raid5.c 159.0 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.
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 * conf->seq_write is the number of the last batch successfully written.
 * conf->seq_flush is the number of the last batch that was closed to
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 *    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
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 * the number of the batch it will be in. This is seq_flush+1.
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 * 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/blkdev.h>
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#include <linux/kthread.h>
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#include <linux/raid/pq.h>
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#include <linux/async_tx.h>
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#include <linux/module.h>
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#include <linux/async.h>
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#include <linux/seq_file.h>
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#include <linux/cpu.h>
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#include <linux/slab.h>
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#include <linux/ratelimit.h>
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#include "md.h"
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#include "raid5.h"
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#include "raid0.h"
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#include "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 BYPASS_THRESHOLD	1
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#define NR_HASH			(PAGE_SIZE / sizeof(struct hlist_head))
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#define HASH_MASK		(NR_HASH - 1)

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static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
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{
	int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
	return &conf->stripe_hashtbl[hash];
}
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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.
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 * This function is used to determine the 'next' bio in the list, given the sector
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 * of the current stripe+device
 */
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static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector)
{
	int sectors = bio->bi_size >> 9;
	if (bio->bi_sector + sectors < sector + STRIPE_SECTORS)
		return bio->bi_next;
	else
		return NULL;
}
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/*
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 * We maintain a biased count of active stripes in the bottom 16 bits of
 * bi_phys_segments, and a count of processed stripes in the upper 16 bits
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 */
static inline int raid5_bi_phys_segments(struct bio *bio)
{
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	return bio->bi_phys_segments & 0xffff;
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}

static inline int raid5_bi_hw_segments(struct bio *bio)
{
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	return (bio->bi_phys_segments >> 16) & 0xffff;
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}

static inline int raid5_dec_bi_phys_segments(struct bio *bio)
{
	--bio->bi_phys_segments;
	return raid5_bi_phys_segments(bio);
}

static inline int raid5_dec_bi_hw_segments(struct bio *bio)
{
	unsigned short val = raid5_bi_hw_segments(bio);

	--val;
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	bio->bi_phys_segments = (val << 16) | raid5_bi_phys_segments(bio);
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	return val;
}

static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt)
{
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	bio->bi_phys_segments = raid5_bi_phys_segments(bio) | (cnt << 16);
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}

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/* Find first data disk in a raid6 stripe */
static inline int raid6_d0(struct stripe_head *sh)
{
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	if (sh->ddf_layout)
		/* ddf always start from first device */
		return 0;
	/* md starts just after Q block */
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	if (sh->qd_idx == sh->disks - 1)
		return 0;
	else
		return sh->qd_idx + 1;
}
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static inline int raid6_next_disk(int disk, int raid_disks)
{
	disk++;
	return (disk < raid_disks) ? disk : 0;
}
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/* When walking through the disks in a raid5, starting at raid6_d0,
 * We need to map each disk to a 'slot', where the data disks are slot
 * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 * is raid_disks-1.  This help does that mapping.
 */
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static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
			     int *count, int syndrome_disks)
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{
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	int slot = *count;
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	if (sh->ddf_layout)
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		(*count)++;
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	if (idx == sh->pd_idx)
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		return syndrome_disks;
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	if (idx == sh->qd_idx)
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		return syndrome_disks + 1;
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	if (!sh->ddf_layout)
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		(*count)++;
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	return slot;
}

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static void return_io(struct bio *return_bi)
{
	struct bio *bi = return_bi;
	while (bi) {

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

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static void print_raid5_conf (struct r5conf *conf);
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static int stripe_operations_active(struct stripe_head *sh)
{
	return sh->check_state || sh->reconstruct_state ||
	       test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
	       test_bit(STRIPE_COMPUTE_RUN, &sh->state);
}

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static void __release_stripe(struct r5conf *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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			else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
				   sh->bm_seq - conf->seq_write > 0)
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				list_add_tail(&sh->lru, &conf->bitmap_list);
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			else {
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				clear_bit(STRIPE_BIT_DELAY, &sh->state);
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				list_add_tail(&sh->lru, &conf->handle_list);
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			}
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			md_wakeup_thread(conf->mddev->thread);
		} else {
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			BUG_ON(stripe_operations_active(sh));
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			if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
				atomic_dec(&conf->preread_active_stripes);
				if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
					md_wakeup_thread(conf->mddev->thread);
			}
			atomic_dec(&conf->active_stripes);
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			if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
				list_add_tail(&sh->lru, &conf->inactive_list);
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				wake_up(&conf->wait_for_stripe);
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				if (conf->retry_read_aligned)
					md_wakeup_thread(conf->mddev->thread);
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			}
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		}
	}
}
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static void release_stripe(struct stripe_head *sh)
{
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	struct r5conf *conf = sh->raid_conf;
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	unsigned long flags;
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	spin_lock_irqsave(&conf->device_lock, flags);
	__release_stripe(conf, sh);
	spin_unlock_irqrestore(&conf->device_lock, flags);
}

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

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static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
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{
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	struct hlist_head *hp = stripe_hash(conf, sh->sector);
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	pr_debug("insert_hash(), stripe %llu\n",
		(unsigned long long)sh->sector);
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	hlist_add_head(&sh->hash, hp);
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}


/* find an idle stripe, make sure it is unhashed, and return it. */
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static struct stripe_head *get_free_stripe(struct r5conf *conf)
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{
	struct stripe_head *sh = NULL;
	struct list_head *first;

	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;
}

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static void shrink_buffers(struct stripe_head *sh)
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{
	struct page *p;
	int i;
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	int num = sh->raid_conf->pool_size;
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	for (i = 0; i < num ; i++) {
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		p = sh->dev[i].page;
		if (!p)
			continue;
		sh->dev[i].page = NULL;
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		put_page(p);
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	}
}

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static int grow_buffers(struct stripe_head *sh)
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{
	int i;
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	int num = sh->raid_conf->pool_size;
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	for (i = 0; i < num; i++) {
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		struct page *page;

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

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static void raid5_build_block(struct stripe_head *sh, int i, int previous);
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static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
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			    struct stripe_head *sh);
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static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
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{
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	struct r5conf *conf = sh->raid_conf;
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	int i;
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	BUG_ON(atomic_read(&sh->count) != 0);
	BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
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	BUG_ON(stripe_operations_active(sh));
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	pr_debug("init_stripe called, stripe %llu\n",
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		(unsigned long long)sh->sector);

	remove_hash(sh);
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	sh->generation = conf->generation - previous;
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	sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
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	sh->sector = sector;
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	stripe_set_idx(sector, conf, previous, sh);
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	sh->state = 0;

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

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		if (dev->toread || dev->read || dev->towrite || dev->written ||
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		    test_bit(R5_LOCKED, &dev->flags)) {
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			printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n",
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			       (unsigned long long)sh->sector, i, dev->toread,
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			       dev->read, dev->towrite, dev->written,
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			       test_bit(R5_LOCKED, &dev->flags));
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			WARN_ON(1);
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		}
		dev->flags = 0;
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		raid5_build_block(sh, i, previous);
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	}
	insert_hash(conf, sh);
}

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static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
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					 short generation)
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{
	struct stripe_head *sh;
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	struct hlist_node *hn;
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	pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
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	hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash)
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		if (sh->sector == sector && sh->generation == generation)
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			return sh;
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	pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
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	return NULL;
}

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/*
 * Need to check if array has failed when deciding whether to:
 *  - start an array
 *  - remove non-faulty devices
 *  - add a spare
 *  - allow a reshape
 * This determination is simple when no reshape is happening.
 * However if there is a reshape, we need to carefully check
 * both the before and after sections.
 * This is because some failed devices may only affect one
 * of the two sections, and some non-in_sync devices may
 * be insync in the section most affected by failed devices.
 */
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static int calc_degraded(struct r5conf *conf)
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{
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	int degraded, degraded2;
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	int i;

	rcu_read_lock();
	degraded = 0;
	for (i = 0; i < conf->previous_raid_disks; i++) {
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		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
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		if (!rdev || test_bit(Faulty, &rdev->flags))
			degraded++;
		else if (test_bit(In_sync, &rdev->flags))
			;
		else
			/* not in-sync or faulty.
			 * If the reshape increases the number of devices,
			 * this is being recovered by the reshape, so
			 * this 'previous' section is not in_sync.
			 * If the number of devices is being reduced however,
			 * the device can only be part of the array if
			 * we are reverting a reshape, so this section will
			 * be in-sync.
			 */
			if (conf->raid_disks >= conf->previous_raid_disks)
				degraded++;
	}
	rcu_read_unlock();
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	if (conf->raid_disks == conf->previous_raid_disks)
		return degraded;
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	rcu_read_lock();
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	degraded2 = 0;
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	for (i = 0; i < conf->raid_disks; i++) {
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		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
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		if (!rdev || test_bit(Faulty, &rdev->flags))
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			degraded2++;
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		else if (test_bit(In_sync, &rdev->flags))
			;
		else
			/* not in-sync or faulty.
			 * If reshape increases the number of devices, this
			 * section has already been recovered, else it
			 * almost certainly hasn't.
			 */
			if (conf->raid_disks <= conf->previous_raid_disks)
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				degraded2++;
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	}
	rcu_read_unlock();
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	if (degraded2 > degraded)
		return degraded2;
	return degraded;
}

static int has_failed(struct r5conf *conf)
{
	int degraded;

	if (conf->mddev->reshape_position == MaxSector)
		return conf->mddev->degraded > conf->max_degraded;

	degraded = calc_degraded(conf);
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	if (degraded > conf->max_degraded)
		return 1;
	return 0;
}

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static struct stripe_head *
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get_active_stripe(struct r5conf *conf, sector_t sector,
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		  int previous, int noblock, int noquiesce)
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{
	struct stripe_head *sh;

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

	do {
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		wait_event_lock_irq(conf->wait_for_stripe,
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				    conf->quiesce == 0 || noquiesce,
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				    conf->device_lock, /* nothing */);
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		sh = __find_stripe(conf, sector, conf->generation - previous);
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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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						    );
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				conf->inactive_blocked = 0;
			} else
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				init_stripe(sh, sector, previous);
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		} else {
			if (atomic_read(&sh->count)) {
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				BUG_ON(!list_empty(&sh->lru)
				    && !test_bit(STRIPE_EXPANDING, &sh->state));
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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 void
raid5_end_read_request(struct bio *bi, int error);
static void
raid5_end_write_request(struct bio *bi, int error);
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static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
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{
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	struct r5conf *conf = sh->raid_conf;
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	int i, disks = sh->disks;

	might_sleep();

	for (i = disks; i--; ) {
		int rw;
		struct bio *bi;
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		struct md_rdev *rdev;
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		if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
			if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
				rw = WRITE_FUA;
			else
				rw = WRITE;
		} else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
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			rw = READ;
		else
			continue;

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

		bi->bi_rw = rw;
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		if (rw & WRITE)
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			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();

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		/* We have already checked bad blocks for reads.  Now
		 * need to check for writes.
		 */
		while ((rw & WRITE) && rdev &&
		       test_bit(WriteErrorSeen, &rdev->flags)) {
			sector_t first_bad;
			int bad_sectors;
			int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
					      &first_bad, &bad_sectors);
			if (!bad)
				break;

			if (bad < 0) {
				set_bit(BlockedBadBlocks, &rdev->flags);
				if (!conf->mddev->external &&
				    conf->mddev->flags) {
					/* It is very unlikely, but we might
					 * still need to write out the
					 * bad block log - better give it
					 * a chance*/
					md_check_recovery(conf->mddev);
				}
				md_wait_for_blocked_rdev(rdev, conf->mddev);
			} else {
				/* Acknowledged bad block - skip the write */
				rdev_dec_pending(rdev, conf->mddev);
				rdev = NULL;
			}
		}

564
		if (rdev) {
565
			if (s->syncing || s->expanding || s->expanded)
566 567
				md_sync_acct(rdev->bdev, STRIPE_SECTORS);

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			set_bit(STRIPE_IO_STARTED, &sh->state);

570 571
			bi->bi_bdev = rdev->bdev;
			pr_debug("%s: for %llu schedule op %ld on disc %d\n",
572
				__func__, (unsigned long long)sh->sector,
573 574 575 576 577 578 579 580 581 582 583 584 585 586
				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;
			generic_make_request(bi);
		} else {
587
			if (rw & WRITE)
588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604
				set_bit(STRIPE_DEGRADED, &sh->state);
			pr_debug("skip op %ld on disc %d for sector %llu\n",
				bi->bi_rw, i, (unsigned long long)sh->sector);
			clear_bit(R5_LOCKED, &sh->dev[i].flags);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
	}
}

static struct dma_async_tx_descriptor *
async_copy_data(int frombio, struct bio *bio, struct page *page,
	sector_t sector, struct dma_async_tx_descriptor *tx)
{
	struct bio_vec *bvl;
	struct page *bio_page;
	int i;
	int page_offset;
605
	struct async_submit_ctl submit;
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	enum async_tx_flags flags = 0;
607 608 609 610 611

	if (bio->bi_sector >= sector)
		page_offset = (signed)(bio->bi_sector - sector) * 512;
	else
		page_offset = (signed)(sector - bio->bi_sector) * -512;
612

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	if (frombio)
		flags |= ASYNC_TX_FENCE;
	init_async_submit(&submit, flags, tx, NULL, NULL, NULL);

617
	bio_for_each_segment(bvl, bio, i) {
618
		int len = bvl->bv_len;
619 620 621 622 623 624 625 626 627 628 629 630 631 632 633
		int clen;
		int b_offset = 0;

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

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

		if (clen > 0) {
634 635
			b_offset += bvl->bv_offset;
			bio_page = bvl->bv_page;
636 637
			if (frombio)
				tx = async_memcpy(page, bio_page, page_offset,
638
						  b_offset, clen, &submit);
639 640
			else
				tx = async_memcpy(bio_page, page, b_offset,
641
						  page_offset, clen, &submit);
642
		}
643 644 645
		/* chain the operations */
		submit.depend_tx = tx;

646 647 648 649 650 651 652 653 654 655 656 657
		if (clen < len) /* hit end of page */
			break;
		page_offset +=  len;
	}

	return tx;
}

static void ops_complete_biofill(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;
	struct bio *return_bi = NULL;
658
	struct r5conf *conf = sh->raid_conf;
659
	int i;
660

661
	pr_debug("%s: stripe %llu\n", __func__,
662 663 664
		(unsigned long long)sh->sector);

	/* clear completed biofills */
665
	spin_lock_irq(&conf->device_lock);
666 667 668 669
	for (i = sh->disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];

		/* acknowledge completion of a biofill operation */
670 671
		/* and check if we need to reply to a read request,
		 * new R5_Wantfill requests are held off until
672
		 * !STRIPE_BIOFILL_RUN
673 674
		 */
		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
675 676 677 678 679 680 681 682
			struct bio *rbi, *rbi2;

			BUG_ON(!dev->read);
			rbi = dev->read;
			dev->read = NULL;
			while (rbi && rbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
				rbi2 = r5_next_bio(rbi, dev->sector);
683
				if (!raid5_dec_bi_phys_segments(rbi)) {
684 685 686 687 688 689 690
					rbi->bi_next = return_bi;
					return_bi = rbi;
				}
				rbi = rbi2;
			}
		}
	}
691 692
	spin_unlock_irq(&conf->device_lock);
	clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
693 694 695

	return_io(return_bi);

696
	set_bit(STRIPE_HANDLE, &sh->state);
697 698 699 700 701 702
	release_stripe(sh);
}

static void ops_run_biofill(struct stripe_head *sh)
{
	struct dma_async_tx_descriptor *tx = NULL;
703
	struct r5conf *conf = sh->raid_conf;
704
	struct async_submit_ctl submit;
705 706
	int i;

707
	pr_debug("%s: stripe %llu\n", __func__,
708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727
		(unsigned long long)sh->sector);

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

	atomic_inc(&sh->count);
728 729
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
	async_trigger_callback(&submit);
730 731
}

732
static void mark_target_uptodate(struct stripe_head *sh, int target)
733
{
734
	struct r5dev *tgt;
735

736 737
	if (target < 0)
		return;
738

739
	tgt = &sh->dev[target];
740 741 742
	set_bit(R5_UPTODATE, &tgt->flags);
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	clear_bit(R5_Wantcompute, &tgt->flags);
743 744
}

745
static void ops_complete_compute(void *stripe_head_ref)
746 747 748
{
	struct stripe_head *sh = stripe_head_ref;

749
	pr_debug("%s: stripe %llu\n", __func__,
750 751
		(unsigned long long)sh->sector);

752
	/* mark the computed target(s) as uptodate */
753
	mark_target_uptodate(sh, sh->ops.target);
754
	mark_target_uptodate(sh, sh->ops.target2);
755

756 757 758
	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
	if (sh->check_state == check_state_compute_run)
		sh->check_state = check_state_compute_result;
759 760 761 762
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

763 764 765 766 767 768 769 770 771
/* return a pointer to the address conversion region of the scribble buffer */
static addr_conv_t *to_addr_conv(struct stripe_head *sh,
				 struct raid5_percpu *percpu)
{
	return percpu->scribble + sizeof(struct page *) * (sh->disks + 2);
}

static struct dma_async_tx_descriptor *
ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
772 773
{
	int disks = sh->disks;
774
	struct page **xor_srcs = percpu->scribble;
775 776 777 778 779
	int target = sh->ops.target;
	struct r5dev *tgt = &sh->dev[target];
	struct page *xor_dest = tgt->page;
	int count = 0;
	struct dma_async_tx_descriptor *tx;
780
	struct async_submit_ctl submit;
781 782 783
	int i;

	pr_debug("%s: stripe %llu block: %d\n",
784
		__func__, (unsigned long long)sh->sector, target);
785 786 787 788 789 790 791 792
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));

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

	atomic_inc(&sh->count);

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	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
794
			  ops_complete_compute, sh, to_addr_conv(sh, percpu));
795
	if (unlikely(count == 1))
796
		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
797
	else
798
		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
799 800 801 802

	return tx;
}

803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820
/* set_syndrome_sources - populate source buffers for gen_syndrome
 * @srcs - (struct page *) array of size sh->disks
 * @sh - stripe_head to parse
 *
 * Populates srcs in proper layout order for the stripe and returns the
 * 'count' of sources to be used in a call to async_gen_syndrome.  The P
 * destination buffer is recorded in srcs[count] and the Q destination
 * is recorded in srcs[count+1]].
 */
static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
{
	int disks = sh->disks;
	int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
	int d0_idx = raid6_d0(sh);
	int count;
	int i;

	for (i = 0; i < disks; i++)
821
		srcs[i] = NULL;
822 823 824 825 826 827 828 829 830 831

	count = 0;
	i = d0_idx;
	do {
		int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);

		srcs[slot] = sh->dev[i].page;
		i = raid6_next_disk(i, disks);
	} while (i != d0_idx);

832
	return syndrome_disks;
833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852
}

static struct dma_async_tx_descriptor *
ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
{
	int disks = sh->disks;
	struct page **blocks = percpu->scribble;
	int target;
	int qd_idx = sh->qd_idx;
	struct dma_async_tx_descriptor *tx;
	struct async_submit_ctl submit;
	struct r5dev *tgt;
	struct page *dest;
	int i;
	int count;

	if (sh->ops.target < 0)
		target = sh->ops.target2;
	else if (sh->ops.target2 < 0)
		target = sh->ops.target;
853
	else
854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869
		/* we should only have one valid target */
		BUG();
	BUG_ON(target < 0);
	pr_debug("%s: stripe %llu block: %d\n",
		__func__, (unsigned long long)sh->sector, target);

	tgt = &sh->dev[target];
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	dest = tgt->page;

	atomic_inc(&sh->count);

	if (target == qd_idx) {
		count = set_syndrome_sources(blocks, sh);
		blocks[count] = NULL; /* regenerating p is not necessary */
		BUG_ON(blocks[count+1] != dest); /* q should already be set */
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		init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
				  ops_complete_compute, sh,
872 873 874 875 876 877 878 879 880 881 882
				  to_addr_conv(sh, percpu));
		tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
	} else {
		/* Compute any data- or p-drive using XOR */
		count = 0;
		for (i = disks; i-- ; ) {
			if (i == target || i == qd_idx)
				continue;
			blocks[count++] = sh->dev[i].page;
		}

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		init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
				  NULL, ops_complete_compute, sh,
885 886 887
				  to_addr_conv(sh, percpu));
		tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
	}
888 889 890 891

	return tx;
}

892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912
static struct dma_async_tx_descriptor *
ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
{
	int i, count, disks = sh->disks;
	int syndrome_disks = sh->ddf_layout ? disks : disks-2;
	int d0_idx = raid6_d0(sh);
	int faila = -1, failb = -1;
	int target = sh->ops.target;
	int target2 = sh->ops.target2;
	struct r5dev *tgt = &sh->dev[target];
	struct r5dev *tgt2 = &sh->dev[target2];
	struct dma_async_tx_descriptor *tx;
	struct page **blocks = percpu->scribble;
	struct async_submit_ctl submit;

	pr_debug("%s: stripe %llu block1: %d block2: %d\n",
		 __func__, (unsigned long long)sh->sector, target, target2);
	BUG_ON(target < 0 || target2 < 0);
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));

913
	/* we need to open-code set_syndrome_sources to handle the
914 915 916
	 * slot number conversion for 'faila' and 'failb'
	 */
	for (i = 0; i < disks ; i++)
917
		blocks[i] = NULL;
918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943
	count = 0;
	i = d0_idx;
	do {
		int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);

		blocks[slot] = sh->dev[i].page;

		if (i == target)
			faila = slot;
		if (i == target2)
			failb = slot;
		i = raid6_next_disk(i, disks);
	} while (i != d0_idx);

	BUG_ON(faila == failb);
	if (failb < faila)
		swap(faila, failb);
	pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
		 __func__, (unsigned long long)sh->sector, faila, failb);

	atomic_inc(&sh->count);

	if (failb == syndrome_disks+1) {
		/* Q disk is one of the missing disks */
		if (faila == syndrome_disks) {
			/* Missing P+Q, just recompute */
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			init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
					  ops_complete_compute, sh,
					  to_addr_conv(sh, percpu));
947
			return async_gen_syndrome(blocks, 0, syndrome_disks+2,
948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966
						  STRIPE_SIZE, &submit);
		} else {
			struct page *dest;
			int data_target;
			int qd_idx = sh->qd_idx;

