sector_t sector, logical_sector, last_sector;
6583	int scnt = 0;
 
6584	int handled = 0;
6585
6586	logical_sector = raid_bio->bi_iter.bi_sector &
6587		~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6588	sector = raid5_compute_sector(conf, logical_sector,
6589				      0, &dd_idx, NULL);
6590	last_sector = bio_end_sector(raid_bio);
6591
6592	for (; logical_sector < last_sector;
6593	     logical_sector += RAID5_STRIPE_SECTORS(conf),
6594		     sector += RAID5_STRIPE_SECTORS(conf),
6595		     scnt++) {
6596
6597		if (scnt < offset)
6598			/* already done this stripe */
6599			continue;
6600
6601		sh = raid5_get_active_stripe(conf, NULL, sector,
6602				R5_GAS_NOBLOCK | R5_GAS_NOQUIESCE);
6603		if (!sh) {
6604			/* failed to get a stripe - must wait */
 
6605			conf->retry_read_aligned = raid_bio;
6606			conf->retry_read_offset = scnt;
6607			return handled;
6608		}
6609
6610		if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6611			raid5_release_stripe(sh);
 
6612			conf->retry_read_aligned = raid_bio;
6613			conf->retry_read_offset = scnt;
6614			return handled;
6615		}
6616
6617		set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6618		handle_stripe(sh);
6619		raid5_release_stripe(sh);
6620		handled++;
6621	}
6622
6623	bio_endio(raid_bio);
6624
 
 
 
6625	if (atomic_dec_and_test(&conf->active_aligned_reads))
6626		wake_up(&conf->wait_for_quiescent);
6627	return handled;
6628}
6629
6630static int handle_active_stripes(struct r5conf *conf, int group,
6631				 struct r5worker *worker,
6632				 struct list_head *temp_inactive_list)
6633		__must_hold(&conf->device_lock)
6634{
6635	struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6636	int i, batch_size = 0, hash;
6637	bool release_inactive = false;
6638
6639	while (batch_size < MAX_STRIPE_BATCH &&
6640			(sh = __get_priority_stripe(conf, group)) != NULL)
6641		batch[batch_size++] = sh;
6642
6643	if (batch_size == 0) {
6644		for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6645			if (!list_empty(temp_inactive_list + i))
6646				break;
6647		if (i == NR_STRIPE_HASH_LOCKS) {
6648			spin_unlock_irq(&conf->device_lock);
6649			log_flush_stripe_to_raid(conf);
6650			spin_lock_irq(&conf->device_lock);
6651			return batch_size;
6652		}
6653		release_inactive = true;
6654	}
6655	spin_unlock_irq(&conf->device_lock);
6656
6657	release_inactive_stripe_list(conf, temp_inactive_list,
6658				     NR_STRIPE_HASH_LOCKS);
6659
6660	r5l_flush_stripe_to_raid(conf->log);
6661	if (release_inactive) {
6662		spin_lock_irq(&conf->device_lock);
6663		return 0;
6664	}
6665
6666	for (i = 0; i < batch_size; i++)
6667		handle_stripe(batch[i]);
6668	log_write_stripe_run(conf);
6669
6670	cond_resched();
6671
6672	spin_lock_irq(&conf->device_lock);
6673	for (i = 0; i < batch_size; i++) {
6674		hash = batch[i]->hash_lock_index;
6675		__release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6676	}
6677	return batch_size;
6678}
6679
6680static void raid5_do_work(struct work_struct *work)
6681{
6682	struct r5worker *worker = container_of(work, struct r5worker, work);
6683	struct r5worker_group *group = worker->group;
6684	struct r5conf *conf = group->conf;
6685	struct mddev *mddev = conf->mddev;
6686	int group_id = group - conf->worker_groups;
6687	int handled;
6688	struct blk_plug plug;
6689
6690	pr_debug("+++ raid5worker active\n");
6691
6692	blk_start_plug(&plug);
6693	handled = 0;
6694	spin_lock_irq(&conf->device_lock);
6695	while (1) {
6696		int batch_size, released;
6697
6698		released = release_stripe_list(conf, worker->temp_inactive_list);
6699
6700		batch_size = handle_active_stripes(conf, group_id, worker,
6701						   worker->temp_inactive_list);
6702		worker->working = false;
6703		if (!batch_size && !released)
6704			break;
6705		handled += batch_size;
6706		wait_event_lock_irq(mddev->sb_wait,
6707			!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6708			conf->device_lock);
6709	}
6710	pr_debug("%d stripes handled\n", handled);
6711
6712	spin_unlock_irq(&conf->device_lock);
6713
6714	flush_deferred_bios(conf);
6715
6716	r5l_flush_stripe_to_raid(conf->log);
6717
6718	async_tx_issue_pending_all();
6719	blk_finish_plug(&plug);
6720
6721	pr_debug("--- raid5worker inactive\n");
6722}
6723
6724/*
6725 * This is our raid5 kernel thread.
6726 *
6727 * We scan the hash table for stripes which can be handled now.
6728 * During the scan, completed stripes are saved for us by the interrupt
6729 * handler, so that they will not have to wait for our next wakeup.
6730 */
6731static void raid5d(struct md_thread *thread)
6732{
6733	struct mddev *mddev = thread->mddev;
6734	struct r5conf *conf = mddev->private;
6735	int handled;
6736	struct blk_plug plug;
6737
6738	pr_debug("+++ raid5d active\n");
6739
6740	md_check_recovery(mddev);
6741
6742	blk_start_plug(&plug);
6743	handled = 0;
6744	spin_lock_irq(&conf->device_lock);
6745	while (1) {
6746		struct bio *bio;
6747		int batch_size, released;
6748		unsigned int offset;
6749
6750		released = release_stripe_list(conf, conf->temp_inactive_list);
6751		if (released)
6752			clear_bit(R5_DID_ALLOC, &conf->cache_state);
6753
6754		if (
6755		    !list_empty(&conf->bitmap_list)) {
6756			/* Now is a good time to flush some bitmap updates */
6757			conf->seq_flush++;
6758			spin_unlock_irq(&conf->device_lock);
6759			md_bitmap_unplug(mddev->bitmap);
6760			spin_lock_irq(&conf->device_lock);
6761			conf->seq_write = conf->seq_flush;
6762			activate_bit_delay(conf, conf->temp_inactive_list);
6763		}
6764		raid5_activate_delayed(conf);
6765
6766		while ((bio = remove_bio_from_retry(conf, &offset))) {
6767			int ok;
6768			spin_unlock_irq(&conf->device_lock);
6769			ok = retry_aligned_read(conf, bio, offset);
6770			spin_lock_irq(&conf->device_lock);
6771			if (!ok)
6772				break;
6773			handled++;
6774		}
6775
6776		batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6777						   conf->temp_inactive_list);
6778		if (!batch_size && !released)
6779			break;
6780		handled += batch_size;
6781
6782		if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6783			spin_unlock_irq(&conf->device_lock);
6784			md_check_recovery(mddev);
6785			spin_lock_irq(&conf->device_lock);
6786
6787			/*
6788			 * Waiting on MD_SB_CHANGE_PENDING below may deadlock
6789			 * seeing md_check_recovery() is needed to clear
6790			 * the flag when using mdmon.
6791			 */
6792			continue;
6793		}
6794
6795		wait_event_lock_irq(mddev->sb_wait,
6796			!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6797			conf->device_lock);
6798	}
6799	pr_debug("%d stripes handled\n", handled);
6800
6801	spin_unlock_irq(&conf->device_lock);
6802	if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6803	    mutex_trylock(&conf->cache_size_mutex)) {
6804		grow_one_stripe(conf, __GFP_NOWARN);
6805		/* Set flag even if allocation failed.  This helps
6806		 * slow down allocation requests when mem is short
6807		 */
6808		set_bit(R5_DID_ALLOC, &conf->cache_state);
6809		mutex_unlock(&conf->cache_size_mutex);
6810	}
6811
6812	flush_deferred_bios(conf);
6813
6814	r5l_flush_stripe_to_raid(conf->log);
6815
6816	async_tx_issue_pending_all();
6817	blk_finish_plug(&plug);
6818
6819	pr_debug("--- raid5d inactive\n");
6820}
6821
6822static ssize_t
6823raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6824{
6825	struct r5conf *conf;
6826	int ret = 0;
6827	spin_lock(&mddev->lock);
6828	conf = mddev->private;
6829	if (conf)
6830		ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6831	spin_unlock(&mddev->lock);
6832	return ret;
6833}
6834
6835int
6836raid5_set_cache_size(struct mddev *mddev, int size)
6837{
6838	int result = 0;
6839	struct r5conf *conf = mddev->private;
 
 
6840
6841	if (size <= 16 || size > 32768)
6842		return -EINVAL;
6843
6844	conf->min_nr_stripes = size;
6845	mutex_lock(&conf->cache_size_mutex);
6846	while (size < conf->max_nr_stripes &&
6847	       drop_one_stripe(conf))
6848		;
6849	mutex_unlock(&conf->cache_size_mutex);
6850
6851	md_allow_write(mddev);
6852
6853	mutex_lock(&conf->cache_size_mutex);
6854	while (size > conf->max_nr_stripes)
6855		if (!grow_one_stripe(conf, GFP_KERNEL)) {
6856			conf->min_nr_stripes = conf->max_nr_stripes;
6857			result = -ENOMEM;
6858			break;
6859		}
6860	mutex_unlock(&conf->cache_size_mutex);
6861
6862	return result;
 
 
 
 
 
 
 
 
 
 
 
6863}
6864EXPORT_SYMBOL(raid5_set_cache_size);
6865
6866static ssize_t
6867raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6868{
6869	struct r5conf *conf;
6870	unsigned long new;
6871	int err;
6872
6873	if (len >= PAGE_SIZE)
6874		return -EINVAL;
 
 
 
6875	if (kstrtoul(page, 10, &new))
6876		return -EINVAL;
6877	err = mddev_lock(mddev);
6878	if (err)
6879		return err;
6880	conf = mddev->private;
6881	if (!conf)
6882		err = -ENODEV;
6883	else
6884		err = raid5_set_cache_size(mddev, new);
6885	mddev_unlock(mddev);
6886
6887	return err ?: len;
6888}
6889
6890static struct md_sysfs_entry
6891raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6892				raid5_show_stripe_cache_size,
6893				raid5_store_stripe_cache_size);
6894
6895static ssize_t
6896raid5_show_rmw_level(struct mddev  *mddev, char *page)
6897{
6898	struct r5conf *conf = mddev->private;
6899	if (conf)
6900		return sprintf(page, "%d\n", conf->rmw_level);
6901	else
6902		return 0;
6903}
6904
6905static ssize_t
6906raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6907{
6908	struct r5conf *conf = mddev->private;
6909	unsigned long new;
6910
6911	if (!conf)
6912		return -ENODEV;
6913
6914	if (len >= PAGE_SIZE)
6915		return -EINVAL;
 
