raid5.c 171.8 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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 */
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static inline int raid5_bi_processed_stripes(struct bio *bio)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	return (atomic_read(segments) >> 16) & 0xffff;
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}

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static inline int raid5_dec_bi_active_stripes(struct bio *bio)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	return atomic_sub_return(1, segments) & 0xffff;
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}

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static inline void raid5_inc_bi_active_stripes(struct bio *bio)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	atomic_inc(segments);
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}

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static inline void raid5_set_bi_processed_stripes(struct bio *bio,
	unsigned int cnt)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	int old, new;
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	do {
		old = atomic_read(segments);
		new = (old & 0xffff) | (cnt << 16);
	} while (atomic_cmpxchg(segments, old, new) != old);
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}

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static inline void raid5_set_bi_stripes(struct bio *bio, unsigned int cnt)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	atomic_set(segments, cnt);
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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 do_release_stripe(struct r5conf *conf, struct stripe_head *sh)
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{
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	BUG_ON(!list_empty(&sh->lru));
	BUG_ON(atomic_read(&conf->active_stripes)==0);
	if (test_bit(STRIPE_HANDLE, &sh->state)) {
		if (test_bit(STRIPE_DELAYED, &sh->state) &&
		    !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
			list_add_tail(&sh->lru, &conf->delayed_list);
		else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
			   sh->bm_seq - conf->seq_write > 0)
			list_add_tail(&sh->lru, &conf->bitmap_list);
		else {
			clear_bit(STRIPE_DELAYED, &sh->state);
			clear_bit(STRIPE_BIT_DELAY, &sh->state);
			list_add_tail(&sh->lru, &conf->handle_list);
		}
		md_wakeup_thread(conf->mddev->thread);
	} else {
		BUG_ON(stripe_operations_active(sh));
		if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
			if (atomic_dec_return(&conf->preread_active_stripes)
			    < IO_THRESHOLD)
				md_wakeup_thread(conf->mddev->thread);
		atomic_dec(&conf->active_stripes);
		if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
			list_add_tail(&sh->lru, &conf->inactive_list);
			wake_up(&conf->wait_for_stripe);
			if (conf->retry_read_aligned)
				md_wakeup_thread(conf->mddev->thread);
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		}
	}
}
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static void __release_stripe(struct r5conf *conf, struct stripe_head *sh)
{
	if (atomic_dec_and_test(&sh->count))
		do_release_stripe(conf, sh);
}

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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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	local_irq_save(flags);
	if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
		do_release_stripe(conf, sh);
		spin_unlock(&conf->device_lock);
	}
	local_irq_restore(flags);
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}

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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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/* Determine if 'data_offset' or 'new_data_offset' should be used
 * in this stripe_head.
 */
static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
{
	sector_t progress = conf->reshape_progress;
	/* Need a memory barrier to make sure we see the value
	 * of conf->generation, or ->data_offset that was set before
	 * reshape_progress was updated.
	 */
	smp_rmb();
	if (progress == MaxSector)
		return 0;
	if (sh->generation == conf->generation - 1)
		return 0;
	/* We are in a reshape, and this is a new-generation stripe,
	 * so use new_data_offset.
	 */
	return 1;
}

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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;
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		int replace_only = 0;
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		struct bio *bi, *rbi;
		struct md_rdev *rdev, *rrdev = NULL;
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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;
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		else if (test_and_clear_bit(R5_WantReplace,
					    &sh->dev[i].flags)) {
			rw = WRITE;
			replace_only = 1;
		} else
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			continue;
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		if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
			rw |= REQ_SYNC;
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		bi = &sh->dev[i].req;
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		rbi = &sh->dev[i].rreq; /* For writing to replacement */
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		bi->bi_rw = rw;
564 565
		rbi->bi_rw = rw;
		if (rw & WRITE) {
566
			bi->bi_end_io = raid5_end_write_request;
567 568
			rbi->bi_end_io = raid5_end_write_request;
		} else
569 570 571
			bi->bi_end_io = raid5_end_read_request;

		rcu_read_lock();
572
		rrdev = rcu_dereference(conf->disks[i].replacement);
573 574 575 576 577 578
		smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
		rdev = rcu_dereference(conf->disks[i].rdev);
		if (!rdev) {
			rdev = rrdev;
			rrdev = NULL;
		}
579 580 581
		if (rw & WRITE) {
			if (replace_only)
				rdev = NULL;
582 583 584
			if (rdev == rrdev)
				/* We raced and saw duplicates */
				rrdev = NULL;
585
		} else {
586
			if (test_bit(R5_ReadRepl, &sh->dev[i].flags) && rrdev)
587 588 589
				rdev = rrdev;
			rrdev = NULL;
		}
590