			/* Missing D+Q: recompute D from P, then recompute Q */
			if (target == qd_idx)
				data_target = target2;
			else
				data_target = target;

			count = 0;
			for (i = disks; i-- ; ) {
				if (i == data_target || i == qd_idx)
					continue;
				blocks[count++] = sh->dev[i].page;
			}
			dest = sh->dev[data_target].page;
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			init_async_submit(&submit,
					  ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
					  NULL, NULL, NULL,
					  to_addr_conv(sh, percpu));
971 972 973 974
			tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
				       &submit);

			count = set_syndrome_sources(blocks, sh);
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			init_async_submit(&submit, ASYNC_TX_FENCE, tx,
					  ops_complete_compute, sh,
					  to_addr_conv(sh, percpu));
978 979 980 981
			return async_gen_syndrome(blocks, 0, count+2,
						  STRIPE_SIZE, &submit);
		}
	} else {
982 983 984 985 986 987 988 989 990 991 992 993 994 995
		init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
				  ops_complete_compute, sh,
				  to_addr_conv(sh, percpu));
		if (failb == syndrome_disks) {
			/* We're missing D+P. */
			return async_raid6_datap_recov(syndrome_disks+2,
						       STRIPE_SIZE, faila,
						       blocks, &submit);
		} else {
			/* We're missing D+D. */
			return async_raid6_2data_recov(syndrome_disks+2,
						       STRIPE_SIZE, faila, failb,
						       blocks, &submit);
		}
996 997 998 999
	}
}


1000 1001 1002 1003
static void ops_complete_prexor(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;

1004
	pr_debug("%s: stripe %llu\n", __func__,
1005 1006 1007 1008
		(unsigned long long)sh->sector);
}

static struct dma_async_tx_descriptor *
1009 1010
ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
	       struct dma_async_tx_descriptor *tx)
1011 1012
{
	int disks = sh->disks;
1013
	struct page **xor_srcs = percpu->scribble;
1014
	int count = 0, pd_idx = sh->pd_idx, i;
1015
	struct async_submit_ctl submit;
1016 1017 1018 1019

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

1020
	pr_debug("%s: stripe %llu\n", __func__,
1021 1022 1023 1024 1025
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		/* Only process blocks that are known to be uptodate */
1026
		if (test_bit(R5_Wantdrain, &dev->flags))
1027 1028 1029
			xor_srcs[count++] = dev->page;
	}

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	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1031
			  ops_complete_prexor, sh, to_addr_conv(sh, percpu));
1032
	tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1033 1034 1035 1036 1037

	return tx;
}

static struct dma_async_tx_descriptor *
1038
ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1039 1040
{
	int disks = sh->disks;
1041
	int i;
1042

1043
	pr_debug("%s: stripe %llu\n", __func__,
1044 1045 1046 1047 1048 1049
		(unsigned long long)sh->sector);

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

1050
		if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
1051 1052
			struct bio *wbi;

1053
			spin_lock_irq(&sh->raid_conf->device_lock);
1054 1055 1056 1057
			chosen = dev->towrite;
			dev->towrite = NULL;
			BUG_ON(dev->written);
			wbi = dev->written = chosen;
1058
			spin_unlock_irq(&sh->raid_conf->device_lock);
1059 1060 1061

			while (wbi && wbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
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1062 1063
				if (wbi->bi_rw & REQ_FUA)
					set_bit(R5_WantFUA, &dev->flags);
1064 1065 1066 1067 1068 1069 1070 1071 1072 1073
				tx = async_copy_data(1, wbi, dev->page,
					dev->sector, tx);
				wbi = r5_next_bio(wbi, dev->sector);
			}
		}
	}

	return tx;
}

1074
static void ops_complete_reconstruct(void *stripe_head_ref)
1075 1076
{
	struct stripe_head *sh = stripe_head_ref;
1077 1078 1079 1080
	int disks = sh->disks;
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	int i;
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1081
	bool fua = false;
1082

1083
	pr_debug("%s: stripe %llu\n", __func__,
1084 1085
		(unsigned long long)sh->sector);

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1086 1087 1088
	for (i = disks; i--; )
		fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);

1089 1090
	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
1091

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1092
		if (dev->written || i == pd_idx || i == qd_idx) {
1093
			set_bit(R5_UPTODATE, &dev->flags);
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1094 1095 1096
			if (fua)
				set_bit(R5_WantFUA, &dev->flags);
		}
1097 1098
	}

1099 1100 1101 1102 1103 1104 1105 1106
	if (sh->reconstruct_state == reconstruct_state_drain_run)
		sh->reconstruct_state = reconstruct_state_drain_result;
	else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
		sh->reconstruct_state = reconstruct_state_prexor_drain_result;
	else {
		BUG_ON(sh->reconstruct_state != reconstruct_state_run);
		sh->reconstruct_state = reconstruct_state_result;
	}
1107 1108 1109 1110 1111 1112

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

static void
1113 1114
ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
		     struct dma_async_tx_descriptor *tx)
1115 1116
{
	int disks = sh->disks;
1117
	struct page **xor_srcs = percpu->scribble;
1118
	struct async_submit_ctl submit;
1119 1120
	int count = 0, pd_idx = sh->pd_idx, i;
	struct page *xor_dest;
1121
	int prexor = 0;
1122 1123
	unsigned long flags;

1124
	pr_debug("%s: stripe %llu\n", __func__,
1125 1126 1127 1128 1129
		(unsigned long long)sh->sector);

	/* check if prexor is active which means only process blocks
	 * that are part of a read-modify-write (written)
	 */
1130 1131
	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
		prexor = 1;
1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
		xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (dev->written)
				xor_srcs[count++] = dev->page;
		}
	} else {
		xor_dest = sh->dev[pd_idx].page;
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (i != pd_idx)
				xor_srcs[count++] = dev->page;
		}
	}

	/* 1/ if we prexor'd then the dest is reused as a source
	 * 2/ if we did not prexor then we are redoing the parity
	 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
	 * for the synchronous xor case
	 */
1152
	flags = ASYNC_TX_ACK |
1153 1154 1155 1156
		(prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);

	atomic_inc(&sh->count);

1157
	init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh,
1158
			  to_addr_conv(sh, percpu));
1159 1160 1161 1162
	if (unlikely(count == 1))
		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
	else
		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1163 1164
}

1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181
static void
ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
		     struct dma_async_tx_descriptor *tx)
{
	struct async_submit_ctl submit;
	struct page **blocks = percpu->scribble;
	int count;

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

	count = set_syndrome_sources(blocks, sh);

	atomic_inc(&sh->count);

	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_reconstruct,
			  sh, to_addr_conv(sh, percpu));
	async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1182 1183 1184 1185 1186 1187
}

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

1188
	pr_debug("%s: stripe %llu\n", __func__,
1189 1190
		(unsigned long long)sh->sector);

1191
	sh->check_state = check_state_check_result;
1192 1193 1194 1195
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1196
static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1197 1198
{
	int disks = sh->disks;
1199 1200 1201
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	struct page *xor_dest;
1202
	struct page **xor_srcs = percpu->scribble;
1203
	struct dma_async_tx_descriptor *tx;
1204
	struct async_submit_ctl submit;
1205 1206
	int count;
	int i;
1207

1208
	pr_debug("%s: stripe %llu\n", __func__,
1209 1210
		(unsigned long long)sh->sector);

1211 1212 1213
	count = 0;
	xor_dest = sh->dev[pd_idx].page;
	xor_srcs[count++] = xor_dest;
1214
	for (i = disks; i--; ) {
1215 1216 1217
		if (i == pd_idx || i == qd_idx)
			continue;
		xor_srcs[count++] = sh->dev[i].page;
1218 1219
	}

1220 1221
	init_async_submit(&submit, 0, NULL, NULL, NULL,
			  to_addr_conv(sh, percpu));
D
Dan Williams 已提交
1222
	tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
1223
			   &sh->ops.zero_sum_result, &submit);
1224 1225

	atomic_inc(&sh->count);
1226 1227
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
	tx = async_trigger_callback(&submit);
1228 1229
}

1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241
static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
{
	struct page **srcs = percpu->scribble;
	struct async_submit_ctl submit;
	int count;

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

	count = set_syndrome_sources(srcs, sh);
	if (!checkp)
		srcs[count] = NULL;
1242 1243

	atomic_inc(&sh->count);
1244 1245 1246 1247
	init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
			  sh, to_addr_conv(sh, percpu));
	async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
			   &sh->ops.zero_sum_result, percpu->spare_page, &submit);
1248 1249
}

1250
static void __raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
1251 1252 1253
{
	int overlap_clear = 0, i, disks = sh->disks;
	struct dma_async_tx_descriptor *tx = NULL;
1254
	struct r5conf *conf = sh->raid_conf;
1255
	int level = conf->level;
1256 1257
	struct raid5_percpu *percpu;
	unsigned long cpu;
1258

1259 1260
	cpu = get_cpu();
	percpu = per_cpu_ptr(conf->percpu, cpu);
1261
	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
1262 1263 1264 1265
		ops_run_biofill(sh);
		overlap_clear++;
	}

1266
	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
1267 1268 1269 1270 1271 1272 1273 1274 1275 1276
		if (level < 6)
			tx = ops_run_compute5(sh, percpu);
		else {
			if (sh->ops.target2 < 0 || sh->ops.target < 0)
				tx = ops_run_compute6_1(sh, percpu);
			else
				tx = ops_run_compute6_2(sh, percpu);
		}
		/* terminate the chain if reconstruct is not set to be run */
		if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
1277 1278
			async_tx_ack(tx);
	}
1279

1280
	if (test_bit(STRIPE_OP_PREXOR, &ops_request))
1281
		tx = ops_run_prexor(sh, percpu, tx);
1282

1283
	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
1284
		tx = ops_run_biodrain(sh, tx);
1285 1286 1287
		overlap_clear++;
	}

1288 1289 1290 1291 1292 1293
	if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
		if (level < 6)
			ops_run_reconstruct5(sh, percpu, tx);
		else
			ops_run_reconstruct6(sh, percpu, tx);
	}
1294

1295 1296 1297 1298 1299 1300 1301 1302 1303 1304
	if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
		if (sh->check_state == check_state_run)
			ops_run_check_p(sh, percpu);
		else if (sh->check_state == check_state_run_q)
			ops_run_check_pq(sh, percpu, 0);
		else if (sh->check_state == check_state_run_pq)
			ops_run_check_pq(sh, percpu, 1);
		else
			BUG();
	}
1305 1306 1307 1308 1309 1310 1311

	if (overlap_clear)
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (test_and_clear_bit(R5_Overlap, &dev->flags))
				wake_up(&sh->raid_conf->wait_for_overlap);
		}
1312
	put_cpu();
1313 1314
}

1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344
#ifdef CONFIG_MULTICORE_RAID456
static void async_run_ops(void *param, async_cookie_t cookie)
{
	struct stripe_head *sh = param;
	unsigned long ops_request = sh->ops.request;

	clear_bit_unlock(STRIPE_OPS_REQ_PENDING, &sh->state);
	wake_up(&sh->ops.wait_for_ops);

	__raid_run_ops(sh, ops_request);
	release_stripe(sh);
}

static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
{
	/* since handle_stripe can be called outside of raid5d context
	 * we need to ensure sh->ops.request is de-staged before another
	 * request arrives
	 */
	wait_event(sh->ops.wait_for_ops,
		   !test_and_set_bit_lock(STRIPE_OPS_REQ_PENDING, &sh->state));
	sh->ops.request = ops_request;

	atomic_inc(&sh->count);
	async_schedule(async_run_ops, sh);
}
#else
#define raid_run_ops __raid_run_ops
#endif

1345
static int grow_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1346 1347
{
	struct stripe_head *sh;
N
Namhyung Kim 已提交
1348
	sh = kmem_cache_zalloc(conf->slab_cache, GFP_KERNEL);
1349 1350
	if (!sh)
		return 0;
N
Namhyung Kim 已提交
1351

1352
	sh->raid_conf = conf;
1353 1354 1355
	#ifdef CONFIG_MULTICORE_RAID456
	init_waitqueue_head(&sh->ops.wait_for_ops);
	#endif
1356

1357 1358
	if (grow_buffers(sh)) {
		shrink_buffers(sh);
1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369
		kmem_cache_free(conf->slab_cache, sh);
		return 0;
	}
	/* 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;
}

1370
static int grow_stripes(struct r5conf *conf, int num)
1371
{
1372
	struct kmem_cache *sc;
1373
	int devs = max(conf->raid_disks, conf->previous_raid_disks);
L
Linus Torvalds 已提交
1374

1375 1376 1377 1378 1379 1380 1381 1382
	if (conf->mddev->gendisk)
		sprintf(conf->cache_name[0],
			"raid%d-%s", conf->level, mdname(conf->mddev));
	else
		sprintf(conf->cache_name[0],
			"raid%d-%p", conf->level, conf->mddev);
	sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);

1383 1384
	conf->active_name = 0;
	sc = kmem_cache_create(conf->cache_name[conf->active_name],
L
Linus Torvalds 已提交
1385
			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
1386
			       0, 0, NULL);
L
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1387 1388 1389
	if (!sc)
		return 1;
	conf->slab_cache = sc;
1390
	conf->pool_size = devs;
1391
	while (num--)
1392
		if (!grow_one_stripe(conf))
L
Linus Torvalds 已提交
1393 1394 1395
			return 1;
	return 0;
}
1396

1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418
/**
 * scribble_len - return the required size of the scribble region
 * @num - total number of disks in the array
 *
 * The size must be enough to contain:
 * 1/ a struct page pointer for each device in the array +2
 * 2/ room to convert each entry in (1) to its corresponding dma
 *    (dma_map_page()) or page (page_address()) address.
 *
 * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
 * calculate over all devices (not just the data blocks), using zeros in place
 * of the P and Q blocks.
 */
static size_t scribble_len(int num)
{
	size_t len;

	len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);

	return len;
}

1419
static int resize_stripes(struct r5conf *conf, int newsize)
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
{
	/* 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;
1447
	unsigned long cpu;
1448
	int err;
1449
	struct kmem_cache *sc;
1450 1451 1452 1453 1454
	int i;

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

1455 1456 1457
	err = md_allow_write(conf->mddev);
	if (err)
		return err;
1458

1459 1460 1461
	/* Step 1 */
	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
1462
			       0, 0, NULL);
1463 1464 1465 1466
	if (!sc)
		return -ENOMEM;

	for (i = conf->max_nr_stripes; i; i--) {
N
Namhyung Kim 已提交
1467
		nsh = kmem_cache_zalloc(sc, GFP_KERNEL);
1468 1469 1470 1471
		if (!nsh)
			break;

		nsh->raid_conf = conf;
1472 1473 1474
		#ifdef CONFIG_MULTICORE_RAID456
		init_waitqueue_head(&nsh->ops.wait_for_ops);
		#endif
1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496

		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,
N
NeilBrown 已提交
1497
				    );
1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511
		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
1512
	 * conf->disks and the scribble region
1513 1514 1515 1516 1517 1518 1519 1520 1521 1522
	 */
	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;

1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541
	get_online_cpus();
	conf->scribble_len = scribble_len(newsize);
	for_each_present_cpu(cpu) {
		struct raid5_percpu *percpu;
		void *scribble;

		percpu = per_cpu_ptr(conf->percpu, cpu);
		scribble = kmalloc(conf->scribble_len, GFP_NOIO);

		if (scribble) {
			kfree(percpu->scribble);
			percpu->scribble = scribble;
		} else {
			err = -ENOMEM;
			break;
		}
	}
	put_online_cpus();

1542 1543 1544 1545
	/* 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);
1546

1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562
		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;
}
L
Linus Torvalds 已提交
1563

1564
static int drop_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1565 1566 1567
{
	struct stripe_head *sh;

1568 1569 1570 1571 1572
	spin_lock_irq(&conf->device_lock);
	sh = get_free_stripe(conf);
	spin_unlock_irq(&conf->device_lock);
	if (!sh)
		return 0;
1573
	BUG_ON(atomic_read(&sh->count));
1574
	shrink_buffers(sh);
1575 1576 1577 1578 1579
	kmem_cache_free(conf->slab_cache, sh);
	atomic_dec(&conf->active_stripes);
	return 1;
}

1580
static void shrink_stripes(struct r5conf *conf)
1581 1582 1583 1584
{
	while (drop_one_stripe(conf))
		;

N
NeilBrown 已提交
1585 1586
	if (conf->slab_cache)
		kmem_cache_destroy(conf->slab_cache);
L
Linus Torvalds 已提交
1587 1588 1589
	conf->slab_cache = NULL;
}

1590
static void raid5_end_read_request(struct bio * bi, int error)
L
Linus Torvalds 已提交
1591
{
1592
	struct stripe_head *sh = bi->bi_private;
1593
	struct r5conf *conf = sh->raid_conf;
1594
	int disks = sh->disks, i;
L
Linus Torvalds 已提交
1595
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1596
	char b[BDEVNAME_SIZE];
1597
	struct md_rdev *rdev;
L
Linus Torvalds 已提交
1598 1599 1600 1601 1602 1603


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

1604 1605
	pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n",
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
L
Linus Torvalds 已提交
1606 1607 1608
		uptodate);
	if (i == disks) {
		BUG();
1609
		return;
L
Linus Torvalds 已提交
1610 1611 1612 1613
	}

	if (uptodate) {
		set_bit(R5_UPTODATE, &sh->dev[i].flags);
1614
		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1615
			rdev = conf->disks[i].rdev;
1616 1617 1618 1619 1620 1621 1622 1623
			printk_ratelimited(
				KERN_INFO
				"md/raid:%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));
1624
			atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1625 1626 1627
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
		}
1628 1629
		if (atomic_read(&conf->disks[i].rdev->read_errors))
			atomic_set(&conf->disks[i].rdev->read_errors, 0);
L
Linus Torvalds 已提交
1630
	} else {
1631
		const char *bdn = bdevname(conf->disks[i].rdev->bdev, b);
1632
		int retry = 0;
1633 1634
		rdev = conf->disks[i].rdev;

L
Linus Torvalds 已提交
1635
		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
1636
		atomic_inc(&rdev->read_errors);
1637
		if (conf->mddev->degraded >= conf->max_degraded)
1638 1639 1640 1641 1642 1643 1644 1645
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error not correctable "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
				(unsigned long long)(sh->sector
						     + rdev->data_offset),
				bdn);
1646
		else if (test_bit(R5_ReWrite, &sh->dev[i].flags))
1647
			/* Oh, no!!! */
1648 1649 1650 1651 1652 1653 1654 1655
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error NOT corrected!! "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
				(unsigned long long)(sh->sector
						     + rdev->data_offset),
				bdn);
1656
		else if (atomic_read(&rdev->read_errors)
1657
			 > conf->max_nr_stripes)
N
NeilBrown 已提交
1658
			printk(KERN_WARNING
1659
			       "md/raid:%s: Too many read errors, failing device %s.\n",
1660
			       mdname(conf->mddev), bdn);
1661 1662 1663 1664 1665
		else
			retry = 1;
		if (retry)
			set_bit(R5_ReadError, &sh->dev[i].flags);
		else {
1666 1667
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1668
			md_error(conf->mddev, rdev);
1669
		}
L
Linus Torvalds 已提交
1670 1671 1672 1673 1674 1675 1676
	}
	rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
	clear_bit(R5_LOCKED, &sh->dev[i].flags);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1677
static void raid5_end_write_request(struct bio *bi, int error)
L
Linus Torvalds 已提交
1678
{
1679
	struct stripe_head *sh = bi->bi_private;
1680
	struct r5conf *conf = sh->raid_conf;
1681
	int disks = sh->disks, i;
L
Linus Torvalds 已提交
1682
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1683 1684
	sector_t first_bad;
	int bad_sectors;
L
Linus Torvalds 已提交
1685 1686 1687 1688 1689

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

1690
	pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
L
Linus Torvalds 已提交
1691 1692 1693 1694
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
		uptodate);
	if (i == disks) {
		BUG();
1695
		return;
L
Linus Torvalds 已提交
1696 1697
	}

1698 1699 1700
	if (!uptodate) {
		set_bit(WriteErrorSeen, &conf->disks[i].rdev->flags);
		set_bit(R5_WriteError, &sh->dev[i].flags);
1701 1702 1703
	} else if (is_badblock(conf->disks[i].rdev, sh->sector, STRIPE_SECTORS,
			       &first_bad, &bad_sectors))
		set_bit(R5_MadeGood, &sh->dev[i].flags);
L
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1704 1705 1706 1707 1708

	rdev_dec_pending(conf->disks[i].rdev, conf->mddev);
	
	clear_bit(R5_LOCKED, &sh->dev[i].flags);
	set_bit(STRIPE_HANDLE, &sh->state);
1709
	release_stripe(sh);
L
Linus Torvalds 已提交
1710 1711 1712
}


1713
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
L
Linus Torvalds 已提交
1714
	
1715
static void raid5_build_block(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730
{
	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;
1731
	dev->sector = compute_blocknr(sh, i, previous);
L
Linus Torvalds 已提交
1732 1733
}

1734
static void error(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
1735 1736
{
	char b[BDEVNAME_SIZE];
1737
	struct r5conf *conf = mddev->private;
1738
	unsigned long flags;
1739
	pr_debug("raid456: error called\n");
L
Linus Torvalds 已提交
1740

1741 1742 1743 1744 1745 1746
	spin_lock_irqsave(&conf->device_lock, flags);
	clear_bit(In_sync, &rdev->flags);
	mddev->degraded = calc_degraded(conf);
	spin_unlock_irqrestore(&conf->device_lock, flags);
	set_bit(MD_RECOVERY_INTR, &mddev->recovery);

1747
	set_bit(Blocked, &rdev->flags);
1748 1749 1750 1751 1752 1753 1754 1755 1756
	set_bit(Faulty, &rdev->flags);
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
	printk(KERN_ALERT
	       "md/raid:%s: Disk failure on %s, disabling device.\n"
	       "md/raid:%s: Operation continuing on %d devices.\n",
	       mdname(mddev),
	       bdevname(rdev->bdev, b),
	       mdname(mddev),
	       conf->raid_disks - mddev->degraded);
1757
}
L
Linus Torvalds 已提交
1758 1759 1760 1761 1762