 
6916
6917	if (kstrtoul(page, 10, &new))
6918		return -EINVAL;
6919
6920	if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6921		return -EINVAL;
6922
6923	if (new != PARITY_DISABLE_RMW &&
6924	    new != PARITY_ENABLE_RMW &&
6925	    new != PARITY_PREFER_RMW)
6926		return -EINVAL;
6927
6928	conf->rmw_level = new;
6929	return len;
6930}
6931
6932static struct md_sysfs_entry
6933raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6934			 raid5_show_rmw_level,
6935			 raid5_store_rmw_level);
6936
6937static ssize_t
6938raid5_show_stripe_size(struct mddev  *mddev, char *page)
6939{
6940	struct r5conf *conf;
6941	int ret = 0;
6942
6943	spin_lock(&mddev->lock);
6944	conf = mddev->private;
6945	if (conf)
6946		ret = sprintf(page, "%lu\n", RAID5_STRIPE_SIZE(conf));
6947	spin_unlock(&mddev->lock);
6948	return ret;
6949}
6950
6951#if PAGE_SIZE != DEFAULT_STRIPE_SIZE
6952static ssize_t
6953raid5_store_stripe_size(struct mddev  *mddev, const char *page, size_t len)
6954{
6955	struct r5conf *conf;
6956	unsigned long new;
6957	int err;
6958	int size;
6959
6960	if (len >= PAGE_SIZE)
6961		return -EINVAL;
6962	if (kstrtoul(page, 10, &new))
6963		return -EINVAL;
6964
6965	/*
6966	 * The value should not be bigger than PAGE_SIZE. It requires to
6967	 * be multiple of DEFAULT_STRIPE_SIZE and the value should be power
6968	 * of two.
6969	 */
6970	if (new % DEFAULT_STRIPE_SIZE != 0 ||
6971			new > PAGE_SIZE || new == 0 ||
6972			new != roundup_pow_of_two(new))
6973		return -EINVAL;
6974
6975	err = mddev_lock(mddev);
6976	if (err)
6977		return err;
6978
6979	conf = mddev->private;
6980	if (!conf) {
6981		err = -ENODEV;
6982		goto out_unlock;
6983	}
6984
6985	if (new == conf->stripe_size)
6986		goto out_unlock;
6987
6988	pr_debug("md/raid: change stripe_size from %lu to %lu\n",
6989			conf->stripe_size, new);
6990
6991	if (mddev->sync_thread ||
6992		test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
6993		mddev->reshape_position != MaxSector ||
6994		mddev->sysfs_active) {
6995		err = -EBUSY;
6996		goto out_unlock;
6997	}
6998
6999	mddev_suspend(mddev);
7000	mutex_lock(&conf->cache_size_mutex);
7001	size = conf->max_nr_stripes;
7002
7003	shrink_stripes(conf);
7004
7005	conf->stripe_size = new;
7006	conf->stripe_shift = ilog2(new) - 9;
7007	conf->stripe_sectors = new >> 9;
7008	if (grow_stripes(conf, size)) {
7009		pr_warn("md/raid:%s: couldn't allocate buffers\n",
7010				mdname(mddev));
7011		err = -ENOMEM;
7012	}
7013	mutex_unlock(&conf->cache_size_mutex);
7014	mddev_resume(mddev);
7015
7016out_unlock:
7017	mddev_unlock(mddev);
7018	return err ?: len;
7019}
7020
7021static struct md_sysfs_entry
7022raid5_stripe_size = __ATTR(stripe_size, 0644,
7023			 raid5_show_stripe_size,
7024			 raid5_store_stripe_size);
7025#else
7026static struct md_sysfs_entry
7027raid5_stripe_size = __ATTR(stripe_size, 0444,
7028			 raid5_show_stripe_size,
7029			 NULL);
7030#endif
7031
7032static ssize_t
7033raid5_show_preread_threshold(struct mddev *mddev, char *page)
7034{
7035	struct r5conf *conf;
7036	int ret = 0;
7037	spin_lock(&mddev->lock);
7038	conf = mddev->private;
7039	if (conf)
7040		ret = sprintf(page, "%d\n", conf->bypass_threshold);
7041	spin_unlock(&mddev->lock);
7042	return ret;
7043}
7044
7045static ssize_t
7046raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
7047{
7048	struct r5conf *conf;
7049	unsigned long new;
7050	int err;
7051
7052	if (len >= PAGE_SIZE)
7053		return -EINVAL;
7054	if (kstrtoul(page, 10, &new))
7055		return -EINVAL;
7056
7057	err = mddev_lock(mddev);
7058	if (err)
7059		return err;
7060	conf = mddev->private;
7061	if (!conf)
7062		err = -ENODEV;
7063	else if (new > conf->min_nr_stripes)
7064		err = -EINVAL;
7065	else
7066		conf->bypass_threshold = new;
7067	mddev_unlock(mddev);
7068	return err ?: len;
7069}
7070
7071static struct md_sysfs_entry
7072raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
7073					S_IRUGO | S_IWUSR,
7074					raid5_show_preread_threshold,
7075					raid5_store_preread_threshold);
7076
7077static ssize_t
7078raid5_show_skip_copy(struct mddev *mddev, char *page)
7079{
7080	struct r5conf *conf;
7081	int ret = 0;
7082	spin_lock(&mddev->lock);
7083	conf = mddev->private;
7084	if (conf)
7085		ret = sprintf(page, "%d\n", conf->skip_copy);
7086	spin_unlock(&mddev->lock);
7087	return ret;
7088}
7089
7090static ssize_t
7091raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
7092{
7093	struct r5conf *conf;
7094	unsigned long new;
7095	int err;
7096
7097	if (len >= PAGE_SIZE)
7098		return -EINVAL;
7099	if (kstrtoul(page, 10, &new))
7100		return -EINVAL;
7101	new = !!new;
7102
7103	err = mddev_lock(mddev);
7104	if (err)
7105		return err;
7106	conf = mddev->private;
7107	if (!conf)
7108		err = -ENODEV;
7109	else if (new != conf->skip_copy) {
7110		struct request_queue *q = mddev->queue;
7111
7112		mddev_suspend(mddev);
7113		conf->skip_copy = new;
7114		if (new)
7115			blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, q);
7116		else
7117			blk_queue_flag_clear(QUEUE_FLAG_STABLE_WRITES, q);
7118		mddev_resume(mddev);
7119	}
7120	mddev_unlock(mddev);
7121	return err ?: len;
7122}
7123
7124static struct md_sysfs_entry
7125raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
7126					raid5_show_skip_copy,
7127					raid5_store_skip_copy);
7128
7129static ssize_t
7130stripe_cache_active_show(struct mddev *mddev, char *page)
7131{
7132	struct r5conf *conf = mddev->private;
7133	if (conf)
7134		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
7135	else
7136		return 0;
7137}
7138
7139static struct md_sysfs_entry
7140raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
7141
7142static ssize_t
7143raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
7144{
7145	struct r5conf *conf;
7146	int ret = 0;
7147	spin_lock(&mddev->lock);
7148	conf = mddev->private;
7149	if (conf)
7150		ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
7151	spin_unlock(&mddev->lock);
7152	return ret;
7153}
7154
7155static int alloc_thread_groups(struct r5conf *conf, int cnt,
7156			       int *group_cnt,
 
7157			       struct r5worker_group **worker_groups);
7158static ssize_t
7159raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
7160{
7161	struct r5conf *conf;
7162	unsigned int new;
7163	int err;
7164	struct r5worker_group *new_groups, *old_groups;
7165	int group_cnt;
7166
7167	if (len >= PAGE_SIZE)
7168		return -EINVAL;
7169	if (kstrtouint(page, 10, &new))
7170		return -EINVAL;
7171	/* 8192 should be big enough */
7172	if (new > 8192)
7173		return -EINVAL;
7174
7175	err = mddev_lock(mddev);
7176	if (err)
7177		return err;
7178	conf = mddev->private;
7179	if (!conf)
7180		err = -ENODEV;
7181	else if (new != conf->worker_cnt_per_group) {
7182		mddev_suspend(mddev);
7183
7184		old_groups = conf->worker_groups;
7185		if (old_groups)
7186			flush_workqueue(raid5_wq);
7187
7188		err = alloc_thread_groups(conf, new, &group_cnt, &new_groups);
7189		if (!err) {
7190			spin_lock_irq(&conf->device_lock);
7191			conf->group_cnt = group_cnt;
7192			conf->worker_cnt_per_group = new;
7193			conf->worker_groups = new_groups;
7194			spin_unlock_irq(&conf->device_lock);
 
 
 
 
 
 
7195
7196			if (old_groups)
7197				kfree(old_groups[0].workers);
7198			kfree(old_groups);
7199		}
7200		mddev_resume(mddev);
7201	}
7202	mddev_unlock(mddev);
7203
7204	return err ?: len;
 
 
 
 
7205}
7206
7207static struct md_sysfs_entry
7208raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
7209				raid5_show_group_thread_cnt,
7210				raid5_store_group_thread_cnt);
7211
7212static struct attribute *raid5_attrs[] =  {
7213	&raid5_stripecache_size.attr,
7214	&raid5_stripecache_active.attr,
7215	&raid5_preread_bypass_threshold.attr,
7216	&raid5_group_thread_cnt.attr,
7217	&raid5_skip_copy.attr,
7218	&raid5_rmw_level.attr,
7219	&raid5_stripe_size.attr,
7220	&r5c_journal_mode.attr,
7221	&ppl_write_hint.attr,
7222	NULL,
7223};
7224static const struct attribute_group raid5_attrs_group = {
7225	.name = NULL,
7226	.attrs = raid5_attrs,
7227};
7228
7229static int alloc_thread_groups(struct r5conf *conf, int cnt, int *group_cnt,
 
 
7230			       struct r5worker_group **worker_groups)
7231{
7232	int i, j, k;
7233	ssize_t size;
7234	struct r5worker *workers;
7235
 
7236	if (cnt == 0) {
7237		*group_cnt = 0;
7238		*worker_groups = NULL;
7239		return 0;
7240	}
7241	*group_cnt = num_possible_nodes();
7242	size = sizeof(struct r5worker) * cnt;
7243	workers = kcalloc(size, *group_cnt, GFP_NOIO);
7244	*worker_groups = kcalloc(*group_cnt, sizeof(struct r5worker_group),
7245				 GFP_NOIO);
7246	if (!*worker_groups || !workers) {
7247		kfree(workers);
7248		kfree(*worker_groups);
7249		return -ENOMEM;
7250	}
7251
7252	for (i = 0; i < *group_cnt; i++) {
7253		struct r5worker_group *group;
7254
7255		group = &(*worker_groups)[i];
7256		INIT_LIST_HEAD(&group->handle_list);
7257		INIT_LIST_HEAD(&group->loprio_list);
7258		group->conf = conf;
7259		group->workers = workers + i * cnt;
7260
7261		for (j = 0; j < cnt; j++) {
7262			struct r5worker *worker = group->workers + j;
7263			worker->group = group;
7264			INIT_WORK(&worker->work, raid5_do_work);
7265
7266			for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
7267				INIT_LIST_HEAD(worker->temp_inactive_list + k);
7268		}
7269	}
7270
7271	return 0;
7272}
7273
7274static void free_thread_groups(struct r5conf *conf)
7275{
7276	if (conf->worker_groups)
7277		kfree(conf->worker_groups[0].workers);
7278	kfree(conf->worker_groups);
7279	conf->worker_groups = NULL;
7280}
7281
7282static sector_t
7283raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
7284{
7285	struct r5conf *conf = mddev->private;
7286
7287	if (!sectors)
7288		sectors = mddev->dev_sectors;
7289	if (!raid_disks)
7290		/* size is defined by the smallest of previous and new size */
7291		raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
7292
7293	sectors &= ~((sector_t)conf->chunk_sectors - 1);
7294	sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
7295	return sectors * (raid_disks - conf->max_degraded);
7296}
7297
7298static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7299{
7300	safe_put_page(percpu->spare_page);
 