591 592 593 594
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
		if (rdev)
			atomic_inc(&rdev->nr_pending);
595 596 597 598
		if (rrdev && test_bit(Faulty, &rrdev->flags))
			rrdev = NULL;
		if (rrdev)
			atomic_inc(&rrdev->nr_pending);
599 600
		rcu_read_unlock();

601
		/* We have already checked bad blocks for reads.  Now
602 603
		 * need to check for writes.  We never accept write errors
		 * on the replacement, so we don't to check rrdev.
604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623
		 */
		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);
				}
624 625 626 627 628 629
				/*
				 * Because md_wait_for_blocked_rdev
				 * will dec nr_pending, we must
				 * increment it first.
				 */
				atomic_inc(&rdev->nr_pending);
630 631 632 633 634 635 636 637
				md_wait_for_blocked_rdev(rdev, conf->mddev);
			} else {
				/* Acknowledged bad block - skip the write */
				rdev_dec_pending(rdev, conf->mddev);
				rdev = NULL;
			}
		}

638
		if (rdev) {
639 640
			if (s->syncing || s->expanding || s->expanded
			    || s->replacing)
641 642
				md_sync_acct(rdev->bdev, STRIPE_SECTORS);

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			set_bit(STRIPE_IO_STARTED, &sh->state);

645 646
			bi->bi_bdev = rdev->bdev;
			pr_debug("%s: for %llu schedule op %ld on disc %d\n",
647
				__func__, (unsigned long long)sh->sector,
648 649
				bi->bi_rw, i);
			atomic_inc(&sh->count);
650 651 652 653 654 655
			if (use_new_offset(conf, sh))
				bi->bi_sector = (sh->sector
						 + rdev->new_data_offset);
			else
				bi->bi_sector = (sh->sector
						 + rdev->data_offset);
656 657 658 659 660 661
			bi->bi_flags = 1 << BIO_UPTODATE;
			bi->bi_idx = 0;
			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;
662 663
			if (rrdev)
				set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
664
			generic_make_request(bi);
665 666
		}
		if (rrdev) {
667 668
			if (s->syncing || s->expanding || s->expanded
			    || s->replacing)
669 670 671 672 673 674 675 676 677 678
				md_sync_acct(rrdev->bdev, STRIPE_SECTORS);

			set_bit(STRIPE_IO_STARTED, &sh->state);

			rbi->bi_bdev = rrdev->bdev;
			pr_debug("%s: for %llu schedule op %ld on "
				 "replacement disc %d\n",
				__func__, (unsigned long long)sh->sector,
				rbi->bi_rw, i);
			atomic_inc(&sh->count);
679 680 681 682 683 684
			if (use_new_offset(conf, sh))
				rbi->bi_sector = (sh->sector
						  + rrdev->new_data_offset);
			else
				rbi->bi_sector = (sh->sector
						  + rrdev->data_offset);
685 686 687 688 689 690 691 692 693
			rbi->bi_flags = 1 << BIO_UPTODATE;
			rbi->bi_idx = 0;
			rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
			rbi->bi_io_vec[0].bv_offset = 0;
			rbi->bi_size = STRIPE_SIZE;
			rbi->bi_next = NULL;
			generic_make_request(rbi);
		}
		if (!rdev && !rrdev) {
694
			if (rw & WRITE)
695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711
				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;
712
	struct async_submit_ctl submit;
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	enum async_tx_flags flags = 0;
714 715 716 717 718

	if (bio->bi_sector >= sector)
		page_offset = (signed)(bio->bi_sector - sector) * 512;
	else
		page_offset = (signed)(sector - bio->bi_sector) * -512;
719

