raid5.c 138.4 KB
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/*
 * raid5.c : Multiple Devices driver for Linux
 *	   Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
 *	   Copyright (C) 1999, 2000 Ingo Molnar
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 *	   Copyright (C) 2002, 2003 H. Peter Anvin
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 *
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 * RAID-4/5/6 management functions.
 * Thanks to Penguin Computing for making the RAID-6 development possible
 * by donating a test server!
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 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * You should have received a copy of the GNU General Public License
 * (for example /usr/src/linux/COPYING); if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

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/*
 * BITMAP UNPLUGGING:
 *
 * The sequencing for updating the bitmap reliably is a little
 * subtle (and I got it wrong the first time) so it deserves some
 * explanation.
 *
 * We group bitmap updates into batches.  Each batch has a number.
 * We may write out several batches at once, but that isn't very important.
 * conf->bm_write is the number of the last batch successfully written.
 * conf->bm_flush is the number of the last batch that was closed to
 *    new additions.
 * When we discover that we will need to write to any block in a stripe
 * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
 * the number of the batch it will be in. This is bm_flush+1.
 * When we are ready to do a write, if that batch hasn't been written yet,
 *   we plug the array and queue the stripe for later.
 * When an unplug happens, we increment bm_flush, thus closing the current
 *   batch.
 * When we notice that bm_flush > bm_write, we write out all pending updates
 * to the bitmap, and advance bm_write to where bm_flush was.
 * This may occasionally write a bit out twice, but is sure never to
 * miss any bits.
 */
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#include <linux/module.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/bitops.h>
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#include <linux/kthread.h>
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#include <asm/atomic.h>
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#include "raid6.h"
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#include <linux/raid/bitmap.h>
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#include <linux/async_tx.h>
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/*
 * Stripe cache
 */

#define NR_STRIPES		256
#define STRIPE_SIZE		PAGE_SIZE
#define STRIPE_SHIFT		(PAGE_SHIFT - 9)
#define STRIPE_SECTORS		(STRIPE_SIZE>>9)
#define	IO_THRESHOLD		1
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#define BYPASS_THRESHOLD	1
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#define NR_HASH			(PAGE_SIZE / sizeof(struct hlist_head))
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#define HASH_MASK		(NR_HASH - 1)

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#define stripe_hash(conf, sect)	(&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
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/* bio's attached to a stripe+device for I/O are linked together in bi_sector
 * order without overlap.  There may be several bio's per stripe+device, and
 * a bio could span several devices.
 * When walking this list for a particular stripe+device, we must never proceed
 * beyond a bio that extends past this device, as the next bio might no longer
 * be valid.
 * This macro is used to determine the 'next' bio in the list, given the sector
 * of the current stripe+device
 */
#define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL)
/*
 * The following can be used to debug the driver
 */
#define RAID5_PARANOIA	1
#if RAID5_PARANOIA && defined(CONFIG_SMP)
# define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
#else
# define CHECK_DEVLOCK()
#endif

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#ifdef DEBUG
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#define inline
#define __inline__
#endif

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#define printk_rl(args...) ((void) (printk_ratelimit() && printk(args)))

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#if !RAID6_USE_EMPTY_ZERO_PAGE
/* In .bss so it's zeroed */
const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
#endif

static inline int raid6_next_disk(int disk, int raid_disks)
{
	disk++;
	return (disk < raid_disks) ? disk : 0;
}
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static void return_io(struct bio *return_bi)
{
	struct bio *bi = return_bi;
	while (bi) {

		return_bi = bi->bi_next;
		bi->bi_next = NULL;
		bi->bi_size = 0;
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		bio_endio(bi, 0);
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		bi = return_bi;
	}
}

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static void print_raid5_conf (raid5_conf_t *conf);

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static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
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{
	if (atomic_dec_and_test(&sh->count)) {
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		BUG_ON(!list_empty(&sh->lru));
		BUG_ON(atomic_read(&conf->active_stripes)==0);
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		if (test_bit(STRIPE_HANDLE, &sh->state)) {
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			if (test_bit(STRIPE_DELAYED, &sh->state)) {
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				list_add_tail(&sh->lru, &conf->delayed_list);
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				blk_plug_device(conf->mddev->queue);
			} else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
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				   sh->bm_seq - conf->seq_write > 0) {
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				list_add_tail(&sh->lru, &conf->bitmap_list);
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				blk_plug_device(conf->mddev->queue);
			} else {
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				clear_bit(STRIPE_BIT_DELAY, &sh->state);
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				list_add_tail(&sh->lru, &conf->handle_list);
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			}
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			md_wakeup_thread(conf->mddev->thread);
		} else {
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			BUG_ON(sh->ops.pending);
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			if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
				atomic_dec(&conf->preread_active_stripes);
				if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
					md_wakeup_thread(conf->mddev->thread);
			}
			atomic_dec(&conf->active_stripes);
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			if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
				list_add_tail(&sh->lru, &conf->inactive_list);
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				wake_up(&conf->wait_for_stripe);
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				if (conf->retry_read_aligned)
					md_wakeup_thread(conf->mddev->thread);
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			}
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		}
	}
}
static void release_stripe(struct stripe_head *sh)
{
	raid5_conf_t *conf = sh->raid_conf;
	unsigned long flags;
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	spin_lock_irqsave(&conf->device_lock, flags);
	__release_stripe(conf, sh);
	spin_unlock_irqrestore(&conf->device_lock, flags);
}

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static inline void remove_hash(struct stripe_head *sh)
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{
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	pr_debug("remove_hash(), stripe %llu\n",
		(unsigned long long)sh->sector);
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	hlist_del_init(&sh->hash);
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}

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static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh)
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{
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	struct hlist_head *hp = stripe_hash(conf, sh->sector);
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	pr_debug("insert_hash(), stripe %llu\n",
		(unsigned long long)sh->sector);
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	CHECK_DEVLOCK();
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	hlist_add_head(&sh->hash, hp);
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}


/* find an idle stripe, make sure it is unhashed, and return it. */
static struct stripe_head *get_free_stripe(raid5_conf_t *conf)
{
	struct stripe_head *sh = NULL;
	struct list_head *first;

	CHECK_DEVLOCK();
	if (list_empty(&conf->inactive_list))
		goto out;
	first = conf->inactive_list.next;
	sh = list_entry(first, struct stripe_head, lru);
	list_del_init(first);
	remove_hash(sh);
	atomic_inc(&conf->active_stripes);
out:
	return sh;
}

static void shrink_buffers(struct stripe_head *sh, int num)
{
	struct page *p;
	int i;

	for (i=0; i<num ; i++) {
		p = sh->dev[i].page;
		if (!p)
			continue;
		sh->dev[i].page = NULL;
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		put_page(p);
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	}
}

static int grow_buffers(struct stripe_head *sh, int num)
{
	int i;

	for (i=0; i<num; i++) {
		struct page *page;

		if (!(page = alloc_page(GFP_KERNEL))) {
			return 1;
		}
		sh->dev[i].page = page;
	}
	return 0;
}

static void raid5_build_block (struct stripe_head *sh, int i);

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static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int disks)
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{
	raid5_conf_t *conf = sh->raid_conf;
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	int i;
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	BUG_ON(atomic_read(&sh->count) != 0);
	BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
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	BUG_ON(sh->ops.pending || sh->ops.ack || sh->ops.complete);

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	CHECK_DEVLOCK();
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	pr_debug("init_stripe called, stripe %llu\n",
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		(unsigned long long)sh->sector);

	remove_hash(sh);
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	sh->sector = sector;
	sh->pd_idx = pd_idx;
	sh->state = 0;

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	sh->disks = disks;

	for (i = sh->disks; i--; ) {
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		struct r5dev *dev = &sh->dev[i];

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		if (dev->toread || dev->read || dev->towrite || dev->written ||
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		    test_bit(R5_LOCKED, &dev->flags)) {
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			printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n",
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			       (unsigned long long)sh->sector, i, dev->toread,
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			       dev->read, dev->towrite, dev->written,
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			       test_bit(R5_LOCKED, &dev->flags));
			BUG();
		}
		dev->flags = 0;
		raid5_build_block(sh, i);
	}
	insert_hash(conf, sh);
}

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static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, int disks)
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{
	struct stripe_head *sh;
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	struct hlist_node *hn;
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	CHECK_DEVLOCK();
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	pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
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	hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
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		if (sh->sector == sector && sh->disks == disks)
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			return sh;
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	pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
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	return NULL;
}

static void unplug_slaves(mddev_t *mddev);
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static void raid5_unplug_device(struct request_queue *q);
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static struct stripe_head *get_active_stripe(raid5_conf_t *conf, sector_t sector, int disks,
					     int pd_idx, int noblock)
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{
	struct stripe_head *sh;

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	pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
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	spin_lock_irq(&conf->device_lock);

	do {
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		wait_event_lock_irq(conf->wait_for_stripe,
				    conf->quiesce == 0,
				    conf->device_lock, /* nothing */);
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		sh = __find_stripe(conf, sector, disks);
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		if (!sh) {
			if (!conf->inactive_blocked)
				sh = get_free_stripe(conf);
			if (noblock && sh == NULL)
				break;
			if (!sh) {
				conf->inactive_blocked = 1;
				wait_event_lock_irq(conf->wait_for_stripe,
						    !list_empty(&conf->inactive_list) &&
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						    (atomic_read(&conf->active_stripes)
						     < (conf->max_nr_stripes *3/4)
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						     || !conf->inactive_blocked),
						    conf->device_lock,
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						    raid5_unplug_device(conf->mddev->queue)
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					);
				conf->inactive_blocked = 0;
			} else
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				init_stripe(sh, sector, pd_idx, disks);
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		} else {
			if (atomic_read(&sh->count)) {
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			  BUG_ON(!list_empty(&sh->lru));
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			} else {
				if (!test_bit(STRIPE_HANDLE, &sh->state))
					atomic_inc(&conf->active_stripes);
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				if (list_empty(&sh->lru) &&
				    !test_bit(STRIPE_EXPANDING, &sh->state))
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					BUG();
				list_del_init(&sh->lru);
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			}
		}
	} while (sh == NULL);

	if (sh)
		atomic_inc(&sh->count);

	spin_unlock_irq(&conf->device_lock);
	return sh;
}

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/* test_and_ack_op() ensures that we only dequeue an operation once */
#define test_and_ack_op(op, pend) \
do {							\
	if (test_bit(op, &sh->ops.pending) &&		\
		!test_bit(op, &sh->ops.complete)) {	\
		if (test_and_set_bit(op, &sh->ops.ack)) \
			clear_bit(op, &pend);		\
		else					\
			ack++;				\
	} else						\
		clear_bit(op, &pend);			\
} while (0)

/* find new work to run, do not resubmit work that is already
 * in flight
 */
static unsigned long get_stripe_work(struct stripe_head *sh)
{
	unsigned long pending;
	int ack = 0;

	pending = sh->ops.pending;

	test_and_ack_op(STRIPE_OP_BIOFILL, pending);
	test_and_ack_op(STRIPE_OP_COMPUTE_BLK, pending);
	test_and_ack_op(STRIPE_OP_PREXOR, pending);
	test_and_ack_op(STRIPE_OP_BIODRAIN, pending);
	test_and_ack_op(STRIPE_OP_POSTXOR, pending);
	test_and_ack_op(STRIPE_OP_CHECK, pending);
	if (test_and_clear_bit(STRIPE_OP_IO, &sh->ops.pending))
		ack++;

	sh->ops.count -= ack;
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	if (unlikely(sh->ops.count < 0)) {
		printk(KERN_ERR "pending: %#lx ops.pending: %#lx ops.ack: %#lx "
			"ops.complete: %#lx\n", pending, sh->ops.pending,
			sh->ops.ack, sh->ops.complete);
		BUG();
	}
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	return pending;
}

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static void
raid5_end_read_request(struct bio *bi, int error);
static void
raid5_end_write_request(struct bio *bi, int error);
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static void ops_run_io(struct stripe_head *sh)
{
	raid5_conf_t *conf = sh->raid_conf;
	int i, disks = sh->disks;

	might_sleep();

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	set_bit(STRIPE_IO_STARTED, &sh->state);
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	for (i = disks; i--; ) {
		int rw;
		struct bio *bi;
		mdk_rdev_t *rdev;
		if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
			rw = WRITE;
		else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
			rw = READ;
		else
			continue;

		bi = &sh->dev[i].req;

		bi->bi_rw = rw;
		if (rw == WRITE)
			bi->bi_end_io = raid5_end_write_request;
		else
			bi->bi_end_io = raid5_end_read_request;

		rcu_read_lock();
		rdev = rcu_dereference(conf->disks[i].rdev);
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
		if (rdev)
			atomic_inc(&rdev->nr_pending);
		rcu_read_unlock();

		if (rdev) {
			if (test_bit(STRIPE_SYNCING, &sh->state) ||
				test_bit(STRIPE_EXPAND_SOURCE, &sh->state) ||
				test_bit(STRIPE_EXPAND_READY, &sh->state))
				md_sync_acct(rdev->bdev, STRIPE_SECTORS);

			bi->bi_bdev = rdev->bdev;
			pr_debug("%s: for %llu schedule op %ld on disc %d\n",
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				__func__, (unsigned long long)sh->sector,
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				bi->bi_rw, i);
			atomic_inc(&sh->count);
			bi->bi_sector = sh->sector + rdev->data_offset;
			bi->bi_flags = 1 << BIO_UPTODATE;
			bi->bi_vcnt = 1;
			bi->bi_max_vecs = 1;
			bi->bi_idx = 0;
			bi->bi_io_vec = &sh->dev[i].vec;
			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
			bi->bi_io_vec[0].bv_offset = 0;
			bi->bi_size = STRIPE_SIZE;
			bi->bi_next = NULL;
			if (rw == WRITE &&
			    test_bit(R5_ReWrite, &sh->dev[i].flags))
				atomic_add(STRIPE_SECTORS,
					&rdev->corrected_errors);
			generic_make_request(bi);
		} else {
			if (rw == WRITE)
				set_bit(STRIPE_DEGRADED, &sh->state);
			pr_debug("skip op %ld on disc %d for sector %llu\n",
				bi->bi_rw, i, (unsigned long long)sh->sector);
			clear_bit(R5_LOCKED, &sh->dev[i].flags);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
	}
}

static struct dma_async_tx_descriptor *
async_copy_data(int frombio, struct bio *bio, struct page *page,
	sector_t sector, struct dma_async_tx_descriptor *tx)
{
	struct bio_vec *bvl;
	struct page *bio_page;
	int i;
	int page_offset;

	if (bio->bi_sector >= sector)
		page_offset = (signed)(bio->bi_sector - sector) * 512;
	else
		page_offset = (signed)(sector - bio->bi_sector) * -512;
	bio_for_each_segment(bvl, bio, i) {
		int len = bio_iovec_idx(bio, i)->bv_len;
		int clen;
		int b_offset = 0;

		if (page_offset < 0) {
			b_offset = -page_offset;
			page_offset += b_offset;
			len -= b_offset;
		}

		if (len > 0 && page_offset + len > STRIPE_SIZE)
			clen = STRIPE_SIZE - page_offset;
		else
			clen = len;

		if (clen > 0) {
			b_offset += bio_iovec_idx(bio, i)->bv_offset;
			bio_page = bio_iovec_idx(bio, i)->bv_page;
			if (frombio)
				tx = async_memcpy(page, bio_page, page_offset,
					b_offset, clen,
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					ASYNC_TX_DEP_ACK,
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					tx, NULL, NULL);
			else
				tx = async_memcpy(bio_page, page, b_offset,
					page_offset, clen,
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					ASYNC_TX_DEP_ACK,
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					tx, NULL, NULL);
		}
		if (clen < len) /* hit end of page */
			break;
		page_offset +=  len;
	}

	return tx;
}

static void ops_complete_biofill(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;
	struct bio *return_bi = NULL;
	raid5_conf_t *conf = sh->raid_conf;
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	int i;
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	pr_debug("%s: stripe %llu\n", __func__,
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		(unsigned long long)sh->sector);

	/* clear completed biofills */
	for (i = sh->disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];

		/* acknowledge completion of a biofill operation */
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		/* and check if we need to reply to a read request,
		 * new R5_Wantfill requests are held off until
		 * !test_bit(STRIPE_OP_BIOFILL, &sh->ops.pending)
		 */
		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
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			struct bio *rbi, *rbi2;

			/* The access to dev->read is outside of the
			 * spin_lock_irq(&conf->device_lock), but is protected
			 * by the STRIPE_OP_BIOFILL pending bit
			 */
			BUG_ON(!dev->read);
			rbi = dev->read;
			dev->read = NULL;
			while (rbi && rbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
				rbi2 = r5_next_bio(rbi, dev->sector);
				spin_lock_irq(&conf->device_lock);
				if (--rbi->bi_phys_segments == 0) {
					rbi->bi_next = return_bi;
					return_bi = rbi;
				}
				spin_unlock_irq(&conf->device_lock);
				rbi = rbi2;
			}
		}
	}
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	set_bit(STRIPE_OP_BIOFILL, &sh->ops.complete);
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	return_io(return_bi);

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	set_bit(STRIPE_HANDLE, &sh->state);
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	release_stripe(sh);
}

static void ops_run_biofill(struct stripe_head *sh)
{
	struct dma_async_tx_descriptor *tx = NULL;
	raid5_conf_t *conf = sh->raid_conf;
	int i;

574
	pr_debug("%s: stripe %llu\n", __func__,
575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604
		(unsigned long long)sh->sector);

	for (i = sh->disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		if (test_bit(R5_Wantfill, &dev->flags)) {
			struct bio *rbi;
			spin_lock_irq(&conf->device_lock);
			dev->read = rbi = dev->toread;
			dev->toread = NULL;
			spin_unlock_irq(&conf->device_lock);
			while (rbi && rbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
				tx = async_copy_data(0, rbi, dev->page,
					dev->sector, tx);
				rbi = r5_next_bio(rbi, dev->sector);
			}
		}
	}

	atomic_inc(&sh->count);
	async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx,
		ops_complete_biofill, sh);
}

static void ops_complete_compute5(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;
	int target = sh->ops.target;
	struct r5dev *tgt = &sh->dev[target];

605
	pr_debug("%s: stripe %llu\n", __func__,
606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629
		(unsigned long long)sh->sector);

	set_bit(R5_UPTODATE, &tgt->flags);
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	clear_bit(R5_Wantcompute, &tgt->flags);
	set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

static struct dma_async_tx_descriptor *
ops_run_compute5(struct stripe_head *sh, unsigned long pending)
{
	/* kernel stack size limits the total number of disks */
	int disks = sh->disks;
	struct page *xor_srcs[disks];
	int target = sh->ops.target;
	struct r5dev *tgt = &sh->dev[target];
	struct page *xor_dest = tgt->page;
	int count = 0;
	struct dma_async_tx_descriptor *tx;
	int i;

	pr_debug("%s: stripe %llu block: %d\n",
630
		__func__, (unsigned long long)sh->sector, target);
631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));

	for (i = disks; i--; )
		if (i != target)
			xor_srcs[count++] = sh->dev[i].page;

	atomic_inc(&sh->count);

	if (unlikely(count == 1))
		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE,
			0, NULL, ops_complete_compute5, sh);
	else
		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
			ASYNC_TX_XOR_ZERO_DST, NULL,
			ops_complete_compute5, sh);

	/* ack now if postxor is not set to be run */
	if (tx && !test_bit(STRIPE_OP_POSTXOR, &pending))
		async_tx_ack(tx);

	return tx;
}

static void ops_complete_prexor(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;

658
	pr_debug("%s: stripe %llu\n", __func__,
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		(unsigned long long)sh->sector);

	set_bit(STRIPE_OP_PREXOR, &sh->ops.complete);
}

static struct dma_async_tx_descriptor *
ops_run_prexor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
{
	/* kernel stack size limits the total number of disks */
	int disks = sh->disks;
	struct page *xor_srcs[disks];
	int count = 0, pd_idx = sh->pd_idx, i;

	/* existing parity data subtracted */
	struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;

675
	pr_debug("%s: stripe %llu\n", __func__,
676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		/* Only process blocks that are known to be uptodate */
		if (dev->towrite && test_bit(R5_Wantprexor, &dev->flags))
			xor_srcs[count++] = dev->page;
	}

	tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
		ASYNC_TX_DEP_ACK | ASYNC_TX_XOR_DROP_DST, tx,
		ops_complete_prexor, sh);

	return tx;
}

static struct dma_async_tx_descriptor *
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ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx,
		 unsigned long pending)
695 696 697 698 699 700 701
{
	int disks = sh->disks;
	int pd_idx = sh->pd_idx, i;

	/* check if prexor is active which means only process blocks
	 * that are part of a read-modify-write (Wantprexor)
	 */
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	int prexor = test_bit(STRIPE_OP_PREXOR, &pending);
703

704
	pr_debug("%s: stripe %llu\n", __func__,
705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		struct bio *chosen;
		int towrite;

		towrite = 0;
		if (prexor) { /* rmw */
			if (dev->towrite &&
			    test_bit(R5_Wantprexor, &dev->flags))
				towrite = 1;
		} else { /* rcw */
			if (i != pd_idx && dev->towrite &&
				test_bit(R5_LOCKED, &dev->flags))
				towrite = 1;
		}

		if (towrite) {
			struct bio *wbi;

			spin_lock(&sh->lock);
			chosen = dev->towrite;
			dev->towrite = NULL;
			BUG_ON(dev->written);
			wbi = dev->written = chosen;
			spin_unlock(&sh->lock);

			while (wbi && wbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
				tx = async_copy_data(1, wbi, dev->page,
					dev->sector, tx);
				wbi = r5_next_bio(wbi, dev->sector);
			}
		}
	}

	return tx;
}

static void ops_complete_postxor(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;