7301	percpu->spare_page = NULL;
7302	kvfree(percpu->scribble);
7303	percpu->scribble = NULL;
7304}
7305
7306static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7307{
7308	if (conf->level == 6 && !percpu->spare_page) {
7309		percpu->spare_page = alloc_page(GFP_KERNEL);
7310		if (!percpu->spare_page)
7311			return -ENOMEM;
7312	}
7313
7314	if (scribble_alloc(percpu,
7315			   max(conf->raid_disks,
7316			       conf->previous_raid_disks),
7317			   max(conf->chunk_sectors,
7318			       conf->prev_chunk_sectors)
7319			   / RAID5_STRIPE_SECTORS(conf))) {
7320		free_scratch_buffer(conf, percpu);
7321		return -ENOMEM;
7322	}
7323
7324	local_lock_init(&percpu->lock);
7325	return 0;
7326}
7327
7328static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
7329{
7330	struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7331
7332	free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
7333	return 0;
7334}
7335
7336static void raid5_free_percpu(struct r5conf *conf)
7337{
 
 
7338	if (!conf->percpu)
7339		return;
7340
7341	cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
 
 
 
 
 
 
 
 
7342	free_percpu(conf->percpu);
7343}
7344
7345static void free_conf(struct r5conf *conf)
7346{
7347	int i;
7348
7349	log_exit(conf);
7350
7351	unregister_shrinker(&conf->shrinker);
7352	free_thread_groups(conf);
7353	shrink_stripes(conf);
7354	raid5_free_percpu(conf);
7355	for (i = 0; i < conf->pool_size; i++)
7356		if (conf->disks[i].extra_page)
7357			put_page(conf->disks[i].extra_page);
7358	kfree(conf->disks);
7359	bioset_exit(&conf->bio_split);
7360	kfree(conf->stripe_hashtbl);
7361	kfree(conf->pending_data);
7362	kfree(conf);
7363}
7364
7365static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
 
 
7366{
7367	struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
 
7368	struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
7369
7370	if (alloc_scratch_buffer(conf, percpu)) {
7371		pr_warn("%s: failed memory allocation for cpu%u\n",
7372			__func__, cpu);
7373		return -ENOMEM;
 
 
 
 
 
 
 
 
 
 
 
7374	}
7375	return 0;
7376}
 
7377
7378static int raid5_alloc_percpu(struct r5conf *conf)
7379{
 
7380	int err = 0;
7381
7382	conf->percpu = alloc_percpu(struct raid5_percpu);
7383	if (!conf->percpu)
7384		return -ENOMEM;
7385
7386	err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7387	if (!err) {
7388		conf->scribble_disks = max(conf->raid_disks,
7389			conf->previous_raid_disks);
7390		conf->scribble_sectors = max(conf->chunk_sectors,
7391			conf->prev_chunk_sectors);
7392	}
7393	return err;
7394}
7395
7396static unsigned long raid5_cache_scan(struct shrinker *shrink,
7397				      struct shrink_control *sc)
7398{
7399	struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
7400	unsigned long ret = SHRINK_STOP;
7401
7402	if (mutex_trylock(&conf->cache_size_mutex)) {
7403		ret= 0;
7404		while (ret < sc->nr_to_scan &&
7405		       conf->max_nr_stripes > conf->min_nr_stripes) {
7406			if (drop_one_stripe(conf) == 0) {
7407				ret = SHRINK_STOP;
7408				break;
7409			}
7410			ret++;
7411		}
7412		mutex_unlock(&conf->cache_size_mutex);
7413	}
7414	return ret;
7415}
7416
7417static unsigned long raid5_cache_count(struct shrinker *shrink,
7418				       struct shrink_control *sc)
7419{
7420	struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
7421
7422	if (conf->max_nr_stripes < conf->min_nr_stripes)
7423		/* unlikely, but not impossible */
7424		return 0;
7425	return conf->max_nr_stripes - conf->min_nr_stripes;
7426}
7427
7428static struct r5conf *setup_conf(struct mddev *mddev)
7429{
7430	struct r5conf *conf;
7431	int raid_disk, memory, max_disks;
7432	struct md_rdev *rdev;
7433	struct disk_info *disk;
7434	char pers_name[6];
7435	int i;
7436	int group_cnt;
7437	struct r5worker_group *new_group;
7438	int ret = -ENOMEM;
7439
7440	if (mddev->new_level != 5
7441	    && mddev->new_level != 4
7442	    && mddev->new_level != 6) {
7443		pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
7444			mdname(mddev), mddev->new_level);
7445		return ERR_PTR(-EIO);
7446	}
7447	if ((mddev->new_level == 5
7448	     && !algorithm_valid_raid5(mddev->new_layout)) ||
7449	    (mddev->new_level == 6
7450	     && !algorithm_valid_raid6(mddev->new_layout))) {
7451		pr_warn("md/raid:%s: layout %d not supported\n",
7452			mdname(mddev), mddev->new_layout);
7453		return ERR_PTR(-EIO);
7454	}
7455	if (mddev->new_level == 6 && mddev->raid_disks < 4) {
7456		pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
7457			mdname(mddev), mddev->raid_disks);
7458		return ERR_PTR(-EINVAL);
7459	}
7460
7461	if (!mddev->new_chunk_sectors ||
7462	    (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
7463	    !is_power_of_2(mddev->new_chunk_sectors)) {
7464		pr_warn("md/raid:%s: invalid chunk size %d\n",
7465			mdname(mddev), mddev->new_chunk_sectors << 9);
7466		return ERR_PTR(-EINVAL);
7467	}
7468
7469	conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
7470	if (conf == NULL)
7471		goto abort;
7472
7473#if PAGE_SIZE != DEFAULT_STRIPE_SIZE
7474	conf->stripe_size = DEFAULT_STRIPE_SIZE;
7475	conf->stripe_shift = ilog2(DEFAULT_STRIPE_SIZE) - 9;
7476	conf->stripe_sectors = DEFAULT_STRIPE_SIZE >> 9;
7477#endif
7478	INIT_LIST_HEAD(&conf->free_list);
7479	INIT_LIST_HEAD(&conf->pending_list);
7480	conf->pending_data = kcalloc(PENDING_IO_MAX,
7481				     sizeof(struct r5pending_data),
7482				     GFP_KERNEL);
7483	if (!conf->pending_data)
7484		goto abort;
7485	for (i = 0; i < PENDING_IO_MAX; i++)
7486		list_add(&conf->pending_data[i].sibling, &conf->free_list);
7487	/* Don't enable multi-threading by default*/
7488	if (!alloc_thread_groups(conf, 0, &group_cnt, &new_group)) {
 
7489		conf->group_cnt = group_cnt;
7490		conf->worker_cnt_per_group = 0;
7491		conf->worker_groups = new_group;
7492	} else
7493		goto abort;
7494	spin_lock_init(&conf->device_lock);
7495	seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock);
7496	mutex_init(&conf->cache_size_mutex);
7497
7498	init_waitqueue_head(&conf->wait_for_quiescent);
7499	init_waitqueue_head(&conf->wait_for_stripe);
7500	init_waitqueue_head(&conf->wait_for_overlap);
7501	INIT_LIST_HEAD(&conf->handle_list);
7502	INIT_LIST_HEAD(&conf->loprio_list);
7503	INIT_LIST_HEAD(&conf->hold_list);
7504	INIT_LIST_HEAD(&conf->delayed_list);
7505	INIT_LIST_HEAD(&conf->bitmap_list);
7506	init_llist_head(&conf->released_stripes);
7507	atomic_set(&conf->active_stripes, 0);
7508	atomic_set(&conf->preread_active_stripes, 0);
7509	atomic_set(&conf->active_aligned_reads, 0);
7510	spin_lock_init(&conf->pending_bios_lock);
7511	conf->batch_bio_dispatch = true;
7512	rdev_for_each(rdev, mddev) {
7513		if (test_bit(Journal, &rdev->flags))
7514			continue;
7515		if (bdev_nonrot(rdev->bdev)) {
7516			conf->batch_bio_dispatch = false;
7517			break;
7518		}
7519	}
7520
7521	conf->bypass_threshold = BYPASS_THRESHOLD;
7522	conf->recovery_disabled = mddev->recovery_disabled - 1;
7523
7524	conf->raid_disks = mddev->raid_disks;
7525	if (mddev->reshape_position == MaxSector)
7526		conf->previous_raid_disks = mddev->raid_disks;
7527	else
7528		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
7529	max_disks = max(conf->raid_disks, conf->previous_raid_disks);
 
7530
7531	conf->disks = kcalloc(max_disks, sizeof(struct disk_info),
7532			      GFP_KERNEL);
7533
7534	if (!conf->disks)
7535		goto abort;
7536
7537	for (i = 0; i < max_disks; i++) {
7538		conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
7539		if (!conf->disks[i].extra_page)
7540			goto abort;
7541	}
7542
7543	ret = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
7544	if (ret)
7545		goto abort;
7546	conf->mddev = mddev;
7547
7548	ret = -ENOMEM;
7549	conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL);
7550	if (!conf->stripe_hashtbl)
7551		goto abort;
7552
7553	/* We init hash_locks[0] separately to that it can be used
7554	 * as the reference lock in the spin_lock_nest_lock() call
7555	 * in lock_all_device_hash_locks_irq in order to convince
7556	 * lockdep that we know what we are doing.
7557	 */
7558	spin_lock_init(conf->hash_locks);
7559	for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
7560		spin_lock_init(conf->hash_locks + i);
7561
7562	for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7563		INIT_LIST_HEAD(conf->inactive_list + i);
7564
7565	for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7566		INIT_LIST_HEAD(conf->temp_inactive_list + i);
7567
7568	atomic_set(&conf->r5c_cached_full_stripes, 0);
7569	INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7570	atomic_set(&conf->r5c_cached_partial_stripes, 0);
7571	INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7572	atomic_set(&conf->r5c_flushing_full_stripes, 0);
7573	atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7574
7575	conf->level = mddev->new_level;
7576	conf->chunk_sectors = mddev->new_chunk_sectors;
7577	ret = raid5_alloc_percpu(conf);
7578	if (ret)
7579		goto abort;
7580
7581	pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7582
7583	ret = -EIO;
7584	rdev_for_each(rdev, mddev) {
7585		raid_disk = rdev->raid_disk;
7586		if (raid_disk >= max_disks
7587		    || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7588			continue;
7589		disk = conf->disks + raid_disk;
7590
7591		if (test_bit(Replacement, &rdev->flags)) {
7592			if (disk->replacement)
7593				goto abort;
7594			RCU_INIT_POINTER(disk->replacement, rdev);
7595		} else {
7596			if (disk->rdev)
7597				goto abort;
7598			RCU_INIT_POINTER(disk->rdev, rdev);
7599		}
7600
7601		if (test_bit(In_sync, &rdev->flags)) {
7602			pr_info("md/raid:%s: device %pg operational as raid disk %d\n",
7603				mdname(mddev), rdev->bdev, raid_disk);
 