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

724
	bio_for_each_segment(bvl, bio, i) {
725
		int len = bvl->bv_len;
726 727 728 729 730 731 732 733 734 735 736 737 738 739 740
		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) {
741 742
			b_offset += bvl->bv_offset;
			bio_page = bvl->bv_page;
743 744
			if (frombio)
				tx = async_memcpy(page, bio_page, page_offset,
745
						  b_offset, clen, &submit);
746 747
			else
				tx = async_memcpy(bio_page, page, b_offset,
748
						  page_offset, clen, &submit);
749
		}
750 751 752
		/* chain the operations */
		submit.depend_tx = tx;

753 754 755 756 757 758 759 760 761 762 763 764
		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;
765
	struct r5conf *conf = sh->raid_conf;
766
	int i;
767

768
	pr_debug("%s: stripe %llu\n", __func__,
769 770 771
		(unsigned long long)sh->sector);

	/* clear completed biofills */
772
	spin_lock_irq(&conf->device_lock);
773 774 775 776
	for (i = sh->disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];

		/* acknowledge completion of a biofill operation */
777 778
		/* and check if we need to reply to a read request,
		 * new R5_Wantfill requests are held off until
779
		 * !STRIPE_BIOFILL_RUN
780 781
		 */
		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
782 783 784 785 786 787 788 789
			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);
790
				if (!raid5_dec_bi_active_stripes(rbi)) {
791 792 793 794 795 796 797
					rbi->bi_next = return_bi;
					return_bi = rbi;
				}
				rbi = rbi2;
			}
		}
	}
798 799
	spin_unlock_irq(&conf->device_lock);
	clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
800 801 802

	return_io(return_bi);

803
	set_bit(STRIPE_HANDLE, &sh->state);
804 805 806 807 808 809
	release_stripe(sh);
}

static void ops_run_biofill(struct stripe_head *sh)
{
	struct dma_async_tx_descriptor *tx = NULL;
810
	struct r5conf *conf = sh->raid_conf;
811
	struct async_submit_ctl submit;
812 813
	int i;

814
	pr_debug("%s: stripe %llu\n", __func__,
815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834
		(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);
835 836
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
	async_trigger_callback(&submit);
837 838
}

839
static void mark_target_uptodate(struct stripe_head *sh, int target)
840
{
841
	struct r5dev *tgt;
842

843 844
	if (target < 0)
		return;
845

846
	tgt = &sh->dev[target];
847 848 849
	set_bit(R5_UPTODATE, &tgt->flags);
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	clear_bit(R5_Wantcompute, &tgt->flags);
850 851
}

852
static void ops_complete_compute(void *stripe_head_ref)
853 854 855
{
	struct stripe_head *sh = stripe_head_ref;

856
	pr_debug("%s: stripe %llu\n", __func__,
857 858
		(unsigned long long)sh->sector);

859
	/* mark the computed target(s) as uptodate */
860
	mark_target_uptodate(sh, sh->ops.target);
861
	mark_target_uptodate(sh, sh->ops.target2);
862

863 864 865
	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
	if (sh->check_state == check_state_compute_run)
		sh->check_state = check_state_compute_result;
866 867 868 869
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

870 871 872 873 874 875 876 877 878
/* 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)
879 880
{
	int disks = sh->disks;
881
	struct page **xor_srcs = percpu->scribble;
882 883 884 885 886
	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;
887
	struct async_submit_ctl submit;
888 889 890
	int i;

	pr_debug("%s: stripe %llu block: %d\n",
891
		__func__, (unsigned long long)sh->sector, target);
892 893 894 895 896 897 898 899
	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,
901
			  ops_complete_compute, sh, to_addr_conv(sh, percpu));
902
	if (unlikely(count == 1))
903
		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
904
	else
905
		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
906 907 908 909

	return tx;
}

910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927
/* 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++)
928
		srcs[i] = NULL;
929 930 931 932 933 934 935 936 937 938

	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);

939
	return syndrome_disks;
940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959
}

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;
960
	else
961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976
		/* 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,
979 980 981 982 983 984 985 986 987 988 989
				  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,
992 993 994
				  to_addr_conv(sh, percpu));
		tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
	}
995 996 997 998

	return tx;
}

999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019
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));

1020
	/* we need to open-code set_syndrome_sources to handle the
1021 1022 1023
	 * slot number conversion for 'faila' and 'failb'
	 */
	for (i = 0; i < disks ; i++)
1024
		blocks[i] = NULL;
1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050
	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));
1054
			return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073
						  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));
1078 1079 1080 1081
			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));
1085 1086 1087 1088
			return async_gen_syndrome(blocks, 0, count+2,
						  STRIPE_SIZE, &submit);
		}
	} else {
1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102
		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);
		}
1103 1104 1105 1106
	}
}