/*
 * Input: a 'big' sector number,
 * Output: index of the data and parity disk, and the sector # in them.
 */
1763
static sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
1764 1765
				     int previous, int *dd_idx,
				     struct stripe_head *sh)
L
Linus Torvalds 已提交
1766
{
N
NeilBrown 已提交
1767
	sector_t stripe, stripe2;
1768
	sector_t chunk_number;
L
Linus Torvalds 已提交
1769
	unsigned int chunk_offset;
1770
	int pd_idx, qd_idx;
1771
	int ddf_layout = 0;
L
Linus Torvalds 已提交
1772
	sector_t new_sector;
1773 1774
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
1775 1776
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
1777 1778 1779
	int raid_disks = previous ? conf->previous_raid_disks
				  : conf->raid_disks;
	int data_disks = raid_disks - conf->max_degraded;
L
Linus Torvalds 已提交
1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791

	/* 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;

	/*
	 * Compute the stripe number
	 */
1792 1793
	stripe = chunk_number;
	*dd_idx = sector_div(stripe, data_disks);
N
NeilBrown 已提交
1794
	stripe2 = stripe;
L
Linus Torvalds 已提交
1795 1796 1797
	/*
	 * Select the parity disk based on the user selected algorithm.
	 */
1798
	pd_idx = qd_idx = -1;
1799 1800
	switch(conf->level) {
	case 4:
1801
		pd_idx = data_disks;
1802 1803
		break;
	case 5:
1804
		switch (algorithm) {
L
Linus Torvalds 已提交
1805
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
1806
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
1807
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
1808 1809 1810
				(*dd_idx)++;
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
1811
			pd_idx = sector_div(stripe2, raid_disks);
1812
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
1813 1814 1815
				(*dd_idx)++;
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
1816
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
1817
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
1818 1819
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
1820
			pd_idx = sector_div(stripe2, raid_disks);
1821
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
1822
			break;
1823 1824 1825 1826 1827 1828 1829
		case ALGORITHM_PARITY_0:
			pd_idx = 0;
			(*dd_idx)++;
			break;
		case ALGORITHM_PARITY_N:
			pd_idx = data_disks;
			break;
L
Linus Torvalds 已提交
1830
		default:
1831
			BUG();
1832 1833 1834 1835
		}
		break;
	case 6:

1836
		switch (algorithm) {
1837
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
1838
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
1839 1840
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
1841
				(*dd_idx)++;	/* Q D D D P */
1842 1843
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
1844 1845 1846
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
1847
			pd_idx = sector_div(stripe2, raid_disks);
1848 1849
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
1850
				(*dd_idx)++;	/* Q D D D P */
1851 1852
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
1853 1854 1855
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
1856
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
1857 1858
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
1859 1860
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
1861
			pd_idx = sector_div(stripe2, raid_disks);
1862 1863
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
1864
			break;
1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879

		case ALGORITHM_PARITY_0:
			pd_idx = 0;
			qd_idx = 1;
			(*dd_idx) += 2;
			break;
		case ALGORITHM_PARITY_N:
			pd_idx = data_disks;
			qd_idx = data_disks + 1;
			break;

		case ALGORITHM_ROTATING_ZERO_RESTART:
			/* Exactly the same as RIGHT_ASYMMETRIC, but or
			 * of blocks for computing Q is different.
			 */
N
NeilBrown 已提交
1880
			pd_idx = sector_div(stripe2, raid_disks);
1881 1882 1883 1884 1885 1886
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
				(*dd_idx)++;	/* Q D D D P */
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
				(*dd_idx) += 2; /* D D P Q D */
1887
			ddf_layout = 1;
1888 1889 1890 1891 1892 1893 1894
			break;

		case ALGORITHM_ROTATING_N_RESTART:
			/* Same a left_asymmetric, by first stripe is
			 * D D D P Q  rather than
			 * Q D D D P
			 */
N
NeilBrown 已提交
1895 1896
			stripe2 += 1;
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
1897 1898 1899 1900 1901 1902
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
				(*dd_idx)++;	/* Q D D D P */
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
				(*dd_idx) += 2; /* D D P Q D */
1903
			ddf_layout = 1;
1904 1905 1906 1907
			break;

		case ALGORITHM_ROTATING_N_CONTINUE:
			/* Same as left_symmetric but Q is before P */
N
NeilBrown 已提交
1908
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
1909 1910
			qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
1911
			ddf_layout = 1;
1912 1913 1914 1915
			break;

		case ALGORITHM_LEFT_ASYMMETRIC_6:
			/* RAID5 left_asymmetric, with Q on last device */
N
NeilBrown 已提交
1916
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
1917 1918 1919 1920 1921 1922
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_RIGHT_ASYMMETRIC_6:
N
NeilBrown 已提交
1923
			pd_idx = sector_div(stripe2, raid_disks-1);
1924 1925 1926 1927 1928 1929
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_LEFT_SYMMETRIC_6:
N
NeilBrown 已提交
1930
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
1931 1932 1933 1934 1935
			*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_RIGHT_SYMMETRIC_6:
N
NeilBrown 已提交
1936
			pd_idx = sector_div(stripe2, raid_disks-1);
1937 1938 1939 1940 1941 1942 1943 1944 1945 1946
			*dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_PARITY_0_6:
			pd_idx = 0;
			(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

1947
		default:
1948
			BUG();
1949 1950
		}
		break;
L
Linus Torvalds 已提交
1951 1952
	}

1953 1954 1955
	if (sh) {
		sh->pd_idx = pd_idx;
		sh->qd_idx = qd_idx;
1956
		sh->ddf_layout = ddf_layout;
1957
	}
L
Linus Torvalds 已提交
1958 1959 1960 1961 1962 1963 1964 1965
	/*
	 * Finally, compute the new sector number
	 */
	new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
	return new_sector;
}


1966
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
1967
{
1968
	struct r5conf *conf = sh->raid_conf;
1969 1970
	int raid_disks = sh->disks;
	int data_disks = raid_disks - conf->max_degraded;
L
Linus Torvalds 已提交
1971
	sector_t new_sector = sh->sector, check;
1972 1973
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
1974 1975
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
L
Linus Torvalds 已提交
1976 1977
	sector_t stripe;
	int chunk_offset;
1978 1979
	sector_t chunk_number;
	int dummy1, dd_idx = i;
L
Linus Torvalds 已提交
1980
	sector_t r_sector;
1981
	struct stripe_head sh2;
L
Linus Torvalds 已提交
1982

1983

L
Linus Torvalds 已提交
1984 1985 1986
	chunk_offset = sector_div(new_sector, sectors_per_chunk);
	stripe = new_sector;

1987 1988 1989 1990 1991
	if (i == sh->pd_idx)
		return 0;
	switch(conf->level) {
	case 4: break;
	case 5:
1992
		switch (algorithm) {
L
Linus Torvalds 已提交
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
		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;
2004 2005 2006 2007 2008
		case ALGORITHM_PARITY_0:
			i -= 1;
			break;
		case ALGORITHM_PARITY_N:
			break;
L
Linus Torvalds 已提交
2009
		default:
2010
			BUG();
2011 2012 2013
		}
		break;
	case 6:
2014
		if (i == sh->qd_idx)
2015
			return 0; /* It is the Q disk */
2016
		switch (algorithm) {
2017 2018
		case ALGORITHM_LEFT_ASYMMETRIC:
		case ALGORITHM_RIGHT_ASYMMETRIC:
2019 2020 2021 2022
		case ALGORITHM_ROTATING_ZERO_RESTART:
		case ALGORITHM_ROTATING_N_RESTART:
			if (sh->pd_idx == raid_disks-1)
				i--;	/* Q D D D P */
2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036
			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;
2037 2038 2039 2040 2041 2042
		case ALGORITHM_PARITY_0:
			i -= 2;
			break;
		case ALGORITHM_PARITY_N:
			break;
		case ALGORITHM_ROTATING_N_CONTINUE:
2043
			/* Like left_symmetric, but P is before Q */
2044 2045
			if (sh->pd_idx == 0)
				i--;	/* P D D D Q */
2046 2047 2048 2049 2050 2051
			else {
				/* D D Q P D */
				if (i < sh->pd_idx)
					i += raid_disks;
				i -= (sh->pd_idx + 1);
			}
2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066
			break;
		case ALGORITHM_LEFT_ASYMMETRIC_6:
		case ALGORITHM_RIGHT_ASYMMETRIC_6:
			if (i > sh->pd_idx)
				i--;
			break;
		case ALGORITHM_LEFT_SYMMETRIC_6:
		case ALGORITHM_RIGHT_SYMMETRIC_6:
			if (i < sh->pd_idx)
				i += data_disks + 1;
			i -= (sh->pd_idx + 1);
			break;
		case ALGORITHM_PARITY_0_6:
			i -= 1;
			break;
2067
		default:
2068
			BUG();
2069 2070
		}
		break;
L
Linus Torvalds 已提交
2071 2072 2073
	}

	chunk_number = stripe * data_disks + i;
2074
	r_sector = chunk_number * sectors_per_chunk + chunk_offset;
L
Linus Torvalds 已提交
2075

2076
	check = raid5_compute_sector(conf, r_sector,
2077
				     previous, &dummy1, &sh2);
2078 2079
	if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
		|| sh2.qd_idx != sh->qd_idx) {
2080 2081
		printk(KERN_ERR "md/raid:%s: compute_blocknr: map not correct\n",
		       mdname(conf->mddev));
L
Linus Torvalds 已提交
2082 2083 2084 2085 2086 2087
		return 0;
	}
	return r_sector;
}


2088
static void
2089
schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
2090
			 int rcw, int expand)
2091 2092
{
	int i, pd_idx = sh->pd_idx, disks = sh->disks;
2093
	struct r5conf *conf = sh->raid_conf;
2094
	int level = conf->level;
2095 2096 2097 2098 2099 2100 2101

	if (rcw) {
		/* if we are not expanding this is a proper write request, and
		 * there will be bios with new data to be drained into the
		 * stripe cache
		 */
		if (!expand) {
2102 2103 2104 2105
			sh->reconstruct_state = reconstruct_state_drain_run;
			set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
		} else
			sh->reconstruct_state = reconstruct_state_run;
2106

2107
		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2108 2109 2110 2111 2112 2113

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

			if (dev->towrite) {
				set_bit(R5_LOCKED, &dev->flags);
2114
				set_bit(R5_Wantdrain, &dev->flags);
2115 2116
				if (!expand)
					clear_bit(R5_UPTODATE, &dev->flags);
2117
				s->locked++;
2118 2119
			}
		}
2120
		if (s->locked + conf->max_degraded == disks)
2121
			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
2122
				atomic_inc(&conf->pending_full_writes);
2123
	} else {
2124
		BUG_ON(level == 6);
2125 2126 2127
		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));

2128
		sh->reconstruct_state = reconstruct_state_prexor_drain_run;
2129 2130
		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
2131
		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2132 2133 2134 2135 2136 2137 2138 2139

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

			if (dev->towrite &&
			    (test_bit(R5_UPTODATE, &dev->flags) ||
2140 2141
			     test_bit(R5_Wantcompute, &dev->flags))) {
				set_bit(R5_Wantdrain, &dev->flags);
2142 2143
				set_bit(R5_LOCKED, &dev->flags);
				clear_bit(R5_UPTODATE, &dev->flags);
2144
				s->locked++;
2145 2146 2147 2148
			}
		}
	}

2149
	/* keep the parity disk(s) locked while asynchronous operations
2150 2151 2152 2153
	 * are in flight
	 */
	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
2154
	s->locked++;
2155

2156 2157 2158 2159 2160 2161 2162 2163 2164
	if (level == 6) {
		int qd_idx = sh->qd_idx;
		struct r5dev *dev = &sh->dev[qd_idx];

		set_bit(R5_LOCKED, &dev->flags);
		clear_bit(R5_UPTODATE, &dev->flags);
		s->locked++;
	}

2165
	pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
2166
		__func__, (unsigned long long)sh->sector,
2167
		s->locked, s->ops_request);
2168
}
2169

L
Linus Torvalds 已提交
2170 2171
/*
 * Each stripe/dev can have one or more bion attached.
2172
 * toread/towrite point to the first in a chain.
L
Linus Torvalds 已提交
2173 2174 2175 2176 2177
 * 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;
2178
	struct r5conf *conf = sh->raid_conf;
2179
	int firstwrite=0;
L
Linus Torvalds 已提交
2180

2181
	pr_debug("adding bi b#%llu to stripe s#%llu\n",
L
Linus Torvalds 已提交
2182 2183 2184 2185 2186
		(unsigned long long)bi->bi_sector,
		(unsigned long long)sh->sector);


	spin_lock_irq(&conf->device_lock);
2187
	if (forwrite) {
L
Linus Torvalds 已提交
2188
		bip = &sh->dev[dd_idx].towrite;
2189 2190 2191
		if (*bip == NULL && sh->dev[dd_idx].written == NULL)
			firstwrite = 1;
	} else
L
Linus Torvalds 已提交
2192 2193 2194 2195 2196 2197 2198 2199 2200
		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;

2201
	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
L
Linus Torvalds 已提交
2202 2203 2204
	if (*bip)
		bi->bi_next = *bip;
	*bip = bi;
2205
	bi->bi_phys_segments++;
2206

L
Linus Torvalds 已提交
2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219
	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);
	}
2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231
	spin_unlock_irq(&conf->device_lock);

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

	if (conf->mddev->bitmap && firstwrite) {
		bitmap_startwrite(conf->mddev->bitmap, sh->sector,
				  STRIPE_SECTORS, 0);
		sh->bm_seq = conf->seq_flush+1;
		set_bit(STRIPE_BIT_DELAY, &sh->state);
	}
L
Linus Torvalds 已提交
2232 2233 2234 2235 2236 2237 2238 2239
	return 1;

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

2240
static void end_reshape(struct r5conf *conf);
2241

2242
static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
2243
			    struct stripe_head *sh)
2244
{
2245
	int sectors_per_chunk =
2246
		previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
2247
	int dd_idx;
2248
	int chunk_offset = sector_div(stripe, sectors_per_chunk);
2249
	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
2250

2251 2252
	raid5_compute_sector(conf,
			     stripe * (disks - conf->max_degraded)
2253
			     *sectors_per_chunk + chunk_offset,
2254
			     previous,
2255
			     &dd_idx, sh);
2256 2257
}

2258
static void
2259
handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
2260 2261 2262 2263 2264 2265 2266 2267 2268
				struct stripe_head_state *s, int disks,
				struct bio **return_bi)
{
	int i;
	for (i = disks; i--; ) {
		struct bio *bi;
		int bitmap_end = 0;

		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2269
			struct md_rdev *rdev;
2270 2271 2272
			rcu_read_lock();
			rdev = rcu_dereference(conf->disks[i].rdev);
			if (rdev && test_bit(In_sync, &rdev->flags))
2273 2274 2275
				atomic_inc(&rdev->nr_pending);
			else
				rdev = NULL;
2276
			rcu_read_unlock();
2277 2278 2279 2280 2281 2282 2283 2284
			if (rdev) {
				if (!rdev_set_badblocks(
					    rdev,
					    sh->sector,
					    STRIPE_SECTORS, 0))
					md_error(conf->mddev, rdev);
				rdev_dec_pending(rdev, conf->mddev);
			}
2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301
		}
		spin_lock_irq(&conf->device_lock);
		/* fail all writes first */
		bi = sh->dev[i].towrite;
		sh->dev[i].towrite = NULL;
		if (bi) {
			s->to_write--;
			bitmap_end = 1;
		}

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

		while (bi && bi->bi_sector <
			sh->dev[i].sector + STRIPE_SECTORS) {
			struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
			clear_bit(BIO_UPTODATE, &bi->bi_flags);
2302
			if (!raid5_dec_bi_phys_segments(bi)) {
2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316
				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);
2317
			if (!raid5_dec_bi_phys_segments(bi)) {
2318 2319 2320 2321 2322 2323 2324
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = bi2;
		}

2325 2326 2327 2328 2329 2330
		/* fail any reads if this device is non-operational and
		 * the data has not reached the cache yet.
		 */
		if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
		    (!test_bit(R5_Insync, &sh->dev[i].flags) ||
		      test_bit(R5_ReadError, &sh->dev[i].flags))) {
2331 2332 2333 2334 2335 2336 2337 2338 2339 2340
			bi = sh->dev[i].toread;
			sh->dev[i].toread = NULL;
			if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
				wake_up(&conf->wait_for_overlap);
			if (bi) s->to_read--;
			while (bi && bi->bi_sector <
			       sh->dev[i].sector + STRIPE_SECTORS) {
				struct bio *nextbi =
					r5_next_bio(bi, sh->dev[i].sector);
				clear_bit(BIO_UPTODATE, &bi->bi_flags);
2341
				if (!raid5_dec_bi_phys_segments(bi)) {
2342 2343 2344 2345 2346 2347 2348 2349 2350 2351
					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);
2352 2353 2354 2355
		/* If we were in the middle of a write the parity block might
		 * still be locked - so just clear all R5_LOCKED flags
		 */
		clear_bit(R5_LOCKED, &sh->dev[i].flags);
2356 2357
	}

2358 2359 2360
	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
		if (atomic_dec_and_test(&conf->pending_full_writes))
			md_wakeup_thread(conf->mddev->thread);
2361 2362
}

2363
static void
2364
handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382
		   struct stripe_head_state *s)
{
	int abort = 0;
	int i;

	md_done_sync(conf->mddev, STRIPE_SECTORS, 0);
	clear_bit(STRIPE_SYNCING, &sh->state);
	s->syncing = 0;
	/* There is nothing more to do for sync/check/repair.
	 * For recover we need to record a bad block on all
	 * non-sync devices, or abort the recovery
	 */
	if (!test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery))
		return;
	/* During recovery devices cannot be removed, so locking and
	 * refcounting of rdevs is not needed
	 */
	for (i = 0; i < conf->raid_disks; i++) {
2383
		struct md_rdev *rdev = conf->disks[i].rdev;
2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397
		if (!rdev
		    || test_bit(Faulty, &rdev->flags)
		    || test_bit(In_sync, &rdev->flags))
			continue;
		if (!rdev_set_badblocks(rdev, sh->sector,
					STRIPE_SECTORS, 0))
			abort = 1;
	}
	if (abort) {
		conf->recovery_disabled = conf->mddev->recovery_disabled;
		set_bit(MD_RECOVERY_INTR, &conf->mddev->recovery);
	}
}

2398
/* fetch_block - checks the given member device to see if its data needs
2399 2400 2401
 * to be read or computed to satisfy a request.
 *
 * Returns 1 when no more member devices need to be checked, otherwise returns
2402
 * 0 to tell the loop in handle_stripe_fill to continue
2403
 */
2404 2405
static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
		       int disk_idx, int disks)
2406
{
2407
	struct r5dev *dev = &sh->dev[disk_idx];
2408 2409
	struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
				  &sh->dev[s->failed_num[1]] };
2410

2411
	/* is the data in this block needed, and can we get it? */
2412 2413 2414 2415 2416
	if (!test_bit(R5_LOCKED, &dev->flags) &&
	    !test_bit(R5_UPTODATE, &dev->flags) &&
	    (dev->toread ||
	     (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
	     s->syncing || s->expanding ||
2417 2418
	     (s->failed >= 1 && fdev[0]->toread) ||
	     (s->failed >= 2 && fdev[1]->toread) ||
2419 2420 2421
	     (sh->raid_conf->level <= 5 && s->failed && fdev[0]->towrite &&
	      !test_bit(R5_OVERWRITE, &fdev[0]->flags)) ||
	     (sh->raid_conf->level == 6 && s->failed && s->to_write))) {
2422 2423 2424 2425 2426 2427
		/* we would like to get this block, possibly by computing it,
		 * otherwise read it if the backing disk is insync
		 */
		BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
		BUG_ON(test_bit(R5_Wantread, &dev->flags));
		if ((s->uptodate == disks - 1) &&
2428 2429
		    (s->failed && (disk_idx == s->failed_num[0] ||
				   disk_idx == s->failed_num[1]))) {
2430 2431
			/* have disk failed, and we're requested to fetch it;
			 * do compute it
2432
			 */
2433 2434 2435 2436 2437 2438 2439 2440
			pr_debug("Computing stripe %llu block %d\n",
			       (unsigned long long)sh->sector, disk_idx);
			set_bit(STRIPE_COMPUTE_RUN, &sh->state);
			set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
			set_bit(R5_Wantcompute, &dev->flags);
			sh->ops.target = disk_idx;
			sh->ops.target2 = -1; /* no 2nd target */
			s->req_compute = 1;
2441 2442 2443 2444 2445 2446
			/* Careful: from this point on 'uptodate' is in the eye
			 * of raid_run_ops which services 'compute' operations
			 * before writes. R5_Wantcompute flags a block that will
			 * be R5_UPTODATE by the time it is needed for a
			 * subsequent operation.
			 */
2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459
			s->uptodate++;
			return 1;
		} else if (s->uptodate == disks-2 && s->failed >= 2) {
			/* Computing 2-failure is *very* expensive; only
			 * do it if failed >= 2
			 */
			int other;
			for (other = disks; other--; ) {
				if (other == disk_idx)
					continue;
				if (!test_bit(R5_UPTODATE,
				      &sh->dev[other].flags))
					break;
2460
			}
2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479
			BUG_ON(other < 0);
			pr_debug("Computing stripe %llu blocks %d,%d\n",
			       (unsigned long long)sh->sector,
			       disk_idx, other);
			set_bit(STRIPE_COMPUTE_RUN, &sh->state);
			set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
			set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
			set_bit(R5_Wantcompute, &sh->dev[other].flags);
			sh->ops.target = disk_idx;
			sh->ops.target2 = other;
			s->uptodate += 2;
			s->req_compute = 1;
			return 1;
		} else if (test_bit(R5_Insync, &dev->flags)) {
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantread, &dev->flags);
			s->locked++;
			pr_debug("Reading block %d (sync=%d)\n",
				disk_idx, s->syncing);
2480 2481
		}
	}
2482 2483 2484 2485 2486

	return 0;
}

/**
2487
 * handle_stripe_fill - read or compute data to satisfy pending requests.
2488
 */
2489 2490 2491
static void handle_stripe_fill(struct stripe_head *sh,
			       struct stripe_head_state *s,
			       int disks)
2492 2493 2494 2495 2496 2497 2498 2499 2500 2501
{
	int i;

	/* look for blocks to read/compute, skip this if a compute
	 * is already in flight, or if the stripe contents are in the
	 * midst of changing due to a write
	 */
	if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
	    !sh->reconstruct_state)
		for (i = disks; i--; )
2502
			if (fetch_block(sh, s, i, disks))
2503
				break;
2504 2505 2506 2507
	set_bit(STRIPE_HANDLE, &sh->state);
}