749
	pr_debug("%s: stripe %llu\n", __func__,
750 751 752 753 754 755 756 757 758 759 760 761
		(unsigned long long)sh->sector);

	set_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

static void ops_complete_write(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;
	int disks = sh->disks, i, pd_idx = sh->pd_idx;

762
	pr_debug("%s: stripe %llu\n", __func__,
763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		if (dev->written || i == pd_idx)
			set_bit(R5_UPTODATE, &dev->flags);
	}

	set_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete);
	set_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);

	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

static void
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ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx,
		unsigned long pending)
781 782 783 784 785 786 787
{
	/* kernel stack size limits the total number of disks */
	int disks = sh->disks;
	struct page *xor_srcs[disks];

	int count = 0, pd_idx = sh->pd_idx, i;
	struct page *xor_dest;
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	int prexor = test_bit(STRIPE_OP_PREXOR, &pending);
789 790 791
	unsigned long flags;
	dma_async_tx_callback callback;

792
	pr_debug("%s: stripe %llu\n", __func__,
793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814
		(unsigned long long)sh->sector);

	/* check if prexor is active which means only process blocks
	 * that are part of a read-modify-write (written)
	 */
	if (prexor) {
		xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (dev->written)
				xor_srcs[count++] = dev->page;
		}
	} else {
		xor_dest = sh->dev[pd_idx].page;
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (i != pd_idx)
				xor_srcs[count++] = dev->page;
		}
	}

	/* check whether this postxor is part of a write */
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	callback = test_bit(STRIPE_OP_BIODRAIN, &pending) ?
816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841
		ops_complete_write : ops_complete_postxor;

	/* 1/ if we prexor'd then the dest is reused as a source
	 * 2/ if we did not prexor then we are redoing the parity
	 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
	 * for the synchronous xor case
	 */
	flags = ASYNC_TX_DEP_ACK | ASYNC_TX_ACK |
		(prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);

	atomic_inc(&sh->count);

	if (unlikely(count == 1)) {
		flags &= ~(ASYNC_TX_XOR_DROP_DST | ASYNC_TX_XOR_ZERO_DST);
		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE,
			flags, tx, callback, sh);
	} else
		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
			flags, tx, callback, sh);
}

static void ops_complete_check(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;
	int pd_idx = sh->pd_idx;

842
	pr_debug("%s: stripe %llu\n", __func__,
843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863
		(unsigned long long)sh->sector);

	if (test_and_clear_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending) &&
		sh->ops.zero_sum_result == 0)
		set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);

	set_bit(STRIPE_OP_CHECK, &sh->ops.complete);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

static void ops_run_check(struct stripe_head *sh)
{
	/* kernel stack size limits the total number of disks */
	int disks = sh->disks;
	struct page *xor_srcs[disks];
	struct dma_async_tx_descriptor *tx;

	int count = 0, pd_idx = sh->pd_idx, i;
	struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;

864
	pr_debug("%s: stripe %llu\n", __func__,
865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		if (i != pd_idx)
			xor_srcs[count++] = dev->page;
	}

	tx = async_xor_zero_sum(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
		&sh->ops.zero_sum_result, 0, NULL, NULL, NULL);

	if (tx)
		set_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending);
	else
		clear_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending);

	atomic_inc(&sh->count);
	tx = async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx,
		ops_complete_check, sh);
}

static void raid5_run_ops(struct stripe_head *sh, unsigned long pending)
{
	int overlap_clear = 0, i, disks = sh->disks;
	struct dma_async_tx_descriptor *tx = NULL;

	if (test_bit(STRIPE_OP_BIOFILL, &pending)) {
		ops_run_biofill(sh);
		overlap_clear++;
	}

	if (test_bit(STRIPE_OP_COMPUTE_BLK, &pending))
		tx = ops_run_compute5(sh, pending);

	if (test_bit(STRIPE_OP_PREXOR, &pending))
		tx = ops_run_prexor(sh, tx);

	if (test_bit(STRIPE_OP_BIODRAIN, &pending)) {
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		tx = ops_run_biodrain(sh, tx, pending);
904 905 906 907
		overlap_clear++;
	}

	if (test_bit(STRIPE_OP_POSTXOR, &pending))
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		ops_run_postxor(sh, tx, pending);
909 910 911 912 913 914 915 916 917 918 919 920 921 922 923

	if (test_bit(STRIPE_OP_CHECK, &pending))
		ops_run_check(sh);

	if (test_bit(STRIPE_OP_IO, &pending))
		ops_run_io(sh);

	if (overlap_clear)
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (test_and_clear_bit(R5_Overlap, &dev->flags))
				wake_up(&sh->raid_conf->wait_for_overlap);
		}
}

924
static int grow_one_stripe(raid5_conf_t *conf)
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{
	struct stripe_head *sh;
927 928 929 930 931 932 933 934 935 936 937 938
	sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL);
	if (!sh)
		return 0;
	memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev));
	sh->raid_conf = conf;
	spin_lock_init(&sh->lock);

	if (grow_buffers(sh, conf->raid_disks)) {
		shrink_buffers(sh, conf->raid_disks);
		kmem_cache_free(conf->slab_cache, sh);
		return 0;
	}
939
	sh->disks = conf->raid_disks;
940 941 942 943 944 945 946 947 948 949
	/* we just created an active stripe so... */
	atomic_set(&sh->count, 1);
	atomic_inc(&conf->active_stripes);
	INIT_LIST_HEAD(&sh->lru);
	release_stripe(sh);
	return 1;
}

static int grow_stripes(raid5_conf_t *conf, int num)
{
950
	struct kmem_cache *sc;
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	int devs = conf->raid_disks;

953 954
	sprintf(conf->cache_name[0], "raid5-%s", mdname(conf->mddev));
	sprintf(conf->cache_name[1], "raid5-%s-alt", mdname(conf->mddev));
955 956
	conf->active_name = 0;
	sc = kmem_cache_create(conf->cache_name[conf->active_name],
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			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
958
			       0, 0, NULL);
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	if (!sc)
		return 1;
	conf->slab_cache = sc;
962
	conf->pool_size = devs;
963
	while (num--)
964
		if (!grow_one_stripe(conf))
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			return 1;
	return 0;
}
968 969

#ifdef CONFIG_MD_RAID5_RESHAPE
970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998
static int resize_stripes(raid5_conf_t *conf, int newsize)
{
	/* Make all the stripes able to hold 'newsize' devices.
	 * New slots in each stripe get 'page' set to a new page.
	 *
	 * This happens in stages:
	 * 1/ create a new kmem_cache and allocate the required number of
	 *    stripe_heads.
	 * 2/ gather all the old stripe_heads and tranfer the pages across
	 *    to the new stripe_heads.  This will have the side effect of
	 *    freezing the array as once all stripe_heads have been collected,
	 *    no IO will be possible.  Old stripe heads are freed once their
	 *    pages have been transferred over, and the old kmem_cache is
	 *    freed when all stripes are done.
	 * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
	 *    we simple return a failre status - no need to clean anything up.
	 * 4/ allocate new pages for the new slots in the new stripe_heads.
	 *    If this fails, we don't bother trying the shrink the
	 *    stripe_heads down again, we just leave them as they are.
	 *    As each stripe_head is processed the new one is released into
	 *    active service.
	 *
	 * Once step2 is started, we cannot afford to wait for a write,
	 * so we use GFP_NOIO allocations.
	 */
	struct stripe_head *osh, *nsh;
	LIST_HEAD(newstripes);
	struct disk_info *ndisks;
	int err = 0;
999
	struct kmem_cache *sc;
1000 1001 1002 1003 1004
	int i;

	if (newsize <= conf->pool_size)
		return 0; /* never bother to shrink */

1005 1006
	md_allow_write(conf->mddev);

1007 1008 1009
	/* Step 1 */
	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
1010
			       0, 0, NULL);
1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044
	if (!sc)
		return -ENOMEM;

	for (i = conf->max_nr_stripes; i; i--) {
		nsh = kmem_cache_alloc(sc, GFP_KERNEL);
		if (!nsh)
			break;

		memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev));

		nsh->raid_conf = conf;
		spin_lock_init(&nsh->lock);

		list_add(&nsh->lru, &newstripes);
	}
	if (i) {
		/* didn't get enough, give up */
		while (!list_empty(&newstripes)) {
			nsh = list_entry(newstripes.next, struct stripe_head, lru);
			list_del(&nsh->lru);
			kmem_cache_free(sc, nsh);
		}
		kmem_cache_destroy(sc);
		return -ENOMEM;
	}
	/* Step 2 - Must use GFP_NOIO now.
	 * OK, we have enough stripes, start collecting inactive
	 * stripes and copying them over
	 */
	list_for_each_entry(nsh, &newstripes, lru) {
		spin_lock_irq(&conf->device_lock);
		wait_event_lock_irq(conf->wait_for_stripe,
				    !list_empty(&conf->inactive_list),
				    conf->device_lock,
1045
				    unplug_slaves(conf->mddev)
1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091
			);
		osh = get_free_stripe(conf);
		spin_unlock_irq(&conf->device_lock);
		atomic_set(&nsh->count, 1);
		for(i=0; i<conf->pool_size; i++)
			nsh->dev[i].page = osh->dev[i].page;
		for( ; i<newsize; i++)
			nsh->dev[i].page = NULL;
		kmem_cache_free(conf->slab_cache, osh);
	}
	kmem_cache_destroy(conf->slab_cache);

	/* Step 3.
	 * At this point, we are holding all the stripes so the array
	 * is completely stalled, so now is a good time to resize
	 * conf->disks.
	 */
	ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
	if (ndisks) {
		for (i=0; i<conf->raid_disks; i++)
			ndisks[i] = conf->disks[i];
		kfree(conf->disks);
		conf->disks = ndisks;
	} else
		err = -ENOMEM;

	/* Step 4, return new stripes to service */
	while(!list_empty(&newstripes)) {
		nsh = list_entry(newstripes.next, struct stripe_head, lru);
		list_del_init(&nsh->lru);
		for (i=conf->raid_disks; i < newsize; i++)
			if (nsh->dev[i].page == NULL) {
				struct page *p = alloc_page(GFP_NOIO);
				nsh->dev[i].page = p;
				if (!p)
					err = -ENOMEM;
			}
		release_stripe(nsh);
	}
	/* critical section pass, GFP_NOIO no longer needed */

	conf->slab_cache = sc;
	conf->active_name = 1-conf->active_name;
	conf->pool_size = newsize;
	return err;
}
1092
#endif
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1094
static int drop_one_stripe(raid5_conf_t *conf)
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{
	struct stripe_head *sh;

1098 1099 1100 1101 1102
	spin_lock_irq(&conf->device_lock);
	sh = get_free_stripe(conf);
	spin_unlock_irq(&conf->device_lock);
	if (!sh)
		return 0;
1103
	BUG_ON(atomic_read(&sh->count));
1104
	shrink_buffers(sh, conf->pool_size);
1105 1106 1107 1108 1109 1110 1111 1112 1113 1114
	kmem_cache_free(conf->slab_cache, sh);
	atomic_dec(&conf->active_stripes);
	return 1;
}

static void shrink_stripes(raid5_conf_t *conf)
{
	while (drop_one_stripe(conf))
		;

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	if (conf->slab_cache)
		kmem_cache_destroy(conf->slab_cache);
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	conf->slab_cache = NULL;
}

1120
static void raid5_end_read_request(struct bio * bi, int error)
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{
 	struct stripe_head *sh = bi->bi_private;
	raid5_conf_t *conf = sh->raid_conf;
1124
	int disks = sh->disks, i;
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	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1126 1127
	char b[BDEVNAME_SIZE];
	mdk_rdev_t *rdev;
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	for (i=0 ; i<disks; i++)
		if (bi == &sh->dev[i].req)
			break;

1134 1135
	pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n",
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
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		uptodate);
	if (i == disks) {
		BUG();
1139
		return;
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	}

	if (uptodate) {
		set_bit(R5_UPTODATE, &sh->dev[i].flags);
1144
		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1145
			rdev = conf->disks[i].rdev;
1146 1147 1148 1149 1150 1151
			printk_rl(KERN_INFO "raid5:%s: read error corrected"
				  " (%lu sectors at %llu on %s)\n",
				  mdname(conf->mddev), STRIPE_SECTORS,
				  (unsigned long long)(sh->sector
						       + rdev->data_offset),
				  bdevname(rdev->bdev, b));
1152 1153 1154
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
		}
1155 1156
		if (atomic_read(&conf->disks[i].rdev->read_errors))
			atomic_set(&conf->disks[i].rdev->read_errors, 0);
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	} else {
1158
		const char *bdn = bdevname(conf->disks[i].rdev->bdev, b);
1159
		int retry = 0;
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		rdev = conf->disks[i].rdev;

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		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
1163
		atomic_inc(&rdev->read_errors);
1164
		if (conf->mddev->degraded)
1165 1166 1167 1168 1169 1170 1171
			printk_rl(KERN_WARNING
				  "raid5:%s: read error not correctable "
				  "(sector %llu on %s).\n",
				  mdname(conf->mddev),
				  (unsigned long long)(sh->sector
						       + rdev->data_offset),
				  bdn);
1172
		else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
1173
			/* Oh, no!!! */
1174 1175 1176 1177 1178 1179 1180
			printk_rl(KERN_WARNING
				  "raid5:%s: read error NOT corrected!! "
				  "(sector %llu on %s).\n",
				  mdname(conf->mddev),
				  (unsigned long long)(sh->sector
						       + rdev->data_offset),
				  bdn);
1181
		else if (atomic_read(&rdev->read_errors)
1182
			 > conf->max_nr_stripes)
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			printk(KERN_WARNING
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			       "raid5:%s: Too many read errors, failing device %s.\n",
			       mdname(conf->mddev), bdn);
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		else
			retry = 1;
		if (retry)
			set_bit(R5_ReadError, &sh->dev[i].flags);
		else {
1191 1192
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1193
			md_error(conf->mddev, rdev);
1194
		}
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	}
	rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
	clear_bit(R5_LOCKED, &sh->dev[i].flags);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1202
static void raid5_end_write_request (struct bio *bi, int error)
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{
 	struct stripe_head *sh = bi->bi_private;
	raid5_conf_t *conf = sh->raid_conf;
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	int disks = sh->disks, i;
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	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);

	for (i=0 ; i<disks; i++)
		if (bi == &sh->dev[i].req)
			break;

1213
	pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
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		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
		uptodate);
	if (i == disks) {
		BUG();
1218
		return;
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	}

	if (!uptodate)
		md_error(conf->mddev, conf->disks[i].rdev);

	rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
	
	clear_bit(R5_LOCKED, &sh->dev[i].flags);
	set_bit(STRIPE_HANDLE, &sh->state);
1228
	release_stripe(sh);
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}


static sector_t compute_blocknr(struct stripe_head *sh, int i);
	
static void raid5_build_block (struct stripe_head *sh, int i)
{
	struct r5dev *dev = &sh->dev[i];

	bio_init(&dev->req);
	dev->req.bi_io_vec = &dev->vec;
	dev->req.bi_vcnt++;
	dev->req.bi_max_vecs++;
	dev->vec.bv_page = dev->page;
	dev->vec.bv_len = STRIPE_SIZE;
	dev->vec.bv_offset = 0;

	dev->req.bi_sector = sh->sector;
	dev->req.bi_private = sh;

	dev->flags = 0;
1250
	dev->sector = compute_blocknr(sh, i);
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}

static void error(mddev_t *mddev, mdk_rdev_t *rdev)
{
	char b[BDEVNAME_SIZE];
	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
1257
	pr_debug("raid5: error called\n");
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1259
	if (!test_bit(Faulty, &rdev->flags)) {
1260
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
1261 1262 1263
		if (test_and_clear_bit(In_sync, &rdev->flags)) {
			unsigned long flags;
			spin_lock_irqsave(&conf->device_lock, flags);
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			mddev->degraded++;
1265
			spin_unlock_irqrestore(&conf->device_lock, flags);
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			/*
			 * if recovery was running, make sure it aborts.
			 */
1269
			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
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		}
1271
		set_bit(Faulty, &rdev->flags);
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		printk (KERN_ALERT
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			"raid5: Disk failure on %s, disabling device.\n"
			"raid5: Operation continuing on %d devices.\n",
1275
			bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
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	}
1277
}
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/*
 * Input: a 'big' sector number,
 * Output: index of the data and parity disk, and the sector # in them.
 */
static sector_t raid5_compute_sector(sector_t r_sector, unsigned int raid_disks,
			unsigned int data_disks, unsigned int * dd_idx,
			unsigned int * pd_idx, raid5_conf_t *conf)
{
	long stripe;
	unsigned long chunk_number;
	unsigned int chunk_offset;
	sector_t new_sector;
	int sectors_per_chunk = conf->chunk_size >> 9;

	/* First compute the information on this sector */

	/*
	 * Compute the chunk number and the sector offset inside the chunk
	 */
	chunk_offset = sector_div(r_sector, sectors_per_chunk);
	chunk_number = r_sector;
	BUG_ON(r_sector != chunk_number);

	/*
	 * Compute the stripe number
	 */
	stripe = chunk_number / data_disks;

	/*
	 * Compute the data disk and parity disk indexes inside the stripe
	 */
	*dd_idx = chunk_number % data_disks;

	/*
	 * Select the parity disk based on the user selected algorithm.
	 */
1315 1316
	switch(conf->level) {
	case 4:
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		*pd_idx = data_disks;
1318 1319 1320
		break;
	case 5:
		switch (conf->algorithm) {
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		case ALGORITHM_LEFT_ASYMMETRIC:
			*pd_idx = data_disks - stripe % raid_disks;
			if (*dd_idx >= *pd_idx)
				(*dd_idx)++;
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
			*pd_idx = stripe % raid_disks;
			if (*dd_idx >= *pd_idx)
				(*dd_idx)++;
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
			*pd_idx = data_disks - stripe % raid_disks;
			*dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
			*pd_idx = stripe % raid_disks;
			*dd_idx = (*pd_idx + 1 + *dd_idx) % raid_disks;
			break;
		default:
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			printk(KERN_ERR "raid5: unsupported algorithm %d\n",
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				conf->algorithm);
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		}
		break;
	case 6:

		/**** FIX THIS ****/
		switch (conf->algorithm) {
		case ALGORITHM_LEFT_ASYMMETRIC:
			*pd_idx = raid_disks - 1 - (stripe % raid_disks);
			if (*pd_idx == raid_disks-1)
				(*dd_idx)++; 	/* Q D D D P */
			else if (*dd_idx >= *pd_idx)
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
			*pd_idx = stripe % raid_disks;
			if (*pd_idx == raid_disks-1)
				(*dd_idx)++; 	/* Q D D D P */
			else if (*dd_idx >= *pd_idx)
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
			*pd_idx = raid_disks - 1 - (stripe % raid_disks);
			*dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
			*pd_idx = stripe % raid_disks;
			*dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks;
			break;
		default:
			printk (KERN_CRIT "raid6: unsupported algorithm %d\n",
				conf->algorithm);
		}
		break;
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	}

	/*
	 * Finally, compute the new sector number
	 */
	new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
	return new_sector;
}


static sector_t compute_blocknr(struct stripe_head *sh, int i)
{
	raid5_conf_t *conf = sh->raid_conf;
1388 1389
	int raid_disks = sh->disks;
	int data_disks = raid_disks - conf->max_degraded;
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	sector_t new_sector = sh->sector, check;
	int sectors_per_chunk = conf->chunk_size >> 9;
	sector_t stripe;
	int chunk_offset;
	int chunk_number, dummy1, dummy2, dd_idx = i;
	sector_t r_sector;

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	chunk_offset = sector_div(new_sector, sectors_per_chunk);
	stripe = new_sector;
	BUG_ON(new_sector != stripe);

1402 1403 1404 1405 1406 1407
	if (i == sh->pd_idx)
		return 0;
	switch(conf->level) {
	case 4: break;
	case 5:
		switch (conf->algorithm) {
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		case ALGORITHM_LEFT_ASYMMETRIC:
		case ALGORITHM_RIGHT_ASYMMETRIC:
			if (i > sh->pd_idx)
				i--;
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
		case ALGORITHM_RIGHT_SYMMETRIC:
			if (i < sh->pd_idx)
				i += raid_disks;
			i -= (sh->pd_idx + 1);
			break;
		default:
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			printk(KERN_ERR "raid5: unsupported algorithm %d\n",
1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447
			       conf->algorithm);
		}
		break;
	case 6:
		if (i == raid6_next_disk(sh->pd_idx, raid_disks))
			return 0; /* It is the Q disk */
		switch (conf->algorithm) {
		case ALGORITHM_LEFT_ASYMMETRIC:
		case ALGORITHM_RIGHT_ASYMMETRIC:
		  	if (sh->pd_idx == raid_disks-1)
				i--; 	/* Q D D D P */
			else if (i > sh->pd_idx)
				i -= 2; /* D D P Q D */
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
		case ALGORITHM_RIGHT_SYMMETRIC:
			if (sh->pd_idx == raid_disks-1)
				i--; /* Q D D D P */
			else {
				/* D D P Q D */
				if (i < sh->pd_idx)
					i += raid_disks;
				i -= (sh->pd_idx + 2);
			}
			break;
		default:
			printk (KERN_CRIT "raid6: unsupported algorithm %d\n",
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				conf->algorithm);
1449 1450
		}
		break;
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	}

	chunk_number = stripe * data_disks + i;
	r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;

	check = raid5_compute_sector (r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf);
	if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_idx) {
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		printk(KERN_ERR "compute_blocknr: map not correct\n");
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		return 0;
	}
	return r_sector;
}



