raid5.c 107.5 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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/*
 * 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 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_DEBUG	0
#define RAID5_PARANOIA	1
#if RAID5_PARANOIA && defined(CONFIG_SMP)
# define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock)
#else
# define CHECK_DEVLOCK()
#endif

#define PRINTK(x...) ((void)(RAID5_DEBUG && printk(x)))
#if RAID5_DEBUG
#define inline
#define __inline__
#endif

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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 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 {
			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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			}
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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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{
	PRINTK("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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	PRINTK("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector);

	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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	CHECK_DEVLOCK();
	PRINTK("init_stripe called, stripe %llu\n", 
		(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];

		if (dev->toread || dev->towrite || dev->written ||
		    test_bit(R5_LOCKED, &dev->flags)) {
			printk("sector=%llx i=%d %p %p %p %d\n",
			       (unsigned long long)sh->sector, i, dev->toread,
			       dev->towrite, dev->written,
			       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();
	PRINTK("__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;
	PRINTK("__stripe %llu not in cache\n", (unsigned long long)sector);
	return NULL;
}

static void unplug_slaves(mddev_t *mddev);
static void raid5_unplug_device(request_queue_t *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;

	PRINTK("get_stripe, sector %llu\n", (unsigned long long)sector);

	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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static int grow_one_stripe(raid5_conf_t *conf)
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{
	struct stripe_head *sh;
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	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;
	}
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	sh->disks = conf->raid_disks;
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	/* 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)
{
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	kmem_cache_t *sc;
	int devs = conf->raid_disks;

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	sprintf(conf->cache_name[0], "raid5/%s", mdname(conf->mddev));
	sprintf(conf->cache_name[1], "raid5/%s-alt", mdname(conf->mddev));
	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),
			       0, 0, NULL, NULL);
	if (!sc)
		return 1;
	conf->slab_cache = sc;
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	conf->pool_size = devs;
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	while (num--)
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		if (!grow_one_stripe(conf))
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			return 1;
	return 0;
}
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#ifdef CONFIG_MD_RAID5_RESHAPE
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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;
	kmem_cache_t *sc;
	int i;

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

	/* Step 1 */
	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
			       0, 0, NULL, NULL);
	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,
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				    unplug_slaves(conf->mddev)
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			);
		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;
}
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#endif
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static int drop_one_stripe(raid5_conf_t *conf)
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{
	struct stripe_head *sh;

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	spin_lock_irq(&conf->device_lock);
	sh = get_free_stripe(conf);
	spin_unlock_irq(&conf->device_lock);
	if (!sh)
		return 0;
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	BUG_ON(atomic_read(&sh->count));
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	shrink_buffers(sh, conf->pool_size);
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	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;
}

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static int raid5_end_read_request(struct bio * bi, unsigned int bytes_done,
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				   int error)
{
 	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);
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	char b[BDEVNAME_SIZE];
	mdk_rdev_t *rdev;
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	if (bi->bi_size)
		return 1;

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

	PRINTK("end_read_request %llu/%d, count: %d, uptodate %d.\n", 
		(unsigned long long)sh->sector, i, atomic_read(&sh->count), 
		uptodate);
	if (i == disks) {
		BUG();
		return 0;
	}

	if (uptodate) {
#if 0
		struct bio *bio;
		unsigned long flags;
		spin_lock_irqsave(&conf->device_lock, flags);
		/* we can return a buffer if we bypassed the cache or
		 * if the top buffer is not in highmem.  If there are
		 * multiple buffers, leave the extra work to
		 * handle_stripe
		 */
		buffer = sh->bh_read[i];
		if (buffer &&
		    (!PageHighMem(buffer->b_page)
		     || buffer->b_page == bh->b_page )
			) {
			sh->bh_read[i] = buffer->b_reqnext;
			buffer->b_reqnext = NULL;
		} else
			buffer = NULL;
		spin_unlock_irqrestore(&conf->device_lock, flags);
		if (sh->bh_page[i]==bh->b_page)
			set_buffer_uptodate(bh);
		if (buffer) {
			if (buffer->b_page != bh->b_page)
				memcpy(buffer->b_data, bh->b_data, bh->b_size);
			buffer->b_end_io(buffer, 1);
		}
#else
		set_bit(R5_UPTODATE, &sh->dev[i].flags);
573 574
#endif
		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
575 576 577 578 579
			rdev = conf->disks[i].rdev;
			printk(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));
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			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
		}
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		if (atomic_read(&conf->disks[i].rdev->read_errors))
			atomic_set(&conf->disks[i].rdev->read_errors, 0);
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	} else {
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		const char *bdn = bdevname(conf->disks[i].rdev->bdev, b);
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		int retry = 0;
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		rdev = conf->disks[i].rdev;

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		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
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		atomic_inc(&rdev->read_errors);
592
		if (conf->mddev->degraded)
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			printk(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);
597
		else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
598
			/* Oh, no!!! */
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			printk(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);
		else if (atomic_read(&rdev->read_errors)
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			 > 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 {
613 614
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
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			md_error(conf->mddev, rdev);
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		}
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	}
	rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
#if 0
	/* must restore b_page before unlocking buffer... */
	if (sh->bh_page[i] != bh->b_page) {
		bh->b_page = sh->bh_page[i];
		bh->b_data = page_address(bh->b_page);
		clear_buffer_uptodate(bh);
	}
#endif
	clear_bit(R5_LOCKED, &sh->dev[i].flags);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
	return 0;
}

static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done,
				    int error)
{
 	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);

	if (bi->bi_size)
		return 1;

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

	PRINTK("end_write_request %llu/%d, count %d, uptodate: %d.\n", 
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
		uptodate);
	if (i == disks) {
		BUG();
		return 0;
	}

	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);
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	release_stripe(sh);
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	return 0;
}


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;
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	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;
	PRINTK("raid5: error called\n");

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	if (!test_bit(Faulty, &rdev->flags)) {
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		set_bit(MD_CHANGE_DEVS, &mddev->flags);
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		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++;
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			spin_unlock_irqrestore(&conf->device_lock, flags);
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			/*
			 * if recovery was running, make sure it aborts.
			 */
			set_bit(MD_RECOVERY_ERR, &mddev->recovery);
		}
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		set_bit(Faulty, &rdev->flags);
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		printk (KERN_ALERT
			"raid5: Disk failure on %s, disabling device."
			" Operation continuing on %d devices\n",
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			bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
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	}
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}
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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.
	 */
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	switch(conf->level) {
	case 4:
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		*pd_idx = data_disks;
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		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;
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	int raid_disks = sh->disks, data_disks = raid_disks - 1;
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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);

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	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",
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			       conf->algorithm);
		}
		break;
	case 6:
		data_disks = raid_disks - 2;
		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);
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		}
		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;
}



/*
903 904 905 906 907
 * 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;
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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;
	}
}

#define check_xor() 	do { 						\
			   if (count == MAX_XOR_BLOCKS) {		\
				xor_block(count, STRIPE_SIZE, ptr);	\
				count = 1;				\
			   }						\
			} while(0)


static void compute_block(struct stripe_head *sh, int dd_idx)
{
961
	int i, count, disks = sh->disks;
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	void *ptr[MAX_XOR_BLOCKS], *p;

	PRINTK("compute_block, stripe %llu, idx %d\n", 
		(unsigned long long)sh->sector, dd_idx);

	ptr[0] = page_address(sh->dev[dd_idx].page);
	memset(ptr[0], 0, STRIPE_SIZE);
	count = 1;
	for (i = disks ; i--; ) {
		if (i == dd_idx)
			continue;
		p = page_address(sh->dev[i].page);
		if (test_bit(R5_UPTODATE, &sh->dev[i].flags))
			ptr[count++] = p;
		else
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			printk(KERN_ERR "compute_block() %d, stripe %llu, %d"
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				" not present\n", dd_idx,
				(unsigned long long)sh->sector, i);

		check_xor();
	}
	if (count != 1)
		xor_block(count, STRIPE_SIZE, ptr);
	set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags);
}

988
static void compute_parity5(struct stripe_head *sh, int method)
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{
	raid5_conf_t *conf = sh->raid_conf;
991
	int i, pd_idx = sh->pd_idx, disks = sh->disks, count;
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	void *ptr[MAX_XOR_BLOCKS];
	struct bio *chosen;