2508
/* handle_stripe_clean_event
2509 2510 2511 2512
 * 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.
 */
2513
static void handle_stripe_clean_event(struct r5conf *conf,
2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526
	struct stripe_head *sh, int disks, struct bio **return_bi)
{
	int i;
	struct r5dev *dev;

	for (i = disks; i--; )
		if (sh->dev[i].written) {
			dev = &sh->dev[i];
			if (!test_bit(R5_LOCKED, &dev->flags) &&
				test_bit(R5_UPTODATE, &dev->flags)) {
				/* We can return any write requests */
				struct bio *wbi, *wbi2;
				int bitmap_end = 0;
2527
				pr_debug("Return write for disc %d\n", i);
2528 2529 2530 2531 2532 2533
				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);
2534
					if (!raid5_dec_bi_phys_segments(wbi)) {
2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551
						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);
			}
		}
2552 2553 2554 2555

	if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
		if (atomic_dec_and_test(&conf->pending_full_writes))
			md_wakeup_thread(conf->mddev->thread);
2556 2557
}

2558
static void handle_stripe_dirtying(struct r5conf *conf,
2559 2560 2561
				   struct stripe_head *sh,
				   struct stripe_head_state *s,
				   int disks)
2562 2563
{
	int rmw = 0, rcw = 0, i;
2564 2565 2566 2567 2568 2569 2570
	if (conf->max_degraded == 2) {
		/* RAID6 requires 'rcw' in current implementation
		 * Calculate the real rcw later - for now fake it
		 * look like rcw is cheaper
		 */
		rcw = 1; rmw = 2;
	} else for (i = disks; i--; ) {
2571 2572 2573 2574
		/* would I have to read this buffer for read_modify_write */
		struct r5dev *dev = &sh->dev[i];
		if ((dev->towrite || i == sh->pd_idx) &&
		    !test_bit(R5_LOCKED, &dev->flags) &&
2575 2576
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		      test_bit(R5_Wantcompute, &dev->flags))) {
2577 2578 2579 2580 2581 2582 2583 2584
			if (test_bit(R5_Insync, &dev->flags))
				rmw++;
			else
				rmw += 2*disks;  /* cannot read it */
		}
		/* Would I have to read this buffer for reconstruct_write */
		if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx &&
		    !test_bit(R5_LOCKED, &dev->flags) &&
2585 2586 2587
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		    test_bit(R5_Wantcompute, &dev->flags))) {
			if (test_bit(R5_Insync, &dev->flags)) rcw++;
2588 2589 2590 2591
			else
				rcw += 2*disks;
		}
	}
2592
	pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2593 2594 2595 2596 2597 2598 2599 2600
		(unsigned long long)sh->sector, rmw, rcw);
	set_bit(STRIPE_HANDLE, &sh->state);
	if (rmw < rcw && rmw > 0)
		/* prefer read-modify-write, but need to get some data */
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if ((dev->towrite || i == sh->pd_idx) &&
			    !test_bit(R5_LOCKED, &dev->flags) &&
2601 2602
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
			    test_bit(R5_Wantcompute, &dev->flags)) &&
2603 2604 2605
			    test_bit(R5_Insync, &dev->flags)) {
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2606
					pr_debug("Read_old block "
2607 2608 2609 2610 2611 2612 2613 2614 2615 2616
						"%d for r-m-w\n", i);
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
					s->locked++;
				} else {
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
2617
	if (rcw <= rmw && rcw > 0) {
2618
		/* want reconstruct write, but need to get some data */
2619
		rcw = 0;
2620 2621 2622
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (!test_bit(R5_OVERWRITE, &dev->flags) &&
2623
			    i != sh->pd_idx && i != sh->qd_idx &&
2624
			    !test_bit(R5_LOCKED, &dev->flags) &&
2625
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
2626 2627 2628 2629
			      test_bit(R5_Wantcompute, &dev->flags))) {
				rcw++;
				if (!test_bit(R5_Insync, &dev->flags))
					continue; /* it's a failed drive */
2630 2631
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2632
					pr_debug("Read_old block "
2633 2634 2635 2636 2637 2638 2639 2640 2641 2642
						"%d for Reconstruct\n", i);
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
					s->locked++;
				} else {
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
2643
	}
2644 2645 2646
	/* now if nothing is locked, and if we have enough data,
	 * we can start a write request
	 */
2647 2648
	/* since handle_stripe can be called at any time we need to handle the
	 * case where a compute block operation has been submitted and then a
2649 2650
	 * subsequent call wants to start a write request.  raid_run_ops only
	 * handles the case where compute block and reconstruct are requested
2651 2652 2653
	 * simultaneously.  If this is not the case then new writes need to be
	 * held off until the compute completes.
	 */
2654 2655 2656
	if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
	    (s->locked == 0 && (rcw == 0 || rmw == 0) &&
	    !test_bit(STRIPE_BIT_DELAY, &sh->state)))
2657
		schedule_reconstruction(sh, s, rcw == 0, 0);
2658 2659
}

2660
static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
2661 2662
				struct stripe_head_state *s, int disks)
{
2663
	struct r5dev *dev = NULL;
2664

2665
	set_bit(STRIPE_HANDLE, &sh->state);
2666

2667 2668 2669
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are no failures */
2670 2671
		if (s->failed == 0) {
			BUG_ON(s->uptodate != disks);
2672 2673
			sh->check_state = check_state_run;
			set_bit(STRIPE_OP_CHECK, &s->ops_request);
2674 2675
			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
			s->uptodate--;
2676
			break;
2677
		}
2678
		dev = &sh->dev[s->failed_num[0]];
2679 2680 2681 2682 2683 2684 2685 2686 2687
		/* fall through */
	case check_state_compute_result:
		sh->check_state = check_state_idle;
		if (!dev)
			dev = &sh->dev[sh->pd_idx];

		/* check that a write has not made the stripe insync */
		if (test_bit(STRIPE_INSYNC, &sh->state))
			break;
D
Dan Williams 已提交
2688

2689 2690 2691 2692 2693
		/* either failed parity check, or recovery is happening */
		BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
		BUG_ON(s->uptodate != disks);

		set_bit(R5_LOCKED, &dev->flags);
2694
		s->locked++;
2695
		set_bit(R5_Wantwrite, &dev->flags);
2696

2697 2698
		clear_bit(STRIPE_DEGRADED, &sh->state);
		set_bit(STRIPE_INSYNC, &sh->state);
2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714
		break;
	case check_state_run:
		break; /* we will be called again upon completion */
	case check_state_check_result:
		sh->check_state = check_state_idle;

		/* if a failure occurred during the check operation, leave
		 * STRIPE_INSYNC not set and let the stripe be handled again
		 */
		if (s->failed)
			break;

		/* handle a successful check operation, if parity is correct
		 * we are done.  Otherwise update the mismatch count and repair
		 * parity if !MD_RECOVERY_CHECK
		 */
D
Dan Williams 已提交
2715
		if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726
			/* parity is correct (on disc,
			 * not in buffer any more)
			 */
			set_bit(STRIPE_INSYNC, &sh->state);
		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);
			else {
				sh->check_state = check_state_compute_run;
2727
				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2728 2729 2730 2731
				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
				set_bit(R5_Wantcompute,
					&sh->dev[sh->pd_idx].flags);
				sh->ops.target = sh->pd_idx;
2732
				sh->ops.target2 = -1;
2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743
				s->uptodate++;
			}
		}
		break;
	case check_state_compute_run:
		break;
	default:
		printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
		       __func__, sh->check_state,
		       (unsigned long long) sh->sector);
		BUG();
2744 2745 2746 2747
	}
}


2748
static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
2749
				  struct stripe_head_state *s,
2750
				  int disks)
2751 2752
{
	int pd_idx = sh->pd_idx;
N
NeilBrown 已提交
2753
	int qd_idx = sh->qd_idx;
2754
	struct r5dev *dev;
2755 2756 2757 2758

	set_bit(STRIPE_HANDLE, &sh->state);

	BUG_ON(s->failed > 2);
2759

2760 2761 2762 2763 2764 2765
	/* 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
	 */

2766 2767 2768
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are < 2 failures */
2769
		if (s->failed == s->q_failed) {
2770
			/* The only possible failed device holds Q, so it
2771 2772 2773
			 * makes sense to check P (If anything else were failed,
			 * we would have used P to recreate it).
			 */
2774
			sh->check_state = check_state_run;
2775
		}
2776
		if (!s->q_failed && s->failed < 2) {
2777
			/* Q is not failed, and we didn't use it to generate
2778 2779
			 * anything, so it makes sense to check it
			 */
2780 2781 2782 2783
			if (sh->check_state == check_state_run)
				sh->check_state = check_state_run_pq;
			else
				sh->check_state = check_state_run_q;
2784 2785
		}

2786 2787
		/* discard potentially stale zero_sum_result */
		sh->ops.zero_sum_result = 0;
2788

2789 2790 2791 2792
		if (sh->check_state == check_state_run) {
			/* async_xor_zero_sum destroys the contents of P */
			clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
			s->uptodate--;
2793
		}
2794 2795 2796 2797 2798 2799 2800
		if (sh->check_state >= check_state_run &&
		    sh->check_state <= check_state_run_pq) {
			/* async_syndrome_zero_sum preserves P and Q, so
			 * no need to mark them !uptodate here
			 */
			set_bit(STRIPE_OP_CHECK, &s->ops_request);
			break;
2801 2802
		}

2803 2804 2805 2806 2807
		/* we have 2-disk failure */
		BUG_ON(s->failed != 2);
		/* fall through */
	case check_state_compute_result:
		sh->check_state = check_state_idle;
2808

2809 2810 2811
		/* check that a write has not made the stripe insync */
		if (test_bit(STRIPE_INSYNC, &sh->state))
			break;
2812 2813

		/* now write out any block on a failed drive,
2814
		 * or P or Q if they were recomputed
2815
		 */
2816
		BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
2817
		if (s->failed == 2) {
2818
			dev = &sh->dev[s->failed_num[1]];
2819 2820 2821 2822 2823
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		if (s->failed >= 1) {
2824
			dev = &sh->dev[s->failed_num[0]];
2825 2826 2827 2828
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
2829
		if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
2830 2831 2832 2833 2834
			dev = &sh->dev[pd_idx];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
2835
		if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
2836 2837 2838 2839 2840 2841 2842 2843
			dev = &sh->dev[qd_idx];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		clear_bit(STRIPE_DEGRADED, &sh->state);

		set_bit(STRIPE_INSYNC, &sh->state);
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 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907
		break;
	case check_state_run:
	case check_state_run_q:
	case check_state_run_pq:
		break; /* we will be called again upon completion */
	case check_state_check_result:
		sh->check_state = check_state_idle;

		/* handle a successful check operation, if parity is correct
		 * we are done.  Otherwise update the mismatch count and repair
		 * parity if !MD_RECOVERY_CHECK
		 */
		if (sh->ops.zero_sum_result == 0) {
			/* both parities are correct */
			if (!s->failed)
				set_bit(STRIPE_INSYNC, &sh->state);
			else {
				/* in contrast to the raid5 case we can validate
				 * parity, but still have a failure to write
				 * back
				 */
				sh->check_state = check_state_compute_result;
				/* Returning at this point means that we may go
				 * off and bring p and/or q uptodate again so
				 * we make sure to check zero_sum_result again
				 * to verify if p or q need writeback
				 */
			}
		} 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);
			else {
				int *target = &sh->ops.target;

				sh->ops.target = -1;
				sh->ops.target2 = -1;
				sh->check_state = check_state_compute_run;
				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
				if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
					set_bit(R5_Wantcompute,
						&sh->dev[pd_idx].flags);
					*target = pd_idx;
					target = &sh->ops.target2;
					s->uptodate++;
				}
				if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
					set_bit(R5_Wantcompute,
						&sh->dev[qd_idx].flags);
					*target = qd_idx;
					s->uptodate++;
				}
			}
		}
		break;
	case check_state_compute_run:
		break;
	default:
		printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
		       __func__, sh->check_state,
		       (unsigned long long) sh->sector);
		BUG();
2908 2909 2910
	}
}

2911
static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
2912 2913 2914 2915 2916 2917
{
	int i;

	/* We have read all the blocks in this stripe and now we need to
	 * copy some of them into a target stripe for expand.
	 */
2918
	struct dma_async_tx_descriptor *tx = NULL;
2919 2920
	clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	for (i = 0; i < sh->disks; i++)
N
NeilBrown 已提交
2921
		if (i != sh->pd_idx && i != sh->qd_idx) {
2922
			int dd_idx, j;
2923
			struct stripe_head *sh2;
2924
			struct async_submit_ctl submit;
2925

2926
			sector_t bn = compute_blocknr(sh, i, 1);
2927 2928
			sector_t s = raid5_compute_sector(conf, bn, 0,
							  &dd_idx, NULL);
2929
			sh2 = get_active_stripe(conf, s, 0, 1, 1);
2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941
			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;
			}
2942 2943

			/* place all the copies on one channel */
2944
			init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
2945
			tx = async_memcpy(sh2->dev[dd_idx].page,
2946
					  sh->dev[i].page, 0, 0, STRIPE_SIZE,
2947
					  &submit);
2948

2949 2950 2951 2952
			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 &&
2953
				    j != sh2->qd_idx &&
2954 2955 2956 2957 2958 2959 2960
				    !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);
2961

2962
		}
2963 2964 2965 2966 2967
	/* done submitting copies, wait for them to complete */
	if (tx) {
		async_tx_ack(tx);
		dma_wait_for_async_tx(tx);
	}
2968
}
L
Linus Torvalds 已提交
2969

2970

L
Linus Torvalds 已提交
2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986
/*
 * handle_stripe - do things to a stripe.
 *
 * We lock the stripe and then examine the state of various bits
 * to see what needs to be done.
 * Possible results:
 *    return some read request which now have data
 *    return some write requests which are safely on disc
 *    schedule a read on some buffers
 *    schedule a write of some buffers
 *    return confirmation of parity correctness
 *
 * buffers are taken off read_list or write_list, and bh_cache buffers
 * get BH_Lock set before the stripe lock is released.
 *
 */
2987

2988
static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
L
Linus Torvalds 已提交
2989
{
2990
	struct r5conf *conf = sh->raid_conf;
2991
	int disks = sh->disks;
2992 2993
	struct r5dev *dev;
	int i;
L
Linus Torvalds 已提交
2994

2995 2996 2997 2998 2999 3000 3001
	memset(s, 0, sizeof(*s));

	s->syncing = test_bit(STRIPE_SYNCING, &sh->state);
	s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
	s->failed_num[0] = -1;
	s->failed_num[1] = -1;
L
Linus Torvalds 已提交
3002

3003
	/* Now to look around and see what can be done */
L
Linus Torvalds 已提交
3004
	rcu_read_lock();
3005
	spin_lock_irq(&conf->device_lock);
3006
	for (i=disks; i--; ) {
3007
		struct md_rdev *rdev;
3008 3009 3010
		sector_t first_bad;
		int bad_sectors;
		int is_bad = 0;
3011

3012
		dev = &sh->dev[i];
L
Linus Torvalds 已提交
3013

3014
		pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
3015
			i, dev->flags, dev->toread, dev->towrite, dev->written);
3016 3017 3018 3019 3020 3021 3022 3023
		/* maybe we can reply to a read
		 *
		 * new wantfill requests are only permitted while
		 * ops_complete_biofill is guaranteed to be inactive
		 */
		if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
		    !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
			set_bit(R5_Wantfill, &dev->flags);
L
Linus Torvalds 已提交
3024

3025
		/* now count some things */
3026 3027 3028 3029
		if (test_bit(R5_LOCKED, &dev->flags))
			s->locked++;
		if (test_bit(R5_UPTODATE, &dev->flags))
			s->uptodate++;
3030
		if (test_bit(R5_Wantcompute, &dev->flags)) {
3031 3032
			s->compute++;
			BUG_ON(s->compute > 2);
3033
		}
L
Linus Torvalds 已提交
3034

3035
		if (test_bit(R5_Wantfill, &dev->flags))
3036
			s->to_fill++;
3037
		else if (dev->toread)
3038
			s->to_read++;
3039
		if (dev->towrite) {
3040
			s->to_write++;
3041
			if (!test_bit(R5_OVERWRITE, &dev->flags))
3042
				s->non_overwrite++;
3043
		}
3044
		if (dev->written)
3045
			s->written++;
3046
		rdev = rcu_dereference(conf->disks[i].rdev);
3047 3048
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060
		if (rdev) {
			is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
					     &first_bad, &bad_sectors);
			if (s->blocked_rdev == NULL
			    && (test_bit(Blocked, &rdev->flags)
				|| is_bad < 0)) {
				if (is_bad < 0)
					set_bit(BlockedBadBlocks,
						&rdev->flags);
				s->blocked_rdev = rdev;
				atomic_inc(&rdev->nr_pending);
			}
3061
		}
3062 3063 3064
		clear_bit(R5_Insync, &dev->flags);
		if (!rdev)
			/* Not in-sync */;
3065 3066 3067 3068 3069 3070 3071 3072 3073 3074
		else if (is_bad) {
			/* also not in-sync */
			if (!test_bit(WriteErrorSeen, &rdev->flags)) {
				/* treat as in-sync, but with a read error
				 * which we can now try to correct
				 */
				set_bit(R5_Insync, &dev->flags);
				set_bit(R5_ReadError, &dev->flags);
			}
		} else if (test_bit(In_sync, &rdev->flags))
3075
			set_bit(R5_Insync, &dev->flags);
3076
		else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
3077
			/* in sync if before recovery_offset */
3078 3079 3080 3081 3082 3083 3084 3085 3086
			set_bit(R5_Insync, &dev->flags);
		else if (test_bit(R5_UPTODATE, &dev->flags) &&
			 test_bit(R5_Expanded, &dev->flags))
			/* If we've reshaped into here, we assume it is Insync.
			 * We will shortly update recovery_offset to make
			 * it official.
			 */
			set_bit(R5_Insync, &dev->flags);

A
Adam Kwolek 已提交
3087
		if (rdev && test_bit(R5_WriteError, &dev->flags)) {
3088 3089 3090 3091 3092 3093 3094
			clear_bit(R5_Insync, &dev->flags);
			if (!test_bit(Faulty, &rdev->flags)) {
				s->handle_bad_blocks = 1;
				atomic_inc(&rdev->nr_pending);
			} else
				clear_bit(R5_WriteError, &dev->flags);
		}
A
Adam Kwolek 已提交
3095
		if (rdev && test_bit(R5_MadeGood, &dev->flags)) {
3096 3097 3098 3099 3100 3101
			if (!test_bit(Faulty, &rdev->flags)) {
				s->handle_bad_blocks = 1;
				atomic_inc(&rdev->nr_pending);
			} else
				clear_bit(R5_MadeGood, &dev->flags);
		}
3102
		if (!test_bit(R5_Insync, &dev->flags)) {
3103 3104 3105
			/* The ReadError flag will just be confusing now */
			clear_bit(R5_ReadError, &dev->flags);
			clear_bit(R5_ReWrite, &dev->flags);
L
Linus Torvalds 已提交
3106
		}
3107 3108 3109
		if (test_bit(R5_ReadError, &dev->flags))
			clear_bit(R5_Insync, &dev->flags);
		if (!test_bit(R5_Insync, &dev->flags)) {
3110 3111 3112
			if (s->failed < 2)
				s->failed_num[s->failed] = i;
			s->failed++;
3113
		}
L
Linus Torvalds 已提交
3114
	}
3115
	spin_unlock_irq(&conf->device_lock);
L
Linus Torvalds 已提交
3116
	rcu_read_unlock();
3117 3118 3119 3120 3121
}

static void handle_stripe(struct stripe_head *sh)
{
	struct stripe_head_state s;
3122
	struct r5conf *conf = sh->raid_conf;
3123
	int i;
3124 3125
	int prexor;
	int disks = sh->disks;
3126
	struct r5dev *pdev, *qdev;
3127 3128

	clear_bit(STRIPE_HANDLE, &sh->state);
3129
	if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146
		/* already being handled, ensure it gets handled
		 * again when current action finishes */
		set_bit(STRIPE_HANDLE, &sh->state);
		return;
	}

	if (test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
		set_bit(STRIPE_SYNCING, &sh->state);
		clear_bit(STRIPE_INSYNC, &sh->state);
	}
	clear_bit(STRIPE_DELAYED, &sh->state);

	pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
		"pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
	       (unsigned long long)sh->sector, sh->state,
	       atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
	       sh->check_state, sh->reconstruct_state);
3147

3148
	analyse_stripe(sh, &s);
3149

3150 3151 3152 3153 3154
	if (s.handle_bad_blocks) {
		set_bit(STRIPE_HANDLE, &sh->state);
		goto finish;
	}

3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177
	if (unlikely(s.blocked_rdev)) {
		if (s.syncing || s.expanding || s.expanded ||
		    s.to_write || s.written) {
			set_bit(STRIPE_HANDLE, &sh->state);
			goto finish;
		}
		/* There is nothing for the blocked_rdev to block */
		rdev_dec_pending(s.blocked_rdev, conf->mddev);
		s.blocked_rdev = NULL;
	}

	if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
		set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
		set_bit(STRIPE_BIOFILL_RUN, &sh->state);
	}

	pr_debug("locked=%d uptodate=%d to_read=%d"
	       " to_write=%d failed=%d failed_num=%d,%d\n",
	       s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
	       s.failed_num[0], s.failed_num[1]);
	/* check if the array has lost more than max_degraded devices and,
	 * if so, some requests might need to be failed.
	 */
3178 3179 3180 3181 3182 3183 3184 3185
	if (s.failed > conf->max_degraded) {
		sh->check_state = 0;
		sh->reconstruct_state = 0;
		if (s.to_read+s.to_write+s.written)
			handle_failed_stripe(conf, sh, &s, disks, &s.return_bi);
		if (s.syncing)
			handle_failed_sync(conf, sh, &s);
	}
3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216

	/*
	 * might be able to return some write requests if the parity blocks
	 * are safe, or on a failed drive
	 */
	pdev = &sh->dev[sh->pd_idx];
	s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
		|| (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
	qdev = &sh->dev[sh->qd_idx];
	s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
		|| (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
		|| conf->level < 6;

	if (s.written &&
	    (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
			     && !test_bit(R5_LOCKED, &pdev->flags)
			     && test_bit(R5_UPTODATE, &pdev->flags)))) &&
	    (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
			     && !test_bit(R5_LOCKED, &qdev->flags)
			     && test_bit(R5_UPTODATE, &qdev->flags)))))
		handle_stripe_clean_event(conf, sh, disks, &s.return_bi);