 
7604		} else if (rdev->saved_raid_disk != raid_disk)
7605			/* Cannot rely on bitmap to complete recovery */
7606			conf->fullsync = 1;
7607	}
7608
 
7609	conf->level = mddev->new_level;
7610	if (conf->level == 6) {
7611		conf->max_degraded = 2;
7612		if (raid6_call.xor_syndrome)
7613			conf->rmw_level = PARITY_ENABLE_RMW;
7614		else
7615			conf->rmw_level = PARITY_DISABLE_RMW;
7616	} else {
7617		conf->max_degraded = 1;
7618		conf->rmw_level = PARITY_ENABLE_RMW;
7619	}
7620	conf->algorithm = mddev->new_layout;
7621	conf->reshape_progress = mddev->reshape_position;
7622	if (conf->reshape_progress != MaxSector) {
7623		conf->prev_chunk_sectors = mddev->chunk_sectors;
7624		conf->prev_algo = mddev->layout;
7625	} else {
7626		conf->prev_chunk_sectors = conf->chunk_sectors;
7627		conf->prev_algo = conf->algorithm;
7628	}
7629
7630	conf->min_nr_stripes = NR_STRIPES;
7631	if (mddev->reshape_position != MaxSector) {
7632		int stripes = max_t(int,
7633			((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4,
7634			((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4);
7635		conf->min_nr_stripes = max(NR_STRIPES, stripes);
7636		if (conf->min_nr_stripes != NR_STRIPES)
7637			pr_info("md/raid:%s: force stripe size %d for reshape\n",
7638				mdname(mddev), conf->min_nr_stripes);
7639	}
7640	memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7641		 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7642	atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7643	if (grow_stripes(conf, conf->min_nr_stripes)) {
7644		pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7645			mdname(mddev), memory);
7646		ret = -ENOMEM;
7647		goto abort;
7648	} else
7649		pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7650	/*
7651	 * Losing a stripe head costs more than the time to refill it,
7652	 * it reduces the queue depth and so can hurt throughput.
7653	 * So set it rather large, scaled by number of devices.
7654	 */
7655	conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7656	conf->shrinker.scan_objects = raid5_cache_scan;
7657	conf->shrinker.count_objects = raid5_cache_count;
7658	conf->shrinker.batch = 128;
7659	conf->shrinker.flags = 0;
7660	ret = register_shrinker(&conf->shrinker, "md-raid5:%s", mdname(mddev));
7661	if (ret) {
7662		pr_warn("md/raid:%s: couldn't register shrinker.\n",
7663			mdname(mddev));
7664		goto abort;
7665	}
7666
7667	sprintf(pers_name, "raid%d", mddev->new_level);
7668	conf->thread = md_register_thread(raid5d, mddev, pers_name);
7669	if (!conf->thread) {
7670		pr_warn("md/raid:%s: couldn't allocate thread.\n",
7671			mdname(mddev));
7672		ret = -ENOMEM;
7673		goto abort;
7674	}
7675
7676	return conf;
7677
7678 abort:
7679	if (conf)
7680		free_conf(conf);
7681	return ERR_PTR(ret);
 
 
7682}
7683
 
7684static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7685{
7686	switch (algo) {
7687	case ALGORITHM_PARITY_0:
7688		if (raid_disk < max_degraded)
7689			return 1;
7690		break;
7691	case ALGORITHM_PARITY_N:
7692		if (raid_disk >= raid_disks - max_degraded)
7693			return 1;
7694		break;
7695	case ALGORITHM_PARITY_0_6:
7696		if (raid_disk == 0 ||
7697		    raid_disk == raid_disks - 1)
7698			return 1;
7699		break;
7700	case ALGORITHM_LEFT_ASYMMETRIC_6:
7701	case ALGORITHM_RIGHT_ASYMMETRIC_6:
7702	case ALGORITHM_LEFT_SYMMETRIC_6:
7703	case ALGORITHM_RIGHT_SYMMETRIC_6:
7704		if (raid_disk == raid_disks - 1)
7705			return 1;
7706	}
7707	return 0;
7708}
7709
7710static void raid5_set_io_opt(struct r5conf *conf)
7711{
7712	blk_queue_io_opt(conf->mddev->queue, (conf->chunk_sectors << 9) *
7713			 (conf->raid_disks - conf->max_degraded));
7714}
7715
7716static int raid5_run(struct mddev *mddev)
7717{
7718	struct r5conf *conf;
7719	int working_disks = 0;
7720	int dirty_parity_disks = 0;
7721	struct md_rdev *rdev;
7722	struct md_rdev *journal_dev = NULL;
7723	sector_t reshape_offset = 0;
7724	int i, ret = 0;
7725	long long min_offset_diff = 0;
7726	int first = 1;
7727
7728	if (acct_bioset_init(mddev)) {
7729		pr_err("md/raid456:%s: alloc acct bioset failed.\n", mdname(mddev));
7730		return -ENOMEM;
7731	}
7732
7733	if (mddev_init_writes_pending(mddev) < 0) {
7734		ret = -ENOMEM;
7735		goto exit_acct_set;
7736	}
7737
7738	if (mddev->recovery_cp != MaxSector)
7739		pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7740			  mdname(mddev));
 
7741
7742	rdev_for_each(rdev, mddev) {
7743		long long diff;
7744
7745		if (test_bit(Journal, &rdev->flags)) {
7746			journal_dev = rdev;
7747			continue;
7748		}
7749		if (rdev->raid_disk < 0)
7750			continue;
7751		diff = (rdev->new_data_offset - rdev->data_offset);
7752		if (first) {
7753			min_offset_diff = diff;
7754			first = 0;
7755		} else if (mddev->reshape_backwards &&
7756			 diff < min_offset_diff)
7757			min_offset_diff = diff;
7758		else if (!mddev->reshape_backwards &&
7759			 diff > min_offset_diff)
7760			min_offset_diff = diff;
7761	}
7762
7763	if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7764	    (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7765		pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7766			  mdname(mddev));
7767		ret = -EINVAL;
7768		goto exit_acct_set;
7769	}
7770
7771	if (mddev->reshape_position != MaxSector) {
7772		/* Check that we can continue the reshape.
7773		 * Difficulties arise if the stripe we would write to
7774		 * next is at or after the stripe we would read from next.
7775		 * For a reshape that changes the number of devices, this
7776		 * is only possible for a very short time, and mdadm makes
7777		 * sure that time appears to have past before assembling
7778		 * the array.  So we fail if that time hasn't passed.
7779		 * For a reshape that keeps the number of devices the same
7780		 * mdadm must be monitoring the reshape can keeping the
7781		 * critical areas read-only and backed up.  It will start
7782		 * the array in read-only mode, so we check for that.
7783		 */
7784		sector_t here_new, here_old;
7785		int old_disks;
7786		int max_degraded = (mddev->level == 6 ? 2 : 1);
7787		int chunk_sectors;
7788		int new_data_disks;
7789
7790		if (journal_dev) {
7791			pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7792				mdname(mddev));
7793			ret = -EINVAL;
7794			goto exit_acct_set;
7795		}
7796
7797		if (mddev->new_level != mddev->level) {
7798			pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7799				mdname(mddev));
7800			ret = -EINVAL;
7801			goto exit_acct_set;
7802		}
7803		old_disks = mddev->raid_disks - mddev->delta_disks;
7804		/* reshape_position must be on a new-stripe boundary, and one
7805		 * further up in new geometry must map after here in old
7806		 * geometry.
7807		 * If the chunk sizes are different, then as we perform reshape
7808		 * in units of the largest of the two, reshape_position needs
7809		 * be a multiple of the largest chunk size times new data disks.
7810		 */
7811		here_new = mddev->reshape_position;
7812		chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7813		new_data_disks = mddev->raid_disks - max_degraded;
7814		if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7815			pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7816				mdname(mddev));
7817			ret = -EINVAL;
7818			goto exit_acct_set;
7819		}
7820		reshape_offset = here_new * chunk_sectors;
7821		/* here_new is the stripe we will write to */
7822		here_old = mddev->reshape_position;
7823		sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
 
7824		/* here_old is the first stripe that we might need to read
7825		 * from */
7826		if (mddev->delta_disks == 0) {
 
 
 
 
 
 
7827			/* We cannot be sure it is safe to start an in-place
7828			 * reshape.  It is only safe if user-space is monitoring
7829			 * and taking constant backups.
7830			 * mdadm always starts a situation like this in
7831			 * readonly mode so it can take control before
7832			 * allowing any writes.  So just check for that.
7833			 */
7834			if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7835			    abs(min_offset_diff) >= mddev->new_chunk_sectors)
7836				/* not really in-place - so OK */;
7837			else if (mddev->ro == 0) {
7838				pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7839					mdname(mddev));
7840				ret = -EINVAL;
7841				goto exit_acct_set;
 
7842			}
7843		} else if (mddev->reshape_backwards
7844		    ? (here_new * chunk_sectors + min_offset_diff <=
7845		       here_old * chunk_sectors)
7846		    : (here_new * chunk_sectors >=
7847		       here_old * chunk_sectors + (-min_offset_diff))) {
7848			/* Reading from the same stripe as writing to - bad */
7849			pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7850				mdname(mddev));
7851			ret = -EINVAL;
7852			goto exit_acct_set;
7853		}
7854		pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
 
7855		/* OK, we should be able to continue; */
7856	} else {
7857		BUG_ON(mddev->level != mddev->new_level);
7858		BUG_ON(mddev->layout != mddev->new_layout);
7859		BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7860		BUG_ON(mddev->delta_disks != 0);
7861	}
7862
7863	if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7864	    test_bit(MD_HAS_PPL, &mddev->flags)) {
7865		pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7866			mdname(mddev));
7867		clear_bit(MD_HAS_PPL, &mddev->flags);
7868		clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7869	}
7870
7871	if (mddev->private == NULL)
7872		conf = setup_conf(mddev);
7873	else
7874		conf = mddev->private;
7875
7876	if (IS_ERR(conf)) {
7877		ret = PTR_ERR(conf);
7878		goto exit_acct_set;
7879	}
7880
7881	if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7882		if (!journal_dev) {
7883			pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7884				mdname(mddev));
7885			mddev->ro = 1;
7886			set_disk_ro(mddev->gendisk, 1);
7887		} else if (mddev->recovery_cp == MaxSector)
7888			set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7889	}
7890
7891	conf->min_offset_diff = min_offset_diff;
7892	mddev->thread = conf->thread;
7893	conf->thread = NULL;
7894	mddev->private = conf;
7895
7896	for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7897	     i++) {
7898		rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev);
7899		if (!rdev && conf->disks[i].replacement) {
7900			/* The replacement is all we have yet */
7901			rdev = rdev_mdlock_deref(mddev,
7902						 conf->disks[i].replacement);
7903			conf->disks[i].replacement = NULL;
7904			clear_bit(Replacement, &rdev->flags);
7905			rcu_assign_pointer(conf->disks[i].rdev, rdev);
7906		}
7907		if (!rdev)
7908			continue;
7909		if (rcu_access_pointer(conf->disks[i].replacement) &&
7910		    conf->reshape_progress != MaxSector) {
7911			/* replacements and reshape simply do not mix. */
7912			pr_warn("md: cannot handle concurrent replacement and reshape.\n");
 