995
	PRINTK("compute_parity5, stripe %llu, method %d\n",
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		(unsigned long long)sh->sector, method);

	count = 1;
	ptr[0] = page_address(sh->dev[pd_idx].page);
	switch(method) {
	case READ_MODIFY_WRITE:
1002
		BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags));
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		for (i=disks ; i-- ;) {
			if (i==pd_idx)
				continue;
			if (sh->dev[i].towrite &&
			    test_bit(R5_UPTODATE, &sh->dev[i].flags)) {
				ptr[count++] = page_address(sh->dev[i].page);
				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);
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				sh->dev[i].written = chosen;
				check_xor();
			}
		}
		break;
	case RECONSTRUCT_WRITE:
		memset(ptr[0], 0, STRIPE_SIZE);
		for (i= disks; i-- ;)
			if (i!=pd_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);
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				sh->dev[i].written = chosen;
			}
		break;
	case CHECK_PARITY:
		break;
	}
	if (count>1) {
		xor_block(count, STRIPE_SIZE, ptr);
		count = 1;
	}
	
	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:
		for (i=disks; i--;)
			if (i != pd_idx) {
				ptr[count++] = page_address(sh->dev[i].page);
				check_xor();
			}
		break;
	case READ_MODIFY_WRITE:
		for (i = disks; i--;)
			if (sh->dev[i].written) {
				ptr[count++] = page_address(sh->dev[i].page);
				check_xor();
			}
	}
	if (count != 1)
		xor_block(count, STRIPE_SIZE, ptr);
	
	if (method != CHECK_PARITY) {
		set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
		set_bit(R5_LOCKED,   &sh->dev[pd_idx].flags);
	} else
		clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
}

1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107
static void compute_parity6(struct stripe_head *sh, int method)
{
	raid6_conf_t *conf = sh->raid_conf;
	int i, pd_idx = sh->pd_idx, qd_idx, d0_idx, disks = conf->raid_disks, count;
	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);

	PRINTK("compute_parity, stripe %llu, method %d\n",
		(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);

E
Eric Sesterhenn 已提交
1108
				BUG_ON(sh->dev[i].written);
1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267
				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)
{
	raid6_conf_t *conf = sh->raid_conf;
	int i, count, disks = conf->raid_disks;
	void *ptr[MAX_XOR_BLOCKS], *p;
	int pd_idx = sh->pd_idx;
	int qd_idx = raid6_next_disk(pd_idx, disks);

	PRINTK("compute_block_1, stripe %llu, idx %d\n",
		(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 {
		ptr[0] = page_address(sh->dev[dd_idx].page);
		if (!nozero) memset(ptr[0], 0, STRIPE_SIZE);
		count = 1;
		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();
		}
		if (count != 1)
			xor_block(count, STRIPE_SIZE, ptr);
		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)
{
	raid6_conf_t *conf = sh->raid_conf;
	int i, count, disks = conf->raid_disks;
	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; }

	PRINTK("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n",
	       (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);
	}
}



L
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/*
 * Each stripe/dev can have one or more bion attached.
1270
 * toread/towrite point to the first in a chain.
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1271 1272 1273 1274 1275 1276
 * 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;
1277
	int firstwrite=0;
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1278 1279 1280 1281 1282 1283 1284 1285

	PRINTK("adding bh b#%llu to stripe s#%llu\n",
		(unsigned long long)bi->bi_sector,
		(unsigned long long)sh->sector);


	spin_lock(&sh->lock);
	spin_lock_irq(&conf->device_lock);
1286
	if (forwrite) {
L
Linus Torvalds 已提交
1287
		bip = &sh->dev[dd_idx].towrite;
1288 1289 1290
		if (*bip == NULL && sh->dev[dd_idx].written == NULL)
			firstwrite = 1;
	} else
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		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;

1300
	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
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	if (*bip)
		bi->bi_next = *bip;
	*bip = bi;
	bi->bi_phys_segments ++;
	spin_unlock_irq(&conf->device_lock);
	spin_unlock(&sh->lock);

	PRINTK("added bi b#%llu to stripe s#%llu, disk %d.\n",
		(unsigned long long)bi->bi_sector,
		(unsigned long long)sh->sector, dd_idx);

1312 1313 1314
	if (conf->mddev->bitmap && firstwrite) {
		bitmap_startwrite(conf->mddev->bitmap, sh->sector,
				  STRIPE_SECTORS, 0);
1315
		sh->bm_seq = conf->seq_flush+1;
1316 1317 1318
		set_bit(STRIPE_BIT_DELAY, &sh->state);
	}

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	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;
}

1341 1342
static void end_reshape(raid5_conf_t *conf);

1343 1344 1345 1346 1347 1348 1349
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);
}

1350 1351 1352 1353
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;
1354 1355
	int chunk_offset = sector_div(stripe, sectors_per_chunk);

1356 1357 1358 1359 1360
	raid5_compute_sector(stripe*(disks-1)*sectors_per_chunk
			     + chunk_offset, disks, disks-1, &dd_idx, &pd_idx, conf);
	return pd_idx;
}

L
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/*
 * 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
 *
 * Parity calculations are done inside the stripe lock
 * buffers are taken off read_list or write_list, and bh_cache buffers
 * get BH_Lock set before the stripe lock is released.
 *
 */
 
1380
static void handle_stripe5(struct stripe_head *sh)
L
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{
	raid5_conf_t *conf = sh->raid_conf;
1383
	int disks = sh->disks;
L
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	struct bio *return_bi= NULL;
	struct bio *bi;
	int i;
1387
	int syncing, expanding, expanded;
L
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	int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
	int non_overwrite = 0;
	int failed_num=0;
	struct r5dev *dev;

	PRINTK("handling stripe %llu, cnt=%d, pd_idx=%d\n",
		(unsigned long long)sh->sector, atomic_read(&sh->count),
		sh->pd_idx);

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

	syncing = test_bit(STRIPE_SYNCING, &sh->state);
1402 1403
	expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
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	/* Now to look around and see what can be done */

1406
	rcu_read_lock();
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1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 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 1448
	for (i=disks; i--; ) {
		mdk_rdev_t *rdev;
		dev = &sh->dev[i];
		clear_bit(R5_Insync, &dev->flags);

		PRINTK("check %d: state 0x%lx read %p write %p written %p\n",
			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;
			PRINTK("Return read for disc %d\n", i);
			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;
			}
		}

		/* now count some things */
		if (test_bit(R5_LOCKED, &dev->flags)) locked++;
		if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;

		
		if (dev->toread) to_read++;
		if (dev->towrite) {
			to_write++;
			if (!test_bit(R5_OVERWRITE, &dev->flags))
				non_overwrite++;
		}
		if (dev->written) written++;
1449
		rdev = rcu_dereference(conf->disks[i].rdev);
1450
		if (!rdev || !test_bit(In_sync, &rdev->flags)) {
N
NeilBrown 已提交
1451
			/* The ReadError flag will just be confusing now */
1452 1453 1454
			clear_bit(R5_ReadError, &dev->flags);
			clear_bit(R5_ReWrite, &dev->flags);
		}
1455
		if (!rdev || !test_bit(In_sync, &rdev->flags)
1456
		    || test_bit(R5_ReadError, &dev->flags)) {
L
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1457 1458 1459 1460 1461
			failed++;
			failed_num = i;
		} else
			set_bit(R5_Insync, &dev->flags);
	}
1462
	rcu_read_unlock();
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	PRINTK("locked=%d uptodate=%d to_read=%d"
		" to_write=%d failed=%d failed_num=%d\n",
		locked, uptodate, to_read, to_write, failed, failed_num);
	/* check if the array has lost two devices and, if so, some requests might
	 * need to be failed
	 */
	if (failed > 1 && to_read+to_write+written) {
		for (i=disks; i--; ) {
1471
			int bitmap_end = 0;
1472 1473

			if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1474 1475 1476
				mdk_rdev_t *rdev;
				rcu_read_lock();
				rdev = rcu_dereference(conf->disks[i].rdev);
1477
				if (rdev && test_bit(In_sync, &rdev->flags))
1478 1479
					/* multiple read failures in one stripe */
					md_error(conf->mddev, rdev);
1480
				rcu_read_unlock();
1481 1482
			}