/*
1467 1468 1469 1470 1471
 * Copy data between a page in the stripe cache, and one or more bion
 * The page could align with the middle of the bio, or there could be
 * several bion, each with several bio_vecs, which cover part of the page
 * Multiple bion are linked together on bi_next.  There may be extras
 * at the end of this list.  We ignore them.
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 */
static void copy_data(int frombio, struct bio *bio,
		     struct page *page,
		     sector_t sector)
{
	char *pa = page_address(page);
	struct bio_vec *bvl;
	int i;
	int page_offset;

	if (bio->bi_sector >= sector)
		page_offset = (signed)(bio->bi_sector - sector) * 512;
	else
		page_offset = (signed)(sector - bio->bi_sector) * -512;
	bio_for_each_segment(bvl, bio, i) {
		int len = bio_iovec_idx(bio,i)->bv_len;
		int clen;
		int b_offset = 0;

		if (page_offset < 0) {
			b_offset = -page_offset;
			page_offset += b_offset;
			len -= b_offset;
		}

		if (len > 0 && page_offset + len > STRIPE_SIZE)
			clen = STRIPE_SIZE - page_offset;
		else clen = len;
1500

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		if (clen > 0) {
			char *ba = __bio_kmap_atomic(bio, i, KM_USER0);
			if (frombio)
				memcpy(pa+page_offset, ba+b_offset, clen);
			else
				memcpy(ba+b_offset, pa+page_offset, clen);
			__bio_kunmap_atomic(ba, KM_USER0);
		}
		if (clen < len) /* hit end of page */
			break;
		page_offset +=  len;
	}
}

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#define check_xor()	do {						  \
				if (count == MAX_XOR_BLOCKS) {		  \
				xor_blocks(count, STRIPE_SIZE, dest, ptr);\
				count = 0;				  \
			   }						  \
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			} while(0)

1522 1523 1524
static void compute_parity6(struct stripe_head *sh, int method)
{
	raid6_conf_t *conf = sh->raid_conf;
1525
	int i, pd_idx = sh->pd_idx, qd_idx, d0_idx, disks = sh->disks, count;
1526 1527 1528 1529 1530 1531 1532
	struct bio *chosen;
	/**** FIX THIS: This could be very bad if disks is close to 256 ****/
	void *ptrs[disks];

	qd_idx = raid6_next_disk(pd_idx, disks);
	d0_idx = raid6_next_disk(qd_idx, disks);

1533
	pr_debug("compute_parity, stripe %llu, method %d\n",
1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547
		(unsigned long long)sh->sector, method);

	switch(method) {
	case READ_MODIFY_WRITE:
		BUG();		/* READ_MODIFY_WRITE N/A for RAID-6 */
	case RECONSTRUCT_WRITE:
		for (i= disks; i-- ;)
			if ( i != pd_idx && i != qd_idx && sh->dev[i].towrite ) {
				chosen = sh->dev[i].towrite;
				sh->dev[i].towrite = NULL;

				if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
					wake_up(&conf->wait_for_overlap);

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				BUG_ON(sh->dev[i].written);
1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605
				sh->dev[i].written = chosen;
			}
		break;
	case CHECK_PARITY:
		BUG();		/* Not implemented yet */
	}

	for (i = disks; i--;)
		if (sh->dev[i].written) {
			sector_t sector = sh->dev[i].sector;
			struct bio *wbi = sh->dev[i].written;
			while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) {
				copy_data(1, wbi, sh->dev[i].page, sector);
				wbi = r5_next_bio(wbi, sector);
			}

			set_bit(R5_LOCKED, &sh->dev[i].flags);
			set_bit(R5_UPTODATE, &sh->dev[i].flags);
		}

//	switch(method) {
//	case RECONSTRUCT_WRITE:
//	case CHECK_PARITY:
//	case UPDATE_PARITY:
		/* Note that unlike RAID-5, the ordering of the disks matters greatly. */
		/* FIX: Is this ordering of drives even remotely optimal? */
		count = 0;
		i = d0_idx;
		do {
			ptrs[count++] = page_address(sh->dev[i].page);
			if (count <= disks-2 && !test_bit(R5_UPTODATE, &sh->dev[i].flags))
				printk("block %d/%d not uptodate on parity calc\n", i,count);
			i = raid6_next_disk(i, disks);
		} while ( i != d0_idx );
//		break;
//	}

	raid6_call.gen_syndrome(disks, STRIPE_SIZE, ptrs);

	switch(method) {
	case RECONSTRUCT_WRITE:
		set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
		set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
		set_bit(R5_LOCKED,   &sh->dev[pd_idx].flags);
		set_bit(R5_LOCKED,   &sh->dev[qd_idx].flags);
		break;
	case UPDATE_PARITY:
		set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
		set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags);
		break;
	}
}


/* Compute one missing block */
static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero)
{
1606
	int i, count, disks = sh->disks;
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	void *ptr[MAX_XOR_BLOCKS], *dest, *p;
1608 1609 1610
	int pd_idx = sh->pd_idx;
	int qd_idx = raid6_next_disk(pd_idx, disks);

1611
	pr_debug("compute_block_1, stripe %llu, idx %d\n",
1612 1613 1614 1615 1616 1617
		(unsigned long long)sh->sector, dd_idx);

	if ( dd_idx == qd_idx ) {
		/* We're actually computing the Q drive */
		compute_parity6(sh, UPDATE_PARITY);
	} else {
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		dest = page_address(sh->dev[dd_idx].page);
		if (!nozero) memset(dest, 0, STRIPE_SIZE);
		count = 0;
1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633
		for (i = disks ; i--; ) {
			if (i == dd_idx || i == qd_idx)
				continue;
			p = page_address(sh->dev[i].page);
			if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
				ptr[count++] = p;
			else
				printk("compute_block() %d, stripe %llu, %d"
				       " not present\n", dd_idx,
				       (unsigned long long)sh->sector, i);

			check_xor();
		}
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		if (count)
			xor_blocks(count, STRIPE_SIZE, dest, ptr);
1636 1637 1638 1639 1640 1641 1642 1643
		if (!nozero) set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
		else clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
	}
}

/* Compute two missing blocks */
static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
{
1644
	int i, count, disks = sh->disks;
1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657
	int pd_idx = sh->pd_idx;
	int qd_idx = raid6_next_disk(pd_idx, disks);
	int d0_idx = raid6_next_disk(qd_idx, disks);
	int faila, failb;

	/* faila and failb are disk numbers relative to d0_idx */
	/* pd_idx become disks-2 and qd_idx become disks-1 */
	faila = (dd_idx1 < d0_idx) ? dd_idx1+(disks-d0_idx) : dd_idx1-d0_idx;
	failb = (dd_idx2 < d0_idx) ? dd_idx2+(disks-d0_idx) : dd_idx2-d0_idx;

	BUG_ON(faila == failb);
	if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; }

1658
	pr_debug("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n",
1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703
	       (unsigned long long)sh->sector, dd_idx1, dd_idx2, faila, failb);

	if ( failb == disks-1 ) {
		/* Q disk is one of the missing disks */
		if ( faila == disks-2 ) {
			/* Missing P+Q, just recompute */
			compute_parity6(sh, UPDATE_PARITY);
			return;
		} else {
			/* We're missing D+Q; recompute D from P */
			compute_block_1(sh, (dd_idx1 == qd_idx) ? dd_idx2 : dd_idx1, 0);
			compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */
			return;
		}
	}

	/* We're missing D+P or D+D; build pointer table */
	{
		/**** FIX THIS: This could be very bad if disks is close to 256 ****/
		void *ptrs[disks];

		count = 0;
		i = d0_idx;
		do {
			ptrs[count++] = page_address(sh->dev[i].page);
			i = raid6_next_disk(i, disks);
			if (i != dd_idx1 && i != dd_idx2 &&
			    !test_bit(R5_UPTODATE, &sh->dev[i].flags))
				printk("compute_2 with missing block %d/%d\n", count, i);
		} while ( i != d0_idx );

		if ( failb == disks-2 ) {
			/* We're missing D+P. */
			raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs);
		} else {
			/* We're missing D+D. */
			raid6_2data_recov(disks, STRIPE_SIZE, faila, failb, ptrs);
		}

		/* Both the above update both missing blocks */
		set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags);
		set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags);
	}
}

1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718
static int
handle_write_operations5(struct stripe_head *sh, int rcw, int expand)
{
	int i, pd_idx = sh->pd_idx, disks = sh->disks;
	int locked = 0;

	if (rcw) {
		/* if we are not expanding this is a proper write request, and
		 * there will be bios with new data to be drained into the
		 * stripe cache
		 */
		if (!expand) {
			set_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);
			sh->ops.count++;
		}
1719

1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732
		set_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
		sh->ops.count++;

		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];

			if (dev->towrite) {
				set_bit(R5_LOCKED, &dev->flags);
				if (!expand)
					clear_bit(R5_UPTODATE, &dev->flags);
				locked++;
			}
		}
1733 1734 1735
		if (locked + 1 == disks)
			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
				atomic_inc(&sh->raid_conf->pending_full_writes);
1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774
	} else {
		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));

		set_bit(STRIPE_OP_PREXOR, &sh->ops.pending);
		set_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);
		set_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);

		sh->ops.count += 3;

		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (i == pd_idx)
				continue;

			/* For a read-modify write there may be blocks that are
			 * locked for reading while others are ready to be
			 * written so we distinguish these blocks by the
			 * R5_Wantprexor bit
			 */
			if (dev->towrite &&
			    (test_bit(R5_UPTODATE, &dev->flags) ||
			    test_bit(R5_Wantcompute, &dev->flags))) {
				set_bit(R5_Wantprexor, &dev->flags);
				set_bit(R5_LOCKED, &dev->flags);
				clear_bit(R5_UPTODATE, &dev->flags);
				locked++;
			}
		}
	}

	/* keep the parity disk locked while asynchronous operations
	 * are in flight
	 */
	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
	locked++;

	pr_debug("%s: stripe %llu locked: %d pending: %lx\n",
1775
		__func__, (unsigned long long)sh->sector,
1776 1777 1778 1779
		locked, sh->ops.pending);

	return locked;
}
1780

L
Linus Torvalds 已提交
1781 1782
/*
 * Each stripe/dev can have one or more bion attached.
1783
 * toread/towrite point to the first in a chain.
L
Linus Torvalds 已提交
1784 1785 1786 1787 1788 1789
 * The bi_next chain must be in order.
 */
static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite)
{
	struct bio **bip;
	raid5_conf_t *conf = sh->raid_conf;
1790
	int firstwrite=0;
L
Linus Torvalds 已提交
1791

1792
	pr_debug("adding bh b#%llu to stripe s#%llu\n",
L
Linus Torvalds 已提交
1793 1794 1795 1796 1797 1798
		(unsigned long long)bi->bi_sector,
		(unsigned long long)sh->sector);


	spin_lock(&sh->lock);
	spin_lock_irq(&conf->device_lock);
1799
	if (forwrite) {
L
Linus Torvalds 已提交
1800
		bip = &sh->dev[dd_idx].towrite;
1801 1802 1803
		if (*bip == NULL && sh->dev[dd_idx].written == NULL)
			firstwrite = 1;
	} else
L
Linus Torvalds 已提交
1804 1805 1806 1807 1808 1809 1810 1811 1812
		bip = &sh->dev[dd_idx].toread;
	while (*bip && (*bip)->bi_sector < bi->bi_sector) {
		if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
			goto overlap;
		bip = & (*bip)->bi_next;
	}
	if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
		goto overlap;

1813
	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
L
Linus Torvalds 已提交
1814 1815 1816 1817 1818 1819 1820
	if (*bip)
		bi->bi_next = *bip;
	*bip = bi;
	bi->bi_phys_segments ++;
	spin_unlock_irq(&conf->device_lock);
	spin_unlock(&sh->lock);

1821
	pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
L
Linus Torvalds 已提交
1822 1823 1824
		(unsigned long long)bi->bi_sector,
		(unsigned long long)sh->sector, dd_idx);

1825 1826 1827
	if (conf->mddev->bitmap && firstwrite) {
		bitmap_startwrite(conf->mddev->bitmap, sh->sector,
				  STRIPE_SECTORS, 0);
1828
		sh->bm_seq = conf->seq_flush+1;
1829 1830 1831
		set_bit(STRIPE_BIT_DELAY, &sh->state);
	}

L
Linus Torvalds 已提交
1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853
	if (forwrite) {
		/* check if page is covered */
		sector_t sector = sh->dev[dd_idx].sector;
		for (bi=sh->dev[dd_idx].towrite;
		     sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
			     bi && bi->bi_sector <= sector;
		     bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
			if (bi->bi_sector + (bi->bi_size>>9) >= sector)
				sector = bi->bi_sector + (bi->bi_size>>9);
		}
		if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
			set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
	}
	return 1;

 overlap:
	set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
	spin_unlock_irq(&conf->device_lock);
	spin_unlock(&sh->lock);
	return 0;
}

1854 1855
static void end_reshape(raid5_conf_t *conf);

1856 1857 1858 1859 1860 1861 1862
static int page_is_zero(struct page *p)
{
	char *a = page_address(p);
	return ((*(u32*)a) == 0 &&
		memcmp(a, a+4, STRIPE_SIZE-4)==0);
}

1863 1864 1865 1866
static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)
{
	int sectors_per_chunk = conf->chunk_size >> 9;
	int pd_idx, dd_idx;
1867 1868
	int chunk_offset = sector_div(stripe, sectors_per_chunk);

1869 1870 1871 1872
	raid5_compute_sector(stripe * (disks - conf->max_degraded)
			     *sectors_per_chunk + chunk_offset,
			     disks, disks - conf->max_degraded,
			     &dd_idx, &pd_idx, conf);
1873 1874 1875
	return pd_idx;
}

1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933
static void
handle_requests_to_failed_array(raid5_conf_t *conf, struct stripe_head *sh,
				struct stripe_head_state *s, int disks,
				struct bio **return_bi)
{
	int i;
	for (i = disks; i--; ) {
		struct bio *bi;
		int bitmap_end = 0;

		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
			mdk_rdev_t *rdev;
			rcu_read_lock();
			rdev = rcu_dereference(conf->disks[i].rdev);
			if (rdev && test_bit(In_sync, &rdev->flags))
				/* multiple read failures in one stripe */
				md_error(conf->mddev, rdev);
			rcu_read_unlock();
		}
		spin_lock_irq(&conf->device_lock);
		/* fail all writes first */
		bi = sh->dev[i].towrite;
		sh->dev[i].towrite = NULL;
		if (bi) {
			s->to_write--;
			bitmap_end = 1;
		}

		if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
			wake_up(&conf->wait_for_overlap);

		while (bi && bi->bi_sector <
			sh->dev[i].sector + STRIPE_SECTORS) {
			struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
			clear_bit(BIO_UPTODATE, &bi->bi_flags);
			if (--bi->bi_phys_segments == 0) {
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = nextbi;
		}
		/* and fail all 'written' */
		bi = sh->dev[i].written;
		sh->dev[i].written = NULL;
		if (bi) bitmap_end = 1;
		while (bi && bi->bi_sector <
		       sh->dev[i].sector + STRIPE_SECTORS) {
			struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
			clear_bit(BIO_UPTODATE, &bi->bi_flags);
			if (--bi->bi_phys_segments == 0) {
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = bi2;
		}

1934 1935 1936 1937 1938 1939
		/* fail any reads if this device is non-operational and
		 * the data has not reached the cache yet.
		 */
		if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
		    (!test_bit(R5_Insync, &sh->dev[i].flags) ||
		      test_bit(R5_ReadError, &sh->dev[i].flags))) {
1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962
			bi = sh->dev[i].toread;
			sh->dev[i].toread = NULL;
			if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
				wake_up(&conf->wait_for_overlap);
			if (bi) s->to_read--;
			while (bi && bi->bi_sector <
			       sh->dev[i].sector + STRIPE_SECTORS) {
				struct bio *nextbi =
					r5_next_bio(bi, sh->dev[i].sector);
				clear_bit(BIO_UPTODATE, &bi->bi_flags);
				if (--bi->bi_phys_segments == 0) {
					bi->bi_next = *return_bi;
					*return_bi = bi;
				}
				bi = nextbi;
			}
		}
		spin_unlock_irq(&conf->device_lock);
		if (bitmap_end)
			bitmap_endwrite(conf->mddev->bitmap, sh->sector,
					STRIPE_SECTORS, 0, 0);
	}

1963 1964 1965
	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
		if (atomic_dec_and_test(&conf->pending_full_writes))
			md_wakeup_thread(conf->mddev->thread);
1966 1967
}

1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
/* __handle_issuing_new_read_requests5 - returns 0 if there are no more disks
 * to process
 */
static int __handle_issuing_new_read_requests5(struct stripe_head *sh,
			struct stripe_head_state *s, int disk_idx, int disks)
{
	struct r5dev *dev = &sh->dev[disk_idx];
	struct r5dev *failed_dev = &sh->dev[s->failed_num];

	/* don't schedule compute operations or reads on the parity block while
	 * a check is in flight
	 */
	if ((disk_idx == sh->pd_idx) &&
	     test_bit(STRIPE_OP_CHECK, &sh->ops.pending))
		return ~0;

	/* is the data in this block needed, and can we get it? */
	if (!test_bit(R5_LOCKED, &dev->flags) &&
	    !test_bit(R5_UPTODATE, &dev->flags) && (dev->toread ||
	    (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
	     s->syncing || s->expanding || (s->failed &&
	     (failed_dev->toread || (failed_dev->towrite &&
	     !test_bit(R5_OVERWRITE, &failed_dev->flags)
	     ))))) {
		/* 1/ We would like to get this block, possibly by computing it,
		 * but we might not be able to.
		 *
		 * 2/ Since parity check operations potentially make the parity
		 * block !uptodate it will need to be refreshed before any
		 * compute operations on data disks are scheduled.
		 *
		 * 3/ We hold off parity block re-reads until check operations
		 * have quiesced.
		 */
		if ((s->uptodate == disks - 1) &&
2003
		    (s->failed && disk_idx == s->failed_num) &&
2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036
		    !test_bit(STRIPE_OP_CHECK, &sh->ops.pending)) {
			set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
			set_bit(R5_Wantcompute, &dev->flags);
			sh->ops.target = disk_idx;
			s->req_compute = 1;
			sh->ops.count++;
			/* Careful: from this point on 'uptodate' is in the eye
			 * of raid5_run_ops which services 'compute' operations
			 * before writes. R5_Wantcompute flags a block that will
			 * be R5_UPTODATE by the time it is needed for a
			 * subsequent operation.
			 */
			s->uptodate++;
			return 0; /* uptodate + compute == disks */
		} else if ((s->uptodate < disks - 1) &&
			test_bit(R5_Insync, &dev->flags)) {
			/* Note: we hold off compute operations while checks are
			 * in flight, but we still prefer 'compute' over 'read'
			 * hence we only read if (uptodate < * disks-1)
			 */
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantread, &dev->flags);
			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
				sh->ops.count++;
			s->locked++;
			pr_debug("Reading block %d (sync=%d)\n", disk_idx,
				s->syncing);
		}
	}

	return ~0;
}

2037 2038 2039 2040
static void handle_issuing_new_read_requests5(struct stripe_head *sh,
			struct stripe_head_state *s, int disks)
{
	int i;
2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063

	/* Clear completed compute operations.  Parity recovery
	 * (STRIPE_OP_MOD_REPAIR_PD) implies a write-back which is handled
	 * later on in this routine
	 */
	if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete) &&
		!test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.ack);
		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
	}