7913			goto abort;
7914		}
7915		if (test_bit(In_sync, &rdev->flags)) {
7916			working_disks++;
7917			continue;
7918		}
7919		/* This disc is not fully in-sync.  However if it
7920		 * just stored parity (beyond the recovery_offset),
7921		 * when we don't need to be concerned about the
7922		 * array being dirty.
7923		 * When reshape goes 'backwards', we never have
7924		 * partially completed devices, so we only need
7925		 * to worry about reshape going forwards.
7926		 */
7927		/* Hack because v0.91 doesn't store recovery_offset properly. */
7928		if (mddev->major_version == 0 &&
7929		    mddev->minor_version > 90)
7930			rdev->recovery_offset = reshape_offset;
7931
7932		if (rdev->recovery_offset < reshape_offset) {
7933			/* We need to check old and new layout */
7934			if (!only_parity(rdev->raid_disk,
7935					 conf->algorithm,
7936					 conf->raid_disks,
7937					 conf->max_degraded))
7938				continue;
7939		}
7940		if (!only_parity(rdev->raid_disk,
7941				 conf->prev_algo,
7942				 conf->previous_raid_disks,
7943				 conf->max_degraded))
7944			continue;
7945		dirty_parity_disks++;
7946	}
7947
7948	/*
7949	 * 0 for a fully functional array, 1 or 2 for a degraded array.
7950	 */
7951	mddev->degraded = raid5_calc_degraded(conf);
7952
7953	if (has_failed(conf)) {
7954		pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
 
7955			mdname(mddev), mddev->degraded, conf->raid_disks);
7956		goto abort;
7957	}
7958
7959	/* device size must be a multiple of chunk size */
7960	mddev->dev_sectors &= ~((sector_t)mddev->chunk_sectors - 1);
7961	mddev->resync_max_sectors = mddev->dev_sectors;
7962
7963	if (mddev->degraded > dirty_parity_disks &&
7964	    mddev->recovery_cp != MaxSector) {
7965		if (test_bit(MD_HAS_PPL, &mddev->flags))
7966			pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7967				mdname(mddev));
7968		else if (mddev->ok_start_degraded)
7969			pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7970				mdname(mddev));
7971		else {
7972			pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7973				mdname(mddev));
 
7974			goto abort;
7975		}
7976	}
7977
7978	pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7979		mdname(mddev), conf->level,
7980		mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7981		mddev->new_layout);
 
 
 
 
 
 
 
7982
7983	print_raid5_conf(conf);
7984
7985	if (conf->reshape_progress != MaxSector) {
7986		conf->reshape_safe = conf->reshape_progress;
7987		atomic_set(&conf->reshape_stripes, 0);
7988		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7989		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7990		set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7991		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7992		mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7993							"reshape");
7994		if (!mddev->sync_thread)
7995			goto abort;
7996	}
7997
 
7998	/* Ok, everything is just fine now */
7999	if (mddev->to_remove == &raid5_attrs_group)
8000		mddev->to_remove = NULL;
8001	else if (mddev->kobj.sd &&
8002	    sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
8003		pr_warn("raid5: failed to create sysfs attributes for %s\n",
8004			mdname(mddev));
 
8005	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
8006
8007	if (mddev->queue) {
8008		int chunk_size;
 
8009		/* read-ahead size must cover two whole stripes, which
8010		 * is 2 * (datadisks) * chunksize where 'n' is the
8011		 * number of raid devices
8012		 */
8013		int data_disks = conf->previous_raid_disks - conf->max_degraded;
8014		int stripe = data_disks *
8015			((mddev->chunk_sectors << 9) / PAGE_SIZE);
 
 
 
 
 
 
 
8016
8017		chunk_size = mddev->chunk_sectors << 9;
8018		blk_queue_io_min(mddev->queue, chunk_size);
8019		raid5_set_io_opt(conf);
 
8020		mddev->queue->limits.raid_partial_stripes_expensive = 1;
8021		/*
8022		 * We can only discard a whole stripe. It doesn't make sense to
8023		 * discard data disk but write parity disk
8024		 */
8025		stripe = stripe * PAGE_SIZE;
8026		stripe = roundup_pow_of_two(stripe);
 
 
 
 
8027		mddev->queue->limits.discard_granularity = stripe;
 
 
 
 
 
8028
8029		blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
8030
8031		rdev_for_each(rdev, mddev) {
8032			disk_stack_limits(mddev->gendisk, rdev->bdev,
8033					  rdev->data_offset << 9);
8034			disk_stack_limits(mddev->gendisk, rdev->bdev,
8035					  rdev->new_data_offset << 9);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8036		}
8037
8038		/*
8039		 * zeroing is required, otherwise data
8040		 * could be lost. Consider a scenario: discard a stripe
8041		 * (the stripe could be inconsistent if
8042		 * discard_zeroes_data is 0); write one disk of the
8043		 * stripe (the stripe could be inconsistent again
8044		 * depending on which disks are used to calculate
8045		 * parity); the disk is broken; The stripe data of this
8046		 * disk is lost.
8047		 *
8048		 * We only allow DISCARD if the sysadmin has confirmed that
8049		 * only safe devices are in use by setting a module parameter.
8050		 * A better idea might be to turn DISCARD into WRITE_ZEROES
8051		 * requests, as that is required to be safe.
8052		 */
8053		if (!devices_handle_discard_safely ||
8054		    mddev->queue->limits.max_discard_sectors < (stripe >> 9) ||
8055		    mddev->queue->limits.discard_granularity < stripe)
8056			blk_queue_max_discard_sectors(mddev->queue, 0);
8057
8058		/*
8059		 * Requests require having a bitmap for each stripe.
8060		 * Limit the max sectors based on this.
8061		 */
8062		blk_queue_max_hw_sectors(mddev->queue,
8063			RAID5_MAX_REQ_STRIPES << RAID5_STRIPE_SHIFT(conf));
8064
8065		/* No restrictions on the number of segments in the request */
8066		blk_queue_max_segments(mddev->queue, USHRT_MAX);
8067	}
8068
8069	if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
8070		goto abort;
8071
8072	return 0;
8073abort:
8074	md_unregister_thread(&mddev->thread);
8075	print_raid5_conf(conf);
8076	free_conf(conf);
8077	mddev->private = NULL;
8078	pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
8079	ret = -EIO;
8080exit_acct_set:
8081	acct_bioset_exit(mddev);
8082	return ret;
8083}
8084
8085static void raid5_free(struct mddev *mddev, void *priv)
8086{
8087	struct r5conf *conf = priv;
8088
 
 
 
8089	free_conf(conf);
8090	acct_bioset_exit(mddev);
8091	mddev->to_remove = &raid5_attrs_group;
 
8092}
8093
8094static void raid5_status(struct seq_file *seq, struct mddev *mddev)
8095{
8096	struct r5conf *conf = mddev->private;
8097	int i;
8098
8099	seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
8100		conf->chunk_sectors / 2, mddev->layout);
8101	seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
8102	rcu_read_lock();
8103	for (i = 0; i < conf->raid_disks; i++) {
8104		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
8105		seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
8106	}
8107	rcu_read_unlock();
8108	seq_printf (seq, "]");
8109}
8110
8111static void print_raid5_conf (struct r5conf *conf)
8112{
8113	struct md_rdev *rdev;
8114	int i;
 
8115
8116	pr_debug("RAID conf printout:\n");
8117	if (!conf) {
8118		pr_debug("(conf==NULL)\n");
8119		return;
8120	}
8121	pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
8122	       conf->raid_disks,
8123	       conf->raid_disks - conf->mddev->degraded);
8124
8125	rcu_read_lock();
8126	for (i = 0; i < conf->raid_disks; i++) {
8127		rdev = rcu_dereference(conf->disks[i].rdev);
8128		if (rdev)
8129			pr_debug(" disk %d, o:%d, dev:%pg\n",
8130			       i, !test_bit(Faulty, &rdev->flags),
8131			       rdev->bdev);
 