1483
			spin_lock_irq(&conf->device_lock);
L
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1484 1485 1486
			/* fail all writes first */
			bi = sh->dev[i].towrite;
			sh->dev[i].towrite = NULL;
1487
			if (bi) { to_write--; bitmap_end = 1; }
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			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;
1505
			if (bi) bitmap_end = 1;
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1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517
			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;
			}

			/* fail any reads if this device is non-operational */
1518 1519
			if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
			    test_bit(R5_ReadError, &sh->dev[i].flags)) {
L
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				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) 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;
				}
			}
1535 1536 1537 1538
			spin_unlock_irq(&conf->device_lock);
			if (bitmap_end)
				bitmap_endwrite(conf->mddev->bitmap, sh->sector,
						STRIPE_SECTORS, 0, 0);
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		}
	}
	if (failed > 1 && syncing) {
		md_done_sync(conf->mddev, STRIPE_SECTORS,0);
		clear_bit(STRIPE_SYNCING, &sh->state);
		syncing = 0;
	}

	/* 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];
	if ( written &&
	     ( (test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) &&
		test_bit(R5_UPTODATE, &dev->flags))
	       || (failed == 1 && failed_num == sh->pd_idx))
	    ) {
	    /* 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.
	     */
	    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;
1567
			    int bitmap_end = 0;
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1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580
			    PRINTK("Return write for disc %d\n", i);
			    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;
			    }
1581 1582
			    if (dev->towrite == NULL)
				    bitmap_end = 1;
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			    spin_unlock_irq(&conf->device_lock);
1584 1585 1586 1587
			    if (bitmap_end)
				    bitmap_endwrite(conf->mddev->bitmap, sh->sector,
						    STRIPE_SECTORS,
						    !test_bit(STRIPE_DEGRADED, &sh->state), 0);
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		    }
		}
	}

	/* 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.
	 */
1596
	if (to_read || non_overwrite || (syncing && (uptodate < disks)) || expanding) {
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		for (i=disks; i--;) {
			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)) ||
			     syncing ||
1603
			     expanding ||
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			     (failed && (sh->dev[failed_num].toread ||
					 (sh->dev[failed_num].towrite && !test_bit(R5_OVERWRITE, &sh->dev[failed_num].flags))))
				    )
				) {
				/* we would like to get this block, possibly
				 * by computing it, but we might not be able to
				 */
				if (uptodate == disks-1) {
					PRINTK("Computing block %d\n", i);
					compute_block(sh, i);
					uptodate++;
				} else if (test_bit(R5_Insync, &dev->flags)) {
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
#if 0
					/* if I am just reading this block and we don't have
					   a failed drive, or any pending writes then sidestep the cache */
					if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext &&
					    ! syncing && !failed && !to_write) {
						sh->bh_cache[i]->b_page =  sh->bh_read[i]->b_page;
						sh->bh_cache[i]->b_data =  sh->bh_read[i]->b_data;
					}
#endif
					locked++;
					PRINTK("Reading block %d (sync=%d)\n", 
						i, syncing);
				}
			}
		}
		set_bit(STRIPE_HANDLE, &sh->state);
	}

	/* now to consider writing and what else, if anything should be read */
	if (to_write) {
		int rmw=0, rcw=0;
		for (i=disks ; i--;) {
			/* would I have to read this buffer for read_modify_write */
			dev = &sh->dev[i];
			if ((dev->towrite || i == sh->pd_idx) &&
			    (!test_bit(R5_LOCKED, &dev->flags) 
#if 0
|| sh->bh_page[i]!=bh->b_page
#endif
				    ) &&
			    !test_bit(R5_UPTODATE, &dev->flags)) {
				if (test_bit(R5_Insync, &dev->flags)
/*				    && !(!mddev->insync && i == sh->pd_idx) */
					)
					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) 
#if 0
|| sh->bh_page[i] != bh->b_page
#endif
				    ) &&
			    !test_bit(R5_UPTODATE, &dev->flags)) {
				if (test_bit(R5_Insync, &dev->flags)) rcw++;
				else rcw += 2*disks;
			}
		}
		PRINTK("for sector %llu, rmw=%d rcw=%d\n", 
			(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--;) {
				dev = &sh->dev[i];
				if ((dev->towrite || i == sh->pd_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))
					{
						PRINTK("Read_old block %d for r-m-w\n", i);
						set_bit(R5_LOCKED, &dev->flags);
						set_bit(R5_Wantread, &dev->flags);
						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--;) {
				dev = &sh->dev[i];
				if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_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))
					{
						PRINTK("Read_old block %d for Reconstruct\n", i);
						set_bit(R5_LOCKED, &dev->flags);
						set_bit(R5_Wantread, &dev->flags);
						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 */
1709 1710
		if (locked == 0 && (rcw == 0 ||rmw == 0) &&
		    !test_bit(STRIPE_BIT_DELAY, &sh->state)) {
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			PRINTK("Computing parity...\n");
1712
			compute_parity5(sh, rcw==0 ? RECONSTRUCT_WRITE : READ_MODIFY_WRITE);
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			/* now every locked buffer is ready to be written */
			for (i=disks; i--;)
				if (test_bit(R5_LOCKED, &sh->dev[i].flags)) {
					PRINTK("Writing block %d\n", i);
					locked++;
					set_bit(R5_Wantwrite, &sh->dev[i].flags);
					if (!test_bit(R5_Insync, &sh->dev[i].flags)
					    || (i==sh->pd_idx && 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);
			}
		}
	}

	/* maybe we need to check and possibly fix the parity for this stripe
	 * Any reads will already have been scheduled, so we just see if enough data
	 * is available
	 */
	if (syncing && locked == 0 &&
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	    !test_bit(STRIPE_INSYNC, &sh->state)) {
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		set_bit(STRIPE_HANDLE, &sh->state);
		if (failed == 0) {
1739
			BUG_ON(uptodate != disks);
1740
			compute_parity5(sh, CHECK_PARITY);
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			uptodate--;
1742
			if (page_is_zero(sh->dev[sh->pd_idx].page)) {
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				/* parity is correct (on disc, not in buffer any more) */
				set_bit(STRIPE_INSYNC, &sh->state);
1745 1746 1747 1748 1749
			} else {
				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);
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				else {
					compute_block(sh, sh->pd_idx);
					uptodate++;
				}
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			}
		}
		if (!test_bit(STRIPE_INSYNC, &sh->state)) {
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			/* either failed parity check, or recovery is happening */
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			if (failed==0)
				failed_num = sh->pd_idx;
			dev = &sh->dev[failed_num];
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			BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
			BUG_ON(uptodate != disks);

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			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
1766
			clear_bit(STRIPE_DEGRADED, &sh->state);
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			locked++;
			set_bit(STRIPE_INSYNC, &sh->state);
		}
	}
	if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
		md_done_sync(conf->mddev, STRIPE_SECTORS,1);
		clear_bit(STRIPE_SYNCING, &sh->state);
	}
1775 1776 1777 1778

	/* If the failed drive is just a ReadError, then we might need to progress
	 * the repair/check process
	 */
1779 1780
	if (failed == 1 && ! conf->mddev->ro &&
	    test_bit(R5_ReadError, &sh->dev[failed_num].flags)
1781 1782 1783 1784 1785 1786 1787 1788
	    && !test_bit(R5_LOCKED, &sh->dev[failed_num].flags)
	    && test_bit(R5_UPTODATE, &sh->dev[failed_num].flags)
		) {
		dev = &sh->dev[failed_num];
		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);
1789
			locked++;
1790 1791 1792 1793
		} else {
			/* let's read it back */
			set_bit(R5_Wantread, &dev->flags);
			set_bit(R5_LOCKED, &dev->flags);
1794
			locked++;
1795 1796 1797
		}
	}

1798 1799 1800 1801
	if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
		/* 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);
1802
		compute_parity5(sh, RECONSTRUCT_WRITE);
1803 1804 1805 1806 1807 1808 1809 1810
		for (i= conf->raid_disks; i--;) {
			set_bit(R5_LOCKED, &sh->dev[i].flags);
			locked++;
			set_bit(R5_Wantwrite, &sh->dev[i].flags);
		}
		clear_bit(STRIPE_EXPANDING, &sh->state);
	} else if (expanded) {
		clear_bit(STRIPE_EXPAND_READY, &sh->state);
1811
		atomic_dec(&conf->reshape_stripes);
1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859
		wake_up(&conf->wait_for_overlap);
		md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
	}

	if (expanding && locked == 0) {
		/* We have read all the blocks in this stripe and now we need to
		 * copy some of them into a target stripe for expand.
		 */
		clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
		for (i=0; i< sh->disks; i++)
			if (i != sh->pd_idx) {
				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-1,
								  &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;
				}
				memcpy(page_address(sh2->dev[dd_idx].page),
				       page_address(sh->dev[i].page),
				       STRIPE_SIZE);
				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 &&
					    !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);
			}
	}