	/* 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 (s.to_read || s.non_overwrite
	    || (conf->level == 6 && s.to_write && s.failed)
	    || (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding)
		handle_stripe_fill(sh, &s, disks);

3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274
	/* Now we check to see if any write operations have recently
	 * completed
	 */
	prexor = 0;
	if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
		prexor = 1;
	if (sh->reconstruct_state == reconstruct_state_drain_result ||
	    sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
		sh->reconstruct_state = reconstruct_state_idle;

		/* All the 'written' buffers and the parity block are ready to
		 * be written back to disk
		 */
		BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags));
		BUG_ON(sh->qd_idx >= 0 &&
		       !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags));
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (test_bit(R5_LOCKED, &dev->flags) &&
				(i == sh->pd_idx || i == sh->qd_idx ||
				 dev->written)) {
				pr_debug("Writing block %d\n", i);
				set_bit(R5_Wantwrite, &dev->flags);
				if (prexor)
					continue;
				if (!test_bit(R5_Insync, &dev->flags) ||
				    ((i == sh->pd_idx || i == sh->qd_idx)  &&
				     s.failed == 0))
					set_bit(STRIPE_INSYNC, &sh->state);
			}
		}
		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
			s.dec_preread_active = 1;
	}

	/* Now to consider new write requests and what else, if anything
	 * should be read.  We do not handle new writes when:
	 * 1/ A 'write' operation (copy+xor) is already in flight.
	 * 2/ A 'check' operation is in flight, as it may clobber the parity
	 *    block.
	 */
	if (s.to_write && !sh->reconstruct_state && !sh->check_state)
		handle_stripe_dirtying(conf, sh, &s, disks);

	/* 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.  The parity check is held off while parity
	 * dependent operations are in flight.
	 */
	if (sh->check_state ||
	    (s.syncing && s.locked == 0 &&
	     !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
	     !test_bit(STRIPE_INSYNC, &sh->state))) {
		if (conf->level == 6)
			handle_parity_checks6(conf, sh, &s, disks);
		else
			handle_parity_checks5(conf, sh, &s, disks);
	}
3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305

	if (s.syncing && s.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 (s.failed <= conf->max_degraded && !conf->mddev->ro)
		for (i = 0; i < s.failed; i++) {
			struct r5dev *dev = &sh->dev[s.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);
					s.locked++;
				} else {
					/* let's read it back */
					set_bit(R5_Wantread, &dev->flags);
					set_bit(R5_LOCKED, &dev->flags);
					s.locked++;
				}
			}
		}


3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332
	/* Finish reconstruct operations initiated by the expansion process */
	if (sh->reconstruct_state == reconstruct_state_result) {
		struct stripe_head *sh_src
			= get_active_stripe(conf, sh->sector, 1, 1, 1);
		if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
			/* sh cannot be written until sh_src has been read.
			 * so arrange for sh to be delayed a little
			 */
			set_bit(STRIPE_DELAYED, &sh->state);
			set_bit(STRIPE_HANDLE, &sh->state);
			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
					      &sh_src->state))
				atomic_inc(&conf->preread_active_stripes);
			release_stripe(sh_src);
			goto finish;
		}
		if (sh_src)
			release_stripe(sh_src);

		sh->reconstruct_state = reconstruct_state_idle;
		clear_bit(STRIPE_EXPANDING, &sh->state);
		for (i = conf->raid_disks; i--; ) {
			set_bit(R5_Wantwrite, &sh->dev[i].flags);
			set_bit(R5_LOCKED, &sh->dev[i].flags);
			s.locked++;
		}
	}
3333

3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349
	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
	    !sh->reconstruct_state) {
		/* Need to write out all blocks after computing parity */
		sh->disks = conf->raid_disks;
		stripe_set_idx(sh->sector, conf, 0, sh);
		schedule_reconstruction(sh, &s, 1, 1);
	} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
		clear_bit(STRIPE_EXPAND_READY, &sh->state);
		atomic_dec(&conf->reshape_stripes);
		wake_up(&conf->wait_for_overlap);
		md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
	}

	if (s.expanding && s.locked == 0 &&
	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
		handle_stripe_expansion(conf, sh);
3350

3351
finish:
3352
	/* wait for this device to become unblocked */
3353
	if (conf->mddev->external && unlikely(s.blocked_rdev))
3354
		md_wait_for_blocked_rdev(s.blocked_rdev, conf->mddev);
3355

3356 3357
	if (s.handle_bad_blocks)
		for (i = disks; i--; ) {
3358
			struct md_rdev *rdev;
3359 3360 3361 3362 3363 3364 3365 3366 3367
			struct r5dev *dev = &sh->dev[i];
			if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
				/* We own a safe reference to the rdev */
				rdev = conf->disks[i].rdev;
				if (!rdev_set_badblocks(rdev, sh->sector,
							STRIPE_SECTORS, 0))
					md_error(conf->mddev, rdev);
				rdev_dec_pending(rdev, conf->mddev);
			}
3368 3369 3370 3371 3372 3373
			if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
				rdev = conf->disks[i].rdev;
				rdev_clear_badblocks(rdev, sh->sector,
						     STRIPE_SECTORS);
				rdev_dec_pending(rdev, conf->mddev);
			}
3374 3375
		}

3376 3377 3378
	if (s.ops_request)
		raid_run_ops(sh, s.ops_request);

D
Dan Williams 已提交
3379
	ops_run_io(sh, &s);
3380

3381
	if (s.dec_preread_active) {
3382
		/* We delay this until after ops_run_io so that if make_request
T
Tejun Heo 已提交
3383
		 * is waiting on a flush, it won't continue until the writes
3384 3385 3386 3387 3388 3389 3390 3391
		 * have actually been submitted.
		 */
		atomic_dec(&conf->preread_active_stripes);
		if (atomic_read(&conf->preread_active_stripes) <
		    IO_THRESHOLD)
			md_wakeup_thread(conf->mddev->thread);
	}

3392
	return_io(s.return_bi);
3393

3394
	clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
3395 3396
}

3397
static void raid5_activate_delayed(struct r5conf *conf)
3398 3399 3400 3401 3402 3403 3404 3405 3406 3407
{
	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);
3408
			list_add_tail(&sh->lru, &conf->hold_list);
3409
		}
N
NeilBrown 已提交
3410
	}
3411 3412
}

3413
static void activate_bit_delay(struct r5conf *conf)
3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426
{
	/* 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);
	}
}

3427
int md_raid5_congested(struct mddev *mddev, int bits)
3428
{
3429
	struct r5conf *conf = mddev->private;
3430 3431 3432 3433

	/* No difference between reads and writes.  Just check
	 * how busy the stripe_cache is
	 */
3434

3435 3436 3437 3438 3439 3440 3441 3442 3443
	if (conf->inactive_blocked)
		return 1;
	if (conf->quiesce)
		return 1;
	if (list_empty_careful(&conf->inactive_list))
		return 1;

	return 0;
}
N
NeilBrown 已提交
3444 3445 3446 3447
EXPORT_SYMBOL_GPL(md_raid5_congested);

static int raid5_congested(void *data, int bits)
{
3448
	struct mddev *mddev = data;
N
NeilBrown 已提交
3449 3450 3451 3452

	return mddev_congested(mddev, bits) ||
		md_raid5_congested(mddev, bits);
}
3453

3454 3455 3456
/* We want read requests to align with chunks where possible,
 * but write requests don't need to.
 */
3457 3458 3459
static int raid5_mergeable_bvec(struct request_queue *q,
				struct bvec_merge_data *bvm,
				struct bio_vec *biovec)
3460
{
3461
	struct mddev *mddev = q->queuedata;
3462
	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
3463
	int max;
3464
	unsigned int chunk_sectors = mddev->chunk_sectors;
3465
	unsigned int bio_sectors = bvm->bi_size >> 9;
3466

3467
	if ((bvm->bi_rw & 1) == WRITE)
3468 3469
		return biovec->bv_len; /* always allow writes to be mergeable */

3470 3471
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3472 3473 3474 3475 3476 3477 3478 3479
	max =  (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
	if (max < 0) max = 0;
	if (max <= biovec->bv_len && bio_sectors == 0)
		return biovec->bv_len;
	else
		return max;
}

3480

3481
static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
3482 3483
{
	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3484
	unsigned int chunk_sectors = mddev->chunk_sectors;
3485 3486
	unsigned int bio_sectors = bio->bi_size >> 9;

3487 3488
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3489 3490 3491 3492
	return  chunk_sectors >=
		((sector & (chunk_sectors - 1)) + bio_sectors);
}

3493 3494 3495 3496
/*
 *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
 *  later sampled by raid5d.
 */
3497
static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510
{
	unsigned long flags;

	spin_lock_irqsave(&conf->device_lock, flags);

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

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


3511
static struct bio *remove_bio_from_retry(struct r5conf *conf)
3512 3513 3514 3515 3516 3517 3518 3519 3520 3521
{
	struct bio *bi;

	bi = conf->retry_read_aligned;
	if (bi) {
		conf->retry_read_aligned = NULL;
		return bi;
	}
	bi = conf->retry_read_aligned_list;
	if(bi) {
3522
		conf->retry_read_aligned_list = bi->bi_next;
3523
		bi->bi_next = NULL;
3524 3525 3526 3527
		/*
		 * this sets the active strip count to 1 and the processed
		 * strip count to zero (upper 8 bits)
		 */
3528 3529 3530 3531 3532 3533 3534
		bi->bi_phys_segments = 1; /* biased count of active stripes */
	}

	return bi;
}


3535 3536 3537 3538 3539 3540
/*
 *  The "raid5_align_endio" should check if the read succeeded and if it
 *  did, call bio_endio on the original bio (having bio_put the new bio
 *  first).
 *  If the read failed..
 */
3541
static void raid5_align_endio(struct bio *bi, int error)
3542 3543
{
	struct bio* raid_bi  = bi->bi_private;
3544
	struct mddev *mddev;
3545
	struct r5conf *conf;
3546
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
3547
	struct md_rdev *rdev;
3548

3549
	bio_put(bi);
3550 3551 3552

	rdev = (void*)raid_bi->bi_next;
	raid_bi->bi_next = NULL;
3553 3554
	mddev = rdev->mddev;
	conf = mddev->private;
3555 3556 3557 3558

	rdev_dec_pending(rdev, conf->mddev);

	if (!error && uptodate) {
3559
		bio_endio(raid_bi, 0);
3560 3561
		if (atomic_dec_and_test(&conf->active_aligned_reads))
			wake_up(&conf->wait_for_stripe);
3562
		return;
3563 3564 3565
	}


3566
	pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
3567 3568

	add_bio_to_retry(raid_bi, conf);
3569 3570
}

3571 3572
static int bio_fits_rdev(struct bio *bi)
{
3573
	struct request_queue *q = bdev_get_queue(bi->bi_bdev);
3574

3575
	if ((bi->bi_size>>9) > queue_max_sectors(q))
3576 3577
		return 0;
	blk_recount_segments(q, bi);
3578
	if (bi->bi_phys_segments > queue_max_segments(q))
3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590
		return 0;

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

	return 1;
}


3591
static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
3592
{
3593
	struct r5conf *conf = mddev->private;
N
NeilBrown 已提交
3594
	int dd_idx;
3595
	struct bio* align_bi;
3596
	struct md_rdev *rdev;
3597 3598

	if (!in_chunk_boundary(mddev, raid_bio)) {
3599
		pr_debug("chunk_aligned_read : non aligned\n");
3600 3601 3602
		return 0;
	}
	/*
3603
	 * use bio_clone_mddev to make a copy of the bio
3604
	 */
3605
	align_bi = bio_clone_mddev(raid_bio, GFP_NOIO, mddev);
3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616
	if (!align_bi)
		return 0;
	/*
	 *   set bi_end_io to a new function, and set bi_private to the
	 *     original bio.
	 */
	align_bi->bi_end_io  = raid5_align_endio;
	align_bi->bi_private = raid_bio;
	/*
	 *	compute position
	 */
3617 3618
	align_bi->bi_sector =  raid5_compute_sector(conf, raid_bio->bi_sector,
						    0,
3619
						    &dd_idx, NULL);
3620 3621 3622 3623

	rcu_read_lock();
	rdev = rcu_dereference(conf->disks[dd_idx].rdev);
	if (rdev && test_bit(In_sync, &rdev->flags)) {
3624 3625 3626
		sector_t first_bad;
		int bad_sectors;

3627 3628
		atomic_inc(&rdev->nr_pending);
		rcu_read_unlock();
3629 3630 3631 3632 3633
		raid_bio->bi_next = (void*)rdev;
		align_bi->bi_bdev =  rdev->bdev;
		align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);
		align_bi->bi_sector += rdev->data_offset;

3634 3635 3636 3637
		if (!bio_fits_rdev(align_bi) ||
		    is_badblock(rdev, align_bi->bi_sector, align_bi->bi_size>>9,
				&first_bad, &bad_sectors)) {
			/* too big in some way, or has a known bad block */
3638 3639 3640 3641 3642
			bio_put(align_bi);
			rdev_dec_pending(rdev, mddev);
			return 0;
		}

3643 3644 3645 3646 3647 3648 3649
		spin_lock_irq(&conf->device_lock);
		wait_event_lock_irq(conf->wait_for_stripe,
				    conf->quiesce == 0,
				    conf->device_lock, /* nothing */);
		atomic_inc(&conf->active_aligned_reads);
		spin_unlock_irq(&conf->device_lock);

3650 3651 3652 3653
		generic_make_request(align_bi);
		return 1;
	} else {
		rcu_read_unlock();
3654
		bio_put(align_bi);
3655 3656 3657 3658
		return 0;
	}
}

3659 3660 3661 3662 3663 3664 3665 3666 3667 3668
/* __get_priority_stripe - get the next stripe to process
 *
 * Full stripe writes are allowed to pass preread active stripes up until
 * the bypass_threshold is exceeded.  In general the bypass_count
 * increments when the handle_list is handled before the hold_list; however, it
 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
 * stripe with in flight i/o.  The bypass_count will be reset when the
 * head of the hold_list has changed, i.e. the head was promoted to the
 * handle_list.
 */
3669
static struct stripe_head *__get_priority_stripe(struct r5conf *conf)
3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710
{
	struct stripe_head *sh;

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

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

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

	list_del_init(&sh->lru);
	atomic_inc(&sh->count);
	BUG_ON(atomic_read(&sh->count) != 1);
	return sh;
}
3711

3712
static void make_request(struct mddev *mddev, struct bio * bi)
L
Linus Torvalds 已提交
3713
{
3714
	struct r5conf *conf = mddev->private;
3715
	int dd_idx;
L
Linus Torvalds 已提交
3716 3717 3718
	sector_t new_sector;
	sector_t logical_sector, last_sector;
	struct stripe_head *sh;
3719
	const int rw = bio_data_dir(bi);
3720
	int remaining;
3721
	int plugged;
L
Linus Torvalds 已提交
3722

T
Tejun Heo 已提交
3723 3724
	if (unlikely(bi->bi_rw & REQ_FLUSH)) {
		md_flush_request(mddev, bi);
3725
		return;
3726 3727
	}

3728
	md_write_start(mddev, bi);
3729

3730
	if (rw == READ &&
3731
	     mddev->reshape_position == MaxSector &&
3732
	     chunk_aligned_read(mddev,bi))
3733
		return;
3734

L
Linus Torvalds 已提交
3735 3736 3737 3738
	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 */
3739

3740
	plugged = mddev_check_plugged(mddev);
L
Linus Torvalds 已提交
3741 3742
	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
		DEFINE_WAIT(w);
3743
		int disks, data_disks;
3744
		int previous;
3745

3746
	retry:
3747
		previous = 0;
3748
		disks = conf->raid_disks;
3749
		prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
3750
		if (unlikely(conf->reshape_progress != MaxSector)) {
3751
			/* spinlock is needed as reshape_progress may be
3752 3753
			 * 64bit on a 32bit platform, and so it might be
			 * possible to see a half-updated value
3754
			 * Of course reshape_progress could change after
3755 3756 3757 3758
			 * the lock is dropped, so once we get a reference
			 * to the stripe that we think it is, we will have
			 * to check again.
			 */
3759
			spin_lock_irq(&conf->device_lock);
3760 3761 3762
			if (mddev->delta_disks < 0
			    ? logical_sector < conf->reshape_progress
			    : logical_sector >= conf->reshape_progress) {
3763
				disks = conf->previous_raid_disks;
3764 3765
				previous = 1;
			} else {
3766 3767 3768
				if (mddev->delta_disks < 0
				    ? logical_sector < conf->reshape_safe
				    : logical_sector >= conf->reshape_safe) {
3769 3770 3771 3772 3773
					spin_unlock_irq(&conf->device_lock);
					schedule();
					goto retry;
				}
			}
3774 3775
			spin_unlock_irq(&conf->device_lock);
		}
3776 3777
		data_disks = disks - conf->max_degraded;

3778 3779
		new_sector = raid5_compute_sector(conf, logical_sector,
						  previous,
3780
						  &dd_idx, NULL);
3781
		pr_debug("raid456: make_request, sector %llu logical %llu\n",
L
Linus Torvalds 已提交
3782 3783 3784
			(unsigned long long)new_sector, 
			(unsigned long long)logical_sector);

3785
		sh = get_active_stripe(conf, new_sector, previous,
3786
				       (bi->bi_rw&RWA_MASK), 0);
L
Linus Torvalds 已提交
3787
		if (sh) {
3788
			if (unlikely(previous)) {
3789
				/* expansion might have moved on while waiting for a
3790 3791 3792 3793 3794 3795
				 * 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.
3796 3797 3798
				 */
				int must_retry = 0;
				spin_lock_irq(&conf->device_lock);
3799 3800 3801
				if (mddev->delta_disks < 0
				    ? logical_sector >= conf->reshape_progress
				    : logical_sector < conf->reshape_progress)
3802 3803 3804 3805 3806
					/* mismatch, need to try again */
					must_retry = 1;
				spin_unlock_irq(&conf->device_lock);
				if (must_retry) {
					release_stripe(sh);
3807
					schedule();
3808 3809 3810
					goto retry;
				}
			}
3811

3812
			if (rw == WRITE &&
3813
			    logical_sector >= mddev->suspend_lo &&
3814 3815
			    logical_sector < mddev->suspend_hi) {
				release_stripe(sh);
3816 3817 3818 3819 3820 3821 3822 3823 3824 3825
				/* As the suspend_* range is controlled by
				 * userspace, we want an interruptible
				 * wait.
				 */
				flush_signals(current);
				prepare_to_wait(&conf->wait_for_overlap,
						&w, TASK_INTERRUPTIBLE);
				if (logical_sector >= mddev->suspend_lo &&
				    logical_sector < mddev->suspend_hi)
					schedule();
3826 3827
				goto retry;
			}
3828 3829

			if (test_bit(STRIPE_EXPANDING, &sh->state) ||
3830
			    !add_stripe_bio(sh, bi, dd_idx, rw)) {
3831 3832
				/* Stripe is busy expanding or
				 * add failed due to overlap.  Flush everything
L
Linus Torvalds 已提交
3833 3834
				 * and wait a while
				 */
N
NeilBrown 已提交
3835
				md_wakeup_thread(mddev->thread);
L
Linus Torvalds 已提交
3836 3837 3838 3839 3840
				release_stripe(sh);
				schedule();
				goto retry;
			}
			finish_wait(&conf->wait_for_overlap, &w);
3841 3842
			set_bit(STRIPE_HANDLE, &sh->state);
			clear_bit(STRIPE_DELAYED, &sh->state);
T
Tejun Heo 已提交
3843
			if ((bi->bi_rw & REQ_SYNC) &&
3844 3845
			    !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
				atomic_inc(&conf->preread_active_stripes);
L
Linus Torvalds 已提交
3846 3847 3848 3849 3850 3851 3852 3853 3854
			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;
		}
			
	}
3855 3856 3857
	if (!plugged)
		md_wakeup_thread(mddev->thread);

L
Linus Torvalds 已提交
3858
	spin_lock_irq(&conf->device_lock);
3859
	remaining = raid5_dec_bi_phys_segments(bi);
3860 3861
	spin_unlock_irq(&conf->device_lock);
	if (remaining == 0) {
L
Linus Torvalds 已提交
3862

3863
		if ( rw == WRITE )
L
Linus Torvalds 已提交
3864
			md_write_end(mddev);
3865

3866
		bio_endio(bi, 0);
L
Linus Torvalds 已提交
3867 3868 3869
	}
}

3870
static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
D
Dan Williams 已提交
3871

3872
static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
L
Linus Torvalds 已提交
3873
{
3874 3875 3876 3877 3878 3879 3880 3881 3882
	/* 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.
	 */
3883
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
3884
	struct stripe_head *sh;
3885
	sector_t first_sector, last_sector;
3886 3887 3888
	int raid_disks = conf->previous_raid_disks;
	int data_disks = raid_disks - conf->max_degraded;
	int new_data_disks = conf->raid_disks - conf->max_degraded;
3889 3890
	int i;
	int dd_idx;
3891
	sector_t writepos, readpos, safepos;
3892
	sector_t stripe_addr;
3893
	int reshape_sectors;
3894
	struct list_head stripes;
3895

3896 3897 3898 3899 3900 3901
	if (sector_nr == 0) {
		/* If restarting in the middle, skip the initial sectors */
		if (mddev->delta_disks < 0 &&
		    conf->reshape_progress < raid5_size(mddev, 0, 0)) {
			sector_nr = raid5_size(mddev, 0, 0)
				- conf->reshape_progress;
3902
		} else if (mddev->delta_disks >= 0 &&
3903 3904
			   conf->reshape_progress > 0)
			sector_nr = conf->reshape_progress;
3905
		sector_div(sector_nr, new_data_disks);
3906
		if (sector_nr) {
3907 3908
			mddev->curr_resync_completed = sector_nr;
			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
3909 3910 3911
			*skipped = 1;
			return sector_nr;
		}
3912 3913
	}

3914 3915 3916 3917
	/* We need to process a full chunk at a time.
	 * If old and new chunk sizes differ, we need to process the
	 * largest of these
	 */
3918 3919
	if (mddev->new_chunk_sectors > mddev->chunk_sectors)
		reshape_sectors = mddev->new_chunk_sectors;
3920
	else
3921
		reshape_sectors = mddev->chunk_sectors;
3922