	/* look for blocks to read/compute, skip this if a compute
	 * is already in flight, or if the stripe contents are in the
	 * midst of changing due to a write
	 */
	if (!test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending) &&
		!test_bit(STRIPE_OP_PREXOR, &sh->ops.pending) &&
		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
		for (i = disks; i--; )
			if (__handle_issuing_new_read_requests5(
				sh, s, i, disks) == 0)
				break;
2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088
	}
	set_bit(STRIPE_HANDLE, &sh->state);
}

static void handle_issuing_new_read_requests6(struct stripe_head *sh,
			struct stripe_head_state *s, struct r6_state *r6s,
			int disks)
{
	int i;
	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		if (!test_bit(R5_LOCKED, &dev->flags) &&
		    !test_bit(R5_UPTODATE, &dev->flags) &&
		    (dev->toread || (dev->towrite &&
		     !test_bit(R5_OVERWRITE, &dev->flags)) ||
		     s->syncing || s->expanding ||
		     (s->failed >= 1 &&
		      (sh->dev[r6s->failed_num[0]].toread ||
		       s->to_write)) ||
		     (s->failed >= 2 &&
		      (sh->dev[r6s->failed_num[1]].toread ||
		       s->to_write)))) {
			/* we would like to get this block, possibly
			 * by computing it, but we might not be able to
			 */
2089 2090 2091
			if ((s->uptodate == disks - 1) &&
			    (s->failed && (i == r6s->failed_num[0] ||
					   i == r6s->failed_num[1]))) {
2092
				pr_debug("Computing stripe %llu block %d\n",
2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108
				       (unsigned long long)sh->sector, i);
				compute_block_1(sh, i, 0);
				s->uptodate++;
			} else if ( s->uptodate == disks-2 && s->failed >= 2 ) {
				/* Computing 2-failure is *very* expensive; only
				 * do it if failed >= 2
				 */
				int other;
				for (other = disks; other--; ) {
					if (other == i)
						continue;
					if (!test_bit(R5_UPTODATE,
					      &sh->dev[other].flags))
						break;
				}
				BUG_ON(other < 0);
2109
				pr_debug("Computing stripe %llu blocks %d,%d\n",
2110 2111 2112 2113 2114 2115 2116 2117
				       (unsigned long long)sh->sector,
				       i, other);
				compute_block_2(sh, i, other);
				s->uptodate += 2;
			} else if (test_bit(R5_Insync, &dev->flags)) {
				set_bit(R5_LOCKED, &dev->flags);
				set_bit(R5_Wantread, &dev->flags);
				s->locked++;
2118
				pr_debug("Reading block %d (sync=%d)\n",
2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145
					i, s->syncing);
			}
		}
	}
	set_bit(STRIPE_HANDLE, &sh->state);
}


/* handle_completed_write_requests
 * any written block on an uptodate or failed drive can be returned.
 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
 * never LOCKED, so we don't need to test 'failed' directly.
 */
static void handle_completed_write_requests(raid5_conf_t *conf,
	struct stripe_head *sh, int disks, struct bio **return_bi)
{
	int i;
	struct r5dev *dev;

	for (i = disks; i--; )
		if (sh->dev[i].written) {
			dev = &sh->dev[i];
			if (!test_bit(R5_LOCKED, &dev->flags) &&
				test_bit(R5_UPTODATE, &dev->flags)) {
				/* We can return any write requests */
				struct bio *wbi, *wbi2;
				int bitmap_end = 0;
2146
				pr_debug("Return write for disc %d\n", i);
2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170
				spin_lock_irq(&conf->device_lock);
				wbi = dev->written;
				dev->written = NULL;
				while (wbi && wbi->bi_sector <
					dev->sector + STRIPE_SECTORS) {
					wbi2 = r5_next_bio(wbi, dev->sector);
					if (--wbi->bi_phys_segments == 0) {
						md_write_end(conf->mddev);
						wbi->bi_next = *return_bi;
						*return_bi = wbi;
					}
					wbi = wbi2;
				}
				if (dev->towrite == NULL)
					bitmap_end = 1;
				spin_unlock_irq(&conf->device_lock);
				if (bitmap_end)
					bitmap_endwrite(conf->mddev->bitmap,
							sh->sector,
							STRIPE_SECTORS,
					 !test_bit(STRIPE_DEGRADED, &sh->state),
							0);
			}
		}
2171 2172 2173 2174

	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
		if (atomic_dec_and_test(&conf->pending_full_writes))
			md_wakeup_thread(conf->mddev->thread);
2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185
}

static void handle_issuing_new_write_requests5(raid5_conf_t *conf,
		struct stripe_head *sh,	struct stripe_head_state *s, int disks)
{
	int rmw = 0, rcw = 0, i;
	for (i = disks; i--; ) {
		/* would I have to read this buffer for read_modify_write */
		struct r5dev *dev = &sh->dev[i];
		if ((dev->towrite || i == sh->pd_idx) &&
		    !test_bit(R5_LOCKED, &dev->flags) &&
2186 2187
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		      test_bit(R5_Wantcompute, &dev->flags))) {
2188 2189 2190 2191 2192 2193 2194 2195
			if (test_bit(R5_Insync, &dev->flags))
				rmw++;
			else
				rmw += 2*disks;  /* cannot read it */
		}
		/* Would I have to read this buffer for reconstruct_write */
		if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
		    !test_bit(R5_LOCKED, &dev->flags) &&
2196 2197 2198
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		    test_bit(R5_Wantcompute, &dev->flags))) {
			if (test_bit(R5_Insync, &dev->flags)) rcw++;
2199 2200 2201 2202
			else
				rcw += 2*disks;
		}
	}
2203
	pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2204 2205 2206 2207 2208 2209 2210 2211
		(unsigned long long)sh->sector, rmw, rcw);
	set_bit(STRIPE_HANDLE, &sh->state);
	if (rmw < rcw && rmw > 0)
		/* prefer read-modify-write, but need to get some data */
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if ((dev->towrite || i == sh->pd_idx) &&
			    !test_bit(R5_LOCKED, &dev->flags) &&
2212 2213
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
			    test_bit(R5_Wantcompute, &dev->flags)) &&
2214 2215 2216
			    test_bit(R5_Insync, &dev->flags)) {
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2217
					pr_debug("Read_old block "
2218 2219 2220
						"%d for r-m-w\n", i);
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
2221 2222 2223
					if (!test_and_set_bit(
						STRIPE_OP_IO, &sh->ops.pending))
						sh->ops.count++;
2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237
					s->locked++;
				} else {
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
	if (rcw <= rmw && rcw > 0)
		/* want reconstruct write, but need to get some data */
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (!test_bit(R5_OVERWRITE, &dev->flags) &&
			    i != sh->pd_idx &&
			    !test_bit(R5_LOCKED, &dev->flags) &&
2238 2239
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
			    test_bit(R5_Wantcompute, &dev->flags)) &&
2240 2241 2242
			    test_bit(R5_Insync, &dev->flags)) {
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2243
					pr_debug("Read_old block "
2244 2245 2246
						"%d for Reconstruct\n", i);
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
2247 2248 2249
					if (!test_and_set_bit(
						STRIPE_OP_IO, &sh->ops.pending))
						sh->ops.count++;
2250 2251 2252 2253 2254 2255 2256 2257 2258 2259
					s->locked++;
				} else {
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
	/* now if nothing is locked, and if we have enough data,
	 * we can start a write request
	 */
2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270
	/* since handle_stripe can be called at any time we need to handle the
	 * case where a compute block operation has been submitted and then a
	 * subsequent call wants to start a write request.  raid5_run_ops only
	 * handles the case where compute block and postxor are requested
	 * simultaneously.  If this is not the case then new writes need to be
	 * held off until the compute completes.
	 */
	if ((s->req_compute ||
	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) &&
		(s->locked == 0 && (rcw == 0 || rmw == 0) &&
		!test_bit(STRIPE_BIT_DELAY, &sh->state)))
2271
		s->locked += handle_write_operations5(sh, rcw == 0, 0);
2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289
}

static void handle_issuing_new_write_requests6(raid5_conf_t *conf,
		struct stripe_head *sh,	struct stripe_head_state *s,
		struct r6_state *r6s, int disks)
{
	int rcw = 0, must_compute = 0, pd_idx = sh->pd_idx, i;
	int qd_idx = r6s->qd_idx;
	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		/* Would I have to read this buffer for reconstruct_write */
		if (!test_bit(R5_OVERWRITE, &dev->flags)
		    && i != pd_idx && i != qd_idx
		    && (!test_bit(R5_LOCKED, &dev->flags)
			    ) &&
		    !test_bit(R5_UPTODATE, &dev->flags)) {
			if (test_bit(R5_Insync, &dev->flags)) rcw++;
			else {
2290
				pr_debug("raid6: must_compute: "
2291 2292 2293 2294 2295
					"disk %d flags=%#lx\n", i, dev->flags);
				must_compute++;
			}
		}
	}
2296
	pr_debug("for sector %llu, rcw=%d, must_compute=%d\n",
2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310
	       (unsigned long long)sh->sector, rcw, must_compute);
	set_bit(STRIPE_HANDLE, &sh->state);

	if (rcw > 0)
		/* want reconstruct write, but need to get some data */
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (!test_bit(R5_OVERWRITE, &dev->flags)
			    && !(s->failed == 0 && (i == pd_idx || i == qd_idx))
			    && !test_bit(R5_LOCKED, &dev->flags) &&
			    !test_bit(R5_UPTODATE, &dev->flags) &&
			    test_bit(R5_Insync, &dev->flags)) {
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2311
					pr_debug("Read_old stripe %llu "
2312 2313 2314 2315 2316 2317
						"block %d for Reconstruct\n",
					     (unsigned long long)sh->sector, i);
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
					s->locked++;
				} else {
2318
					pr_debug("Request delayed stripe %llu "
2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347
						"block %d for Reconstruct\n",
					     (unsigned long long)sh->sector, i);
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
	/* now if nothing is locked, and if we have enough data, we can start a
	 * write request
	 */
	if (s->locked == 0 && rcw == 0 &&
	    !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
		if (must_compute > 0) {
			/* We have failed blocks and need to compute them */
			switch (s->failed) {
			case 0:
				BUG();
			case 1:
				compute_block_1(sh, r6s->failed_num[0], 0);
				break;
			case 2:
				compute_block_2(sh, r6s->failed_num[0],
						r6s->failed_num[1]);
				break;
			default: /* This request should have been failed? */
				BUG();
			}
		}

2348
		pr_debug("Computing parity for stripe %llu\n",
2349 2350 2351 2352 2353
			(unsigned long long)sh->sector);
		compute_parity6(sh, RECONSTRUCT_WRITE);
		/* now every locked buffer is ready to be written */
		for (i = disks; i--; )
			if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
2354
				pr_debug("Writing stripe %llu block %d\n",
2355 2356 2357 2358
				       (unsigned long long)sh->sector, i);
				s->locked++;
				set_bit(R5_Wantwrite, &sh->dev[i].flags);
			}
2359 2360 2361
		if (s->locked == disks)
			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
				atomic_inc(&conf->pending_full_writes);
2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376
		/* after a RECONSTRUCT_WRITE, the stripe MUST be in-sync */
		set_bit(STRIPE_INSYNC, &sh->state);

		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
			atomic_dec(&conf->preread_active_stripes);
			if (atomic_read(&conf->preread_active_stripes) <
			    IO_THRESHOLD)
				md_wakeup_thread(conf->mddev->thread);
		}
	}
}

static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
				struct stripe_head_state *s, int disks)
{
2377 2378
	int canceled_check = 0;

2379
	set_bit(STRIPE_HANDLE, &sh->state);
2380

2381 2382
	/* complete a check operation */
	if (test_and_clear_bit(STRIPE_OP_CHECK, &sh->ops.complete)) {
D
Dan Williams 已提交
2383 2384
		clear_bit(STRIPE_OP_CHECK, &sh->ops.ack);
		clear_bit(STRIPE_OP_CHECK, &sh->ops.pending);
2385
		if (s->failed == 0) {
2386 2387 2388 2389
			if (sh->ops.zero_sum_result == 0)
				/* parity is correct (on disc,
				 * not in buffer any more)
				 */
2390 2391
				set_bit(STRIPE_INSYNC, &sh->state);
			else {
2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408
				conf->mddev->resync_mismatches +=
					STRIPE_SECTORS;
				if (test_bit(
				     MD_RECOVERY_CHECK, &conf->mddev->recovery))
					/* don't try to repair!! */
					set_bit(STRIPE_INSYNC, &sh->state);
				else {
					set_bit(STRIPE_OP_COMPUTE_BLK,
						&sh->ops.pending);
					set_bit(STRIPE_OP_MOD_REPAIR_PD,
						&sh->ops.pending);
					set_bit(R5_Wantcompute,
						&sh->dev[sh->pd_idx].flags);
					sh->ops.target = sh->pd_idx;
					sh->ops.count++;
					s->uptodate++;
				}
2409
			}
2410 2411
		} else
			canceled_check = 1; /* STRIPE_INSYNC is not set */
2412
	}
2413

2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427
	/* start a new check operation if there are no failures, the stripe is
	 * not insync, and a repair is not in flight
	 */
	if (s->failed == 0 &&
	    !test_bit(STRIPE_INSYNC, &sh->state) &&
	    !test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
		if (!test_and_set_bit(STRIPE_OP_CHECK, &sh->ops.pending)) {
			BUG_ON(s->uptodate != disks);
			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
			sh->ops.count++;
			s->uptodate--;
		}
	}

D
Dan Williams 已提交
2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438
	/* check if we can clear a parity disk reconstruct */
	if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete) &&
	    test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {

		clear_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending);
		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.ack);
		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
	}


2439
	/* Wait for check parity and compute block operations to complete
2440 2441 2442
	 * before write-back.  If a failure occurred while the check operation
	 * was in flight we need to cycle this stripe through handle_stripe
	 * since the parity block may not be uptodate
2443
	 */
2444 2445 2446
	if (!canceled_check && !test_bit(STRIPE_INSYNC, &sh->state) &&
	    !test_bit(STRIPE_OP_CHECK, &sh->ops.pending) &&
	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) {
2447 2448 2449 2450 2451 2452 2453 2454 2455 2456
		struct r5dev *dev;
		/* either failed parity check, or recovery is happening */
		if (s->failed == 0)
			s->failed_num = sh->pd_idx;
		dev = &sh->dev[s->failed_num];
		BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
		BUG_ON(s->uptodate != disks);

		set_bit(R5_LOCKED, &dev->flags);
		set_bit(R5_Wantwrite, &dev->flags);
2457 2458 2459
		if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
			sh->ops.count++;

2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567
		clear_bit(STRIPE_DEGRADED, &sh->state);
		s->locked++;
		set_bit(STRIPE_INSYNC, &sh->state);
	}
}


static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh,
				struct stripe_head_state *s,
				struct r6_state *r6s, struct page *tmp_page,
				int disks)
{
	int update_p = 0, update_q = 0;
	struct r5dev *dev;
	int pd_idx = sh->pd_idx;
	int qd_idx = r6s->qd_idx;

	set_bit(STRIPE_HANDLE, &sh->state);

	BUG_ON(s->failed > 2);
	BUG_ON(s->uptodate < disks);
	/* Want to check and possibly repair P and Q.
	 * However there could be one 'failed' device, in which
	 * case we can only check one of them, possibly using the
	 * other to generate missing data
	 */

	/* If !tmp_page, we cannot do the calculations,
	 * but as we have set STRIPE_HANDLE, we will soon be called
	 * by stripe_handle with a tmp_page - just wait until then.
	 */
	if (tmp_page) {
		if (s->failed == r6s->q_failed) {
			/* The only possible failed device holds 'Q', so it
			 * makes sense to check P (If anything else were failed,
			 * we would have used P to recreate it).
			 */
			compute_block_1(sh, pd_idx, 1);
			if (!page_is_zero(sh->dev[pd_idx].page)) {
				compute_block_1(sh, pd_idx, 0);
				update_p = 1;
			}
		}
		if (!r6s->q_failed && s->failed < 2) {
			/* q is not failed, and we didn't use it to generate
			 * anything, so it makes sense to check it
			 */
			memcpy(page_address(tmp_page),
			       page_address(sh->dev[qd_idx].page),
			       STRIPE_SIZE);
			compute_parity6(sh, UPDATE_PARITY);
			if (memcmp(page_address(tmp_page),
				   page_address(sh->dev[qd_idx].page),
				   STRIPE_SIZE) != 0) {
				clear_bit(STRIPE_INSYNC, &sh->state);
				update_q = 1;
			}
		}
		if (update_p || update_q) {
			conf->mddev->resync_mismatches += STRIPE_SECTORS;
			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
				/* don't try to repair!! */
				update_p = update_q = 0;
		}

		/* now write out any block on a failed drive,
		 * or P or Q if they need it
		 */

		if (s->failed == 2) {
			dev = &sh->dev[r6s->failed_num[1]];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		if (s->failed >= 1) {
			dev = &sh->dev[r6s->failed_num[0]];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}

		if (update_p) {
			dev = &sh->dev[pd_idx];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		if (update_q) {
			dev = &sh->dev[qd_idx];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		clear_bit(STRIPE_DEGRADED, &sh->state);

		set_bit(STRIPE_INSYNC, &sh->state);
	}
}

static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
				struct r6_state *r6s)
{
	int i;

	/* We have read all the blocks in this stripe and now we need to
	 * copy some of them into a target stripe for expand.
	 */
2568
	struct dma_async_tx_descriptor *tx = NULL;
2569 2570
	clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	for (i = 0; i < sh->disks; i++)
2571
		if (i != sh->pd_idx && (!r6s || i != r6s->qd_idx)) {
2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593
			int dd_idx, pd_idx, j;
			struct stripe_head *sh2;

			sector_t bn = compute_blocknr(sh, i);
			sector_t s = raid5_compute_sector(bn, conf->raid_disks,
						conf->raid_disks -
						conf->max_degraded, &dd_idx,
						&pd_idx, conf);
			sh2 = get_active_stripe(conf, s, conf->raid_disks,
						pd_idx, 1);
			if (sh2 == NULL)
				/* so far only the early blocks of this stripe
				 * have been requested.  When later blocks
				 * get requested, we will try again
				 */
				continue;
			if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
			   test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
				/* must have already done this block */
				release_stripe(sh2);
				continue;
			}
2594 2595 2596 2597 2598 2599

			/* place all the copies on one channel */
			tx = async_memcpy(sh2->dev[dd_idx].page,
				sh->dev[i].page, 0, 0, STRIPE_SIZE,
				ASYNC_TX_DEP_ACK, tx, NULL, NULL);

2600 2601 2602 2603
			set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
			set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
			for (j = 0; j < conf->raid_disks; j++)
				if (j != sh2->pd_idx &&
2604 2605
				    (!r6s || j != raid6_next_disk(sh2->pd_idx,
								 sh2->disks)) &&
2606 2607 2608 2609 2610 2611 2612
				    !test_bit(R5_Expanded, &sh2->dev[j].flags))
					break;
			if (j == conf->raid_disks) {
				set_bit(STRIPE_EXPAND_READY, &sh2->state);
				set_bit(STRIPE_HANDLE, &sh2->state);
			}
			release_stripe(sh2);
2613

2614
		}
2615 2616 2617 2618 2619
	/* done submitting copies, wait for them to complete */
	if (tx) {
		async_tx_ack(tx);
		dma_wait_for_async_tx(tx);
	}
2620
}
L
Linus Torvalds 已提交
2621

2622

L
Linus Torvalds 已提交
2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638
/*
 * handle_stripe - do things to a stripe.
 *
 * We lock the stripe and then examine the state of various bits
 * to see what needs to be done.
 * Possible results:
 *    return some read request which now have data
 *    return some write requests which are safely on disc
 *    schedule a read on some buffers
 *    schedule a write of some buffers
 *    return confirmation of parity correctness
 *
 * buffers are taken off read_list or write_list, and bh_cache buffers
 * get BH_Lock set before the stripe lock is released.
 *
 */
2639

2640
static void handle_stripe5(struct stripe_head *sh)
L
Linus Torvalds 已提交
2641 2642
{
	raid5_conf_t *conf = sh->raid_conf;
2643 2644 2645
	int disks = sh->disks, i;
	struct bio *return_bi = NULL;
	struct stripe_head_state s;
L
Linus Torvalds 已提交
2646
	struct r5dev *dev;
2647
	unsigned long pending = 0;
2648
	mdk_rdev_t *blocked_rdev = NULL;
2649
	int prexor;
L
Linus Torvalds 已提交
2650

2651
	memset(&s, 0, sizeof(s));
2652 2653 2654 2655
	pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d "
		"ops=%lx:%lx:%lx\n", (unsigned long long)sh->sector, sh->state,
		atomic_read(&sh->count), sh->pd_idx,
		sh->ops.pending, sh->ops.ack, sh->ops.complete);
L
Linus Torvalds 已提交
2656 2657 2658 2659 2660

	spin_lock(&sh->lock);
	clear_bit(STRIPE_HANDLE, &sh->state);
	clear_bit(STRIPE_DELAYED, &sh->state);

2661 2662 2663
	s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
	s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
L
Linus Torvalds 已提交
2664 2665
	/* Now to look around and see what can be done */

N
Neil Brown 已提交
2666 2667 2668 2669 2670 2671 2672
	/* clean-up completed biofill operations */
	if (test_bit(STRIPE_OP_BIOFILL, &sh->ops.complete)) {
		clear_bit(STRIPE_OP_BIOFILL, &sh->ops.pending);
		clear_bit(STRIPE_OP_BIOFILL, &sh->ops.ack);
		clear_bit(STRIPE_OP_BIOFILL, &sh->ops.complete);
	}

2673
	rcu_read_lock();
L
Linus Torvalds 已提交
2674 2675
	for (i=disks; i--; ) {
		mdk_rdev_t *rdev;
2676
		struct r5dev *dev = &sh->dev[i];
L
Linus Torvalds 已提交
2677 2678
		clear_bit(R5_Insync, &dev->flags);

2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690
		pr_debug("check %d: state 0x%lx toread %p read %p write %p "
			"written %p\n",	i, dev->flags, dev->toread, dev->read,
			dev->towrite, dev->written);

		/* maybe we can request a biofill operation
		 *
		 * new wantfill requests are only permitted while
		 * STRIPE_OP_BIOFILL is clear
		 */
		if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
			!test_bit(STRIPE_OP_BIOFILL, &sh->ops.pending))
			set_bit(R5_Wantfill, &dev->flags);
L
Linus Torvalds 已提交
2691 2692

		/* now count some things */
2693 2694
		if (test_bit(R5_LOCKED, &dev->flags)) s.locked++;
		if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++;
2695
		if (test_bit(R5_Wantcompute, &dev->flags)) s.compute++;
L
Linus Torvalds 已提交
2696