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	spin_unlock(&sh->lock);

	while ((bi=return_bi)) {
		int bytes = bi->bi_size;

		return_bi = bi->bi_next;
		bi->bi_next = NULL;
		bi->bi_size = 0;
		bi->bi_end_io(bi, bytes, 0);
	}
	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 = 1;
		else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
			rw = 0;
		else
			continue;
 
		bi = &sh->dev[i].req;
 
		bi->bi_rw = rw;
		if (rw)
			bi->bi_end_io = raid5_end_write_request;
		else
			bi->bi_end_io = raid5_end_read_request;
 
		rcu_read_lock();
1890
		rdev = rcu_dereference(conf->disks[i].rdev);
1891
		if (rdev && test_bit(Faulty, &rdev->flags))
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			rdev = NULL;
		if (rdev)
			atomic_inc(&rdev->nr_pending);
		rcu_read_unlock();
 
		if (rdev) {
1898
			if (syncing || expanding || expanded)
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				md_sync_acct(rdev->bdev, STRIPE_SECTORS);

			bi->bi_bdev = rdev->bdev;
			PRINTK("for %llu schedule op %ld on disc %d\n",
				(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;
1915 1916 1917
			if (rw == WRITE &&
			    test_bit(R5_ReWrite, &sh->dev[i].flags))
				atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
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			generic_make_request(bi);
		} else {
1920 1921
			if (rw == 1)
				set_bit(STRIPE_DEGRADED, &sh->state);
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			PRINTK("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);
		}
	}
}

1930
static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
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{
1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944
	raid6_conf_t *conf = sh->raid_conf;
	int disks = conf->raid_disks;
	struct bio *return_bi= NULL;
	struct bio *bi;
	int i;
	int syncing;
	int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
	int non_overwrite = 0;
	int failed_num[2] = {0, 0};
	struct r5dev *dev, *pdev, *qdev;
	int pd_idx = sh->pd_idx;
	int qd_idx = raid6_next_disk(pd_idx, disks);
	int p_failed, q_failed;
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1946 1947 1948
	PRINTK("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d, qd_idx=%d\n",
	       (unsigned long long)sh->sector, sh->state, atomic_read(&sh->count),
	       pd_idx, qd_idx);
1949

1950 1951 1952 1953 1954 1955
	spin_lock(&sh->lock);
	clear_bit(STRIPE_HANDLE, &sh->state);
	clear_bit(STRIPE_DELAYED, &sh->state);

	syncing = test_bit(STRIPE_SYNCING, &sh->state);
	/* Now to look around and see what can be done */
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	rcu_read_lock();
1958 1959 1960 1961
	for (i=disks; i--; ) {
		mdk_rdev_t *rdev;
		dev = &sh->dev[i];
		clear_bit(R5_Insync, &dev->flags);
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1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986
		PRINTK("check %d: state 0x%lx read %p write %p written %p\n",
			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;
			PRINTK("Return read for disc %d\n", i);
			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;
			}
		}
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1988 1989 1990
		/* now count some things */
		if (test_bit(R5_LOCKED, &dev->flags)) locked++;
		if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
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1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

		if (dev->toread) to_read++;
		if (dev->towrite) {
			to_write++;
			if (!test_bit(R5_OVERWRITE, &dev->flags))
				non_overwrite++;
		}
		if (dev->written) written++;
		rdev = rcu_dereference(conf->disks[i].rdev);
		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);
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		}
2006 2007 2008 2009 2010 2011 2012
		if (!rdev || !test_bit(In_sync, &rdev->flags)
		    || test_bit(R5_ReadError, &dev->flags)) {
			if ( failed < 2 )
				failed_num[failed] = i;
			failed++;
		} else
			set_bit(R5_Insync, &dev->flags);
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	}
	rcu_read_unlock();
2015 2016 2017 2018 2019 2020 2021 2022 2023 2024
	PRINTK("locked=%d uptodate=%d to_read=%d"
	       " to_write=%d failed=%d failed_num=%d,%d\n",
	       locked, uptodate, to_read, to_write, failed,
	       failed_num[0], failed_num[1]);
	/* check if the array has lost >2 devices and, if so, some requests might
	 * need to be failed
	 */
	if (failed > 2 && to_read+to_write+written) {
		for (i=disks; i--; ) {
			int bitmap_end = 0;
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2026 2027 2028 2029 2030 2031 2032 2033 2034
			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();
			}
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2036 2037 2038 2039 2040
			spin_lock_irq(&conf->device_lock);
			/* fail all writes first */
			bi = sh->dev[i].towrite;
			sh->dev[i].towrite = NULL;
			if (bi) { to_write--; bitmap_end = 1; }
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Linus Torvalds 已提交
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			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;
			}

			/* fail any reads if this device is non-operational */
			if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
			    test_bit(R5_ReadError, &sh->dev[i].flags)) {
				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) 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);
		}
	}
	if (failed > 2 && syncing) {
		md_done_sync(conf->mddev, STRIPE_SECTORS,0);
		clear_bit(STRIPE_SYNCING, &sh->state);
		syncing = 0;
	}

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

	if ( written &&
	     ( p_failed || ((test_bit(R5_Insync, &pdev->flags)
			     && !test_bit(R5_LOCKED, &pdev->flags)
			     && test_bit(R5_UPTODATE, &pdev->flags))) ) &&
	     ( q_failed || ((test_bit(R5_Insync, &qdev->flags)
			     && !test_bit(R5_LOCKED, &qdev->flags)
			     && test_bit(R5_UPTODATE, &qdev->flags))) ) ) {
		/* 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.
		 */
		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 */
					int bitmap_end = 0;
					struct bio *wbi, *wbi2;
					PRINTK("Return write for stripe %llu disc %d\n",
					       (unsigned long long)sh->sector, i);
					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);
				}
			}
	}

	/* 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.
	 */
	if (to_read || non_overwrite || (to_write && failed) || (syncing && (uptodate < disks))) {
		for (i=disks; i--;) {
			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)) ||
			     syncing ||
			     (failed >= 1 && (sh->dev[failed_num[0]].toread || to_write)) ||
			     (failed >= 2 && (sh->dev[failed_num[1]].toread || to_write))
				    )
				) {
				/* we would like to get this block, possibly
				 * by computing it, but we might not be able to
				 */
				if (uptodate == disks-1) {
					PRINTK("Computing stripe %llu block %d\n",
					       (unsigned long long)sh->sector, i);
					compute_block_1(sh, i, 0);
					uptodate++;
				} else if ( uptodate == disks-2 && 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);
					PRINTK("Computing stripe %llu blocks %d,%d\n",
					       (unsigned long long)sh->sector, i, other);
					compute_block_2(sh, i, other);
					uptodate += 2;
				} else if (test_bit(R5_Insync, &dev->flags)) {
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
#if 0
					/* if I am just reading this block and we don't have
					   a failed drive, or any pending writes then sidestep the cache */
					if (sh->bh_read[i] && !sh->bh_read[i]->b_reqnext &&
					    ! syncing && !failed && !to_write) {
						sh->bh_cache[i]->b_page =  sh->bh_read[i]->b_page;
						sh->bh_cache[i]->b_data =  sh->bh_read[i]->b_data;
					}
#endif
					locked++;
					PRINTK("Reading block %d (sync=%d)\n",
						i, syncing);
				}
			}
		}
		set_bit(STRIPE_HANDLE, &sh->state);
	}