3923 3924 3925 3926 3927
	/* 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.
3928 3929
	 * i.e. one new_stripe along from reshape_progress new_maps
	 * to after where reshape_safe old_maps to
3930
	 */
3931
	writepos = conf->reshape_progress;
3932
	sector_div(writepos, new_data_disks);
3933 3934
	readpos = conf->reshape_progress;
	sector_div(readpos, data_disks);
3935
	safepos = conf->reshape_safe;
3936
	sector_div(safepos, data_disks);
3937
	if (mddev->delta_disks < 0) {
3938
		writepos -= min_t(sector_t, reshape_sectors, writepos);
3939
		readpos += reshape_sectors;
3940
		safepos += reshape_sectors;
3941
	} else {
3942
		writepos += reshape_sectors;
3943 3944
		readpos -= min_t(sector_t, reshape_sectors, readpos);
		safepos -= min_t(sector_t, reshape_sectors, safepos);
3945
	}
3946

3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963
	/* 'writepos' is the most advanced device address we might write.
	 * 'readpos' is the least advanced device address we might read.
	 * 'safepos' is the least address recorded in the metadata as having
	 *     been reshaped.
	 * If 'readpos' is behind 'writepos', then there is no way that we can
	 * ensure safety in the face of a crash - that must be done by userspace
	 * making a backup of the data.  So in that case there is no particular
	 * rush to update metadata.
	 * Otherwise if 'safepos' is behind 'writepos', then we really need to
	 * update the metadata to advance 'safepos' to match 'readpos' so that
	 * we can be safe in the event of a crash.
	 * So we insist on updating metadata if safepos is behind writepos and
	 * readpos is beyond writepos.
	 * In any case, update the metadata every 10 seconds.
	 * Maybe that number should be configurable, but I'm not sure it is
	 * worth it.... maybe it could be a multiple of safemode_delay???
	 */
3964
	if ((mddev->delta_disks < 0
3965 3966 3967
	     ? (safepos > writepos && readpos < writepos)
	     : (safepos < writepos && readpos > writepos)) ||
	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
3968 3969 3970
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes)==0);
3971
		mddev->reshape_position = conf->reshape_progress;
3972
		mddev->curr_resync_completed = sector_nr;
3973
		conf->reshape_checkpoint = jiffies;
3974
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
3975
		md_wakeup_thread(mddev->thread);
3976
		wait_event(mddev->sb_wait, mddev->flags == 0 ||
3977 3978
			   kthread_should_stop());
		spin_lock_irq(&conf->device_lock);
3979
		conf->reshape_safe = mddev->reshape_position;
3980 3981
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
3982
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
3983 3984
	}

3985 3986 3987 3988
	if (mddev->delta_disks < 0) {
		BUG_ON(conf->reshape_progress == 0);
		stripe_addr = writepos;
		BUG_ON((mddev->dev_sectors &
3989 3990
			~((sector_t)reshape_sectors - 1))
		       - reshape_sectors - stripe_addr
3991 3992
		       != sector_nr);
	} else {
3993
		BUG_ON(writepos != sector_nr + reshape_sectors);
3994 3995
		stripe_addr = sector_nr;
	}
3996
	INIT_LIST_HEAD(&stripes);
3997
	for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
3998
		int j;
3999
		int skipped_disk = 0;
4000
		sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
4001 4002 4003 4004 4005 4006 4007 4008 4009
		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;
4010
			if (conf->level == 6 &&
4011
			    j == sh->qd_idx)
4012
				continue;
4013
			s = compute_blocknr(sh, j, 0);
D
Dan Williams 已提交
4014
			if (s < raid5_size(mddev, 0, 0)) {
4015
				skipped_disk = 1;
4016 4017 4018 4019 4020 4021
				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);
		}
4022
		if (!skipped_disk) {
4023 4024 4025
			set_bit(STRIPE_EXPAND_READY, &sh->state);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
4026
		list_add(&sh->lru, &stripes);
4027 4028
	}
	spin_lock_irq(&conf->device_lock);
4029
	if (mddev->delta_disks < 0)
4030
		conf->reshape_progress -= reshape_sectors * new_data_disks;
4031
	else
4032
		conf->reshape_progress += reshape_sectors * new_data_disks;
4033 4034 4035 4036 4037 4038 4039
	spin_unlock_irq(&conf->device_lock);
	/* Ok, those stripe are ready. We can start scheduling
	 * reads on the source stripes.
	 * The source stripes are determined by mapping the first and last
	 * block on the destination stripes.
	 */
	first_sector =
4040
		raid5_compute_sector(conf, stripe_addr*(new_data_disks),
4041
				     1, &dd_idx, NULL);
4042
	last_sector =
4043
		raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
4044
					    * new_data_disks - 1),
4045
				     1, &dd_idx, NULL);
A
Andre Noll 已提交
4046 4047
	if (last_sector >= mddev->dev_sectors)
		last_sector = mddev->dev_sectors - 1;
4048
	while (first_sector <= last_sector) {
4049
		sh = get_active_stripe(conf, first_sector, 1, 0, 1);
4050 4051 4052 4053 4054
		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
		set_bit(STRIPE_HANDLE, &sh->state);
		release_stripe(sh);
		first_sector += STRIPE_SECTORS;
	}
4055 4056 4057 4058 4059 4060 4061 4062
	/* Now that the sources are clearly marked, we can release
	 * the destination stripes
	 */
	while (!list_empty(&stripes)) {
		sh = list_entry(stripes.next, struct stripe_head, lru);
		list_del_init(&sh->lru);
		release_stripe(sh);
	}
4063 4064 4065
	/* If this takes us to the resync_max point where we have to pause,
	 * then we need to write out the superblock.
	 */
4066
	sector_nr += reshape_sectors;
4067 4068
	if ((sector_nr - mddev->curr_resync_completed) * 2
	    >= mddev->resync_max - mddev->curr_resync_completed) {
4069 4070 4071
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes) == 0);
4072
		mddev->reshape_position = conf->reshape_progress;
4073
		mddev->curr_resync_completed = sector_nr;
4074
		conf->reshape_checkpoint = jiffies;
4075 4076 4077 4078 4079 4080
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		md_wakeup_thread(mddev->thread);
		wait_event(mddev->sb_wait,
			   !test_bit(MD_CHANGE_DEVS, &mddev->flags)
			   || kthread_should_stop());
		spin_lock_irq(&conf->device_lock);
4081
		conf->reshape_safe = mddev->reshape_position;
4082 4083
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4084
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4085
	}
4086
	return reshape_sectors;
4087 4088 4089
}

/* FIXME go_faster isn't used */
4090
static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
4091
{
4092
	struct r5conf *conf = mddev->private;
4093
	struct stripe_head *sh;
A
Andre Noll 已提交
4094
	sector_t max_sector = mddev->dev_sectors;
N
NeilBrown 已提交
4095
	sector_t sync_blocks;
4096 4097
	int still_degraded = 0;
	int i;
L
Linus Torvalds 已提交
4098

4099
	if (sector_nr >= max_sector) {
L
Linus Torvalds 已提交
4100
		/* just being told to finish up .. nothing much to do */
4101

4102 4103 4104 4105
		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
			end_reshape(conf);
			return 0;
		}
4106 4107 4108 4109

		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
					&sync_blocks, 1);
4110
		else /* completed sync */
4111 4112 4113
			conf->fullsync = 0;
		bitmap_close_sync(mddev->bitmap);

L
Linus Torvalds 已提交
4114 4115
		return 0;
	}
4116

4117 4118 4119
	/* Allow raid5_quiesce to complete */
	wait_event(conf->wait_for_overlap, conf->quiesce != 2);

4120 4121
	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
		return reshape_request(mddev, sector_nr, skipped);
4122

4123 4124 4125 4126 4127 4128
	/* No need to check resync_max as we never do more than one
	 * stripe, and as resync_max will always be on a chunk boundary,
	 * if the check in md_do_sync didn't fire, there is no chance
	 * of overstepping resync_max here
	 */

4129
	/* if there is too many failed drives and we are trying
L
Linus Torvalds 已提交
4130 4131 4132
	 * to resync, then assert that we are finished, because there is
	 * nothing we can do.
	 */
4133
	if (mddev->degraded >= conf->max_degraded &&
4134
	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
A
Andre Noll 已提交
4135
		sector_t rv = mddev->dev_sectors - sector_nr;
4136
		*skipped = 1;
L
Linus Torvalds 已提交
4137 4138
		return rv;
	}
4139
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
4140
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
4141 4142 4143 4144 4145 4146
	    !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
4147

N
NeilBrown 已提交
4148 4149 4150

	bitmap_cond_end_sync(mddev->bitmap, sector_nr);

4151
	sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
L
Linus Torvalds 已提交
4152
	if (sh == NULL) {
4153
		sh = get_active_stripe(conf, sector_nr, 0, 0, 0);
L
Linus Torvalds 已提交
4154
		/* make sure we don't swamp the stripe cache if someone else
4155
		 * is trying to get access
L
Linus Torvalds 已提交
4156
		 */
4157
		schedule_timeout_uninterruptible(1);
L
Linus Torvalds 已提交
4158
	}
4159 4160 4161 4162
	/* 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.
	 */
4163
	for (i = 0; i < conf->raid_disks; i++)
4164 4165 4166 4167 4168
		if (conf->disks[i].rdev == NULL)
			still_degraded = 1;

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

4169
	set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
L
Linus Torvalds 已提交
4170

4171
	handle_stripe(sh);
L
Linus Torvalds 已提交
4172 4173 4174 4175 4176
	release_stripe(sh);

	return STRIPE_SECTORS;
}

4177
static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189
{
	/* We may not be able to submit a whole bio at once as there
	 * may not be enough stripe_heads available.
	 * We cannot pre-allocate enough stripe_heads as we may need
	 * more than exist in the cache (if we allow ever large chunks).
	 * So we do one stripe head at a time and record in
	 * ->bi_hw_segments how many have been done.
	 *
	 * We *know* that this entire raid_bio is in one chunk, so
	 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
	 */
	struct stripe_head *sh;
4190
	int dd_idx;
4191 4192 4193 4194 4195 4196
	sector_t sector, logical_sector, last_sector;
	int scnt = 0;
	int remaining;
	int handled = 0;

	logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
4197
	sector = raid5_compute_sector(conf, logical_sector,
4198
				      0, &dd_idx, NULL);
4199 4200 4201
	last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);

	for (; logical_sector < last_sector;
4202 4203 4204
	     logical_sector += STRIPE_SECTORS,
		     sector += STRIPE_SECTORS,
		     scnt++) {
4205

4206
		if (scnt < raid5_bi_hw_segments(raid_bio))
4207 4208 4209
			/* already done this stripe */
			continue;

4210
		sh = get_active_stripe(conf, sector, 0, 1, 0);
4211 4212 4213

		if (!sh) {
			/* failed to get a stripe - must wait */
4214
			raid5_set_bi_hw_segments(raid_bio, scnt);
4215 4216 4217 4218 4219
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

		set_bit(R5_ReadError, &sh->dev[dd_idx].flags);
4220 4221
		if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
			release_stripe(sh);
4222
			raid5_set_bi_hw_segments(raid_bio, scnt);
4223 4224 4225 4226
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4227
		handle_stripe(sh);
4228 4229 4230 4231
		release_stripe(sh);
		handled++;
	}
	spin_lock_irq(&conf->device_lock);
4232
	remaining = raid5_dec_bi_phys_segments(raid_bio);
4233
	spin_unlock_irq(&conf->device_lock);
4234 4235
	if (remaining == 0)
		bio_endio(raid_bio, 0);
4236 4237 4238 4239 4240 4241
	if (atomic_dec_and_test(&conf->active_aligned_reads))
		wake_up(&conf->wait_for_stripe);
	return handled;
}


L
Linus Torvalds 已提交
4242 4243 4244 4245 4246 4247 4248
/*
 * 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.
 */
4249
static void raid5d(struct mddev *mddev)
L
Linus Torvalds 已提交
4250 4251
{
	struct stripe_head *sh;
4252
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4253
	int handled;
4254
	struct blk_plug plug;
L
Linus Torvalds 已提交
4255

4256
	pr_debug("+++ raid5d active\n");
L
Linus Torvalds 已提交
4257 4258 4259

	md_check_recovery(mddev);

4260
	blk_start_plug(&plug);
L
Linus Torvalds 已提交
4261 4262 4263
	handled = 0;
	spin_lock_irq(&conf->device_lock);
	while (1) {
4264
		struct bio *bio;
L
Linus Torvalds 已提交
4265

4266 4267 4268 4269
		if (atomic_read(&mddev->plug_cnt) == 0 &&
		    !list_empty(&conf->bitmap_list)) {
			/* Now is a good time to flush some bitmap updates */
			conf->seq_flush++;
4270
			spin_unlock_irq(&conf->device_lock);
4271
			bitmap_unplug(mddev->bitmap);
4272
			spin_lock_irq(&conf->device_lock);
4273
			conf->seq_write = conf->seq_flush;
4274 4275
			activate_bit_delay(conf);
		}
4276 4277
		if (atomic_read(&mddev->plug_cnt) == 0)
			raid5_activate_delayed(conf);
4278

4279 4280 4281 4282 4283 4284 4285 4286 4287 4288
		while ((bio = remove_bio_from_retry(conf))) {
			int ok;
			spin_unlock_irq(&conf->device_lock);
			ok = retry_aligned_read(conf, bio);
			spin_lock_irq(&conf->device_lock);
			if (!ok)
				break;
			handled++;
		}

4289 4290
		sh = __get_priority_stripe(conf);

4291
		if (!sh)
L
Linus Torvalds 已提交
4292 4293 4294 4295
			break;
		spin_unlock_irq(&conf->device_lock);
		
		handled++;
4296 4297 4298
		handle_stripe(sh);
		release_stripe(sh);
		cond_resched();
L
Linus Torvalds 已提交
4299

4300 4301 4302
		if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
			md_check_recovery(mddev);

L
Linus Torvalds 已提交
4303 4304
		spin_lock_irq(&conf->device_lock);
	}
4305
	pr_debug("%d stripes handled\n", handled);
L
Linus Torvalds 已提交
4306 4307 4308

	spin_unlock_irq(&conf->device_lock);

4309
	async_tx_issue_pending_all();
4310
	blk_finish_plug(&plug);
L
Linus Torvalds 已提交
4311

4312
	pr_debug("--- raid5d inactive\n");
L
Linus Torvalds 已提交
4313 4314
}

4315
static ssize_t
4316
raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
4317
{
4318
	struct r5conf *conf = mddev->private;
4319 4320 4321 4322
	if (conf)
		return sprintf(page, "%d\n", conf->max_nr_stripes);
	else
		return 0;
4323 4324
}

4325
int
4326
raid5_set_cache_size(struct mddev *mddev, int size)
4327
{
4328
	struct r5conf *conf = mddev->private;
4329 4330
	int err;

4331
	if (size <= 16 || size > 32768)
4332
		return -EINVAL;
4333
	while (size < conf->max_nr_stripes) {
4334 4335 4336 4337 4338
		if (drop_one_stripe(conf))
			conf->max_nr_stripes--;
		else
			break;
	}
4339 4340 4341
	err = md_allow_write(mddev);
	if (err)
		return err;
4342
	while (size > conf->max_nr_stripes) {
4343 4344 4345 4346
		if (grow_one_stripe(conf))
			conf->max_nr_stripes++;
		else break;
	}
4347 4348 4349 4350 4351
	return 0;
}
EXPORT_SYMBOL(raid5_set_cache_size);

static ssize_t
4352
raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
4353
{
4354
	struct r5conf *conf = mddev->private;
4355 4356 4357 4358 4359 4360 4361 4362 4363 4364 4365 4366 4367
	unsigned long new;
	int err;

	if (len >= PAGE_SIZE)
		return -EINVAL;
	if (!conf)
		return -ENODEV;

	if (strict_strtoul(page, 10, &new))
		return -EINVAL;
	err = raid5_set_cache_size(mddev, new);
	if (err)
		return err;
4368 4369
	return len;
}
4370

4371 4372 4373 4374
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);
4375

4376
static ssize_t
4377
raid5_show_preread_threshold(struct mddev *mddev, char *page)
4378
{
4379
	struct r5conf *conf = mddev->private;
4380 4381 4382 4383 4384 4385 4386
	if (conf)
		return sprintf(page, "%d\n", conf->bypass_threshold);
	else
		return 0;
}

static ssize_t
4387
raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
4388
{
4389
	struct r5conf *conf = mddev->private;
4390
	unsigned long new;
4391 4392 4393 4394 4395
	if (len >= PAGE_SIZE)
		return -EINVAL;
	if (!conf)
		return -ENODEV;

4396
	if (strict_strtoul(page, 10, &new))
4397
		return -EINVAL;
4398
	if (new > conf->max_nr_stripes)
4399 4400 4401 4402 4403 4404 4405 4406 4407 4408 4409
		return -EINVAL;
	conf->bypass_threshold = new;
	return len;
}

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

4410
static ssize_t
4411
stripe_cache_active_show(struct mddev *mddev, char *page)
4412
{
4413
	struct r5conf *conf = mddev->private;
4414 4415 4416 4417
	if (conf)
		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
	else
		return 0;
4418 4419
}

4420 4421
static struct md_sysfs_entry
raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
4422

4423
static struct attribute *raid5_attrs[] =  {
4424 4425
	&raid5_stripecache_size.attr,
	&raid5_stripecache_active.attr,
4426
	&raid5_preread_bypass_threshold.attr,
4427 4428
	NULL,
};
4429 4430 4431
static struct attribute_group raid5_attrs_group = {
	.name = NULL,
	.attrs = raid5_attrs,
4432 4433
};

4434
static sector_t
4435
raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
4436
{
4437
	struct r5conf *conf = mddev->private;
4438 4439 4440

	if (!sectors)
		sectors = mddev->dev_sectors;
4441
	if (!raid_disks)
4442
		/* size is defined by the smallest of previous and new size */
4443
		raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
4444

4445
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
4446
	sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
4447 4448 4449
	return sectors * (raid_disks - conf->max_degraded);
}

4450
static void raid5_free_percpu(struct r5conf *conf)
4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461
{
	struct raid5_percpu *percpu;
	unsigned long cpu;

	if (!conf->percpu)
		return;

	get_online_cpus();
	for_each_possible_cpu(cpu) {
		percpu = per_cpu_ptr(conf->percpu, cpu);
		safe_put_page(percpu->spare_page);
4462
		kfree(percpu->scribble);
4463 4464 4465 4466 4467 4468 4469 4470 4471
	}
#ifdef CONFIG_HOTPLUG_CPU
	unregister_cpu_notifier(&conf->cpu_notify);
#endif
	put_online_cpus();

	free_percpu(conf->percpu);
}

4472
static void free_conf(struct r5conf *conf)
4473 4474
{
	shrink_stripes(conf);
4475
	raid5_free_percpu(conf);
4476 4477 4478 4479 4480
	kfree(conf->disks);
	kfree(conf->stripe_hashtbl);
	kfree(conf);
}

4481 4482 4483 4484
#ifdef CONFIG_HOTPLUG_CPU
static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action,
			      void *hcpu)
{
4485
	struct r5conf *conf = container_of(nfb, struct r5conf, cpu_notify);
4486 4487 4488 4489 4490 4491
	long cpu = (long)hcpu;
	struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);

	switch (action) {
	case CPU_UP_PREPARE:
	case CPU_UP_PREPARE_FROZEN:
4492
		if (conf->level == 6 && !percpu->spare_page)
4493
			percpu->spare_page = alloc_page(GFP_KERNEL);
4494 4495 4496 4497 4498 4499 4500
		if (!percpu->scribble)
			percpu->scribble = kmalloc(conf->scribble_len, GFP_KERNEL);

		if (!percpu->scribble ||
		    (conf->level == 6 && !percpu->spare_page)) {
			safe_put_page(percpu->spare_page);
			kfree(percpu->scribble);
4501 4502
			pr_err("%s: failed memory allocation for cpu%ld\n",
			       __func__, cpu);
4503
			return notifier_from_errno(-ENOMEM);
4504 4505 4506 4507 4508
		}
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		safe_put_page(percpu->spare_page);
4509
		kfree(percpu->scribble);
4510
		percpu->spare_page = NULL;
4511
		percpu->scribble = NULL;
4512 4513 4514 4515 4516 4517 4518 4519
		break;
	default:
		break;
	}
	return NOTIFY_OK;
}
#endif

4520
static int raid5_alloc_percpu(struct r5conf *conf)
4521 4522 4523
{
	unsigned long cpu;
	struct page *spare_page;
4524
	struct raid5_percpu __percpu *allcpus;
4525
	void *scribble;
4526 4527 4528 4529 4530 4531 4532 4533 4534 4535
	int err;

	allcpus = alloc_percpu(struct raid5_percpu);
	if (!allcpus)
		return -ENOMEM;
	conf->percpu = allcpus;

	get_online_cpus();
	err = 0;
	for_each_present_cpu(cpu) {
4536 4537 4538 4539 4540 4541 4542 4543
		if (conf->level == 6) {
			spare_page = alloc_page(GFP_KERNEL);
			if (!spare_page) {
				err = -ENOMEM;
				break;
			}
			per_cpu_ptr(conf->percpu, cpu)->spare_page = spare_page;
		}
4544
		scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
4545
		if (!scribble) {
4546 4547 4548
			err = -ENOMEM;
			break;
		}
4549
		per_cpu_ptr(conf->percpu, cpu)->scribble = scribble;
4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561
	}
#ifdef CONFIG_HOTPLUG_CPU
	conf->cpu_notify.notifier_call = raid456_cpu_notify;
	conf->cpu_notify.priority = 0;
	if (err == 0)
		err = register_cpu_notifier(&conf->cpu_notify);
#endif
	put_online_cpus();

	return err;
}

4562
static struct r5conf *setup_conf(struct mddev *mddev)
L
Linus Torvalds 已提交
4563
{
4564
	struct r5conf *conf;
4565
	int raid_disk, memory, max_disks;
4566
	struct md_rdev *rdev;
L
Linus Torvalds 已提交
4567 4568
	struct disk_info *disk;