2697 2698 2699
		if (test_bit(R5_Wantfill, &dev->flags))
			s.to_fill++;
		else if (dev->toread)
2700
			s.to_read++;
L
Linus Torvalds 已提交
2701
		if (dev->towrite) {
2702
			s.to_write++;
L
Linus Torvalds 已提交
2703
			if (!test_bit(R5_OVERWRITE, &dev->flags))
2704
				s.non_overwrite++;
L
Linus Torvalds 已提交
2705
		}
2706 2707
		if (dev->written)
			s.written++;
2708
		rdev = rcu_dereference(conf->disks[i].rdev);
2709 2710 2711 2712 2713
		if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
			blocked_rdev = rdev;
			atomic_inc(&rdev->nr_pending);
			break;
		}
2714
		if (!rdev || !test_bit(In_sync, &rdev->flags)) {
N
NeilBrown 已提交
2715
			/* The ReadError flag will just be confusing now */
2716 2717 2718
			clear_bit(R5_ReadError, &dev->flags);
			clear_bit(R5_ReWrite, &dev->flags);
		}
2719
		if (!rdev || !test_bit(In_sync, &rdev->flags)
2720
		    || test_bit(R5_ReadError, &dev->flags)) {
2721 2722
			s.failed++;
			s.failed_num = i;
L
Linus Torvalds 已提交
2723 2724 2725
		} else
			set_bit(R5_Insync, &dev->flags);
	}
2726
	rcu_read_unlock();
2727

2728 2729 2730 2731 2732
	if (unlikely(blocked_rdev)) {
		set_bit(STRIPE_HANDLE, &sh->state);
		goto unlock;
	}

2733 2734 2735
	if (s.to_fill && !test_and_set_bit(STRIPE_OP_BIOFILL, &sh->ops.pending))
		sh->ops.count++;

2736
	pr_debug("locked=%d uptodate=%d to_read=%d"
L
Linus Torvalds 已提交
2737
		" to_write=%d failed=%d failed_num=%d\n",
2738 2739
		s.locked, s.uptodate, s.to_read, s.to_write,
		s.failed, s.failed_num);
L
Linus Torvalds 已提交
2740 2741 2742
	/* check if the array has lost two devices and, if so, some requests might
	 * need to be failed
	 */
2743 2744 2745 2746
	if (s.failed > 1 && s.to_read+s.to_write+s.written)
		handle_requests_to_failed_array(conf, sh, &s, disks,
						&return_bi);
	if (s.failed > 1 && s.syncing) {
L
Linus Torvalds 已提交
2747 2748
		md_done_sync(conf->mddev, STRIPE_SECTORS,0);
		clear_bit(STRIPE_SYNCING, &sh->state);
2749
		s.syncing = 0;
L
Linus Torvalds 已提交
2750 2751 2752 2753 2754 2755
	}

	/* might be able to return some write requests if the parity block
	 * is safe, or on a failed drive
	 */
	dev = &sh->dev[sh->pd_idx];
2756 2757 2758 2759 2760 2761
	if ( s.written &&
	     ((test_bit(R5_Insync, &dev->flags) &&
	       !test_bit(R5_LOCKED, &dev->flags) &&
	       test_bit(R5_UPTODATE, &dev->flags)) ||
	       (s.failed == 1 && s.failed_num == sh->pd_idx)))
		handle_completed_write_requests(conf, sh, disks, &return_bi);
L
Linus Torvalds 已提交
2762 2763 2764 2765 2766

	/* Now we might consider reading some blocks, either to check/generate
	 * parity, or to satisfy requests
	 * or to load a block that is being partially written.
	 */
2767
	if (s.to_read || s.non_overwrite ||
2768 2769
	    (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding ||
	    test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending))
2770
		handle_issuing_new_read_requests5(sh, &s, disks);
L
Linus Torvalds 已提交
2771

2772 2773 2774 2775 2776 2777 2778
	/* Now we check to see if any write operations have recently
	 * completed
	 */

	/* leave prexor set until postxor is done, allows us to distinguish
	 * a rmw from a rcw during biodrain
	 */
2779
	prexor = 0;
2780 2781 2782
	if (test_bit(STRIPE_OP_PREXOR, &sh->ops.complete) &&
		test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete)) {

2783
		prexor = 1;
2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816
		clear_bit(STRIPE_OP_PREXOR, &sh->ops.complete);
		clear_bit(STRIPE_OP_PREXOR, &sh->ops.ack);
		clear_bit(STRIPE_OP_PREXOR, &sh->ops.pending);

		for (i = disks; i--; )
			clear_bit(R5_Wantprexor, &sh->dev[i].flags);
	}

	/* if only POSTXOR is set then this is an 'expand' postxor */
	if (test_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete) &&
		test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete)) {

		clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete);
		clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.ack);
		clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);

		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.ack);
		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);

		/* All the 'written' buffers and the parity block are ready to
		 * be written back to disk
		 */
		BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags));
		for (i = disks; i--; ) {
			dev = &sh->dev[i];
			if (test_bit(R5_LOCKED, &dev->flags) &&
				(i == sh->pd_idx || dev->written)) {
				pr_debug("Writing block %d\n", i);
				set_bit(R5_Wantwrite, &dev->flags);
				if (!test_and_set_bit(
				    STRIPE_OP_IO, &sh->ops.pending))
					sh->ops.count++;
2817 2818
				if (prexor)
					continue;
2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839
				if (!test_bit(R5_Insync, &dev->flags) ||
				    (i == sh->pd_idx && s.failed == 0))
					set_bit(STRIPE_INSYNC, &sh->state);
			}
		}
		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
			atomic_dec(&conf->preread_active_stripes);
			if (atomic_read(&conf->preread_active_stripes) <
				IO_THRESHOLD)
				md_wakeup_thread(conf->mddev->thread);
		}
	}

	/* Now to consider new write requests and what else, if anything
	 * should be read.  We do not handle new writes when:
	 * 1/ A 'write' operation (copy+xor) is already in flight.
	 * 2/ A 'check' operation is in flight, as it may clobber the parity
	 *    block.
	 */
	if (s.to_write && !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending) &&
			  !test_bit(STRIPE_OP_CHECK, &sh->ops.pending))
2840
		handle_issuing_new_write_requests5(conf, sh, &s, disks);
L
Linus Torvalds 已提交
2841 2842

	/* maybe we need to check and possibly fix the parity for this stripe
2843 2844 2845
	 * Any reads will already have been scheduled, so we just see if enough
	 * data is available.  The parity check is held off while parity
	 * dependent operations are in flight.
L
Linus Torvalds 已提交
2846
	 */
2847 2848 2849 2850 2851
	if ((s.syncing && s.locked == 0 &&
	     !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending) &&
	     !test_bit(STRIPE_INSYNC, &sh->state)) ||
	      test_bit(STRIPE_OP_CHECK, &sh->ops.pending) ||
	      test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending))
2852
		handle_parity_checks5(conf, sh, &s, disks);
2853

2854
	if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
L
Linus Torvalds 已提交
2855 2856 2857
		md_done_sync(conf->mddev, STRIPE_SECTORS,1);
		clear_bit(STRIPE_SYNCING, &sh->state);
	}
2858 2859 2860 2861

	/* If the failed drive is just a ReadError, then we might need to progress
	 * the repair/check process
	 */
2862 2863 2864 2865
	if (s.failed == 1 && !conf->mddev->ro &&
	    test_bit(R5_ReadError, &sh->dev[s.failed_num].flags)
	    && !test_bit(R5_LOCKED, &sh->dev[s.failed_num].flags)
	    && test_bit(R5_UPTODATE, &sh->dev[s.failed_num].flags)
2866
		) {
2867
		dev = &sh->dev[s.failed_num];
2868 2869
		if (!test_bit(R5_ReWrite, &dev->flags)) {
			set_bit(R5_Wantwrite, &dev->flags);
2870 2871
			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
				sh->ops.count++;
2872 2873
			set_bit(R5_ReWrite, &dev->flags);
			set_bit(R5_LOCKED, &dev->flags);
2874
			s.locked++;
2875 2876 2877
		} else {
			/* let's read it back */
			set_bit(R5_Wantread, &dev->flags);
2878 2879
			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
				sh->ops.count++;
2880
			set_bit(R5_LOCKED, &dev->flags);
2881
			s.locked++;
2882 2883 2884
		}
	}

2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896
	/* Finish postxor operations initiated by the expansion
	 * process
	 */
	if (test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete) &&
		!test_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending)) {

		clear_bit(STRIPE_EXPANDING, &sh->state);

		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.ack);
		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);

2897
		for (i = conf->raid_disks; i--; ) {
2898
			set_bit(R5_Wantwrite, &sh->dev[i].flags);
2899 2900
			set_bit(R5_LOCKED, &dev->flags);
			s.locked++;
2901 2902
			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
				sh->ops.count++;
2903
		}
2904 2905 2906 2907 2908 2909 2910 2911
	}

	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
		/* Need to write out all blocks after computing parity */
		sh->disks = conf->raid_disks;
		sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
			conf->raid_disks);
2912
		s.locked += handle_write_operations5(sh, 1, 1);
2913
	} else if (s.expanded &&
2914
		   s.locked == 0 &&
2915
		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
2916
		clear_bit(STRIPE_EXPAND_READY, &sh->state);
2917
		atomic_dec(&conf->reshape_stripes);
2918 2919 2920 2921
		wake_up(&conf->wait_for_overlap);
		md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
	}

2922 2923
	if (s.expanding && s.locked == 0 &&
	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending))
2924
		handle_stripe_expansion(conf, sh, NULL);
2925

2926 2927 2928
	if (sh->ops.count)
		pending = get_stripe_work(sh);

2929
 unlock:
L
Linus Torvalds 已提交
2930 2931
	spin_unlock(&sh->lock);

2932 2933 2934 2935
	/* wait for this device to become unblocked */
	if (unlikely(blocked_rdev))
		md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);

2936 2937 2938
	if (pending)
		raid5_run_ops(sh, pending);

2939
	return_io(return_bi);
L
Linus Torvalds 已提交
2940 2941 2942

}

2943
static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
L
Linus Torvalds 已提交
2944
{
2945
	raid6_conf_t *conf = sh->raid_conf;
2946
	int disks = sh->disks;
2947 2948 2949 2950
	struct bio *return_bi = NULL;
	int i, pd_idx = sh->pd_idx;
	struct stripe_head_state s;
	struct r6_state r6s;
2951
	struct r5dev *dev, *pdev, *qdev;
2952
	mdk_rdev_t *blocked_rdev = NULL;
L
Linus Torvalds 已提交
2953

2954
	r6s.qd_idx = raid6_next_disk(pd_idx, disks);
2955
	pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
2956 2957 2958 2959
		"pd_idx=%d, qd_idx=%d\n",
	       (unsigned long long)sh->sector, sh->state,
	       atomic_read(&sh->count), pd_idx, r6s.qd_idx);
	memset(&s, 0, sizeof(s));
2960

2961 2962 2963 2964
	spin_lock(&sh->lock);
	clear_bit(STRIPE_HANDLE, &sh->state);
	clear_bit(STRIPE_DELAYED, &sh->state);

2965 2966 2967
	s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
	s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
2968
	/* Now to look around and see what can be done */
L
Linus Torvalds 已提交
2969 2970

	rcu_read_lock();
2971 2972 2973 2974
	for (i=disks; i--; ) {
		mdk_rdev_t *rdev;
		dev = &sh->dev[i];
		clear_bit(R5_Insync, &dev->flags);
L
Linus Torvalds 已提交
2975

2976
		pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
2977 2978 2979 2980
			i, dev->flags, dev->toread, dev->towrite, dev->written);
		/* maybe we can reply to a read */
		if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
			struct bio *rbi, *rbi2;
2981
			pr_debug("Return read for disc %d\n", i);
2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999
			spin_lock_irq(&conf->device_lock);
			rbi = dev->toread;
			dev->toread = NULL;
			if (test_and_clear_bit(R5_Overlap, &dev->flags))
				wake_up(&conf->wait_for_overlap);
			spin_unlock_irq(&conf->device_lock);
			while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) {
				copy_data(0, rbi, dev->page, dev->sector);
				rbi2 = r5_next_bio(rbi, dev->sector);
				spin_lock_irq(&conf->device_lock);
				if (--rbi->bi_phys_segments == 0) {
					rbi->bi_next = return_bi;
					return_bi = rbi;
				}
				spin_unlock_irq(&conf->device_lock);
				rbi = rbi2;
			}
		}
L
Linus Torvalds 已提交
3000

3001
		/* now count some things */
3002 3003
		if (test_bit(R5_LOCKED, &dev->flags)) s.locked++;
		if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++;
L
Linus Torvalds 已提交
3004

3005

3006 3007
		if (dev->toread)
			s.to_read++;
3008
		if (dev->towrite) {
3009
			s.to_write++;
3010
			if (!test_bit(R5_OVERWRITE, &dev->flags))
3011
				s.non_overwrite++;
3012
		}
3013 3014
		if (dev->written)
			s.written++;
3015
		rdev = rcu_dereference(conf->disks[i].rdev);
3016 3017 3018 3019 3020
		if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
			blocked_rdev = rdev;
			atomic_inc(&rdev->nr_pending);
			break;
		}
3021 3022 3023 3024
		if (!rdev || !test_bit(In_sync, &rdev->flags)) {
			/* The ReadError flag will just be confusing now */
			clear_bit(R5_ReadError, &dev->flags);
			clear_bit(R5_ReWrite, &dev->flags);
L
Linus Torvalds 已提交
3025
		}
3026 3027
		if (!rdev || !test_bit(In_sync, &rdev->flags)
		    || test_bit(R5_ReadError, &dev->flags)) {
3028 3029 3030
			if (s.failed < 2)
				r6s.failed_num[s.failed] = i;
			s.failed++;
3031 3032
		} else
			set_bit(R5_Insync, &dev->flags);
L
Linus Torvalds 已提交
3033 3034
	}
	rcu_read_unlock();
3035 3036 3037 3038 3039

	if (unlikely(blocked_rdev)) {
		set_bit(STRIPE_HANDLE, &sh->state);
		goto unlock;
	}
3040
	pr_debug("locked=%d uptodate=%d to_read=%d"
3041
	       " to_write=%d failed=%d failed_num=%d,%d\n",
3042 3043 3044 3045
	       s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
	       r6s.failed_num[0], r6s.failed_num[1]);
	/* check if the array has lost >2 devices and, if so, some requests
	 * might need to be failed
3046
	 */
3047 3048 3049 3050
	if (s.failed > 2 && s.to_read+s.to_write+s.written)
		handle_requests_to_failed_array(conf, sh, &s, disks,
						&return_bi);
	if (s.failed > 2 && s.syncing) {
3051 3052
		md_done_sync(conf->mddev, STRIPE_SECTORS,0);
		clear_bit(STRIPE_SYNCING, &sh->state);
3053
		s.syncing = 0;
3054 3055 3056 3057 3058 3059 3060
	}

	/*
	 * might be able to return some write requests if the parity blocks
	 * are safe, or on a failed drive
	 */
	pdev = &sh->dev[pd_idx];
3061 3062 3063 3064 3065 3066 3067 3068
	r6s.p_failed = (s.failed >= 1 && r6s.failed_num[0] == pd_idx)
		|| (s.failed >= 2 && r6s.failed_num[1] == pd_idx);
	qdev = &sh->dev[r6s.qd_idx];
	r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == r6s.qd_idx)
		|| (s.failed >= 2 && r6s.failed_num[1] == r6s.qd_idx);

	if ( s.written &&
	     ( r6s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
3069
			     && !test_bit(R5_LOCKED, &pdev->flags)
3070 3071
			     && test_bit(R5_UPTODATE, &pdev->flags)))) &&
	     ( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
3072
			     && !test_bit(R5_LOCKED, &qdev->flags)
3073 3074
			     && test_bit(R5_UPTODATE, &qdev->flags)))))
		handle_completed_write_requests(conf, sh, disks, &return_bi);
3075 3076 3077 3078 3079

	/* Now we might consider reading some blocks, either to check/generate
	 * parity, or to satisfy requests
	 * or to load a block that is being partially written.
	 */
3080 3081 3082
	if (s.to_read || s.non_overwrite || (s.to_write && s.failed) ||
	    (s.syncing && (s.uptodate < disks)) || s.expanding)
		handle_issuing_new_read_requests6(sh, &s, &r6s, disks);
3083 3084

	/* now to consider writing and what else, if anything should be read */
3085 3086
	if (s.to_write)
		handle_issuing_new_write_requests6(conf, sh, &s, &r6s, disks);
3087 3088

	/* maybe we need to check and possibly fix the parity for this stripe
3089 3090
	 * Any reads will already have been scheduled, so we just see if enough
	 * data is available
3091
	 */
3092 3093
	if (s.syncing && s.locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state))
		handle_parity_checks6(conf, sh, &s, &r6s, tmp_page, disks);
3094

3095
	if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
3096 3097 3098 3099 3100 3101 3102
		md_done_sync(conf->mddev, STRIPE_SECTORS,1);
		clear_bit(STRIPE_SYNCING, &sh->state);
	}

	/* If the failed drives are just a ReadError, then we might need
	 * to progress the repair/check process
	 */
3103 3104 3105
	if (s.failed <= 2 && !conf->mddev->ro)
		for (i = 0; i < s.failed; i++) {
			dev = &sh->dev[r6s.failed_num[i]];
3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120
			if (test_bit(R5_ReadError, &dev->flags)
			    && !test_bit(R5_LOCKED, &dev->flags)
			    && test_bit(R5_UPTODATE, &dev->flags)
				) {
				if (!test_bit(R5_ReWrite, &dev->flags)) {
					set_bit(R5_Wantwrite, &dev->flags);
					set_bit(R5_ReWrite, &dev->flags);
					set_bit(R5_LOCKED, &dev->flags);
				} else {
					/* let's read it back */
					set_bit(R5_Wantread, &dev->flags);
					set_bit(R5_LOCKED, &dev->flags);
				}
			}
		}
3121

3122
	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
3123 3124 3125 3126 3127 3128 3129
		/* Need to write out all blocks after computing P&Q */
		sh->disks = conf->raid_disks;
		sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
					     conf->raid_disks);
		compute_parity6(sh, RECONSTRUCT_WRITE);
		for (i = conf->raid_disks ; i-- ;  ) {
			set_bit(R5_LOCKED, &sh->dev[i].flags);
3130
			s.locked++;
3131 3132 3133
			set_bit(R5_Wantwrite, &sh->dev[i].flags);
		}
		clear_bit(STRIPE_EXPANDING, &sh->state);
3134
	} else if (s.expanded) {
3135 3136 3137 3138 3139 3140
		clear_bit(STRIPE_EXPAND_READY, &sh->state);
		atomic_dec(&conf->reshape_stripes);
		wake_up(&conf->wait_for_overlap);
		md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
	}

3141 3142
	if (s.expanding && s.locked == 0 &&
	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending))
3143
		handle_stripe_expansion(conf, sh, &r6s);
3144

3145
 unlock:
3146 3147
	spin_unlock(&sh->lock);

3148 3149 3150 3151
	/* wait for this device to become unblocked */
	if (unlikely(blocked_rdev))
		md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);

3152
	return_io(return_bi);
3153 3154 3155 3156 3157 3158

	for (i=disks; i-- ;) {
		int rw;
		struct bio *bi;
		mdk_rdev_t *rdev;
		if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
3159
			rw = WRITE;
3160
		else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
3161
			rw = READ;
3162 3163 3164
		else
			continue;

3165 3166
		set_bit(STRIPE_IO_STARTED, &sh->state);

3167 3168 3169
		bi = &sh->dev[i].req;

		bi->bi_rw = rw;
3170
		if (rw == WRITE)
3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183
			bi->bi_end_io = raid5_end_write_request;
		else
			bi->bi_end_io = raid5_end_read_request;

		rcu_read_lock();
		rdev = rcu_dereference(conf->disks[i].rdev);
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
		if (rdev)
			atomic_inc(&rdev->nr_pending);
		rcu_read_unlock();

		if (rdev) {
3184
			if (s.syncing || s.expanding || s.expanded)
3185 3186 3187
				md_sync_acct(rdev->bdev, STRIPE_SECTORS);

			bi->bi_bdev = rdev->bdev;
3188
			pr_debug("for %llu schedule op %ld on disc %d\n",
3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205
				(unsigned long long)sh->sector, bi->bi_rw, i);
			atomic_inc(&sh->count);
			bi->bi_sector = sh->sector + rdev->data_offset;
			bi->bi_flags = 1 << BIO_UPTODATE;
			bi->bi_vcnt = 1;
			bi->bi_max_vecs = 1;
			bi->bi_idx = 0;
			bi->bi_io_vec = &sh->dev[i].vec;
			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
			bi->bi_io_vec[0].bv_offset = 0;
			bi->bi_size = STRIPE_SIZE;
			bi->bi_next = NULL;
			if (rw == WRITE &&
			    test_bit(R5_ReWrite, &sh->dev[i].flags))
				atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
			generic_make_request(bi);
		} else {
3206
			if (rw == WRITE)
3207
				set_bit(STRIPE_DEGRADED, &sh->state);
3208
			pr_debug("skip op %ld on disc %d for sector %llu\n",
3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236
				bi->bi_rw, i, (unsigned long long)sh->sector);
			clear_bit(R5_LOCKED, &sh->dev[i].flags);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
	}
}

static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
{
	if (sh->raid_conf->level == 6)
		handle_stripe6(sh, tmp_page);
	else
		handle_stripe5(sh);
}



static void raid5_activate_delayed(raid5_conf_t *conf)
{
	if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
		while (!list_empty(&conf->delayed_list)) {
			struct list_head *l = conf->delayed_list.next;
			struct stripe_head *sh;
			sh = list_entry(l, struct stripe_head, lru);
			list_del_init(l);
			clear_bit(STRIPE_DELAYED, &sh->state);
			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
				atomic_inc(&conf->preread_active_stripes);
3237
			list_add_tail(&sh->lru, &conf->hold_list);
3238
		}
3239 3240
	} else
		blk_plug_device(conf->mddev->queue);
3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265
}

static void activate_bit_delay(raid5_conf_t *conf)
{
	/* device_lock is held */
	struct list_head head;
	list_add(&head, &conf->bitmap_list);
	list_del_init(&conf->bitmap_list);
	while (!list_empty(&head)) {
		struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
		list_del_init(&sh->lru);
		atomic_inc(&sh->count);
		__release_stripe(conf, sh);
	}
}

static void unplug_slaves(mddev_t *mddev)
{
	raid5_conf_t *conf = mddev_to_conf(mddev);
	int i;

	rcu_read_lock();
	for (i=0; i<mddev->raid_disks; i++) {
		mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
		if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
3266
			struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
3267 3268 3269 3270

			atomic_inc(&rdev->nr_pending);
			rcu_read_unlock();