	/* now to consider writing and what else, if anything should be read */
	if (to_write) {
		int rcw=0, must_compute=0;
		for (i=disks ; i--;) {
			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)
#if 0
				|| sh->bh_page[i] != bh->b_page
#endif
				    ) &&
			    !test_bit(R5_UPTODATE, &dev->flags)) {
				if (test_bit(R5_Insync, &dev->flags)) rcw++;
				else {
					PRINTK("raid6: must_compute: disk %d flags=%#lx\n", i, dev->flags);
					must_compute++;
				}
			}
		}
		PRINTK("for sector %llu, rcw=%d, must_compute=%d\n",
		       (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--;) {
				dev = &sh->dev[i];
				if (!test_bit(R5_OVERWRITE, &dev->flags)
				    && !(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))
					{
						PRINTK("Read_old stripe %llu block %d for Reconstruct\n",
						       (unsigned long long)sh->sector, i);
						set_bit(R5_LOCKED, &dev->flags);
						set_bit(R5_Wantread, &dev->flags);
						locked++;
					} else {
						PRINTK("Request delayed stripe %llu 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 (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 ( failed ) {
				case 0:	BUG();
				case 1: compute_block_1(sh, failed_num[0], 0); break;
				case 2: compute_block_2(sh, failed_num[0], failed_num[1]); break;
				default: BUG();	/* This request should have been failed? */
				}
			}

			PRINTK("Computing parity for stripe %llu\n", (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)) {
					PRINTK("Writing stripe %llu block %d\n",
					       (unsigned long long)sh->sector, i);
					locked++;
					set_bit(R5_Wantwrite, &sh->dev[i].flags);
				}
			/* 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);
			}
		}
	}

	/* maybe we need to check and possibly fix the parity for this stripe
	 * Any reads will already have been scheduled, so we just see if enough data
	 * is available
	 */
	if (syncing && locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state)) {
		int update_p = 0, update_q = 0;
		struct r5dev *dev;

		set_bit(STRIPE_HANDLE, &sh->state);

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

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

	if (syncing && locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
		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
	 */
	if (failed <= 2 && ! conf->mddev->ro)
		for (i=0; i<failed;i++) {
			dev = &sh->dev[failed_num[i]];
			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);
				}
			}
		}
	spin_unlock(&sh->lock);

	while ((bi=return_bi)) {
		int bytes = bi->bi_size;

		return_bi = bi->bi_next;
		bi->bi_next = NULL;
		bi->bi_size = 0;
		bi->bi_end_io(bi, bytes, 0);
	}
	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 = 1;
		else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
			rw = 0;
		else
			continue;

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

		bi->bi_rw = rw;
		if (rw)
			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 (syncing)
				md_sync_acct(rdev->bdev, STRIPE_SECTORS);

			bi->bi_bdev = rdev->bdev;
			PRINTK("for %llu schedule op %ld on disc %d\n",
				(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 {
			if (rw == 1)
				set_bit(STRIPE_DEGRADED, &sh->state);
			PRINTK("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 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);
			list_add_tail(&sh->lru, &conf->handle_list);
		}
	}
}

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)) {
			request_queue_t *r_queue = bdev_get_queue(rdev->bdev);

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

			if (r_queue->unplug_fn)
				r_queue->unplug_fn(r_queue);

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

static void raid5_unplug_device(request_queue_t *q)
{
	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);
2558
	}
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	md_wakeup_thread(mddev->thread);

	spin_unlock_irqrestore(&conf->device_lock, flags);

	unplug_slaves(mddev);
}

static int raid5_issue_flush(request_queue_t *q, struct gendisk *disk,
			     sector_t *error_sector)
{
	mddev_t *mddev = q->queuedata;
	raid5_conf_t *conf = mddev_to_conf(mddev);
	int i, ret = 0;

	rcu_read_lock();
	for (i=0; i<mddev->raid_disks && ret == 0; i++) {
2575
		mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
2576
		if (rdev && !test_bit(Faulty, &rdev->flags)) {
L
Linus Torvalds 已提交
2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595
			struct block_device *bdev = rdev->bdev;
			request_queue_t *r_queue = bdev_get_queue(bdev);

			if (!r_queue->issue_flush_fn)
				ret = -EOPNOTSUPP;
			else {
				atomic_inc(&rdev->nr_pending);
				rcu_read_unlock();
				ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
							      error_sector);
				rdev_dec_pending(rdev, mddev);
				rcu_read_lock();
			}
		}
	}
	rcu_read_unlock();
	return ret;
}

2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613
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;
}

2614
static int make_request(request_queue_t *q, struct bio * bi)
L
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2615 2616 2617 2618 2619 2620 2621
{
	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;
2622
	const int rw = bio_data_dir(bi);
2623
	int remaining;
L
Linus Torvalds 已提交
2624

2625 2626 2627 2628 2629
	if (unlikely(bio_barrier(bi))) {
		bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
		return 0;
	}

2630
	md_write_start(mddev, bi);
2631

2632 2633
	disk_stat_inc(mddev->gendisk, ios[rw]);
	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
L
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2634 2635 2636 2637 2638

	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 */
2639

L
Linus Torvalds 已提交
2640 2641
	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
		DEFINE_WAIT(w);
2642
		int disks, data_disks;
2643

2644
	retry:
2645
		prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
2646 2647 2648
		if (likely(conf->expand_progress == MaxSector))
			disks = conf->raid_disks;
		else {
2649 2650 2651 2652 2653 2654 2655 2656
			/* 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.
			 */
2657 2658 2659 2660
			spin_lock_irq(&conf->device_lock);
			disks = conf->raid_disks;
			if (logical_sector >= conf->expand_progress)
				disks = conf->previous_raid_disks;
2661 2662 2663 2664 2665 2666 2667
			else {
				if (logical_sector >= conf->expand_lo) {
					spin_unlock_irq(&conf->device_lock);
					schedule();
					goto retry;
				}
			}
2668 2669
			spin_unlock_irq(&conf->device_lock);
		}
2670 2671 2672
		data_disks = disks - conf->max_degraded;

 		new_sector = raid5_compute_sector(logical_sector, disks, data_disks,
2673
						  &dd_idx, &pd_idx, conf);
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2674 2675 2676 2677
		PRINTK("raid5: make_request, sector %llu logical %llu\n",
			(unsigned long long)new_sector, 
			(unsigned long long)logical_sector);

2678
		sh = get_active_stripe(conf, new_sector, disks, pd_idx, (bi->bi_rw&RWA_MASK));
L
Linus Torvalds 已提交
2679
		if (sh) {
2680 2681
			if (unlikely(conf->expand_progress != MaxSector)) {
				/* expansion might have moved on while waiting for a
2682 2683 2684 2685 2686 2687
				 * 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.
2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700
				 */
				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;
				}
			}
2701 2702 2703 2704 2705 2706 2707 2708 2709
			/* 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;
			}
2710 2711 2712 2713 2714

			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
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2715 2716 2717 2718 2719 2720 2721 2722
				 * and wait a while
				 */
				raid5_unplug_device(mddev->queue);
				release_stripe(sh);
				schedule();
				goto retry;
			}
			finish_wait(&conf->wait_for_overlap, &w);
2723
			handle_stripe(sh, NULL);
L
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2724 2725 2726 2727 2728 2729 2730 2731 2732 2733
			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);
2734 2735 2736
	remaining = --bi->bi_phys_segments;
	spin_unlock_irq(&conf->device_lock);
	if (remaining == 0) {
L
Linus Torvalds 已提交
2737 2738
		int bytes = bi->bi_size;

2739
		if ( rw == WRITE )
L
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2740 2741 2742 2743 2744 2745 2746
			md_write_end(mddev);
		bi->bi_size = 0;
		bi->bi_end_io(bi, bytes, 0);
	}
	return 0;
}