8132	}
8133	rcu_read_unlock();
8134}
8135
8136static int raid5_spare_active(struct mddev *mddev)
8137{
8138	int i;
8139	struct r5conf *conf = mddev->private;
8140	struct md_rdev *rdev, *replacement;
8141	int count = 0;
8142	unsigned long flags;
8143
8144	for (i = 0; i < conf->raid_disks; i++) {
8145		rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev);
8146		replacement = rdev_mdlock_deref(mddev,
8147						conf->disks[i].replacement);
8148		if (replacement
8149		    && replacement->recovery_offset == MaxSector
8150		    && !test_bit(Faulty, &replacement->flags)
8151		    && !test_and_set_bit(In_sync, &replacement->flags)) {
8152			/* Replacement has just become active. */
8153			if (!rdev
8154			    || !test_and_clear_bit(In_sync, &rdev->flags))
8155				count++;
8156			if (rdev) {
8157				/* Replaced device not technically faulty,
8158				 * but we need to be sure it gets removed
8159				 * and never re-added.
8160				 */
8161				set_bit(Faulty, &rdev->flags);
8162				sysfs_notify_dirent_safe(
8163					rdev->sysfs_state);
8164			}
8165			sysfs_notify_dirent_safe(replacement->sysfs_state);
8166		} else if (rdev
8167		    && rdev->recovery_offset == MaxSector
8168		    && !test_bit(Faulty, &rdev->flags)
8169		    && !test_and_set_bit(In_sync, &rdev->flags)) {
8170			count++;
8171			sysfs_notify_dirent_safe(rdev->sysfs_state);
8172		}
8173	}
8174	spin_lock_irqsave(&conf->device_lock, flags);
8175	mddev->degraded = raid5_calc_degraded(conf);
8176	spin_unlock_irqrestore(&conf->device_lock, flags);
8177	print_raid5_conf(conf);
8178	return count;
8179}
8180
8181static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
8182{
8183	struct r5conf *conf = mddev->private;
8184	int err = 0;
8185	int number = rdev->raid_disk;
8186	struct md_rdev __rcu **rdevp;
8187	struct disk_info *p;
8188	struct md_rdev *tmp;
8189
8190	print_raid5_conf(conf);
8191	if (test_bit(Journal, &rdev->flags) && conf->log) {
8192		/*
8193		 * we can't wait pending write here, as this is called in
8194		 * raid5d, wait will deadlock.
8195		 * neilb: there is no locking about new writes here,
8196		 * so this cannot be safe.
8197		 */
8198		if (atomic_read(&conf->active_stripes) ||
8199		    atomic_read(&conf->r5c_cached_full_stripes) ||
8200		    atomic_read(&conf->r5c_cached_partial_stripes)) {
8201			return -EBUSY;
8202		}
8203		log_exit(conf);
8204		return 0;
8205	}
8206	if (unlikely(number >= conf->pool_size))
8207		return 0;
8208	p = conf->disks + number;
8209	if (rdev == rcu_access_pointer(p->rdev))
8210		rdevp = &p->rdev;
8211	else if (rdev == rcu_access_pointer(p->replacement))
8212		rdevp = &p->replacement;
8213	else
8214		return 0;
8215
8216	if (number >= conf->raid_disks &&
8217	    conf->reshape_progress == MaxSector)
8218		clear_bit(In_sync, &rdev->flags);
8219
8220	if (test_bit(In_sync, &rdev->flags) ||
8221	    atomic_read(&rdev->nr_pending)) {
8222		err = -EBUSY;
8223		goto abort;
8224	}
8225	/* Only remove non-faulty devices if recovery
8226	 * isn't possible.
8227	 */
8228	if (!test_bit(Faulty, &rdev->flags) &&
8229	    mddev->recovery_disabled != conf->recovery_disabled &&
8230	    !has_failed(conf) &&
8231	    (!rcu_access_pointer(p->replacement) ||
8232	     rcu_access_pointer(p->replacement) == rdev) &&
8233	    number < conf->raid_disks) {
8234		err = -EBUSY;
8235		goto abort;
8236	}
8237	*rdevp = NULL;
8238	if (!test_bit(RemoveSynchronized, &rdev->flags)) {
8239		lockdep_assert_held(&mddev->reconfig_mutex);
8240		synchronize_rcu();
8241		if (atomic_read(&rdev->nr_pending)) {
8242			/* lost the race, try later */
8243			err = -EBUSY;
8244			rcu_assign_pointer(*rdevp, rdev);
8245		}
8246	}
8247	if (!err) {
8248		err = log_modify(conf, rdev, false);
8249		if (err)
8250			goto abort;
8251	}
8252
8253	tmp = rcu_access_pointer(p->replacement);
8254	if (tmp) {
8255		/* We must have just cleared 'rdev' */
8256		rcu_assign_pointer(p->rdev, tmp);
8257		clear_bit(Replacement, &tmp->flags);
8258		smp_mb(); /* Make sure other CPUs may see both as identical
8259			   * but will never see neither - if they are careful
8260			   */
8261		rcu_assign_pointer(p->replacement, NULL);
8262
8263		if (!err)
8264			err = log_modify(conf, tmp, true);
8265	}
8266
8267	clear_bit(WantReplacement, &rdev->flags);
8268abort:
8269
8270	print_raid5_conf(conf);
8271	return err;
8272}
8273
8274static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
8275{
8276	struct r5conf *conf = mddev->private;
8277	int ret, err = -EEXIST;
8278	int disk;
8279	struct disk_info *p;
8280	struct md_rdev *tmp;
8281	int first = 0;
8282	int last = conf->raid_disks - 1;
8283
8284	if (test_bit(Journal, &rdev->flags)) {
8285		if (conf->log)
8286			return -EBUSY;
8287
8288		rdev->raid_disk = 0;
8289		/*
8290		 * The array is in readonly mode if journal is missing, so no
8291		 * write requests running. We should be safe
8292		 */
8293		ret = log_init(conf, rdev, false);
8294		if (ret)
8295			return ret;
8296
8297		ret = r5l_start(conf->log);
8298		if (ret)
8299			return ret;
8300
8301		return 0;
8302	}
8303	if (mddev->recovery_disabled == conf->recovery_disabled)
8304		return -EBUSY;
8305
8306	if (rdev->saved_raid_disk < 0 && has_failed(conf))
8307		/* no point adding a device */
8308		return -EINVAL;
8309
8310	if (rdev->raid_disk >= 0)
8311		first = last = rdev->raid_disk;
8312
8313	/*
8314	 * find the disk ... but prefer rdev->saved_raid_disk
8315	 * if possible.
8316	 */
8317	if (rdev->saved_raid_disk >= first &&
8318	    rdev->saved_raid_disk <= last &&
8319	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
8320		first = rdev->saved_raid_disk;
8321
8322	for (disk = first; disk <= last; disk++) {
8323		p = conf->disks + disk;
8324		if (p->rdev == NULL) {
8325			clear_bit(In_sync, &rdev->flags);
8326			rdev->raid_disk = disk;
 
8327			if (rdev->saved_raid_disk != disk)
8328				conf->fullsync = 1;
8329			rcu_assign_pointer(p->rdev, rdev);
8330
8331			err = log_modify(conf, rdev, true);
8332
8333			goto out;
8334		}
8335	}
8336	for (disk = first; disk <= last; disk++) {
8337		p = conf->disks + disk;
8338		tmp = rdev_mdlock_deref(mddev, p->rdev);
8339		if (test_bit(WantReplacement, &tmp->flags) &&
8340		    p->replacement == NULL) {
8341			clear_bit(In_sync, &rdev->flags);
8342			set_bit(Replacement, &rdev->flags);
8343			rdev->raid_disk = disk;
8344			err = 0;
8345			conf->fullsync = 1;
8346			rcu_assign_pointer(p->replacement, rdev);
8347			break;
8348		}
8349	}
8350out:
8351	print_raid5_conf(conf);
8352	return err;
8353}
8354
8355static int raid5_resize(struct mddev *mddev, sector_t sectors)
8356{
8357	/* no resync is happening, and there is enough space
8358	 * on all devices, so we can resize.
8359	 * We need to make sure resync covers any new space.
8360	 * If the array is shrinking we should possibly wait until
8361	 * any io in the removed space completes, but it hardly seems
8362	 * worth it.
8363	 */
8364	sector_t newsize;
8365	struct r5conf *conf = mddev->private;
8366
8367	if (raid5_has_log(conf) || raid5_has_ppl(conf))
8368		return -EINVAL;
8369	sectors &= ~((sector_t)conf->chunk_sectors - 1);
8370	newsize = raid5_size(mddev, sectors, mddev->raid_disks);
8371	if (mddev->external_size &&
8372	    mddev->array_sectors > newsize)
8373		return -EINVAL;
8374	if (mddev->bitmap) {
8375		int ret = md_bitmap_resize(mddev->bitmap, sectors, 0, 0);
8376		if (ret)
8377			return ret;
8378	}
8379	md_set_array_sectors(mddev, newsize);
 
 
8380	if (sectors > mddev->dev_sectors &&
8381	    mddev->recovery_cp > mddev->dev_sectors) {
8382		mddev->recovery_cp = mddev->dev_sectors;
8383		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8384	}
8385	mddev->dev_sectors = sectors;
8386	mddev->resync_max_sectors = sectors;
8387	return 0;
8388}
8389
8390static int check_stripe_cache(struct mddev *mddev)
8391{
8392	/* Can only proceed if there are plenty of stripe_heads.
8393	 * We need a minimum of one full stripe,, and for sensible progress
8394	 * it is best to have about 4 times that.
8395	 * If we require 4 times, then the default 256 4K stripe_heads will
8396	 * allow for chunk sizes up to 256K, which is probably OK.
8397	 * If the chunk size is greater, user-space should request more
8398	 * stripe_heads first.
8399	 */
8400	struct r5conf *conf = mddev->private;
8401	if (((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8402	    > conf->min_nr_stripes ||
8403	    ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8404	    > conf->min_nr_stripes) {
8405		pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
8406			mdname(mddev),
8407			((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
8408			 / RAID5_STRIPE_SIZE(conf))*4);
8409		return 0;
8410	}
8411	return 1;
8412}
8413
8414static int check_reshape(struct mddev *mddev)
8415{
8416	struct r5conf *conf = mddev->private;
8417
8418	if (raid5_has_log(conf) || raid5_has_ppl(conf))
8419		return -EINVAL;
8420	if (mddev->delta_disks == 0 &&
8421	    mddev->new_layout == mddev->layout &&
8422	    mddev->new_chunk_sectors == mddev->chunk_sectors)
8423		return 0; /* nothing to do */
8424	if (has_failed(conf))
8425		return -EINVAL;
8426	if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
8427		/* We might be able to shrink, but the devices must
8428		 * be made bigger first.
8429		 * For raid6, 4 is the minimum size.
8430		 * Otherwise 2 is the minimum
8431		 */
8432		int min = 2;
8433		if (mddev->level == 6)
8434			min = 4;
8435		if (mddev->raid_disks + mddev->delta_disks < min)
8436			return -EINVAL;
8437	}
8438
8439	if (!check_stripe_cache(mddev))
8440		return -ENOSPC;
8441
8442	if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
8443	    mddev->delta_disks > 0)
8444		if (resize_chunks(conf,
8445				  conf->previous_raid_disks
8446				  + max(0, mddev->delta_disks),
8447				  max(mddev->new_chunk_sectors,
8448				      mddev->chunk_sectors)
8449			    ) < 0)
8450			return -ENOMEM;
8451
8452	if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
8453		return 0; /* never bother to shrink */
8454	return resize_stripes(conf, (conf->previous_raid_disks
8455				     + mddev->delta_disks));
8456}
8457
8458static int raid5_start_reshape(struct mddev *mddev)
8459{
8460	struct r5conf *conf = mddev->private;
8461	struct md_rdev *rdev;
8462	int spares = 0;
8463	unsigned long flags;
8464
8465	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
8466		return -EBUSY;
8467
8468	if (!check_stripe_cache(mddev))
8469		return -ENOSPC;
8470
8471	if (has_failed(conf))
8472		return -EINVAL;
8473
8474	rdev_for_each(rdev, mddev) {
8475		if (!test_bit(In_sync, &rdev->flags)
8476		    && !test_bit(Faulty, &rdev->flags))
8477			spares++;
8478	}
8479
8480	if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
8481		/* Not enough devices even to make a degraded array
8482		 * of that size
8483		 */
8484		return -EINVAL;
8485
8486	/* Refuse to reduce size of the array.  Any reductions in
8487	 * array size must be through explicit setting of array_size
8488	 * attribute.
8489	 */
8490	if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
8491	    < mddev->array_sectors) {
8492		pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
8493			mdname(mddev));
8494		return -EINVAL;
8495	}
8496
8497	atomic_set(&conf->reshape_stripes, 0);
8498	spin_lock_irq(&conf->device_lock);
8499	write_seqcount_begin(&conf->gen_lock);
8500	conf->previous_raid_disks = conf->raid_disks;
8501	conf->raid_disks += mddev->delta_disks;
8502	conf->prev_chunk_sectors = conf->chunk_sectors;
8503	conf->chunk_sectors = mddev->new_chunk_sectors;
8504	conf->prev_algo = conf->algorithm;
8505	conf->algorithm = mddev->new_layout;
8506	conf->generation++;
8507	/* Code that selects data_offset needs to see the generation update
8508	 * if reshape_progress has been set - so a memory barrier needed.
8509	 */
8510	smp_mb();
8511	if (mddev->reshape_backwards)
8512		conf->reshape_progress = raid5_size(mddev, 0, 0);
8513	else
8514		conf->reshape_progress = 0;
8515	conf->reshape_safe = conf->reshape_progress;
8516	write_seqcount_end(&conf->gen_lock);
8517	spin_unlock_irq(&conf->device_lock);
8518
8519	/* Now make sure any requests that proceeded on the assumption
8520	 * the reshape wasn't running - like Discard or Read - have
8521	 * completed.
8522	 */
8523	mddev_suspend(mddev);
8524	mddev_resume(mddev);
8525
8526	/* Add some new drives, as many as will fit.
8527	 * We know there are enough to make the newly sized array work.
8528	 * Don't add devices if we are reducing the number of
8529	 * devices in the array.  This is because it is not possible
8530	 * to correctly record the "partially reconstructed" state of
8531	 * such devices during the reshape and confusion could result.
8532	 */
8533	if (mddev->delta_disks >= 0) {
8534		rdev_for_each(rdev, mddev)
8535			if (rdev->raid_disk < 0 &&
8536			    !test_bit(Faulty, &rdev->flags)) {
8537				if (raid5_add_disk(mddev, rdev) == 0) {
8538					if (rdev->raid_disk
8539					    >= conf->previous_raid_disks)
8540						set_bit(In_sync, &rdev->flags);
8541					else
8542						rdev->recovery_offset = 0;
8543
8544					/* Failure here is OK */
8545					sysfs_link_rdev(mddev, rdev);
8546				}
8547			} else if (rdev->raid_disk >= conf->previous_raid_disks
8548				   && !test_bit(Faulty, &rdev->flags)) {
8549				/* This is a spare that was manually added */
8550				set_bit(In_sync, &rdev->flags);
8551			}
8552
8553		/* When a reshape changes the number of devices,
8554		 * ->degraded is measured against the larger of the
8555		 * pre and post number of devices.
8556		 */
8557		spin_lock_irqsave(&conf->device_lock, flags);
8558		mddev->degraded = raid5_calc_degraded(conf);
8559		spin_unlock_irqrestore(&conf->device_lock, flags);
8560	}
8561	mddev->raid_disks = conf->raid_disks;
8562	mddev->reshape_position = conf->reshape_progress;
8563	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8564
8565	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
8566	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
8567	clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
8568	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
8569	set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
8570	mddev->sync_thread = md_register_thread(md_do_sync, mddev,
8571						"reshape");
8572	if (!mddev->sync_thread) {
8573		mddev->recovery = 0;
8574		spin_lock_irq(&conf->device_lock);
8575		write_seqcount_begin(&conf->gen_lock);
8576		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
8577		mddev->new_chunk_sectors =
8578			conf->chunk_sectors = conf->prev_chunk_sectors;
8579		mddev->new_layout = conf->algorithm = conf->prev_algo;
8580		rdev_for_each(rdev, mddev)
8581			rdev->new_data_offset = rdev->data_offset;
8582		smp_wmb();
8583		conf->generation --;
8584		conf->reshape_progress = MaxSector;
8585		mddev->reshape_position = MaxSector;
8586		write_seqcount_end(&conf->gen_lock);
8587		spin_unlock_irq(&conf->device_lock);
8588		return -EAGAIN;
8589	}
8590	conf->reshape_checkpoint = jiffies;
8591	md_wakeup_thread(mddev->sync_thread);
8592	md_new_event();
8593	return 0;
8594}
8595
8596/* This is called from the reshape thread and should make any
8597 * changes needed in 'conf'
8598 */
8599static void end_reshape(struct r5conf *conf)
8600{
8601
8602	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
8603		struct md_rdev *rdev;
8604
8605		spin_lock_irq(&conf->device_lock);
8606		conf->previous_raid_disks = conf->raid_disks;
8607		md_finish_reshape(conf->mddev);
 