1107 1108 1109 1110
static void ops_complete_prexor(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;

1111
	pr_debug("%s: stripe %llu\n", __func__,
1112 1113 1114 1115
		(unsigned long long)sh->sector);
}

static struct dma_async_tx_descriptor *
1116 1117
ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
	       struct dma_async_tx_descriptor *tx)
1118 1119
{
	int disks = sh->disks;
1120
	struct page **xor_srcs = percpu->scribble;
1121
	int count = 0, pd_idx = sh->pd_idx, i;
1122
	struct async_submit_ctl submit;
1123 1124 1125 1126

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

1127
	pr_debug("%s: stripe %llu\n", __func__,
1128 1129 1130 1131 1132
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		/* Only process blocks that are known to be uptodate */
1133
		if (test_bit(R5_Wantdrain, &dev->flags))
1134 1135 1136
			xor_srcs[count++] = dev->page;
	}

D
Dan Williams 已提交
1137
	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1138
			  ops_complete_prexor, sh, to_addr_conv(sh, percpu));
1139
	tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1140 1141 1142 1143 1144

	return tx;
}

static struct dma_async_tx_descriptor *
1145
ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1146 1147
{
	int disks = sh->disks;
1148
	int i;
1149

1150
	pr_debug("%s: stripe %llu\n", __func__,
1151 1152 1153 1154 1155 1156
		(unsigned long long)sh->sector);

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

1157
		if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
1158 1159
			struct bio *wbi;

1160
			spin_lock_irq(&sh->raid_conf->device_lock);
1161 1162 1163 1164
			chosen = dev->towrite;
			dev->towrite = NULL;
			BUG_ON(dev->written);
			wbi = dev->written = chosen;
1165
			spin_unlock_irq(&sh->raid_conf->device_lock);
1166 1167 1168

			while (wbi && wbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
T
Tejun Heo 已提交
1169 1170
				if (wbi->bi_rw & REQ_FUA)
					set_bit(R5_WantFUA, &dev->flags);
S
Shaohua Li 已提交
1171 1172
				if (wbi->bi_rw & REQ_SYNC)
					set_bit(R5_SyncIO, &dev->flags);
1173 1174 1175 1176 1177 1178 1179 1180 1181 1182
				tx = async_copy_data(1, wbi, dev->page,
					dev->sector, tx);
				wbi = r5_next_bio(wbi, dev->sector);
			}
		}
	}

	return tx;
}

1183
static void ops_complete_reconstruct(void *stripe_head_ref)
1184 1185
{
	struct stripe_head *sh = stripe_head_ref;
1186 1187 1188 1189
	int disks = sh->disks;
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	int i;
S
Shaohua Li 已提交
1190
	bool fua = false, sync = false;
1191

1192
	pr_debug("%s: stripe %llu\n", __func__,
1193 1194
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
1195
	for (i = disks; i--; ) {
T
Tejun Heo 已提交
1196
		fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
S
Shaohua Li 已提交
1197 1198
		sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
	}
T
Tejun Heo 已提交
1199

1200 1201
	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
1202

T
Tejun Heo 已提交
1203
		if (dev->written || i == pd_idx || i == qd_idx) {
1204
			set_bit(R5_UPTODATE, &dev->flags);
T
Tejun Heo 已提交
1205 1206
			if (fua)
				set_bit(R5_WantFUA, &dev->flags);
S
Shaohua Li 已提交
1207 1208
			if (sync)
				set_bit(R5_SyncIO, &dev->flags);
T
Tejun Heo 已提交
1209
		}
1210 1211
	}

1212 1213 1214 1215 1216 1217 1218 1219
	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;
	}
1220 1221 1222 1223 1224 1225

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

static void
1226 1227
ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
		     struct dma_async_tx_descriptor *tx)
1228 1229
{
	int disks = sh->disks;
1230
	struct page **xor_srcs = percpu->scribble;
1231
	struct async_submit_ctl submit;
1232 1233
	int count = 0, pd_idx = sh->pd_idx, i;
	struct page *xor_dest;
1234
	int prexor = 0;
1235 1236
	unsigned long flags;