N
NeilBrown 已提交
4569 4570 4571
	if (mddev->new_level != 5
	    && mddev->new_level != 4
	    && mddev->new_level != 6) {
4572
		printk(KERN_ERR "md/raid:%s: raid level not set to 4/5/6 (%d)\n",
N
NeilBrown 已提交
4573 4574
		       mdname(mddev), mddev->new_level);
		return ERR_PTR(-EIO);
L
Linus Torvalds 已提交
4575
	}
N
NeilBrown 已提交
4576 4577 4578 4579
	if ((mddev->new_level == 5
	     && !algorithm_valid_raid5(mddev->new_layout)) ||
	    (mddev->new_level == 6
	     && !algorithm_valid_raid6(mddev->new_layout))) {
4580
		printk(KERN_ERR "md/raid:%s: layout %d not supported\n",
N
NeilBrown 已提交
4581 4582
		       mdname(mddev), mddev->new_layout);
		return ERR_PTR(-EIO);
4583
	}
N
NeilBrown 已提交
4584
	if (mddev->new_level == 6 && mddev->raid_disks < 4) {
4585
		printk(KERN_ERR "md/raid:%s: not enough configured devices (%d, minimum 4)\n",
N
NeilBrown 已提交
4586 4587
		       mdname(mddev), mddev->raid_disks);
		return ERR_PTR(-EINVAL);
4588 4589
	}

4590 4591 4592
	if (!mddev->new_chunk_sectors ||
	    (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
	    !is_power_of_2(mddev->new_chunk_sectors)) {
4593 4594
		printk(KERN_ERR "md/raid:%s: invalid chunk size %d\n",
		       mdname(mddev), mddev->new_chunk_sectors << 9);
N
NeilBrown 已提交
4595
		return ERR_PTR(-EINVAL);
4596 4597
	}

4598
	conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
N
NeilBrown 已提交
4599
	if (conf == NULL)
L
Linus Torvalds 已提交
4600
		goto abort;
4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612
	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->hold_list);
	INIT_LIST_HEAD(&conf->delayed_list);
	INIT_LIST_HEAD(&conf->bitmap_list);
	INIT_LIST_HEAD(&conf->inactive_list);
	atomic_set(&conf->active_stripes, 0);
	atomic_set(&conf->preread_active_stripes, 0);
	atomic_set(&conf->active_aligned_reads, 0);
	conf->bypass_threshold = BYPASS_THRESHOLD;
4613
	conf->recovery_disabled = mddev->recovery_disabled - 1;
N
NeilBrown 已提交
4614 4615 4616 4617 4618

	conf->raid_disks = mddev->raid_disks;
	if (mddev->reshape_position == MaxSector)
		conf->previous_raid_disks = mddev->raid_disks;
	else
4619
		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
4620 4621
	max_disks = max(conf->raid_disks, conf->previous_raid_disks);
	conf->scribble_len = scribble_len(max_disks);
4622

4623
	conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
4624 4625 4626
			      GFP_KERNEL);
	if (!conf->disks)
		goto abort;
4627

L
Linus Torvalds 已提交
4628 4629
	conf->mddev = mddev;

4630
	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
L
Linus Torvalds 已提交
4631 4632
		goto abort;

4633 4634 4635 4636
	conf->level = mddev->new_level;
	if (raid5_alloc_percpu(conf) != 0)
		goto abort;

4637
	pr_debug("raid456: run(%s) called.\n", mdname(mddev));
L
Linus Torvalds 已提交
4638

4639
	list_for_each_entry(rdev, &mddev->disks, same_set) {
L
Linus Torvalds 已提交
4640
		raid_disk = rdev->raid_disk;
4641
		if (raid_disk >= max_disks
L
Linus Torvalds 已提交
4642 4643 4644 4645 4646 4647
		    || raid_disk < 0)
			continue;
		disk = conf->disks + raid_disk;

		disk->rdev = rdev;

4648
		if (test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
4649
			char b[BDEVNAME_SIZE];
4650 4651 4652
			printk(KERN_INFO "md/raid:%s: device %s operational as raid"
			       " disk %d\n",
			       mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
J
Jonathan Brassow 已提交
4653
		} else if (rdev->saved_raid_disk != raid_disk)
4654 4655
			/* Cannot rely on bitmap to complete recovery */
			conf->fullsync = 1;
L
Linus Torvalds 已提交
4656 4657
	}

4658
	conf->chunk_sectors = mddev->new_chunk_sectors;
N
NeilBrown 已提交
4659
	conf->level = mddev->new_level;
4660 4661 4662 4663
	if (conf->level == 6)
		conf->max_degraded = 2;
	else
		conf->max_degraded = 1;
N
NeilBrown 已提交
4664
	conf->algorithm = mddev->new_layout;
L
Linus Torvalds 已提交
4665
	conf->max_nr_stripes = NR_STRIPES;
4666
	conf->reshape_progress = mddev->reshape_position;
4667
	if (conf->reshape_progress != MaxSector) {
4668
		conf->prev_chunk_sectors = mddev->chunk_sectors;
4669 4670
		conf->prev_algo = mddev->layout;
	}
L
Linus Torvalds 已提交
4671

N
NeilBrown 已提交
4672
	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
4673
		 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
N
NeilBrown 已提交
4674 4675
	if (grow_stripes(conf, conf->max_nr_stripes)) {
		printk(KERN_ERR
4676 4677
		       "md/raid:%s: couldn't allocate %dkB for buffers\n",
		       mdname(mddev), memory);
N
NeilBrown 已提交
4678 4679
		goto abort;
	} else
4680 4681
		printk(KERN_INFO "md/raid:%s: allocated %dkB\n",
		       mdname(mddev), memory);
L
Linus Torvalds 已提交
4682

4683
	conf->thread = md_register_thread(raid5d, mddev, NULL);
N
NeilBrown 已提交
4684 4685
	if (!conf->thread) {
		printk(KERN_ERR
4686
		       "md/raid:%s: couldn't allocate thread.\n",
N
NeilBrown 已提交
4687
		       mdname(mddev));
4688 4689
		goto abort;
	}
N
NeilBrown 已提交
4690 4691 4692 4693 4694

	return conf;

 abort:
	if (conf) {
4695
		free_conf(conf);
N
NeilBrown 已提交
4696 4697 4698 4699 4700
		return ERR_PTR(-EIO);
	} else
		return ERR_PTR(-ENOMEM);
}

4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 4723 4724 4725 4726 4727

static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
{
	switch (algo) {
	case ALGORITHM_PARITY_0:
		if (raid_disk < max_degraded)
			return 1;
		break;
	case ALGORITHM_PARITY_N:
		if (raid_disk >= raid_disks - max_degraded)
			return 1;
		break;
	case ALGORITHM_PARITY_0_6:
		if (raid_disk == 0 || 
		    raid_disk == raid_disks - 1)
			return 1;
		break;
	case ALGORITHM_LEFT_ASYMMETRIC_6:
	case ALGORITHM_RIGHT_ASYMMETRIC_6:
	case ALGORITHM_LEFT_SYMMETRIC_6:
	case ALGORITHM_RIGHT_SYMMETRIC_6:
		if (raid_disk == raid_disks - 1)
			return 1;
	}
	return 0;
}

4728
static int run(struct mddev *mddev)
N
NeilBrown 已提交
4729
{
4730
	struct r5conf *conf;
4731
	int working_disks = 0;
4732
	int dirty_parity_disks = 0;
4733
	struct md_rdev *rdev;
4734
	sector_t reshape_offset = 0;
N
NeilBrown 已提交
4735

4736
	if (mddev->recovery_cp != MaxSector)
4737
		printk(KERN_NOTICE "md/raid:%s: not clean"
4738 4739
		       " -- starting background reconstruction\n",
		       mdname(mddev));
N
NeilBrown 已提交
4740 4741 4742 4743 4744 4745 4746 4747
	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;
4748
		int max_degraded = (mddev->level == 6 ? 2 : 1);
N
NeilBrown 已提交
4749

4750
		if (mddev->new_level != mddev->level) {
4751
			printk(KERN_ERR "md/raid:%s: unsupported reshape "
N
NeilBrown 已提交
4752 4753 4754 4755 4756 4757 4758 4759 4760 4761
			       "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;
4762
		if (sector_div(here_new, mddev->new_chunk_sectors *
N
NeilBrown 已提交
4763
			       (mddev->raid_disks - max_degraded))) {
4764 4765
			printk(KERN_ERR "md/raid:%s: reshape_position not "
			       "on a stripe boundary\n", mdname(mddev));
N
NeilBrown 已提交
4766 4767
			return -EINVAL;
		}
4768
		reshape_offset = here_new * mddev->new_chunk_sectors;
N
NeilBrown 已提交
4769 4770
		/* here_new is the stripe we will write to */
		here_old = mddev->reshape_position;
4771
		sector_div(here_old, mddev->chunk_sectors *
N
NeilBrown 已提交
4772 4773 4774
			   (old_disks-max_degraded));
		/* here_old is the first stripe that we might need to read
		 * from */
4775 4776 4777 4778 4779 4780 4781 4782 4783 4784 4785
		if (mddev->delta_disks == 0) {
			/* We cannot be sure it is safe to start an in-place
			 * reshape.  It is only safe if user-space if monitoring
			 * and taking constant backups.
			 * mdadm always starts a situation like this in
			 * readonly mode so it can take control before
			 * allowing any writes.  So just check for that.
			 */
			if ((here_new * mddev->new_chunk_sectors != 
			     here_old * mddev->chunk_sectors) ||
			    mddev->ro == 0) {
4786 4787 4788
				printk(KERN_ERR "md/raid:%s: in-place reshape must be started"
				       " in read-only mode - aborting\n",
				       mdname(mddev));
4789 4790 4791 4792 4793 4794 4795
				return -EINVAL;
			}
		} else if (mddev->delta_disks < 0
		    ? (here_new * mddev->new_chunk_sectors <=
		       here_old * mddev->chunk_sectors)
		    : (here_new * mddev->new_chunk_sectors >=
		       here_old * mddev->chunk_sectors)) {
N
NeilBrown 已提交
4796
			/* Reading from the same stripe as writing to - bad */
4797 4798 4799
			printk(KERN_ERR "md/raid:%s: reshape_position too early for "
			       "auto-recovery - aborting.\n",
			       mdname(mddev));
N
NeilBrown 已提交
4800 4801
			return -EINVAL;
		}
4802 4803
		printk(KERN_INFO "md/raid:%s: reshape will continue\n",
		       mdname(mddev));
N
NeilBrown 已提交
4804 4805 4806 4807
		/* OK, we should be able to continue; */
	} else {
		BUG_ON(mddev->level != mddev->new_level);
		BUG_ON(mddev->layout != mddev->new_layout);
4808
		BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
N
NeilBrown 已提交
4809
		BUG_ON(mddev->delta_disks != 0);
L
Linus Torvalds 已提交
4810
	}
N
NeilBrown 已提交
4811

4812 4813 4814 4815 4816
	if (mddev->private == NULL)
		conf = setup_conf(mddev);
	else
		conf = mddev->private;

N
NeilBrown 已提交
4817 4818 4819 4820 4821 4822 4823 4824 4825 4826
	if (IS_ERR(conf))
		return PTR_ERR(conf);

	mddev->thread = conf->thread;
	conf->thread = NULL;
	mddev->private = conf;

	/*
	 * 0 for a fully functional array, 1 or 2 for a degraded array.
	 */
4827 4828 4829
	list_for_each_entry(rdev, &mddev->disks, same_set) {
		if (rdev->raid_disk < 0)
			continue;
4830
		if (test_bit(In_sync, &rdev->flags)) {
N
NeilBrown 已提交
4831
			working_disks++;
4832 4833
			continue;
		}
4834 4835 4836 4837 4838 4839 4840 4841 4842 4843 4844 4845 4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857 4858 4859 4860 4861
		/* This disc is not fully in-sync.  However if it
		 * just stored parity (beyond the recovery_offset),
		 * when we don't need to be concerned about the
		 * array being dirty.
		 * When reshape goes 'backwards', we never have
		 * partially completed devices, so we only need
		 * to worry about reshape going forwards.
		 */
		/* Hack because v0.91 doesn't store recovery_offset properly. */
		if (mddev->major_version == 0 &&
		    mddev->minor_version > 90)
			rdev->recovery_offset = reshape_offset;
			
		if (rdev->recovery_offset < reshape_offset) {
			/* We need to check old and new layout */
			if (!only_parity(rdev->raid_disk,
					 conf->algorithm,
					 conf->raid_disks,
					 conf->max_degraded))
				continue;
		}
		if (!only_parity(rdev->raid_disk,
				 conf->prev_algo,
				 conf->previous_raid_disks,
				 conf->max_degraded))
			continue;
		dirty_parity_disks++;
	}
N
NeilBrown 已提交
4862

4863
	mddev->degraded = calc_degraded(conf);
N
NeilBrown 已提交
4864

4865
	if (has_failed(conf)) {
4866
		printk(KERN_ERR "md/raid:%s: not enough operational devices"
L
Linus Torvalds 已提交
4867
			" (%d/%d failed)\n",
4868
			mdname(mddev), mddev->degraded, conf->raid_disks);
L
Linus Torvalds 已提交
4869 4870 4871
		goto abort;
	}

N
NeilBrown 已提交
4872
	/* device size must be a multiple of chunk size */
4873
	mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
N
NeilBrown 已提交
4874 4875
	mddev->resync_max_sectors = mddev->dev_sectors;

4876
	if (mddev->degraded > dirty_parity_disks &&
L
Linus Torvalds 已提交
4877
	    mddev->recovery_cp != MaxSector) {
4878 4879
		if (mddev->ok_start_degraded)
			printk(KERN_WARNING
4880 4881
			       "md/raid:%s: starting dirty degraded array"
			       " - data corruption possible.\n",
4882 4883 4884
			       mdname(mddev));
		else {
			printk(KERN_ERR
4885
			       "md/raid:%s: cannot start dirty degraded array.\n",
4886 4887 4888
			       mdname(mddev));
			goto abort;
		}
L
Linus Torvalds 已提交
4889 4890 4891
	}

	if (mddev->degraded == 0)
4892 4893
		printk(KERN_INFO "md/raid:%s: raid level %d active with %d out of %d"
		       " devices, algorithm %d\n", mdname(mddev), conf->level,
4894 4895
		       mddev->raid_disks-mddev->degraded, mddev->raid_disks,
		       mddev->new_layout);
L
Linus Torvalds 已提交
4896
	else
4897 4898 4899 4900 4901
		printk(KERN_ALERT "md/raid:%s: raid level %d active with %d"
		       " out of %d devices, algorithm %d\n",
		       mdname(mddev), conf->level,
		       mddev->raid_disks - mddev->degraded,
		       mddev->raid_disks, mddev->new_layout);
L
Linus Torvalds 已提交
4902 4903 4904

	print_raid5_conf(conf);

4905 4906
	if (conf->reshape_progress != MaxSector) {
		conf->reshape_safe = conf->reshape_progress;
4907 4908 4909 4910 4911 4912
		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,
4913
							"reshape");
4914 4915
	}

L
Linus Torvalds 已提交
4916 4917

	/* Ok, everything is just fine now */
4918 4919
	if (mddev->to_remove == &raid5_attrs_group)
		mddev->to_remove = NULL;
N
NeilBrown 已提交
4920 4921
	else if (mddev->kobj.sd &&
	    sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
4922
		printk(KERN_WARNING
4923
		       "raid5: failed to create sysfs attributes for %s\n",
4924
		       mdname(mddev));
4925
	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
4926

4927
	if (mddev->queue) {
4928
		int chunk_size;
4929 4930 4931 4932 4933 4934 4935 4936 4937
		/* 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 *
			((mddev->chunk_sectors << 9) / PAGE_SIZE);
		if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
			mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
N
NeilBrown 已提交
4938

4939
		blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
4940

N
NeilBrown 已提交
4941 4942
		mddev->queue->backing_dev_info.congested_data = mddev;
		mddev->queue->backing_dev_info.congested_fn = raid5_congested;
4943

4944 4945 4946 4947
		chunk_size = mddev->chunk_sectors << 9;
		blk_queue_io_min(mddev->queue, chunk_size);
		blk_queue_io_opt(mddev->queue, chunk_size *
				 (conf->raid_disks - conf->max_degraded));
4948

4949 4950 4951 4952
		list_for_each_entry(rdev, &mddev->disks, same_set)
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
	}
4953

L
Linus Torvalds 已提交
4954 4955
	return 0;
abort:
4956
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
4957 4958
	print_raid5_conf(conf);
	free_conf(conf);
L
Linus Torvalds 已提交
4959
	mddev->private = NULL;
4960
	printk(KERN_ALERT "md/raid:%s: failed to run raid set.\n", mdname(mddev));
L
Linus Torvalds 已提交
4961 4962 4963
	return -EIO;
}

4964
static int stop(struct mddev *mddev)
L
Linus Torvalds 已提交
4965
{
4966
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4967

4968
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
4969 4970
	if (mddev->queue)
		mddev->queue->backing_dev_info.congested_fn = NULL;
4971
	free_conf(conf);
4972 4973
	mddev->private = NULL;
	mddev->to_remove = &raid5_attrs_group;
L
Linus Torvalds 已提交
4974 4975 4976
	return 0;
}

4977
static void status(struct seq_file *seq, struct mddev *mddev)
L
Linus Torvalds 已提交
4978
{
4979
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4980 4981
	int i;

4982 4983
	seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
		mddev->chunk_sectors / 2, mddev->layout);
4984
	seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
L
Linus Torvalds 已提交
4985 4986 4987
	for (i = 0; i < conf->raid_disks; i++)
		seq_printf (seq, "%s",
			       conf->disks[i].rdev &&
4988
			       test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
L
Linus Torvalds 已提交
4989 4990 4991
	seq_printf (seq, "]");
}

4992
static void print_raid5_conf (struct r5conf *conf)
L
Linus Torvalds 已提交
4993 4994 4995 4996
{
	int i;
	struct disk_info *tmp;

4997
	printk(KERN_DEBUG "RAID conf printout:\n");
L
Linus Torvalds 已提交
4998 4999 5000 5001
	if (!conf) {
		printk("(conf==NULL)\n");
		return;
	}
5002 5003 5004
	printk(KERN_DEBUG " --- level:%d rd:%d wd:%d\n", conf->level,
	       conf->raid_disks,
	       conf->raid_disks - conf->mddev->degraded);
L
Linus Torvalds 已提交
5005 5006 5007 5008 5009

	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
		tmp = conf->disks + i;
		if (tmp->rdev)
5010 5011 5012
			printk(KERN_DEBUG " disk %d, o:%d, dev:%s\n",
			       i, !test_bit(Faulty, &tmp->rdev->flags),
			       bdevname(tmp->rdev->bdev, b));
L
Linus Torvalds 已提交
5013 5014 5015
	}
}

5016
static int raid5_spare_active(struct mddev *mddev)
L
Linus Torvalds 已提交
5017 5018
{
	int i;
5019
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5020
	struct disk_info *tmp;
5021 5022
	int count = 0;
	unsigned long flags;
L
Linus Torvalds 已提交
5023 5024 5025 5026

	for (i = 0; i < conf->raid_disks; i++) {
		tmp = conf->disks + i;
		if (tmp->rdev
5027
		    && tmp->rdev->recovery_offset == MaxSector
5028
		    && !test_bit(Faulty, &tmp->rdev->flags)
5029
		    && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
5030
			count++;
5031
			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
L
Linus Torvalds 已提交
5032 5033
		}
	}
5034
	spin_lock_irqsave(&conf->device_lock, flags);
5035
	mddev->degraded = calc_degraded(conf);
5036
	spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
5037
	print_raid5_conf(conf);
5038
	return count;
L
Linus Torvalds 已提交
5039 5040
}

5041
static int raid5_remove_disk(struct mddev *mddev, int number)
L
Linus Torvalds 已提交
5042
{
5043
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5044
	int err = 0;
5045
	struct md_rdev *rdev;
L
Linus Torvalds 已提交
5046 5047 5048 5049 5050
	struct disk_info *p = conf->disks + number;

	print_raid5_conf(conf);
	rdev = p->rdev;
	if (rdev) {
5051 5052 5053 5054
		if (number >= conf->raid_disks &&
		    conf->reshape_progress == MaxSector)
			clear_bit(In_sync, &rdev->flags);

5055
		if (test_bit(In_sync, &rdev->flags) ||
L
Linus Torvalds 已提交
5056 5057 5058 5059
		    atomic_read(&rdev->nr_pending)) {
			err = -EBUSY;
			goto abort;
		}
5060 5061 5062 5063
		/* Only remove non-faulty devices if recovery
		 * isn't possible.
		 */
		if (!test_bit(Faulty, &rdev->flags) &&
5064
		    mddev->recovery_disabled != conf->recovery_disabled &&
5065
		    !has_failed(conf) &&
5066
		    number < conf->raid_disks) {
5067 5068 5069
			err = -EBUSY;
			goto abort;
		}
L
Linus Torvalds 已提交
5070
		p->rdev = NULL;
5071
		synchronize_rcu();
L
Linus Torvalds 已提交
5072 5073 5074 5075 5076 5077 5078 5079 5080 5081 5082 5083
		if (atomic_read(&rdev->nr_pending)) {
			/* lost the race, try later */
			err = -EBUSY;
			p->rdev = rdev;
		}
	}
abort:

	print_raid5_conf(conf);
	return err;
}

5084
static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5085
{
5086
	struct r5conf *conf = mddev->private;
5087
	int err = -EEXIST;
L
Linus Torvalds 已提交
5088 5089
	int disk;
	struct disk_info *p;
5090 5091
	int first = 0;
	int last = conf->raid_disks - 1;
L
Linus Torvalds 已提交
5092

5093 5094 5095
	if (mddev->recovery_disabled == conf->recovery_disabled)
		return -EBUSY;

5096
	if (has_failed(conf))
L
Linus Torvalds 已提交
5097
		/* no point adding a device */
5098
		return -EINVAL;
L
Linus Torvalds 已提交
5099

5100 5101
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;
L
Linus Torvalds 已提交
5102 5103

	/*
5104 5105
	 * find the disk ... but prefer rdev->saved_raid_disk
	 * if possible.
L
Linus Torvalds 已提交
5106
	 */
5107
	if (rdev->saved_raid_disk >= 0 &&
5108
	    rdev->saved_raid_disk >= first &&
5109 5110 5111
	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
		disk = rdev->saved_raid_disk;
	else
5112 5113
		disk = first;
	for ( ; disk <= last ; disk++)
L
Linus Torvalds 已提交
5114
		if ((p=conf->disks + disk)->rdev == NULL) {
5115
			clear_bit(In_sync, &rdev->flags);
L
Linus Torvalds 已提交
5116
			rdev->raid_disk = disk;
5117
			err = 0;
5118 5119
			if (rdev->saved_raid_disk != disk)
				conf->fullsync = 1;
5120
			rcu_assign_pointer(p->rdev, rdev);
L
Linus Torvalds 已提交
5121 5122 5123
			break;
		}
	print_raid5_conf(conf);
5124
	return err;
L
Linus Torvalds 已提交
5125 5126
}