3271
			blk_unplug(r_queue);
3272 3273 3274 3275 3276 3277 3278 3279

			rdev_dec_pending(rdev, mddev);
			rcu_read_lock();
		}
	}
	rcu_read_unlock();
}

3280
static void raid5_unplug_device(struct request_queue *q)
3281 3282 3283 3284 3285 3286 3287 3288 3289 3290
{
	mddev_t *mddev = q->queuedata;
	raid5_conf_t *conf = mddev_to_conf(mddev);
	unsigned long flags;

	spin_lock_irqsave(&conf->device_lock, flags);

	if (blk_remove_plug(q)) {
		conf->seq_flush++;
		raid5_activate_delayed(conf);
3291
	}
L
Linus Torvalds 已提交
3292 3293 3294 3295 3296 3297 3298
	md_wakeup_thread(mddev->thread);

	spin_unlock_irqrestore(&conf->device_lock, flags);

	unplug_slaves(mddev);
}

3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316
static int raid5_congested(void *data, int bits)
{
	mddev_t *mddev = data;
	raid5_conf_t *conf = mddev_to_conf(mddev);

	/* No difference between reads and writes.  Just check
	 * how busy the stripe_cache is
	 */
	if (conf->inactive_blocked)
		return 1;
	if (conf->quiesce)
		return 1;
	if (list_empty_careful(&conf->inactive_list))
		return 1;

	return 0;
}

3317 3318 3319
/* We want read requests to align with chunks where possible,
 * but write requests don't need to.
 */
3320
static int raid5_mergeable_bvec(struct request_queue *q, struct bio *bio, struct bio_vec *biovec)
3321 3322 3323 3324 3325 3326 3327
{
	mddev_t *mddev = q->queuedata;
	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
	int max;
	unsigned int chunk_sectors = mddev->chunk_size >> 9;
	unsigned int bio_sectors = bio->bi_size >> 9;

3328
	if (bio_data_dir(bio) == WRITE)
3329 3330 3331 3332 3333 3334 3335 3336 3337 3338
		return biovec->bv_len; /* always allow writes to be mergeable */

	max =  (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
	if (max < 0) max = 0;
	if (max <= biovec->bv_len && bio_sectors == 0)
		return biovec->bv_len;
	else
		return max;
}

3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349

static int in_chunk_boundary(mddev_t *mddev, struct bio *bio)
{
	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
	unsigned int chunk_sectors = mddev->chunk_size >> 9;
	unsigned int bio_sectors = bio->bi_size >> 9;

	return  chunk_sectors >=
		((sector & (chunk_sectors - 1)) + bio_sectors);
}

3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378
/*
 *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
 *  later sampled by raid5d.
 */
static void add_bio_to_retry(struct bio *bi,raid5_conf_t *conf)
{
	unsigned long flags;

	spin_lock_irqsave(&conf->device_lock, flags);

	bi->bi_next = conf->retry_read_aligned_list;
	conf->retry_read_aligned_list = bi;

	spin_unlock_irqrestore(&conf->device_lock, flags);
	md_wakeup_thread(conf->mddev->thread);
}


static struct bio *remove_bio_from_retry(raid5_conf_t *conf)
{
	struct bio *bi;

	bi = conf->retry_read_aligned;
	if (bi) {
		conf->retry_read_aligned = NULL;
		return bi;
	}
	bi = conf->retry_read_aligned_list;
	if(bi) {
3379
		conf->retry_read_aligned_list = bi->bi_next;
3380 3381 3382 3383 3384 3385 3386 3387 3388
		bi->bi_next = NULL;
		bi->bi_phys_segments = 1; /* biased count of active stripes */
		bi->bi_hw_segments = 0; /* count of processed stripes */
	}

	return bi;
}


3389 3390 3391 3392 3393 3394
/*
 *  The "raid5_align_endio" should check if the read succeeded and if it
 *  did, call bio_endio on the original bio (having bio_put the new bio
 *  first).
 *  If the read failed..
 */
3395
static void raid5_align_endio(struct bio *bi, int error)
3396 3397
{
	struct bio* raid_bi  = bi->bi_private;
3398 3399 3400 3401 3402
	mddev_t *mddev;
	raid5_conf_t *conf;
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
	mdk_rdev_t *rdev;

3403
	bio_put(bi);
3404 3405 3406 3407 3408 3409 3410 3411 3412

	mddev = raid_bi->bi_bdev->bd_disk->queue->queuedata;
	conf = mddev_to_conf(mddev);
	rdev = (void*)raid_bi->bi_next;
	raid_bi->bi_next = NULL;

	rdev_dec_pending(rdev, conf->mddev);

	if (!error && uptodate) {
3413
		bio_endio(raid_bi, 0);
3414 3415
		if (atomic_dec_and_test(&conf->active_aligned_reads))
			wake_up(&conf->wait_for_stripe);
3416
		return;
3417 3418 3419
	}


3420
	pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
3421 3422

	add_bio_to_retry(raid_bi, conf);
3423 3424
}

3425 3426
static int bio_fits_rdev(struct bio *bi)
{
3427
	struct request_queue *q = bdev_get_queue(bi->bi_bdev);
3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445

	if ((bi->bi_size>>9) > q->max_sectors)
		return 0;
	blk_recount_segments(q, bi);
	if (bi->bi_phys_segments > q->max_phys_segments ||
	    bi->bi_hw_segments > q->max_hw_segments)
		return 0;

	if (q->merge_bvec_fn)
		/* it's too hard to apply the merge_bvec_fn at this stage,
		 * just just give up
		 */
		return 0;

	return 1;
}


3446
static int chunk_aligned_read(struct request_queue *q, struct bio * raid_bio)
3447 3448 3449 3450
{
	mddev_t *mddev = q->queuedata;
	raid5_conf_t *conf = mddev_to_conf(mddev);
	const unsigned int raid_disks = conf->raid_disks;
3451
	const unsigned int data_disks = raid_disks - conf->max_degraded;
3452 3453 3454 3455 3456
	unsigned int dd_idx, pd_idx;
	struct bio* align_bi;
	mdk_rdev_t *rdev;

	if (!in_chunk_boundary(mddev, raid_bio)) {
3457
		pr_debug("chunk_aligned_read : non aligned\n");
3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486
		return 0;
	}
	/*
 	 * use bio_clone to make a copy of the bio
	 */
	align_bi = bio_clone(raid_bio, GFP_NOIO);
	if (!align_bi)
		return 0;
	/*
	 *   set bi_end_io to a new function, and set bi_private to the
	 *     original bio.
	 */
	align_bi->bi_end_io  = raid5_align_endio;
	align_bi->bi_private = raid_bio;
	/*
	 *	compute position
	 */
	align_bi->bi_sector =  raid5_compute_sector(raid_bio->bi_sector,
					raid_disks,
					data_disks,
					&dd_idx,
					&pd_idx,
					conf);

	rcu_read_lock();
	rdev = rcu_dereference(conf->disks[dd_idx].rdev);
	if (rdev && test_bit(In_sync, &rdev->flags)) {
		atomic_inc(&rdev->nr_pending);
		rcu_read_unlock();
3487 3488 3489 3490 3491
		raid_bio->bi_next = (void*)rdev;
		align_bi->bi_bdev =  rdev->bdev;
		align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);
		align_bi->bi_sector += rdev->data_offset;

3492 3493 3494 3495 3496 3497 3498
		if (!bio_fits_rdev(align_bi)) {
			/* too big in some way */
			bio_put(align_bi);
			rdev_dec_pending(rdev, mddev);
			return 0;
		}

3499 3500 3501 3502 3503 3504 3505
		spin_lock_irq(&conf->device_lock);
		wait_event_lock_irq(conf->wait_for_stripe,
				    conf->quiesce == 0,
				    conf->device_lock, /* nothing */);
		atomic_inc(&conf->active_aligned_reads);
		spin_unlock_irq(&conf->device_lock);

3506 3507 3508 3509
		generic_make_request(align_bi);
		return 1;
	} else {
		rcu_read_unlock();
3510
		bio_put(align_bi);
3511 3512 3513 3514
		return 0;
	}
}

3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566
/* __get_priority_stripe - get the next stripe to process
 *
 * Full stripe writes are allowed to pass preread active stripes up until
 * the bypass_threshold is exceeded.  In general the bypass_count
 * increments when the handle_list is handled before the hold_list; however, it
 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
 * stripe with in flight i/o.  The bypass_count will be reset when the
 * head of the hold_list has changed, i.e. the head was promoted to the
 * handle_list.
 */
static struct stripe_head *__get_priority_stripe(raid5_conf_t *conf)
{
	struct stripe_head *sh;

	pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
		  __func__,
		  list_empty(&conf->handle_list) ? "empty" : "busy",
		  list_empty(&conf->hold_list) ? "empty" : "busy",
		  atomic_read(&conf->pending_full_writes), conf->bypass_count);

	if (!list_empty(&conf->handle_list)) {
		sh = list_entry(conf->handle_list.next, typeof(*sh), lru);

		if (list_empty(&conf->hold_list))
			conf->bypass_count = 0;
		else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
			if (conf->hold_list.next == conf->last_hold)
				conf->bypass_count++;
			else {
				conf->last_hold = conf->hold_list.next;
				conf->bypass_count -= conf->bypass_threshold;
				if (conf->bypass_count < 0)
					conf->bypass_count = 0;
			}
		}
	} else if (!list_empty(&conf->hold_list) &&
		   ((conf->bypass_threshold &&
		     conf->bypass_count > conf->bypass_threshold) ||
		    atomic_read(&conf->pending_full_writes) == 0)) {
		sh = list_entry(conf->hold_list.next,
				typeof(*sh), lru);
		conf->bypass_count -= conf->bypass_threshold;
		if (conf->bypass_count < 0)
			conf->bypass_count = 0;
	} else
		return NULL;

	list_del_init(&sh->lru);
	atomic_inc(&sh->count);
	BUG_ON(atomic_read(&sh->count) != 1);
	return sh;
}
3567

3568
static int make_request(struct request_queue *q, struct bio * bi)
L
Linus Torvalds 已提交
3569 3570 3571 3572 3573 3574 3575
{
	mddev_t *mddev = q->queuedata;
	raid5_conf_t *conf = mddev_to_conf(mddev);
	unsigned int dd_idx, pd_idx;
	sector_t new_sector;
	sector_t logical_sector, last_sector;
	struct stripe_head *sh;
3576
	const int rw = bio_data_dir(bi);
3577
	int remaining;
L
Linus Torvalds 已提交
3578

3579
	if (unlikely(bio_barrier(bi))) {
3580
		bio_endio(bi, -EOPNOTSUPP);
3581 3582 3583
		return 0;
	}

3584
	md_write_start(mddev, bi);
3585

3586 3587
	disk_stat_inc(mddev->gendisk, ios[rw]);
	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
L
Linus Torvalds 已提交
3588

3589
	if (rw == READ &&
3590 3591 3592 3593
	     mddev->reshape_position == MaxSector &&
	     chunk_aligned_read(q,bi))
            	return 0;

L
Linus Torvalds 已提交
3594 3595 3596 3597
	logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
	last_sector = bi->bi_sector + (bi->bi_size>>9);
	bi->bi_next = NULL;
	bi->bi_phys_segments = 1;	/* over-loaded to count active stripes */
3598

L
Linus Torvalds 已提交
3599 3600
	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
		DEFINE_WAIT(w);
3601
		int disks, data_disks;
3602

3603
	retry:
3604
		prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
3605 3606 3607
		if (likely(conf->expand_progress == MaxSector))
			disks = conf->raid_disks;
		else {
3608 3609 3610 3611 3612 3613 3614 3615
			/* spinlock is needed as expand_progress may be
			 * 64bit on a 32bit platform, and so it might be
			 * possible to see a half-updated value
			 * Ofcourse expand_progress could change after
			 * the lock is dropped, so once we get a reference
			 * to the stripe that we think it is, we will have
			 * to check again.
			 */
3616 3617 3618 3619
			spin_lock_irq(&conf->device_lock);
			disks = conf->raid_disks;
			if (logical_sector >= conf->expand_progress)
				disks = conf->previous_raid_disks;
3620 3621 3622 3623 3624 3625 3626
			else {
				if (logical_sector >= conf->expand_lo) {
					spin_unlock_irq(&conf->device_lock);
					schedule();
					goto retry;
				}
			}
3627 3628
			spin_unlock_irq(&conf->device_lock);
		}
3629 3630 3631
		data_disks = disks - conf->max_degraded;

 		new_sector = raid5_compute_sector(logical_sector, disks, data_disks,
3632
						  &dd_idx, &pd_idx, conf);
3633
		pr_debug("raid5: make_request, sector %llu logical %llu\n",
L
Linus Torvalds 已提交
3634 3635 3636
			(unsigned long long)new_sector, 
			(unsigned long long)logical_sector);

3637
		sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK));
L
Linus Torvalds 已提交
3638
		if (sh) {
3639 3640
			if (unlikely(conf->expand_progress != MaxSector)) {
				/* expansion might have moved on while waiting for a
3641 3642 3643 3644 3645 3646
				 * stripe, so we must do the range check again.
				 * Expansion could still move past after this
				 * test, but as we are holding a reference to
				 * 'sh', we know that if that happens,
				 *  STRIPE_EXPANDING will get set and the expansion
				 * won't proceed until we finish with the stripe.
3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659
				 */
				int must_retry = 0;
				spin_lock_irq(&conf->device_lock);
				if (logical_sector <  conf->expand_progress &&
				    disks == conf->previous_raid_disks)
					/* mismatch, need to try again */
					must_retry = 1;
				spin_unlock_irq(&conf->device_lock);
				if (must_retry) {
					release_stripe(sh);
					goto retry;
				}
			}
3660 3661 3662 3663 3664 3665 3666 3667 3668
			/* FIXME what if we get a false positive because these
			 * are being updated.
			 */
			if (logical_sector >= mddev->suspend_lo &&
			    logical_sector < mddev->suspend_hi) {
				release_stripe(sh);
				schedule();
				goto retry;
			}
3669 3670 3671 3672 3673

			if (test_bit(STRIPE_EXPANDING, &sh->state) ||
			    !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) {
				/* Stripe is busy expanding or
				 * add failed due to overlap.  Flush everything
L
Linus Torvalds 已提交
3674 3675 3676 3677 3678 3679 3680 3681
				 * and wait a while
				 */
				raid5_unplug_device(mddev->queue);
				release_stripe(sh);
				schedule();
				goto retry;
			}
			finish_wait(&conf->wait_for_overlap, &w);
3682 3683
			set_bit(STRIPE_HANDLE, &sh->state);
			clear_bit(STRIPE_DELAYED, &sh->state);
L
Linus Torvalds 已提交
3684 3685 3686 3687 3688 3689 3690 3691 3692 3693
			release_stripe(sh);
		} else {
			/* cannot get stripe for read-ahead, just give-up */
			clear_bit(BIO_UPTODATE, &bi->bi_flags);
			finish_wait(&conf->wait_for_overlap, &w);
			break;
		}
			
	}
	spin_lock_irq(&conf->device_lock);
3694 3695 3696
	remaining = --bi->bi_phys_segments;
	spin_unlock_irq(&conf->device_lock);
	if (remaining == 0) {
L
Linus Torvalds 已提交
3697

3698
		if ( rw == WRITE )
L
Linus Torvalds 已提交
3699
			md_write_end(mddev);
3700

3701
		bio_endio(bi, 0);
L
Linus Torvalds 已提交
3702 3703 3704 3705
	}
	return 0;
}

3706
static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped)
L
Linus Torvalds 已提交
3707
{
3708 3709 3710 3711 3712 3713 3714 3715 3716
	/* reshaping is quite different to recovery/resync so it is
	 * handled quite separately ... here.
	 *
	 * On each call to sync_request, we gather one chunk worth of
	 * destination stripes and flag them as expanding.
	 * Then we find all the source stripes and request reads.
	 * As the reads complete, handle_stripe will copy the data
	 * into the destination stripe and release that stripe.
	 */
L
Linus Torvalds 已提交
3717 3718
	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
	struct stripe_head *sh;
3719 3720
	int pd_idx;
	sector_t first_sector, last_sector;
3721 3722 3723
	int raid_disks = conf->previous_raid_disks;
	int data_disks = raid_disks - conf->max_degraded;
	int new_data_disks = conf->raid_disks - conf->max_degraded;
3724 3725 3726 3727 3728 3729 3730 3731
	int i;
	int dd_idx;
	sector_t writepos, safepos, gap;

	if (sector_nr == 0 &&
	    conf->expand_progress != 0) {
		/* restarting in the middle, skip the initial sectors */
		sector_nr = conf->expand_progress;
3732
		sector_div(sector_nr, new_data_disks);
3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745
		*skipped = 1;
		return sector_nr;
	}

	/* we update the metadata when there is more than 3Meg
	 * in the block range (that is rather arbitrary, should
	 * probably be time based) or when the data about to be
	 * copied would over-write the source of the data at
	 * the front of the range.
	 * i.e. one new_stripe forward from expand_progress new_maps
	 * to after where expand_lo old_maps to
	 */
	writepos = conf->expand_progress +
3746 3747
		conf->chunk_size/512*(new_data_disks);
	sector_div(writepos, new_data_disks);
3748
	safepos = conf->expand_lo;
3749
	sector_div(safepos, data_disks);
3750 3751 3752
	gap = conf->expand_progress - conf->expand_lo;

	if (writepos >= safepos ||
3753
	    gap > (new_data_disks)*3000*2 /*3Meg*/) {
3754 3755 3756 3757
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes)==0);
		mddev->reshape_position = conf->expand_progress;
3758
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
3759
		md_wakeup_thread(mddev->thread);
3760
		wait_event(mddev->sb_wait, mddev->flags == 0 ||
3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782
			   kthread_should_stop());
		spin_lock_irq(&conf->device_lock);
		conf->expand_lo = mddev->reshape_position;
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
	}

	for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) {
		int j;
		int skipped = 0;
		pd_idx = stripe_to_pdidx(sector_nr+i, conf, conf->raid_disks);
		sh = get_active_stripe(conf, sector_nr+i,
				       conf->raid_disks, pd_idx, 0);
		set_bit(STRIPE_EXPANDING, &sh->state);
		atomic_inc(&conf->reshape_stripes);
		/* If any of this stripe is beyond the end of the old
		 * array, then we need to zero those blocks
		 */
		for (j=sh->disks; j--;) {
			sector_t s;
			if (j == sh->pd_idx)
				continue;
3783 3784 3785
			if (conf->level == 6 &&
			    j == raid6_next_disk(sh->pd_idx, sh->disks))
				continue;
3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801
			s = compute_blocknr(sh, j);
			if (s < (mddev->array_size<<1)) {
				skipped = 1;
				continue;
			}
			memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
			set_bit(R5_Expanded, &sh->dev[j].flags);
			set_bit(R5_UPTODATE, &sh->dev[j].flags);
		}
		if (!skipped) {
			set_bit(STRIPE_EXPAND_READY, &sh->state);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
		release_stripe(sh);
	}
	spin_lock_irq(&conf->device_lock);
N
NeilBrown 已提交
3802
	conf->expand_progress = (sector_nr + i) * new_data_disks;
3803 3804 3805 3806 3807 3808 3809
	spin_unlock_irq(&conf->device_lock);
	/* Ok, those stripe are ready. We can start scheduling
	 * reads on the source stripes.
	 * The source stripes are determined by mapping the first and last
	 * block on the destination stripes.
	 */
	first_sector =
3810
		raid5_compute_sector(sector_nr*(new_data_disks),
3811 3812 3813 3814
				     raid_disks, data_disks,
				     &dd_idx, &pd_idx, conf);
	last_sector =
		raid5_compute_sector((sector_nr+conf->chunk_size/512)
3815
				     *(new_data_disks) -1,
3816 3817 3818 3819 3820
				     raid_disks, data_disks,
				     &dd_idx, &pd_idx, conf);
	if (last_sector >= (mddev->size<<1))
		last_sector = (mddev->size<<1)-1;
	while (first_sector <= last_sector) {
3821 3822
		pd_idx = stripe_to_pdidx(first_sector, conf,
					 conf->previous_raid_disks);
3823 3824 3825 3826 3827 3828 3829
		sh = get_active_stripe(conf, first_sector,
				       conf->previous_raid_disks, pd_idx, 0);
		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
		set_bit(STRIPE_HANDLE, &sh->state);
		release_stripe(sh);
		first_sector += STRIPE_SECTORS;
	}
3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848
	/* If this takes us to the resync_max point where we have to pause,
	 * then we need to write out the superblock.
	 */
	sector_nr += conf->chunk_size>>9;
	if (sector_nr >= mddev->resync_max) {
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes) == 0);
		mddev->reshape_position = conf->expand_progress;
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		md_wakeup_thread(mddev->thread);
		wait_event(mddev->sb_wait,
			   !test_bit(MD_CHANGE_DEVS, &mddev->flags)
			   || kthread_should_stop());
		spin_lock_irq(&conf->device_lock);
		conf->expand_lo = mddev->reshape_position;
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
	}
3849 3850 3851 3852 3853 3854 3855 3856 3857
	return conf->chunk_size>>9;
}