8608		smp_wmb();
8609		conf->reshape_progress = MaxSector;
8610		conf->mddev->reshape_position = MaxSector;
8611		rdev_for_each(rdev, conf->mddev)
8612			if (rdev->raid_disk >= 0 &&
8613			    !test_bit(Journal, &rdev->flags) &&
8614			    !test_bit(In_sync, &rdev->flags))
8615				rdev->recovery_offset = MaxSector;
8616		spin_unlock_irq(&conf->device_lock);
8617		wake_up(&conf->wait_for_overlap);
8618
8619		if (conf->mddev->queue)
8620			raid5_set_io_opt(conf);
 
 
 
 
 
 
 
 
8621	}
8622}
8623
8624/* This is called from the raid5d thread with mddev_lock held.
8625 * It makes config changes to the device.
8626 */
8627static void raid5_finish_reshape(struct mddev *mddev)
8628{
8629	struct r5conf *conf = mddev->private;
8630	struct md_rdev *rdev;
8631
8632	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8633
8634		if (mddev->delta_disks <= 0) {
 
 
 
 
8635			int d;
8636			spin_lock_irq(&conf->device_lock);
8637			mddev->degraded = raid5_calc_degraded(conf);
8638			spin_unlock_irq(&conf->device_lock);
8639			for (d = conf->raid_disks ;
8640			     d < conf->raid_disks - mddev->delta_disks;
8641			     d++) {
8642				rdev = rdev_mdlock_deref(mddev,
8643							 conf->disks[d].rdev);
8644				if (rdev)
8645					clear_bit(In_sync, &rdev->flags);
8646				rdev = rdev_mdlock_deref(mddev,
8647						conf->disks[d].replacement);
8648				if (rdev)
8649					clear_bit(In_sync, &rdev->flags);
8650			}
8651		}
8652		mddev->layout = conf->algorithm;
8653		mddev->chunk_sectors = conf->chunk_sectors;
8654		mddev->reshape_position = MaxSector;
8655		mddev->delta_disks = 0;
8656		mddev->reshape_backwards = 0;
8657	}
8658}
8659
8660static void raid5_quiesce(struct mddev *mddev, int quiesce)
8661{
8662	struct r5conf *conf = mddev->private;
8663
8664	if (quiesce) {
8665		/* stop all writes */
 
 
 
 
8666		lock_all_device_hash_locks_irq(conf);
8667		/* '2' tells resync/reshape to pause so that all
8668		 * active stripes can drain
8669		 */
8670		r5c_flush_cache(conf, INT_MAX);
8671		/* need a memory barrier to make sure read_one_chunk() sees
8672		 * quiesce started and reverts to slow (locked) path.
8673		 */
8674		smp_store_release(&conf->quiesce, 2);
8675		wait_event_cmd(conf->wait_for_quiescent,
8676				    atomic_read(&conf->active_stripes) == 0 &&
8677				    atomic_read(&conf->active_aligned_reads) == 0,
8678				    unlock_all_device_hash_locks_irq(conf),
8679				    lock_all_device_hash_locks_irq(conf));
8680		conf->quiesce = 1;
8681		unlock_all_device_hash_locks_irq(conf);
8682		/* allow reshape to continue */
8683		wake_up(&conf->wait_for_overlap);
8684	} else {
8685		/* re-enable writes */
 
8686		lock_all_device_hash_locks_irq(conf);
8687		conf->quiesce = 0;
8688		wake_up(&conf->wait_for_quiescent);
8689		wake_up(&conf->wait_for_overlap);
8690		unlock_all_device_hash_locks_irq(conf);
 
8691	}
8692	log_quiesce(conf, quiesce);
8693}
8694
 
8695static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8696{
8697	struct r0conf *raid0_conf = mddev->private;
8698	sector_t sectors;
8699
8700	/* for raid0 takeover only one zone is supported */
8701	if (raid0_conf->nr_strip_zones > 1) {
8702		pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8703			mdname(mddev));
8704		return ERR_PTR(-EINVAL);
8705	}
8706
8707	sectors = raid0_conf->strip_zone[0].zone_end;
8708	sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8709	mddev->dev_sectors = sectors;
8710	mddev->new_level = level;
8711	mddev->new_layout = ALGORITHM_PARITY_N;
8712	mddev->new_chunk_sectors = mddev->chunk_sectors;
8713	mddev->raid_disks += 1;
8714	mddev->delta_disks = 1;
8715	/* make sure it will be not marked as dirty */
8716	mddev->recovery_cp = MaxSector;
8717
8718	return setup_conf(mddev);
8719}
8720
 
8721static void *raid5_takeover_raid1(struct mddev *mddev)
8722{
8723	int chunksect;
8724	void *ret;
8725
8726	if (mddev->raid_disks != 2 ||
8727	    mddev->degraded > 1)
8728		return ERR_PTR(-EINVAL);
8729
8730	/* Should check if there are write-behind devices? */
8731
8732	chunksect = 64*2; /* 64K by default */
8733
8734	/* The array must be an exact multiple of chunksize */
8735	while (chunksect && (mddev->array_sectors & (chunksect-1)))
8736		chunksect >>= 1;
8737
8738	if ((chunksect<<9) < RAID5_STRIPE_SIZE((struct r5conf *)mddev->private))
8739		/* array size does not allow a suitable chunk size */
8740		return ERR_PTR(-EINVAL);
8741
8742	mddev->new_level = 5;
8743	mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8744	mddev->new_chunk_sectors = chunksect;
8745
8746	ret = setup_conf(mddev);
8747	if (!IS_ERR(ret))
8748		mddev_clear_unsupported_flags(mddev,
8749			UNSUPPORTED_MDDEV_FLAGS);
8750	return ret;
8751}
8752
8753static void *raid5_takeover_raid6(struct mddev *mddev)
8754{
8755	int new_layout;
8756
8757	switch (mddev->layout) {
8758	case ALGORITHM_LEFT_ASYMMETRIC_6:
8759		new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8760		break;
8761	case ALGORITHM_RIGHT_ASYMMETRIC_6:
8762		new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8763		break;
8764	case ALGORITHM_LEFT_SYMMETRIC_6:
8765		new_layout = ALGORITHM_LEFT_SYMMETRIC;
8766		break;
8767	case ALGORITHM_RIGHT_SYMMETRIC_6:
8768		new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8769		break;
8770	case ALGORITHM_PARITY_0_6:
8771		new_layout = ALGORITHM_PARITY_0;
8772		break;
8773	case ALGORITHM_PARITY_N:
8774		new_layout = ALGORITHM_PARITY_N;
8775		break;
8776	default:
8777		return ERR_PTR(-EINVAL);
8778	}
8779	mddev->new_level = 5;
8780	mddev->new_layout = new_layout;
8781	mddev->delta_disks = -1;
8782	mddev->raid_disks -= 1;
8783	return setup_conf(mddev);
8784}
8785
 