2747
static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped)
L
Linus Torvalds 已提交
2748
{
2749 2750 2751 2752 2753 2754 2755 2756 2757
	/* 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
2758 2759
	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;
	struct stripe_head *sh;
2760 2761
	int pd_idx;
	sector_t first_sector, last_sector;
2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797
	int raid_disks;
	int data_disks;
	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;
		sector_div(sector_nr, conf->raid_disks-1);
		*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 +
		conf->chunk_size/512*(conf->raid_disks-1);
	sector_div(writepos, conf->raid_disks-1);
	safepos = conf->expand_lo;
	sector_div(safepos, conf->previous_raid_disks-1);
	gap = conf->expand_progress - conf->expand_lo;

	if (writepos >= safepos ||
	    gap > (conf->raid_disks-1)*3000*2 /*3Meg*/) {
		/* 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;
2798
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
2799
		md_wakeup_thread(mddev->thread);
2800
		wait_event(mddev->sb_wait, mddev->flags == 0 ||
2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876
			   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;
			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);
	conf->expand_progress = (sector_nr + i)*(conf->raid_disks-1);
	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.
	 */
	raid_disks = conf->previous_raid_disks;
	data_disks = raid_disks - 1;
	first_sector =
		raid5_compute_sector(sector_nr*(conf->raid_disks-1),
				     raid_disks, data_disks,
				     &dd_idx, &pd_idx, conf);
	last_sector =
		raid5_compute_sector((sector_nr+conf->chunk_size/512)
				     *(conf->raid_disks-1) -1,
				     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) {
		pd_idx = stripe_to_pdidx(first_sector, conf, conf->previous_raid_disks);
		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;
	}
	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
2877
	int raid_disks = conf->raid_disks;
2878 2879
	sector_t max_sector = mddev->size << 1;
	int sync_blocks;
2880 2881
	int still_degraded = 0;
	int i;
L
Linus Torvalds 已提交
2882

2883
	if (sector_nr >= max_sector) {
L
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2884 2885
		/* just being told to finish up .. nothing much to do */
		unplug_slaves(mddev);
2886 2887 2888 2889
		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
			end_reshape(conf);
			return 0;
		}
2890 2891 2892 2893

		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
					&sync_blocks, 1);
2894
		else /* completed sync */
2895 2896 2897
			conf->fullsync = 0;
		bitmap_close_sync(mddev->bitmap);

L
Linus Torvalds 已提交
2898 2899
		return 0;
	}
2900

2901 2902
	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
		return reshape_request(mddev, sector_nr, skipped);
2903

2904
	/* if there is too many failed drives and we are trying
L
Linus Torvalds 已提交
2905 2906 2907
	 * to resync, then assert that we are finished, because there is
	 * nothing we can do.
	 */
2908
	if (mddev->degraded >= conf->max_degraded &&
2909
	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2910 2911
		sector_t rv = (mddev->size << 1) - sector_nr;
		*skipped = 1;
L
Linus Torvalds 已提交
2912 2913
		return rv;
	}
2914
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2915
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2916 2917 2918 2919 2920 2921
	    !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
2922

2923
	pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks);
2924
	sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1);
L
Linus Torvalds 已提交
2925
	if (sh == NULL) {
2926
		sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 0);
L
Linus Torvalds 已提交
2927
		/* make sure we don't swamp the stripe cache if someone else
2928
		 * is trying to get access
L
Linus Torvalds 已提交
2929
		 */
2930
		schedule_timeout_uninterruptible(1);
L
Linus Torvalds 已提交
2931
	}
2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942
	/* 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
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2943 2944 2945 2946
	set_bit(STRIPE_SYNCING, &sh->state);
	clear_bit(STRIPE_INSYNC, &sh->state);
	spin_unlock(&sh->lock);

2947
	handle_stripe(sh, NULL);
L
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2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974
	release_stripe(sh);

	return STRIPE_SECTORS;
}

/*
 * 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.
 */
static void raid5d (mddev_t *mddev)
{
	struct stripe_head *sh;
	raid5_conf_t *conf = mddev_to_conf(mddev);
	int handled;

	PRINTK("+++ raid5d active\n");

	md_check_recovery(mddev);

	handled = 0;
	spin_lock_irq(&conf->device_lock);
	while (1) {
		struct list_head *first;

2975
		if (conf->seq_flush != conf->seq_write) {
2976
			int seq = conf->seq_flush;
2977
			spin_unlock_irq(&conf->device_lock);
2978
			bitmap_unplug(mddev->bitmap);
2979
			spin_lock_irq(&conf->device_lock);
2980 2981 2982 2983
			conf->seq_write = seq;
			activate_bit_delay(conf);
		}

L
Linus Torvalds 已提交
2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997
		if (list_empty(&conf->handle_list) &&
		    atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
		    !blk_queue_plugged(mddev->queue) &&
		    !list_empty(&conf->delayed_list))
			raid5_activate_delayed(conf);

		if (list_empty(&conf->handle_list))
			break;

		first = conf->handle_list.next;
		sh = list_entry(first, struct stripe_head, lru);

		list_del_init(first);
		atomic_inc(&sh->count);
2998
		BUG_ON(atomic_read(&sh->count)!= 1);
L
Linus Torvalds 已提交
2999 3000 3001
		spin_unlock_irq(&conf->device_lock);
		
		handled++;
3002
		handle_stripe(sh, conf->spare_page);
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Linus Torvalds 已提交
3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015
		release_stripe(sh);

		spin_lock_irq(&conf->device_lock);
	}
	PRINTK("%d stripes handled\n", handled);

	spin_unlock_irq(&conf->device_lock);

	unplug_slaves(mddev);

	PRINTK("--- raid5d inactive\n");
}

3016
static ssize_t
3017
raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
3018
{
3019
	raid5_conf_t *conf = mddev_to_conf(mddev);
3020 3021 3022 3023
	if (conf)
		return sprintf(page, "%d\n", conf->max_nr_stripes);
	else
		return 0;
3024 3025 3026
}

static ssize_t
3027
raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
3028
{
3029
	raid5_conf_t *conf = mddev_to_conf(mddev);
3030 3031 3032 3033
	char *end;
	int new;
	if (len >= PAGE_SIZE)
		return -EINVAL;
3034 3035
	if (!conf)
		return -ENODEV;
3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054

	new = simple_strtoul(page, &end, 10);
	if (!*page || (*end && *end != '\n') )
		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;
	}
	while (new > conf->max_nr_stripes) {
		if (grow_one_stripe(conf))
			conf->max_nr_stripes++;
		else break;
	}
	return len;
}
3055

3056 3057 3058 3059
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);
3060 3061

static ssize_t
3062
stripe_cache_active_show(mddev_t *mddev, char *page)
3063
{
3064
	raid5_conf_t *conf = mddev_to_conf(mddev);
3065 3066 3067 3068
	if (conf)
		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
	else
		return 0;
3069 3070
}

3071 3072
static struct md_sysfs_entry
raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
3073

3074
static struct attribute *raid5_attrs[] =  {
3075 3076 3077 3078
	&raid5_stripecache_size.attr,
	&raid5_stripecache_active.attr,
	NULL,
};
3079 3080 3081
static struct attribute_group raid5_attrs_group = {
	.name = NULL,
	.attrs = raid5_attrs,
3082 3083
};

3084
static int run(mddev_t *mddev)
L
Linus Torvalds 已提交
3085 3086 3087 3088 3089 3090
{
	raid5_conf_t *conf;
	int raid_disk, memory;
	mdk_rdev_t *rdev;
	struct disk_info *disk;
	struct list_head *tmp;
3091
	int working_disks = 0;
L
Linus Torvalds 已提交
3092

3093 3094
	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
3095
		       mdname(mddev), mddev->level);
L
Linus Torvalds 已提交
3096 3097 3098
		return -EIO;
	}

3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142
	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;

		if (mddev->new_level != mddev->level ||
		    mddev->new_layout != mddev->layout ||
		    mddev->new_chunk != mddev->chunk_size) {
			printk(KERN_ERR "raid5: %s: unsupported reshape required - aborting.\n",
			       mdname(mddev));
			return -EINVAL;
		}
		if (mddev->delta_disks <= 0) {
			printk(KERN_ERR "raid5: %s: unsupported reshape (reduce disks) required - aborting.\n",
			       mdname(mddev));
			return -EINVAL;
		}
		old_disks = mddev->raid_disks - mddev->delta_disks;
		/* reshape_position must be on a new-stripe boundary, and one
		 * further up in new geometry must map after here in old geometry.
		 */
		here_new = mddev->reshape_position;
		if (sector_div(here_new, (mddev->chunk_size>>9)*(mddev->raid_disks-1))) {
			printk(KERN_ERR "raid5: reshape_position not on a stripe boundary\n");
			return -EINVAL;
		}
		/* here_new is the stripe we will write to */
		here_old = mddev->reshape_position;
		sector_div(here_old, (mddev->chunk_size>>9)*(old_disks-1));
		/* here_old is the first stripe that we might need to read from */
		if (here_new >= here_old) {
			/* Reading from the same stripe as writing to - bad */
			printk(KERN_ERR "raid5: reshape_position too early for auto-recovery - aborting.\n");
			return -EINVAL;
		}
		printk(KERN_INFO "raid5: reshape will continue\n");
		/* OK, we should be able to continue; */
	}