/* FIXME go_faster isn't used */
static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
{
	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
	struct stripe_head *sh;
	int pd_idx;
L
Linus Torvalds 已提交
3858
	int raid_disks = conf->raid_disks;
3859 3860
	sector_t max_sector = mddev->size << 1;
	int sync_blocks;
3861 3862
	int still_degraded = 0;
	int i;
L
Linus Torvalds 已提交
3863

3864
	if (sector_nr >= max_sector) {
L
Linus Torvalds 已提交
3865 3866
		/* just being told to finish up .. nothing much to do */
		unplug_slaves(mddev);
3867 3868 3869 3870
		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
			end_reshape(conf);
			return 0;
		}
3871 3872 3873 3874

		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
					&sync_blocks, 1);
3875
		else /* completed sync */
3876 3877 3878
			conf->fullsync = 0;
		bitmap_close_sync(mddev->bitmap);

L
Linus Torvalds 已提交
3879 3880
		return 0;
	}
3881

3882 3883
	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
		return reshape_request(mddev, sector_nr, skipped);
3884

3885 3886 3887 3888 3889 3890
	/* No need to check resync_max as we never do more than one
	 * stripe, and as resync_max will always be on a chunk boundary,
	 * if the check in md_do_sync didn't fire, there is no chance
	 * of overstepping resync_max here
	 */

3891
	/* if there is too many failed drives and we are trying
L
Linus Torvalds 已提交
3892 3893 3894
	 * to resync, then assert that we are finished, because there is
	 * nothing we can do.
	 */
3895
	if (mddev->degraded >= conf->max_degraded &&
3896
	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3897 3898
		sector_t rv = (mddev->size << 1) - sector_nr;
		*skipped = 1;
L
Linus Torvalds 已提交
3899 3900
		return rv;
	}
3901
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
3902
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
3903 3904 3905 3906 3907 3908
	    !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
		/* we can skip this block, and probably more */
		sync_blocks /= STRIPE_SECTORS;
		*skipped = 1;
		return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
	}
L
Linus Torvalds 已提交
3909

N
NeilBrown 已提交
3910 3911 3912

	bitmap_cond_end_sync(mddev->bitmap, sector_nr);

3913
	pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks);
3914
	sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1);
L
Linus Torvalds 已提交
3915
	if (sh == NULL) {
3916
		sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0);
L
Linus Torvalds 已提交
3917
		/* make sure we don't swamp the stripe cache if someone else
3918
		 * is trying to get access
L
Linus Torvalds 已提交
3919
		 */
3920
		schedule_timeout_uninterruptible(1);
L
Linus Torvalds 已提交
3921
	}
3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932
	/* Need to check if array will still be degraded after recovery/resync
	 * We don't need to check the 'failed' flag as when that gets set,
	 * recovery aborts.
	 */
	for (i=0; i<mddev->raid_disks; i++)
		if (conf->disks[i].rdev == NULL)
			still_degraded = 1;

	bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);

	spin_lock(&sh->lock);
L
Linus Torvalds 已提交
3933 3934 3935 3936
	set_bit(STRIPE_SYNCING, &sh->state);
	clear_bit(STRIPE_INSYNC, &sh->state);
	spin_unlock(&sh->lock);

3937
	handle_stripe(sh, NULL);
L
Linus Torvalds 已提交
3938 3939 3940 3941 3942
	release_stripe(sh);

	return STRIPE_SECTORS;
}

3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971
static int  retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
{
	/* We may not be able to submit a whole bio at once as there
	 * may not be enough stripe_heads available.
	 * We cannot pre-allocate enough stripe_heads as we may need
	 * more than exist in the cache (if we allow ever large chunks).
	 * So we do one stripe head at a time and record in
	 * ->bi_hw_segments how many have been done.
	 *
	 * We *know* that this entire raid_bio is in one chunk, so
	 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
	 */
	struct stripe_head *sh;
	int dd_idx, pd_idx;
	sector_t sector, logical_sector, last_sector;
	int scnt = 0;
	int remaining;
	int handled = 0;

	logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
	sector = raid5_compute_sector(	logical_sector,
					conf->raid_disks,
					conf->raid_disks - conf->max_degraded,
					&dd_idx,
					&pd_idx,
					conf);
	last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);

	for (; logical_sector < last_sector;
3972 3973 3974
	     logical_sector += STRIPE_SECTORS,
		     sector += STRIPE_SECTORS,
		     scnt++) {
3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989

		if (scnt < raid_bio->bi_hw_segments)
			/* already done this stripe */
			continue;

		sh = get_active_stripe(conf, sector, conf->raid_disks, pd_idx, 1);

		if (!sh) {
			/* failed to get a stripe - must wait */
			raid_bio->bi_hw_segments = scnt;
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

		set_bit(R5_ReadError, &sh->dev[dd_idx].flags);
3990 3991 3992 3993 3994 3995 3996
		if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
			release_stripe(sh);
			raid_bio->bi_hw_segments = scnt;
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

3997 3998 3999 4000 4001 4002 4003
		handle_stripe(sh, NULL);
		release_stripe(sh);
		handled++;
	}
	spin_lock_irq(&conf->device_lock);
	remaining = --raid_bio->bi_phys_segments;
	spin_unlock_irq(&conf->device_lock);
4004 4005
	if (remaining == 0)
		bio_endio(raid_bio, 0);
4006 4007 4008 4009 4010 4011 4012
	if (atomic_dec_and_test(&conf->active_aligned_reads))
		wake_up(&conf->wait_for_stripe);
	return handled;
}



L
Linus Torvalds 已提交
4013 4014 4015 4016 4017 4018 4019
/*
 * This is our raid5 kernel thread.
 *
 * We scan the hash table for stripes which can be handled now.
 * During the scan, completed stripes are saved for us by the interrupt
 * handler, so that they will not have to wait for our next wakeup.
 */
4020
static void raid5d(mddev_t *mddev)
L
Linus Torvalds 已提交
4021 4022 4023 4024 4025
{
	struct stripe_head *sh;
	raid5_conf_t *conf = mddev_to_conf(mddev);
	int handled;

4026
	pr_debug("+++ raid5d active\n");
L
Linus Torvalds 已提交
4027 4028 4029 4030 4031 4032

	md_check_recovery(mddev);

	handled = 0;
	spin_lock_irq(&conf->device_lock);
	while (1) {
4033
		struct bio *bio;
L
Linus Torvalds 已提交
4034

4035
		if (conf->seq_flush != conf->seq_write) {
4036
			int seq = conf->seq_flush;
4037
			spin_unlock_irq(&conf->device_lock);
4038
			bitmap_unplug(mddev->bitmap);
4039
			spin_lock_irq(&conf->device_lock);
4040 4041 4042 4043
			conf->seq_write = seq;
			activate_bit_delay(conf);
		}

4044 4045 4046 4047 4048 4049 4050 4051 4052 4053
		while ((bio = remove_bio_from_retry(conf))) {
			int ok;
			spin_unlock_irq(&conf->device_lock);
			ok = retry_aligned_read(conf, bio);
			spin_lock_irq(&conf->device_lock);
			if (!ok)
				break;
			handled++;
		}

4054 4055 4056
		sh = __get_priority_stripe(conf);

		if (!sh) {
4057
			async_tx_issue_pending_all();
L
Linus Torvalds 已提交
4058
			break;
4059
		}
L
Linus Torvalds 已提交
4060 4061 4062
		spin_unlock_irq(&conf->device_lock);
		
		handled++;
4063
		handle_stripe(sh, conf->spare_page);
L
Linus Torvalds 已提交
4064 4065 4066 4067
		release_stripe(sh);

		spin_lock_irq(&conf->device_lock);
	}
4068
	pr_debug("%d stripes handled\n", handled);
L
Linus Torvalds 已提交
4069 4070 4071 4072 4073

	spin_unlock_irq(&conf->device_lock);

	unplug_slaves(mddev);

4074
	pr_debug("--- raid5d inactive\n");
L
Linus Torvalds 已提交
4075 4076
}

4077
static ssize_t
4078
raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
4079
{
4080
	raid5_conf_t *conf = mddev_to_conf(mddev);
4081 4082 4083 4084
	if (conf)
		return sprintf(page, "%d\n", conf->max_nr_stripes);
	else
		return 0;
4085 4086 4087
}

static ssize_t
4088
raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
4089
{
4090
	raid5_conf_t *conf = mddev_to_conf(mddev);
4091
	unsigned long new;
4092 4093
	if (len >= PAGE_SIZE)
		return -EINVAL;
4094 4095
	if (!conf)
		return -ENODEV;
4096

4097
	if (strict_strtoul(page, 10, &new))
4098 4099 4100 4101 4102 4103 4104 4105 4106
		return -EINVAL;
	if (new <= 16 || new > 32768)
		return -EINVAL;
	while (new < conf->max_nr_stripes) {
		if (drop_one_stripe(conf))
			conf->max_nr_stripes--;
		else
			break;
	}
4107
	md_allow_write(mddev);
4108 4109 4110 4111 4112 4113 4114
	while (new > conf->max_nr_stripes) {
		if (grow_one_stripe(conf))
			conf->max_nr_stripes++;
		else break;
	}
	return len;
}
4115

4116 4117 4118 4119
static struct md_sysfs_entry
raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
				raid5_show_stripe_cache_size,
				raid5_store_stripe_cache_size);
4120

4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134
static ssize_t
raid5_show_preread_threshold(mddev_t *mddev, char *page)
{
	raid5_conf_t *conf = mddev_to_conf(mddev);
	if (conf)
		return sprintf(page, "%d\n", conf->bypass_threshold);
	else
		return 0;
}

static ssize_t
raid5_store_preread_threshold(mddev_t *mddev, const char *page, size_t len)
{
	raid5_conf_t *conf = mddev_to_conf(mddev);
4135
	unsigned long new;
4136 4137 4138 4139 4140
	if (len >= PAGE_SIZE)
		return -EINVAL;
	if (!conf)
		return -ENODEV;

4141
	if (strict_strtoul(page, 10, &new))
4142
		return -EINVAL;
4143
	if (new > conf->max_nr_stripes)
4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154
		return -EINVAL;
	conf->bypass_threshold = new;
	return len;
}

static struct md_sysfs_entry
raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
					S_IRUGO | S_IWUSR,
					raid5_show_preread_threshold,
					raid5_store_preread_threshold);

4155
static ssize_t
4156
stripe_cache_active_show(mddev_t *mddev, char *page)
4157
{
4158
	raid5_conf_t *conf = mddev_to_conf(mddev);
4159 4160 4161 4162
	if (conf)
		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
	else
		return 0;
4163 4164
}

4165 4166
static struct md_sysfs_entry
raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
4167

4168
static struct attribute *raid5_attrs[] =  {
4169 4170
	&raid5_stripecache_size.attr,
	&raid5_stripecache_active.attr,
4171
	&raid5_preread_bypass_threshold.attr,
4172 4173
	NULL,
};
4174 4175 4176
static struct attribute_group raid5_attrs_group = {
	.name = NULL,
	.attrs = raid5_attrs,
4177 4178
};

4179
static int run(mddev_t *mddev)
L
Linus Torvalds 已提交
4180 4181 4182 4183 4184 4185
{
	raid5_conf_t *conf;
	int raid_disk, memory;
	mdk_rdev_t *rdev;
	struct disk_info *disk;
	struct list_head *tmp;
4186
	int working_disks = 0;
L
Linus Torvalds 已提交
4187

4188 4189
	if (mddev->level != 5 && mddev->level != 4 && mddev->level != 6) {
		printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n",
N
NeilBrown 已提交
4190
		       mdname(mddev), mddev->level);
L
Linus Torvalds 已提交
4191 4192 4193
		return -EIO;
	}

4194 4195 4196 4197 4198 4199 4200 4201
	if (mddev->reshape_position != MaxSector) {
		/* Check that we can continue the reshape.
		 * Currently only disks can change, it must
		 * increase, and we must be past the point where
		 * a stripe over-writes itself
		 */
		sector_t here_new, here_old;
		int old_disks;
4202
		int max_degraded = (mddev->level == 5 ? 1 : 2);
4203 4204 4205 4206

		if (mddev->new_level != mddev->level ||
		    mddev->new_layout != mddev->layout ||
		    mddev->new_chunk != mddev->chunk_size) {
4207 4208
			printk(KERN_ERR "raid5: %s: unsupported reshape "
			       "required - aborting.\n",
4209 4210 4211 4212
			       mdname(mddev));
			return -EINVAL;
		}
		if (mddev->delta_disks <= 0) {
4213 4214
			printk(KERN_ERR "raid5: %s: unsupported reshape "
			       "(reduce disks) required - aborting.\n",
4215 4216 4217 4218 4219
			       mdname(mddev));
			return -EINVAL;
		}
		old_disks = mddev->raid_disks - mddev->delta_disks;
		/* reshape_position must be on a new-stripe boundary, and one
4220 4221
		 * further up in new geometry must map after here in old
		 * geometry.
4222 4223
		 */
		here_new = mddev->reshape_position;
4224 4225 4226 4227
		if (sector_div(here_new, (mddev->chunk_size>>9)*
			       (mddev->raid_disks - max_degraded))) {
			printk(KERN_ERR "raid5: reshape_position not "
			       "on a stripe boundary\n");
4228 4229 4230 4231
			return -EINVAL;
		}
		/* here_new is the stripe we will write to */
		here_old = mddev->reshape_position;
4232 4233 4234 4235
		sector_div(here_old, (mddev->chunk_size>>9)*
			   (old_disks-max_degraded));
		/* here_old is the first stripe that we might need to read
		 * from */
4236 4237
		if (here_new >= here_old) {
			/* Reading from the same stripe as writing to - bad */
4238 4239
			printk(KERN_ERR "raid5: reshape_position too early for "
			       "auto-recovery - aborting.\n");
4240 4241 4242 4243 4244 4245 4246
			return -EINVAL;
		}
		printk(KERN_INFO "raid5: reshape will continue\n");
		/* OK, we should be able to continue; */
	}


4247
	mddev->private = kzalloc(sizeof (raid5_conf_t), GFP_KERNEL);
L
Linus Torvalds 已提交
4248 4249
	if ((conf = mddev->private) == NULL)
		goto abort;
4250 4251 4252 4253 4254 4255 4256 4257
	if (mddev->reshape_position == MaxSector) {
		conf->previous_raid_disks = conf->raid_disks = mddev->raid_disks;
	} else {
		conf->raid_disks = mddev->raid_disks;
		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
	}

	conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info),
4258 4259 4260
			      GFP_KERNEL);
	if (!conf->disks)
		goto abort;
4261

L
Linus Torvalds 已提交
4262 4263
	conf->mddev = mddev;

4264
	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
L
Linus Torvalds 已提交
4265 4266
		goto abort;

4267 4268 4269 4270 4271
	if (mddev->level == 6) {
		conf->spare_page = alloc_page(GFP_KERNEL);
		if (!conf->spare_page)
			goto abort;
	}
L
Linus Torvalds 已提交
4272
	spin_lock_init(&conf->device_lock);
4273
	mddev->queue->queue_lock = &conf->device_lock;
L
Linus Torvalds 已提交
4274 4275 4276
	init_waitqueue_head(&conf->wait_for_stripe);
	init_waitqueue_head(&conf->wait_for_overlap);
	INIT_LIST_HEAD(&conf->handle_list);
4277
	INIT_LIST_HEAD(&conf->hold_list);
L
Linus Torvalds 已提交
4278
	INIT_LIST_HEAD(&conf->delayed_list);
4279
	INIT_LIST_HEAD(&conf->bitmap_list);
L
Linus Torvalds 已提交
4280 4281 4282
	INIT_LIST_HEAD(&conf->inactive_list);
	atomic_set(&conf->active_stripes, 0);
	atomic_set(&conf->preread_active_stripes, 0);
4283
	atomic_set(&conf->active_aligned_reads, 0);
4284
	conf->bypass_threshold = BYPASS_THRESHOLD;
L
Linus Torvalds 已提交
4285

4286
	pr_debug("raid5: run(%s) called.\n", mdname(mddev));
L
Linus Torvalds 已提交
4287

4288
	rdev_for_each(rdev, tmp, mddev) {
L
Linus Torvalds 已提交
4289
		raid_disk = rdev->raid_disk;
4290
		if (raid_disk >= conf->raid_disks
L
Linus Torvalds 已提交
4291 4292 4293 4294 4295 4296
		    || raid_disk < 0)
			continue;
		disk = conf->disks + raid_disk;

		disk->rdev = rdev;

4297
		if (test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
4298 4299 4300 4301
			char b[BDEVNAME_SIZE];
			printk(KERN_INFO "raid5: device %s operational as raid"
				" disk %d\n", bdevname(rdev->bdev,b),
				raid_disk);
4302
			working_disks++;
4303 4304 4305
		} else
			/* Cannot rely on bitmap to complete recovery */
			conf->fullsync = 1;
L
Linus Torvalds 已提交
4306 4307 4308
	}

	/*
4309
	 * 0 for a fully functional array, 1 or 2 for a degraded array.
L
Linus Torvalds 已提交
4310
	 */
4311
	mddev->degraded = conf->raid_disks - working_disks;
L
Linus Torvalds 已提交
4312 4313 4314
	conf->mddev = mddev;
	conf->chunk_size = mddev->chunk_size;
	conf->level = mddev->level;
4315 4316 4317 4318
	if (conf->level == 6)
		conf->max_degraded = 2;
	else
		conf->max_degraded = 1;
L
Linus Torvalds 已提交
4319 4320
	conf->algorithm = mddev->layout;
	conf->max_nr_stripes = NR_STRIPES;
4321
	conf->expand_progress = mddev->reshape_position;
L
Linus Torvalds 已提交
4322 4323 4324

	/* device size must be a multiple of chunk size */
	mddev->size &= ~(mddev->chunk_size/1024 -1);
4325
	mddev->resync_max_sectors = mddev->size << 1;
L
Linus Torvalds 已提交
4326

4327 4328 4329 4330 4331
	if (conf->level == 6 && conf->raid_disks < 4) {
		printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
		       mdname(mddev), conf->raid_disks);
		goto abort;
	}
L
Linus Torvalds 已提交
4332 4333 4334 4335 4336 4337 4338 4339 4340 4341 4342
	if (!conf->chunk_size || conf->chunk_size % 4) {
		printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
			conf->chunk_size, mdname(mddev));
		goto abort;
	}
	if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) {
		printk(KERN_ERR 
			"raid5: unsupported parity algorithm %d for %s\n",
			conf->algorithm, mdname(mddev));
		goto abort;
	}
4343
	if (mddev->degraded > conf->max_degraded) {
L
Linus Torvalds 已提交
4344 4345
		printk(KERN_ERR "raid5: not enough operational devices for %s"
			" (%d/%d failed)\n",
4346
			mdname(mddev), mddev->degraded, conf->raid_disks);
L
Linus Torvalds 已提交
4347 4348 4349
		goto abort;
	}

4350
	if (mddev->degraded > 0 &&
L
Linus Torvalds 已提交
4351
	    mddev->recovery_cp != MaxSector) {
4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362
		if (mddev->ok_start_degraded)
			printk(KERN_WARNING
			       "raid5: starting dirty degraded array: %s"
			       "- data corruption possible.\n",
			       mdname(mddev));
		else {
			printk(KERN_ERR
			       "raid5: cannot start dirty degraded array for %s\n",
			       mdname(mddev));
			goto abort;
		}
L
Linus Torvalds 已提交
4363 4364 4365 4366 4367 4368 4369 4370 4371 4372 4373
	}

	{
		mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5");
		if (!mddev->thread) {
			printk(KERN_ERR 
				"raid5: couldn't allocate thread for %s\n",
				mdname(mddev));
			goto abort;
		}
	}
4374
	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
L
Linus Torvalds 已提交
4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398
		 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
	if (grow_stripes(conf, conf->max_nr_stripes)) {
		printk(KERN_ERR 
			"raid5: couldn't allocate %dkB for buffers\n", memory);
		shrink_stripes(conf);
		md_unregister_thread(mddev->thread);
		goto abort;
	} else
		printk(KERN_INFO "raid5: allocated %dkB for %s\n",
			memory, mdname(mddev));

	if (mddev->degraded == 0)
		printk("raid5: raid level %d set %s active with %d out of %d"
			" devices, algorithm %d\n", conf->level, mdname(mddev), 
			mddev->raid_disks-mddev->degraded, mddev->raid_disks,
			conf->algorithm);
	else
		printk(KERN_ALERT "raid5: raid level %d set %s active with %d"
			" out of %d devices, algorithm %d\n", conf->level,
			mdname(mddev), mddev->raid_disks - mddev->degraded,
			mddev->raid_disks, conf->algorithm);

	print_raid5_conf(conf);