8786static int raid5_check_reshape(struct mddev *mddev)
8787{
8788	/* For a 2-drive array, the layout and chunk size can be changed
8789	 * immediately as not restriping is needed.
8790	 * For larger arrays we record the new value - after validation
8791	 * to be used by a reshape pass.
8792	 */
8793	struct r5conf *conf = mddev->private;
8794	int new_chunk = mddev->new_chunk_sectors;
8795
8796	if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8797		return -EINVAL;
8798	if (new_chunk > 0) {
8799		if (!is_power_of_2(new_chunk))
8800			return -EINVAL;
8801		if (new_chunk < (PAGE_SIZE>>9))
8802			return -EINVAL;
8803		if (mddev->array_sectors & (new_chunk-1))
8804			/* not factor of array size */
8805			return -EINVAL;
8806	}
8807
8808	/* They look valid */
8809
8810	if (mddev->raid_disks == 2) {
8811		/* can make the change immediately */
8812		if (mddev->new_layout >= 0) {
8813			conf->algorithm = mddev->new_layout;
8814			mddev->layout = mddev->new_layout;
8815		}
8816		if (new_chunk > 0) {
8817			conf->chunk_sectors = new_chunk ;
8818			mddev->chunk_sectors = new_chunk;
8819		}
8820		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8821		md_wakeup_thread(mddev->thread);
8822	}
8823	return check_reshape(mddev);
8824}
8825
8826static int raid6_check_reshape(struct mddev *mddev)
8827{
8828	int new_chunk = mddev->new_chunk_sectors;
8829
8830	if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8831		return -EINVAL;
8832	if (new_chunk > 0) {
8833		if (!is_power_of_2(new_chunk))
8834			return -EINVAL;
8835		if (new_chunk < (PAGE_SIZE >> 9))
8836			return -EINVAL;
8837		if (mddev->array_sectors & (new_chunk-1))
8838			/* not factor of array size */
8839			return -EINVAL;
8840	}
8841
8842	/* They look valid */
8843	return check_reshape(mddev);
8844}
8845
8846static void *raid5_takeover(struct mddev *mddev)
8847{
8848	/* raid5 can take over:
8849	 *  raid0 - if there is only one strip zone - make it a raid4 layout
8850	 *  raid1 - if there are two drives.  We need to know the chunk size
8851	 *  raid4 - trivial - just use a raid4 layout.
8852	 *  raid6 - Providing it is a *_6 layout
8853	 */
8854	if (mddev->level == 0)
8855		return raid45_takeover_raid0(mddev, 5);
8856	if (mddev->level == 1)
8857		return raid5_takeover_raid1(mddev);
8858	if (mddev->level == 4) {
8859		mddev->new_layout = ALGORITHM_PARITY_N;
8860		mddev->new_level = 5;
8861		return setup_conf(mddev);
8862	}
8863	if (mddev->level == 6)
8864		return raid5_takeover_raid6(mddev);
8865
8866	return ERR_PTR(-EINVAL);
8867}
8868
8869static void *raid4_takeover(struct mddev *mddev)
8870{
8871	/* raid4 can take over:
8872	 *  raid0 - if there is only one strip zone
8873	 *  raid5 - if layout is right
8874	 */
8875	if (mddev->level == 0)
8876		return raid45_takeover_raid0(mddev, 4);
8877	if (mddev->level == 5 &&
8878	    mddev->layout == ALGORITHM_PARITY_N) {
8879		mddev->new_layout = 0;
8880		mddev->new_level = 4;
8881		return setup_conf(mddev);
8882	}
8883	return ERR_PTR(-EINVAL);
8884}
8885
8886static struct md_personality raid5_personality;
8887
8888static void *raid6_takeover(struct mddev *mddev)
8889{
8890	/* Currently can only take over a raid5.  We map the
8891	 * personality to an equivalent raid6 personality
8892	 * with the Q block at the end.
8893	 */
8894	int new_layout;
8895
8896	if (mddev->pers != &raid5_personality)
8897		return ERR_PTR(-EINVAL);
8898	if (mddev->degraded > 1)
8899		return ERR_PTR(-EINVAL);
8900	if (mddev->raid_disks > 253)
8901		return ERR_PTR(-EINVAL);
8902	if (mddev->raid_disks < 3)
8903		return ERR_PTR(-EINVAL);
8904
8905	switch (mddev->layout) {
8906	case ALGORITHM_LEFT_ASYMMETRIC:
8907		new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8908		break;
8909	case ALGORITHM_RIGHT_ASYMMETRIC:
8910		new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8911		break;
8912	case ALGORITHM_LEFT_SYMMETRIC:
8913		new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8914		break;
8915	case ALGORITHM_RIGHT_SYMMETRIC:
8916		new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8917		break;
8918	case ALGORITHM_PARITY_0:
8919		new_layout = ALGORITHM_PARITY_0_6;
8920		break;
8921	case ALGORITHM_PARITY_N:
8922		new_layout = ALGORITHM_PARITY_N;
8923		break;
8924	default:
8925		return ERR_PTR(-EINVAL);
8926	}
8927	mddev->new_level = 6;
8928	mddev->new_layout = new_layout;
8929	mddev->delta_disks = 1;
8930	mddev->raid_disks += 1;
8931	return setup_conf(mddev);
8932}
8933
8934static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8935{
8936	struct r5conf *conf;
8937	int err;
8938
8939	err = mddev_lock(mddev);
8940	if (err)
8941		return err;
8942	conf = mddev->private;
8943	if (!conf) {
8944		mddev_unlock(mddev);
8945		return -ENODEV;
8946	}
8947
8948	if (strncmp(buf, "ppl", 3) == 0) {
8949		/* ppl only works with RAID 5 */
8950		if (!raid5_has_ppl(conf) && conf->level == 5) {
8951			err = log_init(conf, NULL, true);
8952			if (!err) {
8953				err = resize_stripes(conf, conf->pool_size);
8954				if (err) {
8955					mddev_suspend(mddev);
8956					log_exit(conf);
8957					mddev_resume(mddev);
8958				}
8959			}
8960		} else
8961			err = -EINVAL;
8962	} else if (strncmp(buf, "resync", 6) == 0) {
8963		if (raid5_has_ppl(conf)) {
8964			mddev_suspend(mddev);
8965			log_exit(conf);
8966			mddev_resume(mddev);
8967			err = resize_stripes(conf, conf->pool_size);
8968		} else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8969			   r5l_log_disk_error(conf)) {
8970			bool journal_dev_exists = false;
8971			struct md_rdev *rdev;
8972
8973			rdev_for_each(rdev, mddev)
8974				if (test_bit(Journal, &rdev->flags)) {
8975					journal_dev_exists = true;
8976					break;
8977				}
8978
8979			if (!journal_dev_exists) {
8980				mddev_suspend(mddev);
8981				clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8982				mddev_resume(mddev);
8983			} else  /* need remove journal device first */
8984				err = -EBUSY;
8985		} else
8986			err = -EINVAL;
8987	} else {
8988		err = -EINVAL;
8989	}
8990
8991	if (!err)
8992		md_update_sb(mddev, 1);
8993
8994	mddev_unlock(mddev);
8995
8996	return err;
8997}
8998
8999static int raid5_start(struct mddev *mddev)
9000{
9001	struct r5conf *conf = mddev->private;
9002
9003	return r5l_start(conf->log);
9004}
9005
9006static struct md_personality raid6_personality =
9007{
9008	.name		= "raid6",
9009	.level		= 6,
9010	.owner		= THIS_MODULE,
9011	.make_request	= raid5_make_request,
9012	.run		= raid5_run,
9013	.start		= raid5_start,
9014	.free		= raid5_free,
9015	.status		= raid5_status,
9016	.error_handler	= raid5_error,
9017	.hot_add_disk	= raid5_add_disk,
9018	.hot_remove_disk= raid5_remove_disk,
9019	.spare_active	= raid5_spare_active,
9020	.sync_request	= raid5_sync_request,
9021	.resize		= raid5_resize,
9022	.size		= raid5_size,
9023	.check_reshape	= raid6_check_reshape,
9024	.start_reshape  = raid5_start_reshape,
9025	.finish_reshape = raid5_finish_reshape,
9026	.quiesce	= raid5_quiesce,
9027	.takeover	= raid6_takeover,
9028	.change_consistency_policy = raid5_change_consistency_policy,
9029};
9030static struct md_personality raid5_personality =
9031{
9032	.name		= "raid5",
9033	.level		= 5,
9034	.owner		= THIS_MODULE,
9035	.make_request	= raid5_make_request,
9036	.run		= raid5_run,
9037	.start		= raid5_start,
9038	.free		= raid5_free,
9039	.status		= raid5_status,
9040	.error_handler	= raid5_error,
9041	.hot_add_disk	= raid5_add_disk,
9042	.hot_remove_disk= raid5_remove_disk,
9043	.spare_active	= raid5_spare_active,
9044	.sync_request	= raid5_sync_request,
9045	.resize		= raid5_resize,
9046	.size		= raid5_size,
9047	.check_reshape	= raid5_check_reshape,
9048	.start_reshape  = raid5_start_reshape,
9049	.finish_reshape = raid5_finish_reshape,
9050	.quiesce	= raid5_quiesce,
9051	.takeover	= raid5_takeover,
9052	.change_consistency_policy = raid5_change_consistency_policy,
9053};
9054
9055static struct md_personality raid4_personality =
9056{
9057	.name		= "raid4",
9058	.level		= 4,
9059	.owner		= THIS_MODULE,
9060	.make_request	= raid5_make_request,
9061	.run		= raid5_run,
9062	.start		= raid5_start,
9063	.free		= raid5_free,
9064	.status		= raid5_status,
9065	.error_handler	= raid5_error,
9066	.hot_add_disk	= raid5_add_disk,
9067	.hot_remove_disk= raid5_remove_disk,
9068	.spare_active	= raid5_spare_active,
9069	.sync_request	= raid5_sync_request,
9070	.resize		= raid5_resize,
9071	.size		= raid5_size,
9072	.check_reshape	= raid5_check_reshape,
9073	.start_reshape  = raid5_start_reshape,
9074	.finish_reshape = raid5_finish_reshape,
9075	.quiesce	= raid5_quiesce,
9076	.takeover	= raid4_takeover,
9077	.change_consistency_policy = raid5_change_consistency_policy,
9078};
9079
9080static int __init raid5_init(void)
9081{
9082	int ret;
9083
9084	raid5_wq = alloc_workqueue("raid5wq",
9085		WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
9086	if (!raid5_wq)
9087		return -ENOMEM;
9088
9089	ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
9090				      "md/raid5:prepare",
9091				      raid456_cpu_up_prepare,
9092				      raid456_cpu_dead);
9093	if (ret) {
9094		destroy_workqueue(raid5_wq);
9095		return ret;
9096	}
9097	register_md_personality(&raid6_personality);
9098	register_md_personality(&raid5_personality);
9099	register_md_personality(&raid4_personality);
9100	return 0;
9101}
9102
9103static void raid5_exit(void)
9104{
9105	unregister_md_personality(&raid6_personality);
9106	unregister_md_personality(&raid5_personality);
9107	unregister_md_personality(&raid4_personality);
9108	cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
9109	destroy_workqueue(raid5_wq);
9110}
9111
9112module_init(raid5_init);
9113module_exit(raid5_exit);
9114MODULE_LICENSE("GPL");
9115MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
9116MODULE_ALIAS("md-personality-4"); /* RAID5 */
9117MODULE_ALIAS("md-raid5");
9118MODULE_ALIAS("md-raid4");
9119MODULE_ALIAS("md-level-5");
9120MODULE_ALIAS("md-level-4");
9121MODULE_ALIAS("md-personality-8"); /* RAID6 */
9122MODULE_ALIAS("md-raid6");
9123MODULE_ALIAS("md-level-6");
9124
9125/* This used to be two separate modules, they were: */
9126MODULE_ALIAS("raid5");
9127MODULE_ALIAS("raid6");