3143
	mddev->private = kzalloc(sizeof (raid5_conf_t), GFP_KERNEL);
L
Linus Torvalds 已提交
3144 3145
	if ((conf = mddev->private) == NULL)
		goto abort;
3146 3147 3148 3149 3150 3151 3152 3153
	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),
3154 3155 3156
			      GFP_KERNEL);
	if (!conf->disks)
		goto abort;
3157

L
Linus Torvalds 已提交
3158 3159
	conf->mddev = mddev;

3160
	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
L
Linus Torvalds 已提交
3161 3162
		goto abort;

3163 3164 3165 3166 3167
	if (mddev->level == 6) {
		conf->spare_page = alloc_page(GFP_KERNEL);
		if (!conf->spare_page)
			goto abort;
	}
L
Linus Torvalds 已提交
3168 3169 3170 3171 3172
	spin_lock_init(&conf->device_lock);
	init_waitqueue_head(&conf->wait_for_stripe);
	init_waitqueue_head(&conf->wait_for_overlap);
	INIT_LIST_HEAD(&conf->handle_list);
	INIT_LIST_HEAD(&conf->delayed_list);
3173
	INIT_LIST_HEAD(&conf->bitmap_list);
L
Linus Torvalds 已提交
3174 3175 3176 3177 3178 3179 3180 3181
	INIT_LIST_HEAD(&conf->inactive_list);
	atomic_set(&conf->active_stripes, 0);
	atomic_set(&conf->preread_active_stripes, 0);

	PRINTK("raid5: run(%s) called.\n", mdname(mddev));

	ITERATE_RDEV(mddev,rdev,tmp) {
		raid_disk = rdev->raid_disk;
3182
		if (raid_disk >= conf->raid_disks
L
Linus Torvalds 已提交
3183 3184 3185 3186 3187 3188
		    || raid_disk < 0)
			continue;
		disk = conf->disks + raid_disk;

		disk->rdev = rdev;

3189
		if (test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
3190 3191 3192 3193
			char b[BDEVNAME_SIZE];
			printk(KERN_INFO "raid5: device %s operational as raid"
				" disk %d\n", bdevname(rdev->bdev,b),
				raid_disk);
3194
			working_disks++;
L
Linus Torvalds 已提交
3195 3196 3197 3198
		}
	}

	/*
3199
	 * 0 for a fully functional array, 1 or 2 for a degraded array.
L
Linus Torvalds 已提交
3200
	 */
3201
	mddev->degraded = conf->raid_disks - working_disks;
L
Linus Torvalds 已提交
3202 3203 3204
	conf->mddev = mddev;
	conf->chunk_size = mddev->chunk_size;
	conf->level = mddev->level;
3205 3206 3207 3208
	if (conf->level == 6)
		conf->max_degraded = 2;
	else
		conf->max_degraded = 1;
L
Linus Torvalds 已提交
3209 3210
	conf->algorithm = mddev->layout;
	conf->max_nr_stripes = NR_STRIPES;
3211
	conf->expand_progress = mddev->reshape_position;
L
Linus Torvalds 已提交
3212 3213 3214

	/* device size must be a multiple of chunk size */
	mddev->size &= ~(mddev->chunk_size/1024 -1);
3215
	mddev->resync_max_sectors = mddev->size << 1;
L
Linus Torvalds 已提交
3216

3217 3218 3219 3220 3221
	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
3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232
	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;
	}
3233
	if (mddev->degraded > conf->max_degraded) {
L
Linus Torvalds 已提交
3234 3235
		printk(KERN_ERR "raid5: not enough operational devices for %s"
			" (%d/%d failed)\n",
3236
			mdname(mddev), mddev->degraded, conf->raid_disks);
L
Linus Torvalds 已提交
3237 3238 3239
		goto abort;
	}

3240
	if (mddev->degraded > 0 &&
L
Linus Torvalds 已提交
3241
	    mddev->recovery_cp != MaxSector) {
3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252
		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
3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263
	}

	{
		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;
		}
	}
3264
	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
L
Linus Torvalds 已提交
3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288
		 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);

3289 3290
	if (conf->expand_progress != MaxSector) {
		printk("...ok start reshape thread\n");
3291
		conf->expand_lo = conf->expand_progress;
3292 3293 3294 3295 3296 3297 3298 3299 3300
		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
3301
	/* read-ahead size must cover two whole stripes, which is
3302
	 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
L
Linus Torvalds 已提交
3303 3304
	 */
	{
3305 3306
		int data_disks = conf->previous_raid_disks - conf->max_degraded;
		int stripe = data_disks *
3307
			(mddev->chunk_size / PAGE_SIZE);
L
Linus Torvalds 已提交
3308 3309 3310 3311 3312
		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 */
3313
	sysfs_create_group(&mddev->kobj, &raid5_attrs_group);
3314 3315 3316

	mddev->queue->unplug_fn = raid5_unplug_device;
	mddev->queue->issue_flush_fn = raid5_issue_flush;
3317 3318 3319
	mddev->queue->backing_dev_info.congested_fn = raid5_congested;
	mddev->queue->backing_dev_info.congested_data = mddev;

3320 3321
	mddev->array_size =  mddev->size * (conf->previous_raid_disks -
					    conf->max_degraded);
3322

L
Linus Torvalds 已提交
3323 3324 3325 3326
	return 0;
abort:
	if (conf) {
		print_raid5_conf(conf);
3327
		safe_put_page(conf->spare_page);
3328
		kfree(conf->disks);
3329
		kfree(conf->stripe_hashtbl);
L
Linus Torvalds 已提交
3330 3331 3332 3333 3334 3335 3336 3337 3338
		kfree(conf);
	}
	mddev->private = NULL;
	printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev));
	return -EIO;
}



3339
static int stop(mddev_t *mddev)
L
Linus Torvalds 已提交
3340 3341 3342 3343 3344 3345
{
	raid5_conf_t *conf = (raid5_conf_t *) mddev->private;

	md_unregister_thread(mddev->thread);
	mddev->thread = NULL;
	shrink_stripes(conf);
3346
	kfree(conf->stripe_hashtbl);
L
Linus Torvalds 已提交
3347
	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
3348
	sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
3349
	kfree(conf->disks);
3350
	kfree(conf);
L
Linus Torvalds 已提交
3351 3352 3353 3354 3355
	mddev->private = NULL;
	return 0;
}

#if RAID5_DEBUG
3356
static void print_sh (struct seq_file *seq, struct stripe_head *sh)
L
Linus Torvalds 已提交
3357 3358 3359
{
	int i;

3360 3361 3362 3363 3364
	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);
3365
	for (i = 0; i < sh->disks; i++) {
3366 3367
		seq_printf(seq, "(cache%d: %p %ld) ",
			   i, sh->dev[i].page, sh->dev[i].flags);
L
Linus Torvalds 已提交
3368
	}
3369
	seq_printf(seq, "\n");
L
Linus Torvalds 已提交
3370 3371
}

3372
static void printall (struct seq_file *seq, raid5_conf_t *conf)
L
Linus Torvalds 已提交
3373 3374
{
	struct stripe_head *sh;
3375
	struct hlist_node *hn;
L
Linus Torvalds 已提交
3376 3377 3378 3379
	int i;

	spin_lock_irq(&conf->device_lock);
	for (i = 0; i < NR_HASH; i++) {
3380
		hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) {
L
Linus Torvalds 已提交
3381 3382
			if (sh->raid_conf != conf)
				continue;
3383
			print_sh(seq, sh);
L
Linus Torvalds 已提交
3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395
		}
	}
	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);
3396
	seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
L
Linus Torvalds 已提交
3397 3398 3399
	for (i = 0; i < conf->raid_disks; i++)
		seq_printf (seq, "%s",
			       conf->disks[i].rdev &&
3400
			       test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
L
Linus Torvalds 已提交
3401 3402
	seq_printf (seq, "]");
#if RAID5_DEBUG
3403 3404
	seq_printf (seq, "\n");
	printall(seq, conf);
L
Linus Torvalds 已提交
3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417
#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;
	}
3418 3419
	printk(" --- rd:%d wd:%d\n", conf->raid_disks,
		 conf->raid_disks - conf->mddev->degraded);
L
Linus Torvalds 已提交
3420 3421 3422 3423 3424 3425