5127
static int raid5_resize(struct mddev *mddev, sector_t sectors)
L
Linus Torvalds 已提交
5128 5129 5130 5131 5132 5133 5134 5135
{
	/* 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.
	 */
5136
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5137 5138
	md_set_array_sectors(mddev, raid5_size(mddev, sectors,
					       mddev->raid_disks));
D
Dan Williams 已提交
5139 5140 5141
	if (mddev->array_sectors >
	    raid5_size(mddev, sectors, mddev->raid_disks))
		return -EINVAL;
5142
	set_capacity(mddev->gendisk, mddev->array_sectors);
5143
	revalidate_disk(mddev->gendisk);
5144 5145
	if (sectors > mddev->dev_sectors &&
	    mddev->recovery_cp > mddev->dev_sectors) {
A
Andre Noll 已提交
5146
		mddev->recovery_cp = mddev->dev_sectors;
L
Linus Torvalds 已提交
5147 5148
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
A
Andre Noll 已提交
5149
	mddev->dev_sectors = sectors;
5150
	mddev->resync_max_sectors = sectors;
L
Linus Torvalds 已提交
5151 5152 5153
	return 0;
}

5154
static int check_stripe_cache(struct mddev *mddev)
5155 5156 5157 5158 5159 5160 5161 5162 5163
{
	/* 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.
	 */
5164
	struct r5conf *conf = mddev->private;
5165 5166 5167 5168
	if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes ||
	    ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes) {
5169 5170
		printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
		       mdname(mddev),
5171 5172 5173 5174 5175 5176 5177
		       ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
			/ STRIPE_SIZE)*4);
		return 0;
	}
	return 1;
}

5178
static int check_reshape(struct mddev *mddev)
5179
{
5180
	struct r5conf *conf = mddev->private;
5181

5182 5183
	if (mddev->delta_disks == 0 &&
	    mddev->new_layout == mddev->layout &&
5184
	    mddev->new_chunk_sectors == mddev->chunk_sectors)
5185
		return 0; /* nothing to do */
5186 5187 5188
	if (mddev->bitmap)
		/* Cannot grow a bitmap yet */
		return -EBUSY;
5189
	if (has_failed(conf))
5190 5191 5192 5193 5194 5195 5196 5197 5198 5199 5200 5201 5202
		return -EINVAL;
	if (mddev->delta_disks < 0) {
		/* We might be able to shrink, but the devices must
		 * be made bigger first.
		 * For raid6, 4 is the minimum size.
		 * Otherwise 2 is the minimum
		 */
		int min = 2;
		if (mddev->level == 6)
			min = 4;
		if (mddev->raid_disks + mddev->delta_disks < min)
			return -EINVAL;
	}
5203

5204
	if (!check_stripe_cache(mddev))
5205 5206
		return -ENOSPC;

5207
	return resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
5208 5209
}

5210
static int raid5_start_reshape(struct mddev *mddev)
5211
{
5212
	struct r5conf *conf = mddev->private;
5213
	struct md_rdev *rdev;
5214
	int spares = 0;
5215
	unsigned long flags;
5216

5217
	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
5218 5219
		return -EBUSY;

5220 5221 5222
	if (!check_stripe_cache(mddev))
		return -ENOSPC;

5223
	list_for_each_entry(rdev, &mddev->disks, same_set)
5224 5225
		if (!test_bit(In_sync, &rdev->flags)
		    && !test_bit(Faulty, &rdev->flags))
5226
			spares++;
5227

5228
	if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
5229 5230 5231 5232 5233
		/* Not enough devices even to make a degraded array
		 * of that size
		 */
		return -EINVAL;

5234 5235 5236 5237 5238 5239
	/* Refuse to reduce size of the array.  Any reductions in
	 * array size must be through explicit setting of array_size
	 * attribute.
	 */
	if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
	    < mddev->array_sectors) {
5240
		printk(KERN_ERR "md/raid:%s: array size must be reduced "
5241 5242 5243 5244
		       "before number of disks\n", mdname(mddev));
		return -EINVAL;
	}

5245
	atomic_set(&conf->reshape_stripes, 0);
5246 5247
	spin_lock_irq(&conf->device_lock);
	conf->previous_raid_disks = conf->raid_disks;
5248
	conf->raid_disks += mddev->delta_disks;
5249 5250
	conf->prev_chunk_sectors = conf->chunk_sectors;
	conf->chunk_sectors = mddev->new_chunk_sectors;
5251 5252
	conf->prev_algo = conf->algorithm;
	conf->algorithm = mddev->new_layout;
5253 5254 5255 5256 5257
	if (mddev->delta_disks < 0)
		conf->reshape_progress = raid5_size(mddev, 0, 0);
	else
		conf->reshape_progress = 0;
	conf->reshape_safe = conf->reshape_progress;
5258
	conf->generation++;
5259 5260 5261 5262
	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.
5263 5264 5265 5266
	 * Don't add devices if we are reducing the number of
	 * devices in the array.  This is because it is not possible
	 * to correctly record the "partially reconstructed" state of
	 * such devices during the reshape and confusion could result.
5267
	 */
5268 5269 5270 5271 5272 5273 5274 5275 5276 5277 5278 5279
	if (mddev->delta_disks >= 0) {
		int added_devices = 0;
		list_for_each_entry(rdev, &mddev->disks, same_set)
			if (rdev->raid_disk < 0 &&
			    !test_bit(Faulty, &rdev->flags)) {
				if (raid5_add_disk(mddev, rdev) == 0) {
					if (rdev->raid_disk
					    >= conf->previous_raid_disks) {
						set_bit(In_sync, &rdev->flags);
						added_devices++;
					} else
						rdev->recovery_offset = 0;
5280 5281

					if (sysfs_link_rdev(mddev, rdev))
5282
						/* Failure here is OK */;
5283
				}
5284 5285 5286 5287 5288 5289
			} else if (rdev->raid_disk >= conf->previous_raid_disks
				   && !test_bit(Faulty, &rdev->flags)) {
				/* This is a spare that was manually added */
				set_bit(In_sync, &rdev->flags);
				added_devices++;
			}
5290

5291 5292 5293 5294
		/* When a reshape changes the number of devices,
		 * ->degraded is measured against the larger of the
		 * pre and post number of devices.
		 */
5295
		spin_lock_irqsave(&conf->device_lock, flags);
5296
		mddev->degraded = calc_degraded(conf);
5297 5298
		spin_unlock_irqrestore(&conf->device_lock, flags);
	}
5299
	mddev->raid_disks = conf->raid_disks;
5300
	mddev->reshape_position = conf->reshape_progress;
5301
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
5302

5303 5304 5305 5306 5307
	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,
5308
						"reshape");
5309 5310 5311 5312
	if (!mddev->sync_thread) {
		mddev->recovery = 0;
		spin_lock_irq(&conf->device_lock);
		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
5313
		conf->reshape_progress = MaxSector;
5314 5315 5316
		spin_unlock_irq(&conf->device_lock);
		return -EAGAIN;
	}
5317
	conf->reshape_checkpoint = jiffies;
5318 5319 5320 5321 5322
	md_wakeup_thread(mddev->sync_thread);
	md_new_event(mddev);
	return 0;
}

5323 5324 5325
/* This is called from the reshape thread and should make any
 * changes needed in 'conf'
 */
5326
static void end_reshape(struct r5conf *conf)
5327 5328
{

5329 5330 5331
	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {

		spin_lock_irq(&conf->device_lock);
5332
		conf->previous_raid_disks = conf->raid_disks;
5333
		conf->reshape_progress = MaxSector;
5334
		spin_unlock_irq(&conf->device_lock);
5335
		wake_up(&conf->wait_for_overlap);
5336 5337 5338 5339

		/* read-ahead size must cover two whole stripes, which is
		 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
		 */
5340
		if (conf->mddev->queue) {
5341
			int data_disks = conf->raid_disks - conf->max_degraded;
5342
			int stripe = data_disks * ((conf->chunk_sectors << 9)
5343
						   / PAGE_SIZE);
5344 5345 5346
			if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
				conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
		}
5347 5348 5349
	}
}

5350 5351 5352
/* This is called from the raid5d thread with mddev_lock held.
 * It makes config changes to the device.
 */
5353
static void raid5_finish_reshape(struct mddev *mddev)
5354
{
5355
	struct r5conf *conf = mddev->private;
5356 5357 5358

	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {

5359 5360 5361
		if (mddev->delta_disks > 0) {
			md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
			set_capacity(mddev->gendisk, mddev->array_sectors);
5362
			revalidate_disk(mddev->gendisk);
5363 5364
		} else {
			int d;
5365 5366 5367
			spin_lock_irq(&conf->device_lock);
			mddev->degraded = calc_degraded(conf);
			spin_unlock_irq(&conf->device_lock);
5368 5369
			for (d = conf->raid_disks ;
			     d < conf->raid_disks - mddev->delta_disks;
5370
			     d++) {
5371
				struct md_rdev *rdev = conf->disks[d].rdev;
5372
				if (rdev && raid5_remove_disk(mddev, d) == 0) {
5373
					sysfs_unlink_rdev(mddev, rdev);
5374 5375 5376
					rdev->raid_disk = -1;
				}
			}
5377
		}
5378
		mddev->layout = conf->algorithm;
5379
		mddev->chunk_sectors = conf->chunk_sectors;
5380 5381
		mddev->reshape_position = MaxSector;
		mddev->delta_disks = 0;
5382 5383 5384
	}
}

5385
static void raid5_quiesce(struct mddev *mddev, int state)
5386
{
5387
	struct r5conf *conf = mddev->private;
5388 5389

	switch(state) {
5390 5391 5392 5393
	case 2: /* resume for a suspend */
		wake_up(&conf->wait_for_overlap);
		break;

5394 5395
	case 1: /* stop all writes */
		spin_lock_irq(&conf->device_lock);
5396 5397 5398 5399
		/* '2' tells resync/reshape to pause so that all
		 * active stripes can drain
		 */
		conf->quiesce = 2;
5400
		wait_event_lock_irq(conf->wait_for_stripe,
5401 5402
				    atomic_read(&conf->active_stripes) == 0 &&
				    atomic_read(&conf->active_aligned_reads) == 0,
5403
				    conf->device_lock, /* nothing */);
5404
		conf->quiesce = 1;
5405
		spin_unlock_irq(&conf->device_lock);
5406 5407
		/* allow reshape to continue */
		wake_up(&conf->wait_for_overlap);
5408 5409 5410 5411 5412 5413
		break;

	case 0: /* re-enable writes */
		spin_lock_irq(&conf->device_lock);
		conf->quiesce = 0;
		wake_up(&conf->wait_for_stripe);
5414
		wake_up(&conf->wait_for_overlap);
5415 5416 5417 5418
		spin_unlock_irq(&conf->device_lock);
		break;
	}
}
5419

5420

5421
static void *raid45_takeover_raid0(struct mddev *mddev, int level)
5422
{
5423
	struct r0conf *raid0_conf = mddev->private;
5424
	sector_t sectors;
5425

D
Dan Williams 已提交
5426
	/* for raid0 takeover only one zone is supported */
5427
	if (raid0_conf->nr_strip_zones > 1) {
5428 5429
		printk(KERN_ERR "md/raid:%s: cannot takeover raid0 with more than one zone.\n",
		       mdname(mddev));
D
Dan Williams 已提交
5430 5431 5432
		return ERR_PTR(-EINVAL);
	}

5433 5434
	sectors = raid0_conf->strip_zone[0].zone_end;
	sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
5435
	mddev->dev_sectors = sectors;
D
Dan Williams 已提交
5436
	mddev->new_level = level;
5437 5438 5439 5440 5441 5442 5443 5444 5445 5446 5447
	mddev->new_layout = ALGORITHM_PARITY_N;
	mddev->new_chunk_sectors = mddev->chunk_sectors;
	mddev->raid_disks += 1;
	mddev->delta_disks = 1;
	/* make sure it will be not marked as dirty */
	mddev->recovery_cp = MaxSector;

	return setup_conf(mddev);
}


5448
static void *raid5_takeover_raid1(struct mddev *mddev)
5449 5450 5451 5452 5453 5454 5455 5456 5457 5458 5459 5460 5461 5462 5463 5464 5465 5466 5467 5468 5469
{
	int chunksect;

	if (mddev->raid_disks != 2 ||
	    mddev->degraded > 1)
		return ERR_PTR(-EINVAL);

	/* Should check if there are write-behind devices? */

	chunksect = 64*2; /* 64K by default */

	/* The array must be an exact multiple of chunksize */
	while (chunksect && (mddev->array_sectors & (chunksect-1)))
		chunksect >>= 1;

	if ((chunksect<<9) < STRIPE_SIZE)
		/* array size does not allow a suitable chunk size */
		return ERR_PTR(-EINVAL);

	mddev->new_level = 5;
	mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
5470
	mddev->new_chunk_sectors = chunksect;
5471 5472 5473 5474

	return setup_conf(mddev);
}

5475
static void *raid5_takeover_raid6(struct mddev *mddev)
5476 5477 5478 5479 5480 5481 5482 5483 5484 5485 5486 5487 5488 5489 5490 5491 5492 5493 5494 5495 5496 5497 5498 5499 5500 5501 5502 5503 5504 5505 5506 5507
{
	int new_layout;

	switch (mddev->layout) {
	case ALGORITHM_LEFT_ASYMMETRIC_6:
		new_layout = ALGORITHM_LEFT_ASYMMETRIC;
		break;
	case ALGORITHM_RIGHT_ASYMMETRIC_6:
		new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
		break;
	case ALGORITHM_LEFT_SYMMETRIC_6:
		new_layout = ALGORITHM_LEFT_SYMMETRIC;
		break;
	case ALGORITHM_RIGHT_SYMMETRIC_6:
		new_layout = ALGORITHM_RIGHT_SYMMETRIC;
		break;
	case ALGORITHM_PARITY_0_6:
		new_layout = ALGORITHM_PARITY_0;
		break;
	case ALGORITHM_PARITY_N:
		new_layout = ALGORITHM_PARITY_N;
		break;
	default:
		return ERR_PTR(-EINVAL);
	}
	mddev->new_level = 5;
	mddev->new_layout = new_layout;
	mddev->delta_disks = -1;
	mddev->raid_disks -= 1;
	return setup_conf(mddev);
}

5508

5509
static int raid5_check_reshape(struct mddev *mddev)
5510
{
5511 5512 5513 5514
	/* For a 2-drive array, the layout and chunk size can be changed
	 * immediately as not restriping is needed.
	 * For larger arrays we record the new value - after validation
	 * to be used by a reshape pass.
5515
	 */
5516
	struct r5conf *conf = mddev->private;
5517
	int new_chunk = mddev->new_chunk_sectors;
5518

5519
	if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
5520 5521
		return -EINVAL;
	if (new_chunk > 0) {
5522
		if (!is_power_of_2(new_chunk))
5523
			return -EINVAL;
5524
		if (new_chunk < (PAGE_SIZE>>9))
5525
			return -EINVAL;
5526
		if (mddev->array_sectors & (new_chunk-1))
5527 5528 5529 5530 5531 5532
			/* not factor of array size */
			return -EINVAL;
	}

	/* They look valid */

5533
	if (mddev->raid_disks == 2) {
5534 5535 5536 5537
		/* can make the change immediately */
		if (mddev->new_layout >= 0) {
			conf->algorithm = mddev->new_layout;
			mddev->layout = mddev->new_layout;
5538 5539
		}
		if (new_chunk > 0) {
5540 5541
			conf->chunk_sectors = new_chunk ;
			mddev->chunk_sectors = new_chunk;
5542 5543 5544
		}
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		md_wakeup_thread(mddev->thread);
5545
	}
5546
	return check_reshape(mddev);
5547 5548
}

5549
static int raid6_check_reshape(struct mddev *mddev)
5550
{
5551
	int new_chunk = mddev->new_chunk_sectors;
5552

5553
	if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
5554
		return -EINVAL;
5555
	if (new_chunk > 0) {
5556
		if (!is_power_of_2(new_chunk))
5557
			return -EINVAL;
5558
		if (new_chunk < (PAGE_SIZE >> 9))
5559
			return -EINVAL;
5560
		if (mddev->array_sectors & (new_chunk-1))
5561 5562
			/* not factor of array size */
			return -EINVAL;
5563
	}
5564 5565

	/* They look valid */
5566
	return check_reshape(mddev);
5567 5568
}

5569
static void *raid5_takeover(struct mddev *mddev)
5570 5571
{
	/* raid5 can take over:
D
Dan Williams 已提交
5572
	 *  raid0 - if there is only one strip zone - make it a raid4 layout
5573 5574 5575 5576
	 *  raid1 - if there are two drives.  We need to know the chunk size
	 *  raid4 - trivial - just use a raid4 layout.
	 *  raid6 - Providing it is a *_6 layout
	 */
D
Dan Williams 已提交
5577 5578
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 5);
5579 5580
	if (mddev->level == 1)
		return raid5_takeover_raid1(mddev);
5581 5582 5583 5584 5585
	if (mddev->level == 4) {
		mddev->new_layout = ALGORITHM_PARITY_N;
		mddev->new_level = 5;
		return setup_conf(mddev);
	}
5586 5587
	if (mddev->level == 6)
		return raid5_takeover_raid6(mddev);
5588 5589 5590 5591

	return ERR_PTR(-EINVAL);
}

5592
static void *raid4_takeover(struct mddev *mddev)
5593
{
D
Dan Williams 已提交
5594 5595 5596
	/* raid4 can take over:
	 *  raid0 - if there is only one strip zone
	 *  raid5 - if layout is right
5597
	 */
D
Dan Williams 已提交
5598 5599
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 4);
5600 5601 5602 5603 5604 5605 5606 5607
	if (mddev->level == 5 &&
	    mddev->layout == ALGORITHM_PARITY_N) {
		mddev->new_layout = 0;
		mddev->new_level = 4;
		return setup_conf(mddev);
	}
	return ERR_PTR(-EINVAL);
}
5608

5609
static struct md_personality raid5_personality;
5610

5611
static void *raid6_takeover(struct mddev *mddev)
5612 5613 5614 5615 5616 5617 5618 5619 5620 5621 5622 5623 5624 5625 5626 5627 5628 5629 5630 5631 5632 5633 5634 5635 5636 5637 5638 5639 5640 5641 5642 5643 5644 5645 5646 5647 5648 5649 5650 5651 5652 5653 5654 5655 5656 5657
{
	/* Currently can only take over a raid5.  We map the
	 * personality to an equivalent raid6 personality
	 * with the Q block at the end.
	 */
	int new_layout;

	if (mddev->pers != &raid5_personality)
		return ERR_PTR(-EINVAL);
	if (mddev->degraded > 1)
		return ERR_PTR(-EINVAL);
	if (mddev->raid_disks > 253)
		return ERR_PTR(-EINVAL);
	if (mddev->raid_disks < 3)
		return ERR_PTR(-EINVAL);

	switch (mddev->layout) {
	case ALGORITHM_LEFT_ASYMMETRIC:
		new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
		break;
	case ALGORITHM_RIGHT_ASYMMETRIC:
		new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
		break;
	case ALGORITHM_LEFT_SYMMETRIC:
		new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
		break;
	case ALGORITHM_RIGHT_SYMMETRIC:
		new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
		break;
	case ALGORITHM_PARITY_0:
		new_layout = ALGORITHM_PARITY_0_6;
		break;
	case ALGORITHM_PARITY_N:
		new_layout = ALGORITHM_PARITY_N;
		break;
	default:
		return ERR_PTR(-EINVAL);
	}
	mddev->new_level = 6;
	mddev->new_layout = new_layout;
	mddev->delta_disks = 1;
	mddev->raid_disks += 1;
	return setup_conf(mddev);
}


5658
static struct md_personality raid6_personality =
5659 5660 5661 5662 5663 5664 5665 5666 5667 5668 5669 5670 5671 5672
{
	.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,
5673
	.size		= raid5_size,
5674
	.check_reshape	= raid6_check_reshape,
5675
	.start_reshape  = raid5_start_reshape,
5676
	.finish_reshape = raid5_finish_reshape,
5677
	.quiesce	= raid5_quiesce,
5678
	.takeover	= raid6_takeover,
5679
};
5680
static struct md_personality raid5_personality =
L
Linus Torvalds 已提交
5681 5682
{
	.name		= "raid5",
5683
	.level		= 5,
L
Linus Torvalds 已提交
5684 5685 5686 5687 5688 5689 5690 5691 5692 5693 5694
	.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,
5695
	.size		= raid5_size,
5696 5697
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
5698
	.finish_reshape = raid5_finish_reshape,
5699
	.quiesce	= raid5_quiesce,
5700
	.takeover	= raid5_takeover,
L
Linus Torvalds 已提交
5701 5702
};

5703
static struct md_personality raid4_personality =
L
Linus Torvalds 已提交
5704
{
5705 5706 5707 5708 5709 5710 5711 5712 5713 5714 5715 5716 5717
	.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,
5718
	.size		= raid5_size,
5719 5720
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
5721
	.finish_reshape = raid5_finish_reshape,
5722
	.quiesce	= raid5_quiesce,
5723
	.takeover	= raid4_takeover,
5724 5725 5726 5727
};

static int __init raid5_init(void)
{
5728
	register_md_personality(&raid6_personality);
5729 5730 5731
	register_md_personality(&raid5_personality);
	register_md_personality(&raid4_personality);
	return 0;
L
Linus Torvalds 已提交
5732 5733
}

5734
static void raid5_exit(void)
L
Linus Torvalds 已提交
5735
{
5736
	unregister_md_personality(&raid6_personality);
5737 5738
	unregister_md_personality(&raid5_personality);
	unregister_md_personality(&raid4_personality);
L
Linus Torvalds 已提交
5739 5740 5741 5742 5743
}

module_init(raid5_init);
module_exit(raid5_exit);
MODULE_LICENSE("GPL");
5744
MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
L
Linus Torvalds 已提交
5745
MODULE_ALIAS("md-personality-4"); /* RAID5 */
5746 5747
MODULE_ALIAS("md-raid5");
MODULE_ALIAS("md-raid4");
5748 5749
MODULE_ALIAS("md-level-5");
MODULE_ALIAS("md-level-4");
5750 5751 5752 5753 5754 5755 5756
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");