1237
	pr_debug("%s: stripe %llu\n", __func__,
1238 1239 1240 1241 1242
		(unsigned long long)sh->sector);

	/* check if prexor is active which means only process blocks
	 * that are part of a read-modify-write (written)
	 */
1243 1244
	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
		prexor = 1;
1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264
		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
	 */
1265
	flags = ASYNC_TX_ACK |
1266 1267 1268 1269
		(prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);

	atomic_inc(&sh->count);

1270
	init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh,
1271
			  to_addr_conv(sh, percpu));
1272 1273 1274 1275
	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);
1276 1277
}

1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294
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);
1295 1296 1297 1298 1299 1300
}

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

1301
	pr_debug("%s: stripe %llu\n", __func__,
1302 1303
		(unsigned long long)sh->sector);

1304
	sh->check_state = check_state_check_result;
1305 1306 1307 1308
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1309
static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1310 1311
{
	int disks = sh->disks;
1312 1313 1314
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	struct page *xor_dest;
1315
	struct page **xor_srcs = percpu->scribble;
1316
	struct dma_async_tx_descriptor *tx;
1317
	struct async_submit_ctl submit;
1318 1319
	int count;
	int i;
1320

1321
	pr_debug("%s: stripe %llu\n", __func__,
1322 1323
		(unsigned long long)sh->sector);

1324 1325 1326
	count = 0;
	xor_dest = sh->dev[pd_idx].page;
	xor_srcs[count++] = xor_dest;
1327
	for (i = disks; i--; ) {
1328 1329 1330
		if (i == pd_idx || i == qd_idx)
			continue;
		xor_srcs[count++] = sh->dev[i].page;
1331 1332
	}

1333 1334
	init_async_submit(&submit, 0, NULL, NULL, NULL,
			  to_addr_conv(sh, percpu));
D
Dan Williams 已提交
1335
	tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
1336
			   &sh->ops.zero_sum_result, &submit);
1337 1338

	atomic_inc(&sh->count);
1339 1340
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
	tx = async_trigger_callback(&submit);
1341 1342
}

1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354
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;
1355 1356

	atomic_inc(&sh->count);
1357 1358 1359 1360
	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);
1361 1362
}

1363
static void __raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
1364 1365 1366
{
	int overlap_clear = 0, i, disks = sh->disks;
	struct dma_async_tx_descriptor *tx = NULL;
1367
	struct r5conf *conf = sh->raid_conf;
1368
	int level = conf->level;
1369 1370
	struct raid5_percpu *percpu;
	unsigned long cpu;
1371

1372 1373
	cpu = get_cpu();
	percpu = per_cpu_ptr(conf->percpu, cpu);
1374
	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
1375 1376 1377 1378
		ops_run_biofill(sh);
		overlap_clear++;
	}

1379
	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
1380 1381 1382 1383 1384 1385 1386 1387 1388 1389
		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))
1390 1391
			async_tx_ack(tx);
	}
1392

1393
	if (test_bit(STRIPE_OP_PREXOR, &ops_request))
1394
		tx = ops_run_prexor(sh, percpu, tx);
1395

1396
	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
1397
		tx = ops_run_biodrain(sh, tx);
1398 1399 1400
		overlap_clear++;
	}

1401 1402 1403 1404 1405 1406
	if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
		if (level < 6)
			ops_run_reconstruct5(sh, percpu, tx);
		else
			ops_run_reconstruct6(sh, percpu, tx);
	}
1407

1408 1409 1410 1411 1412 1413 1414 1415 1416 1417
	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();
	}
1418 1419 1420 1421 1422 1423 1424

	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);
		}
1425
	put_cpu();
1426 1427
}

1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457
#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

1458
static int grow_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1459 1460
{
	struct stripe_head *sh;
N
Namhyung Kim 已提交
1461
	sh = kmem_cache_zalloc(conf->slab_cache, GFP_KERNEL);
1462 1463
	if (!sh)
		return 0;
N
Namhyung Kim 已提交
1464

1465
	sh->raid_conf = conf;
1466 1467 1468
	#ifdef CONFIG_MULTICORE_RAID456
	init_waitqueue_head(&sh->ops.wait_for_ops);
	#endif
1469