4399 4400
	if (conf->expand_progress != MaxSector) {
		printk("...ok start reshape thread\n");
4401
		conf->expand_lo = conf->expand_progress;
4402 4403 4404 4405 4406 4407 4408 4409 4410
		atomic_set(&conf->reshape_stripes, 0);
		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
		set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
		mddev->sync_thread = md_register_thread(md_do_sync, mddev,
							"%s_reshape");
	}

L
Linus Torvalds 已提交
4411
	/* read-ahead size must cover two whole stripes, which is
4412
	 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
L
Linus Torvalds 已提交
4413 4414
	 */
	{
4415 4416
		int data_disks = conf->previous_raid_disks - conf->max_degraded;
		int stripe = data_disks *
4417
			(mddev->chunk_size / PAGE_SIZE);
L
Linus Torvalds 已提交
4418 4419 4420 4421 4422
		if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
			mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
	}

	/* Ok, everything is just fine now */
4423 4424 4425 4426
	if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
		printk(KERN_WARNING
		       "raid5: failed to create sysfs attributes for %s\n",
		       mdname(mddev));
4427 4428

	mddev->queue->unplug_fn = raid5_unplug_device;
4429
	mddev->queue->backing_dev_info.congested_data = mddev;
4430
	mddev->queue->backing_dev_info.congested_fn = raid5_congested;
4431

4432 4433
	mddev->array_size =  mddev->size * (conf->previous_raid_disks -
					    conf->max_degraded);
4434

4435 4436
	blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);

L
Linus Torvalds 已提交
4437 4438 4439 4440
	return 0;
abort:
	if (conf) {
		print_raid5_conf(conf);
4441
		safe_put_page(conf->spare_page);
4442
		kfree(conf->disks);
4443
		kfree(conf->stripe_hashtbl);
L
Linus Torvalds 已提交
4444 4445 4446 4447 4448 4449 4450 4451 4452
		kfree(conf);
	}
	mddev->private = NULL;
	printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev));
	return -EIO;
}



4453
static int stop(mddev_t *mddev)
L
Linus Torvalds 已提交
4454 4455 4456 4457 4458 4459
{
	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;

	md_unregister_thread(mddev->thread);
	mddev->thread = NULL;
	shrink_stripes(conf);
4460
	kfree(conf->stripe_hashtbl);
4461
	mddev->queue->backing_dev_info.congested_fn = NULL;
L
Linus Torvalds 已提交
4462
	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
4463
	sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
4464
	kfree(conf->disks);
4465
	kfree(conf);
L
Linus Torvalds 已提交
4466 4467 4468 4469
	mddev->private = NULL;
	return 0;
}

4470
#ifdef DEBUG
4471
static void print_sh (struct seq_file *seq, struct stripe_head *sh)
L
Linus Torvalds 已提交
4472 4473 4474
{
	int i;

4475 4476 4477 4478 4479
	seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n",
		   (unsigned long long)sh->sector, sh->pd_idx, sh->state);
	seq_printf(seq, "sh %llu,  count %d.\n",
		   (unsigned long long)sh->sector, atomic_read(&sh->count));
	seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector);
4480
	for (i = 0; i < sh->disks; i++) {
4481 4482
		seq_printf(seq, "(cache%d: %p %ld) ",
			   i, sh->dev[i].page, sh->dev[i].flags);
L
Linus Torvalds 已提交
4483
	}
4484
	seq_printf(seq, "\n");
L
Linus Torvalds 已提交
4485 4486
}

4487
static void printall (struct seq_file *seq, raid5_conf_t *conf)
L
Linus Torvalds 已提交
4488 4489
{
	struct stripe_head *sh;
4490
	struct hlist_node *hn;
L
Linus Torvalds 已提交
4491 4492 4493 4494
	int i;

	spin_lock_irq(&conf->device_lock);
	for (i = 0; i < NR_HASH; i++) {
4495
		hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
L
Linus Torvalds 已提交
4496 4497
			if (sh->raid_conf != conf)
				continue;
4498
			print_sh(seq, sh);
L
Linus Torvalds 已提交
4499 4500 4501 4502 4503 4504 4505 4506 4507 4508 4509 4510
		}
	}
	spin_unlock_irq(&conf->device_lock);
}
#endif

static void status (struct seq_file *seq, mddev_t *mddev)
{
	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
	int i;

	seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout);
4511
	seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
L
Linus Torvalds 已提交
4512 4513 4514
	for (i = 0; i < conf->raid_disks; i++)
		seq_printf (seq, "%s",
			       conf->disks[i].rdev &&
4515
			       test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
L
Linus Torvalds 已提交
4516
	seq_printf (seq, "]");
4517
#ifdef DEBUG
4518 4519
	seq_printf (seq, "\n");
	printall(seq, conf);
L
Linus Torvalds 已提交
4520 4521 4522 4523 4524 4525 4526 4527 4528 4529 4530 4531 4532
#endif
}

static void print_raid5_conf (raid5_conf_t *conf)
{
	int i;
	struct disk_info *tmp;

	printk("RAID5 conf printout:\n");
	if (!conf) {
		printk("(conf==NULL)\n");
		return;
	}
4533 4534
	printk(" --- rd:%d wd:%d\n", conf->raid_disks,
		 conf->raid_disks - conf->mddev->degraded);
L
Linus Torvalds 已提交
4535 4536 4537 4538 4539 4540

	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
		tmp = conf->disks + i;
		if (tmp->rdev)
		printk(" disk %d, o:%d, dev:%s\n",
4541
			i, !test_bit(Faulty, &tmp->rdev->flags),
L
Linus Torvalds 已提交
4542 4543 4544 4545 4546 4547 4548 4549 4550 4551 4552 4553 4554
			bdevname(tmp->rdev->bdev,b));
	}
}

static int raid5_spare_active(mddev_t *mddev)
{
	int i;
	raid5_conf_t *conf = mddev->private;
	struct disk_info *tmp;

	for (i = 0; i < conf->raid_disks; i++) {
		tmp = conf->disks + i;
		if (tmp->rdev
4555
		    && !test_bit(Faulty, &tmp->rdev->flags)
4556 4557 4558
		    && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
			unsigned long flags;
			spin_lock_irqsave(&conf->device_lock, flags);
L
Linus Torvalds 已提交
4559
			mddev->degraded--;
4560
			spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576
		}
	}
	print_raid5_conf(conf);
	return 0;
}

static int raid5_remove_disk(mddev_t *mddev, int number)
{
	raid5_conf_t *conf = mddev->private;
	int err = 0;
	mdk_rdev_t *rdev;
	struct disk_info *p = conf->disks + number;

	print_raid5_conf(conf);
	rdev = p->rdev;
	if (rdev) {
4577
		if (test_bit(In_sync, &rdev->flags) ||
L
Linus Torvalds 已提交
4578 4579 4580 4581
		    atomic_read(&rdev->nr_pending)) {
			err = -EBUSY;
			goto abort;
		}
4582 4583 4584 4585 4586 4587 4588 4589
		/* Only remove non-faulty devices if recovery
		 * isn't possible.
		 */
		if (!test_bit(Faulty, &rdev->flags) &&
		    mddev->degraded <= conf->max_degraded) {
			err = -EBUSY;
			goto abort;
		}
L
Linus Torvalds 已提交
4590
		p->rdev = NULL;
4591
		synchronize_rcu();
L
Linus Torvalds 已提交
4592 4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606
		if (atomic_read(&rdev->nr_pending)) {
			/* lost the race, try later */
			err = -EBUSY;
			p->rdev = rdev;
		}
	}
abort:

	print_raid5_conf(conf);
	return err;
}

static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
{
	raid5_conf_t *conf = mddev->private;
4607
	int err = -EEXIST;
L
Linus Torvalds 已提交
4608 4609
	int disk;
	struct disk_info *p;
4610 4611
	int first = 0;
	int last = conf->raid_disks - 1;
L
Linus Torvalds 已提交
4612

4613
	if (mddev->degraded > conf->max_degraded)
L
Linus Torvalds 已提交
4614
		/* no point adding a device */
4615
		return -EINVAL;
L
Linus Torvalds 已提交
4616

4617 4618 4619
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;

L
Linus Torvalds 已提交
4620
	/*
4621 4622
	 * find the disk ... but prefer rdev->saved_raid_disk
	 * if possible.
L
Linus Torvalds 已提交
4623
	 */
4624
	if (rdev->saved_raid_disk >= 0 &&
4625
	    rdev->saved_raid_disk >= first &&
4626 4627 4628
	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
		disk = rdev->saved_raid_disk;
	else
4629 4630
		disk = first;
	for ( ; disk <= last ; disk++)
L
Linus Torvalds 已提交
4631
		if ((p=conf->disks + disk)->rdev == NULL) {
4632
			clear_bit(In_sync, &rdev->flags);
L
Linus Torvalds 已提交
4633
			rdev->raid_disk = disk;
4634
			err = 0;
4635 4636
			if (rdev->saved_raid_disk != disk)
				conf->fullsync = 1;
4637
			rcu_assign_pointer(p->rdev, rdev);
L
Linus Torvalds 已提交
4638 4639 4640
			break;
		}
	print_raid5_conf(conf);
4641
	return err;
L
Linus Torvalds 已提交
4642 4643 4644 4645 4646 4647 4648 4649 4650 4651 4652
}

static int raid5_resize(mddev_t *mddev, sector_t sectors)
{
	/* no resync is happening, and there is enough space
	 * on all devices, so we can resize.
	 * We need to make sure resync covers any new space.
	 * If the array is shrinking we should possibly wait until
	 * any io in the removed space completes, but it hardly seems
	 * worth it.
	 */
4653 4654
	raid5_conf_t *conf = mddev_to_conf(mddev);

L
Linus Torvalds 已提交
4655
	sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
4656
	mddev->array_size = (sectors * (mddev->raid_disks-conf->max_degraded))>>1;
L
Linus Torvalds 已提交
4657
	set_capacity(mddev->gendisk, mddev->array_size << 1);
4658
	mddev->changed = 1;
L
Linus Torvalds 已提交
4659 4660 4661 4662 4663
	if (sectors/2  > mddev->size && mddev->recovery_cp == MaxSector) {
		mddev->recovery_cp = mddev->size << 1;
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
	mddev->size = sectors /2;
4664
	mddev->resync_max_sectors = sectors;
L
Linus Torvalds 已提交
4665 4666 4667
	return 0;
}

4668
#ifdef CONFIG_MD_RAID5_RESHAPE
4669
static int raid5_check_reshape(mddev_t *mddev)
4670 4671 4672 4673
{
	raid5_conf_t *conf = mddev_to_conf(mddev);
	int err;

4674 4675 4676 4677
	if (mddev->delta_disks < 0 ||
	    mddev->new_level != mddev->level)
		return -EINVAL; /* Cannot shrink array or change level yet */
	if (mddev->delta_disks == 0)
4678 4679 4680 4681 4682 4683 4684 4685 4686 4687
		return 0; /* nothing to do */

	/* Can only proceed if there are plenty of stripe_heads.
	 * We need a minimum of one full stripe,, and for sensible progress
	 * it is best to have about 4 times that.
	 * If we require 4 times, then the default 256 4K stripe_heads will
	 * allow for chunk sizes up to 256K, which is probably OK.
	 * If the chunk size is greater, user-space should request more
	 * stripe_heads first.
	 */
4688 4689
	if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes ||
	    (mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) {
4690 4691 4692 4693 4694
		printk(KERN_WARNING "raid5: reshape: not enough stripes.  Needed %lu\n",
		       (mddev->chunk_size / STRIPE_SIZE)*4);
		return -ENOSPC;
	}

4695 4696 4697 4698
	err = resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
	if (err)
		return err;

4699 4700
	if (mddev->degraded > conf->max_degraded)
		return -EINVAL;
4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711
	/* looks like we might be able to manage this */
	return 0;
}

static int raid5_start_reshape(mddev_t *mddev)
{
	raid5_conf_t *conf = mddev_to_conf(mddev);
	mdk_rdev_t *rdev;
	struct list_head *rtmp;
	int spares = 0;
	int added_devices = 0;
4712
	unsigned long flags;
4713

4714
	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4715 4716
		return -EBUSY;

4717
	rdev_for_each(rdev, rtmp, mddev)
4718 4719 4720
		if (rdev->raid_disk < 0 &&
		    !test_bit(Faulty, &rdev->flags))
			spares++;
4721

4722
	if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
4723 4724 4725 4726 4727
		/* Not enough devices even to make a degraded array
		 * of that size
		 */
		return -EINVAL;

4728
	atomic_set(&conf->reshape_stripes, 0);
4729 4730
	spin_lock_irq(&conf->device_lock);
	conf->previous_raid_disks = conf->raid_disks;
4731
	conf->raid_disks += mddev->delta_disks;
4732
	conf->expand_progress = 0;
4733
	conf->expand_lo = 0;
4734 4735 4736 4737 4738
	spin_unlock_irq(&conf->device_lock);

	/* Add some new drives, as many as will fit.
	 * We know there are enough to make the newly sized array work.
	 */
4739
	rdev_for_each(rdev, rtmp, mddev)
4740 4741
		if (rdev->raid_disk < 0 &&
		    !test_bit(Faulty, &rdev->flags)) {
4742
			if (raid5_add_disk(mddev, rdev) == 0) {
4743 4744 4745
				char nm[20];
				set_bit(In_sync, &rdev->flags);
				added_devices++;
4746
				rdev->recovery_offset = 0;
4747
				sprintf(nm, "rd%d", rdev->raid_disk);
4748 4749 4750 4751 4752 4753
				if (sysfs_create_link(&mddev->kobj,
						      &rdev->kobj, nm))
					printk(KERN_WARNING
					       "raid5: failed to create "
					       " link %s for %s\n",
					       nm, mdname(mddev));
4754 4755 4756 4757
			} else
				break;
		}

4758
	spin_lock_irqsave(&conf->device_lock, flags);
4759
	mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) - added_devices;
4760
	spin_unlock_irqrestore(&conf->device_lock, flags);
4761
	mddev->raid_disks = conf->raid_disks;
4762
	mddev->reshape_position = 0;
4763
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
4764

4765 4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777 4778 4779 4780 4781 4782 4783 4784 4785 4786 4787 4788
	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
	set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
	mddev->sync_thread = md_register_thread(md_do_sync, mddev,
						"%s_reshape");
	if (!mddev->sync_thread) {
		mddev->recovery = 0;
		spin_lock_irq(&conf->device_lock);
		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
		conf->expand_progress = MaxSector;
		spin_unlock_irq(&conf->device_lock);
		return -EAGAIN;
	}
	md_wakeup_thread(mddev->sync_thread);
	md_new_event(mddev);
	return 0;
}
#endif

static void end_reshape(raid5_conf_t *conf)
{
	struct block_device *bdev;

4789
	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
4790 4791
		conf->mddev->array_size = conf->mddev->size *
			(conf->raid_disks - conf->max_degraded);
4792
		set_capacity(conf->mddev->gendisk, conf->mddev->array_size << 1);
4793
		conf->mddev->changed = 1;
4794 4795 4796 4797

		bdev = bdget_disk(conf->mddev->gendisk, 0);
		if (bdev) {
			mutex_lock(&bdev->bd_inode->i_mutex);
4798
			i_size_write(bdev->bd_inode, (loff_t)conf->mddev->array_size << 10);
4799 4800 4801 4802 4803 4804 4805
			mutex_unlock(&bdev->bd_inode->i_mutex);
			bdput(bdev);
		}
		spin_lock_irq(&conf->device_lock);
		conf->expand_progress = MaxSector;
		spin_unlock_irq(&conf->device_lock);
		conf->mddev->reshape_position = MaxSector;
4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816

		/* read-ahead size must cover two whole stripes, which is
		 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
		 */
		{
			int data_disks = conf->previous_raid_disks - conf->max_degraded;
			int stripe = data_disks *
				(conf->mddev->chunk_size / PAGE_SIZE);
			if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
				conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
		}
4817 4818 4819
	}
}

4820 4821 4822 4823 4824
static void raid5_quiesce(mddev_t *mddev, int state)
{
	raid5_conf_t *conf = mddev_to_conf(mddev);

	switch(state) {
4825 4826 4827 4828
	case 2: /* resume for a suspend */
		wake_up(&conf->wait_for_overlap);
		break;

4829 4830 4831 4832
	case 1: /* stop all writes */
		spin_lock_irq(&conf->device_lock);
		conf->quiesce = 1;
		wait_event_lock_irq(conf->wait_for_stripe,
4833 4834
				    atomic_read(&conf->active_stripes) == 0 &&
				    atomic_read(&conf->active_aligned_reads) == 0,
4835 4836 4837 4838 4839 4840 4841 4842
				    conf->device_lock, /* nothing */);
		spin_unlock_irq(&conf->device_lock);
		break;

	case 0: /* re-enable writes */
		spin_lock_irq(&conf->device_lock);
		conf->quiesce = 0;
		wake_up(&conf->wait_for_stripe);
4843
		wake_up(&conf->wait_for_overlap);
4844 4845 4846 4847
		spin_unlock_irq(&conf->device_lock);
		break;
	}
}
4848

4849 4850 4851 4852 4853 4854 4855 4856 4857 4858 4859 4860 4861 4862 4863
static struct mdk_personality raid6_personality =
{
	.name		= "raid6",
	.level		= 6,
	.owner		= THIS_MODULE,
	.make_request	= make_request,
	.run		= run,
	.stop		= stop,
	.status		= status,
	.error_handler	= error,
	.hot_add_disk	= raid5_add_disk,
	.hot_remove_disk= raid5_remove_disk,
	.spare_active	= raid5_spare_active,
	.sync_request	= sync_request,
	.resize		= raid5_resize,
4864 4865 4866 4867
#ifdef CONFIG_MD_RAID5_RESHAPE
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
#endif
4868 4869
	.quiesce	= raid5_quiesce,
};
4870
static struct mdk_personality raid5_personality =
L
Linus Torvalds 已提交
4871 4872
{
	.name		= "raid5",
4873
	.level		= 5,
L
Linus Torvalds 已提交
4874 4875 4876 4877 4878 4879 4880 4881 4882 4883 4884
	.owner		= THIS_MODULE,
	.make_request	= make_request,
	.run		= run,
	.stop		= stop,
	.status		= status,
	.error_handler	= error,
	.hot_add_disk	= raid5_add_disk,
	.hot_remove_disk= raid5_remove_disk,
	.spare_active	= raid5_spare_active,
	.sync_request	= sync_request,
	.resize		= raid5_resize,
4885
#ifdef CONFIG_MD_RAID5_RESHAPE
4886 4887
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
4888
#endif
4889
	.quiesce	= raid5_quiesce,
L
Linus Torvalds 已提交
4890 4891
};

4892
static struct mdk_personality raid4_personality =
L
Linus Torvalds 已提交
4893
{
4894 4895 4896 4897 4898 4899 4900 4901 4902 4903 4904 4905 4906
	.name		= "raid4",
	.level		= 4,
	.owner		= THIS_MODULE,
	.make_request	= make_request,
	.run		= run,
	.stop		= stop,
	.status		= status,
	.error_handler	= error,
	.hot_add_disk	= raid5_add_disk,
	.hot_remove_disk= raid5_remove_disk,
	.spare_active	= raid5_spare_active,
	.sync_request	= sync_request,
	.resize		= raid5_resize,
4907 4908 4909 4910
#ifdef CONFIG_MD_RAID5_RESHAPE
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
#endif
4911 4912 4913 4914 4915
	.quiesce	= raid5_quiesce,
};

static int __init raid5_init(void)
{
4916 4917 4918 4919 4920 4921
	int e;

	e = raid6_select_algo();
	if ( e )
		return e;
	register_md_personality(&raid6_personality);
4922 4923 4924
	register_md_personality(&raid5_personality);
	register_md_personality(&raid4_personality);
	return 0;
L
Linus Torvalds 已提交
4925 4926
}

4927
static void raid5_exit(void)
L
Linus Torvalds 已提交
4928
{
4929
	unregister_md_personality(&raid6_personality);
4930 4931
	unregister_md_personality(&raid5_personality);
	unregister_md_personality(&raid4_personality);
L
Linus Torvalds 已提交
4932 4933 4934 4935 4936 4937
}

module_init(raid5_init);
module_exit(raid5_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS("md-personality-4"); /* RAID5 */
4938 4939
MODULE_ALIAS("md-raid5");
MODULE_ALIAS("md-raid4");
4940 4941
MODULE_ALIAS("md-level-5");
MODULE_ALIAS("md-level-4");
4942 4943 4944 4945 4946 4947 4948
MODULE_ALIAS("md-personality-8"); /* RAID6 */
MODULE_ALIAS("md-raid6");
MODULE_ALIAS("md-level-6");

/* This used to be two separate modules, they were: */
MODULE_ALIAS("raid5");
MODULE_ALIAS("raid6");