	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",
3426
			i, !test_bit(Faulty, &tmp->rdev->flags),
L
Linus Torvalds 已提交
3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439
			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
3440
		    && !test_bit(Faulty, &tmp->rdev->flags)
3441 3442 3443
		    && !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
3444
			mddev->degraded--;
3445
			spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461
		}
	}
	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) {
3462
		if (test_bit(In_sync, &rdev->flags) ||
L
Linus Torvalds 已提交
3463 3464 3465 3466 3467
		    atomic_read(&rdev->nr_pending)) {
			err = -EBUSY;
			goto abort;
		}
		p->rdev = NULL;
3468
		synchronize_rcu();
L
Linus Torvalds 已提交
3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487
		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;
	int found = 0;
	int disk;
	struct disk_info *p;

3488
	if (mddev->degraded > conf->max_degraded)
L
Linus Torvalds 已提交
3489 3490 3491 3492
		/* no point adding a device */
		return 0;

	/*
3493 3494
	 * find the disk ... but prefer rdev->saved_raid_disk
	 * if possible.
L
Linus Torvalds 已提交
3495
	 */
3496 3497 3498 3499 3500 3501
	if (rdev->saved_raid_disk >= 0 &&
	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
		disk = rdev->saved_raid_disk;
	else
		disk = 0;
	for ( ; disk < conf->raid_disks; disk++)
L
Linus Torvalds 已提交
3502
		if ((p=conf->disks + disk)->rdev == NULL) {
3503
			clear_bit(In_sync, &rdev->flags);
L
Linus Torvalds 已提交
3504 3505
			rdev->raid_disk = disk;
			found = 1;
3506 3507
			if (rdev->saved_raid_disk != disk)
				conf->fullsync = 1;
3508
			rcu_assign_pointer(p->rdev, rdev);
L
Linus Torvalds 已提交
3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523
			break;
		}
	print_raid5_conf(conf);
	return found;
}

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.
	 */
3524 3525
	raid5_conf_t *conf = mddev_to_conf(mddev);

L
Linus Torvalds 已提交
3526
	sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
3527
	mddev->array_size = (sectors * (mddev->raid_disks-conf->max_degraded))>>1;
L
Linus Torvalds 已提交
3528 3529 3530 3531 3532 3533 3534
	set_capacity(mddev->gendisk, mddev->array_size << 1);
	mddev->changed = 1;
	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;
3535
	mddev->resync_max_sectors = sectors;
L
Linus Torvalds 已提交
3536 3537 3538
	return 0;
}

3539
#ifdef CONFIG_MD_RAID5_RESHAPE
3540
static int raid5_check_reshape(mddev_t *mddev)
3541 3542 3543 3544
{
	raid5_conf_t *conf = mddev_to_conf(mddev);
	int err;

3545 3546 3547 3548
	if (mddev->delta_disks < 0 ||
	    mddev->new_level != mddev->level)
		return -EINVAL; /* Cannot shrink array or change level yet */
	if (mddev->delta_disks == 0)
3549 3550 3551 3552 3553 3554 3555 3556 3557 3558
		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.
	 */
3559 3560
	if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes ||
	    (mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) {
3561 3562 3563 3564 3565
		printk(KERN_WARNING "raid5: reshape: not enough stripes.  Needed %lu\n",
		       (mddev->chunk_size / STRIPE_SIZE)*4);
		return -ENOSPC;
	}

3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580
	err = resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
	if (err)
		return err;

	/* 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;
3581
	unsigned long flags;
3582 3583 3584 3585 3586

	if (mddev->degraded ||
	    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
		return -EBUSY;

3587 3588 3589 3590
	ITERATE_RDEV(mddev, rdev, rtmp)
		if (rdev->raid_disk < 0 &&
		    !test_bit(Faulty, &rdev->flags))
			spares++;
3591 3592

	if (spares < mddev->delta_disks-1)
3593 3594 3595 3596 3597
		/* Not enough devices even to make a degraded array
		 * of that size
		 */
		return -EINVAL;

3598
	atomic_set(&conf->reshape_stripes, 0);
3599 3600
	spin_lock_irq(&conf->device_lock);
	conf->previous_raid_disks = conf->raid_disks;
3601
	conf->raid_disks += mddev->delta_disks;
3602
	conf->expand_progress = 0;
3603
	conf->expand_lo = 0;
3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615
	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.
	 */
	ITERATE_RDEV(mddev, rdev, rtmp)
		if (rdev->raid_disk < 0 &&
		    !test_bit(Faulty, &rdev->flags)) {
			if (raid5_add_disk(mddev, rdev)) {
				char nm[20];
				set_bit(In_sync, &rdev->flags);
				added_devices++;
3616
				rdev->recovery_offset = 0;
3617 3618 3619 3620 3621 3622
				sprintf(nm, "rd%d", rdev->raid_disk);
				sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
			} else
				break;
		}

3623
	spin_lock_irqsave(&conf->device_lock, flags);
3624
	mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) - added_devices;
3625
	spin_unlock_irqrestore(&conf->device_lock, flags);
3626
	mddev->raid_disks = conf->raid_disks;
3627
	mddev->reshape_position = 0;
3628
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
3629

3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653
	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;

3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669
	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
		conf->mddev->array_size = conf->mddev->size * (conf->raid_disks-1);
		set_capacity(conf->mddev->gendisk, conf->mddev->array_size << 1);
		conf->mddev->changed = 1;

		bdev = bdget_disk(conf->mddev->gendisk, 0);
		if (bdev) {
			mutex_lock(&bdev->bd_inode->i_mutex);
			i_size_write(bdev->bd_inode, conf->mddev->array_size << 10);
			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;
3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680

		/* 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;
		}
3681 3682 3683
	}
}

3684 3685 3686 3687 3688
static void raid5_quiesce(mddev_t *mddev, int state)
{
	raid5_conf_t *conf = mddev_to_conf(mddev);

	switch(state) {
3689 3690 3691 3692
	case 2: /* resume for a suspend */
		wake_up(&conf->wait_for_overlap);
		break;

3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705
	case 1: /* stop all writes */
		spin_lock_irq(&conf->device_lock);
		conf->quiesce = 1;
		wait_event_lock_irq(conf->wait_for_stripe,
				    atomic_read(&conf->active_stripes) == 0,
				    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);
3706
		wake_up(&conf->wait_for_overlap);
3707 3708 3709 3710
		spin_unlock_irq(&conf->device_lock);
		break;
	}
}
3711

3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728
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,
	.quiesce	= raid5_quiesce,
};
3729
static struct mdk_personality raid5_personality =
L
Linus Torvalds 已提交
3730 3731
{
	.name		= "raid5",
3732
	.level		= 5,
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Linus Torvalds 已提交
3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743
	.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,
3744
#ifdef CONFIG_MD_RAID5_RESHAPE
3745 3746
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
3747
#endif
3748
	.quiesce	= raid5_quiesce,
L
Linus Torvalds 已提交
3749 3750
};

3751
static struct mdk_personality raid4_personality =
L
Linus Torvalds 已提交
3752
{
3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770
	.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,
	.quiesce	= raid5_quiesce,
};

static int __init raid5_init(void)
{
3771 3772 3773 3774 3775 3776
	int e;

	e = raid6_select_algo();
	if ( e )
		return e;
	register_md_personality(&raid6_personality);
3777 3778 3779
	register_md_personality(&raid5_personality);
	register_md_personality(&raid4_personality);
	return 0;
L
Linus Torvalds 已提交
3780 3781
}

3782
static void raid5_exit(void)
L
Linus Torvalds 已提交
3783
{
3784
	unregister_md_personality(&raid6_personality);
3785 3786
	unregister_md_personality(&raid5_personality);
	unregister_md_personality(&raid4_personality);
L
Linus Torvalds 已提交
3787 3788 3789 3790 3791 3792
}

module_init(raid5_init);
module_exit(raid5_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS("md-personality-4"); /* RAID5 */
3793 3794
MODULE_ALIAS("md-raid5");
MODULE_ALIAS("md-raid4");
3795 3796
MODULE_ALIAS("md-level-5");
MODULE_ALIAS("md-level-4");
3797 3798 3799 3800 3801 3802 3803
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");