1470 1471
	if (grow_buffers(sh)) {
		shrink_buffers(sh);
1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482
		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;
}

1483
static int grow_stripes(struct r5conf *conf, int num)
1484
{
1485
	struct kmem_cache *sc;
1486
	int devs = max(conf->raid_disks, conf->previous_raid_disks);
L
Linus Torvalds 已提交
1487

1488 1489 1490 1491 1492 1493 1494 1495
	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]);

1496 1497
	conf->active_name = 0;
	sc = kmem_cache_create(conf->cache_name[conf->active_name],
L
Linus Torvalds 已提交
1498
			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
1499
			       0, 0, NULL);
L
Linus Torvalds 已提交
1500 1501 1502
	if (!sc)
		return 1;
	conf->slab_cache = sc;
1503
	conf->pool_size = devs;
1504
	while (num--)
1505
		if (!grow_one_stripe(conf))
L
Linus Torvalds 已提交
1506 1507 1508
			return 1;
	return 0;
}
1509

1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531
/**
 * 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;
}

1532
static int resize_stripes(struct r5conf *conf, int newsize)
1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559
{
	/* 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;
1560
	unsigned long cpu;
1561
	int err;
1562
	struct kmem_cache *sc;
1563 1564 1565 1566 1567
	int i;

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

1568 1569 1570
	err = md_allow_write(conf->mddev);
	if (err)
		return err;
1571

1572 1573 1574
	/* Step 1 */
	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
1575
			       0, 0, NULL);
1576 1577 1578 1579
	if (!sc)
		return -ENOMEM;

	for (i = conf->max_nr_stripes; i; i--) {
N
Namhyung Kim 已提交
1580
		nsh = kmem_cache_zalloc(sc, GFP_KERNEL);
1581 1582 1583 1584
		if (!nsh)
			break;

		nsh->raid_conf = conf;
1585 1586 1587
		#ifdef CONFIG_MULTICORE_RAID456
		init_waitqueue_head(&nsh->ops.wait_for_ops);
		#endif
1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609

		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
1610
				    );
1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624
		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
1625
	 * conf->disks and the scribble region
1626 1627 1628 1629 1630 1631 1632 1633 1634 1635
	 */
	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;

1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654
	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();

1655 1656 1657 1658
	/* 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);
1659

1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675
		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
1676

1677
static int drop_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1678 1679 1680
{
	struct stripe_head *sh;

1681 1682 1683 1684 1685
	spin_lock_irq(&conf->device_lock);
	sh = get_free_stripe(conf);
	spin_unlock_irq(&conf->device_lock);
	if (!sh)
		return 0;
1686
	BUG_ON(atomic_read(&sh->count));
1687
	shrink_buffers(sh);
1688 1689 1690 1691 1692
	kmem_cache_free(conf->slab_cache, sh);
	atomic_dec(&conf->active_stripes);
	return 1;
}

1693
static void shrink_stripes(struct r5conf *conf)
1694 1695 1696 1697
{
	while (drop_one_stripe(conf))
		;

N
NeilBrown 已提交
1698 1699
	if (conf->slab_cache)
		kmem_cache_destroy(conf->slab_cache);
L
Linus Torvalds 已提交
1700 1701 1702
	conf->slab_cache = NULL;
}

1703
static void raid5_end_read_request(struct bio * bi, int error)
L
Linus Torvalds 已提交
1704
{
1705
	struct stripe_head *sh = bi->bi_private;
1706
	struct r5conf *conf = sh->raid_conf;
1707
	int disks = sh->disks, i;
L
Linus Torvalds 已提交
1708
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1709
	char b[BDEVNAME_SIZE];
1710
	struct md_rdev *rdev = NULL;
1711
	sector_t s;
L
Linus Torvalds 已提交
1712 1713 1714 1715 1716

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

1717 1718
	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
1719 1720 1721
		uptodate);
	if (i == disks) {
		BUG();
1722
		return;
L
Linus Torvalds 已提交
1723
	}
1724
	if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
1725 1726 1727 1728 1729
		/* If replacement finished while this request was outstanding,
		 * 'replacement' might be NULL already.
		 * In that case it moved down to 'rdev'.
		 * rdev is not removed until all requests are finished.
		 */
1730
		rdev = conf->disks[i].replacement;
1731
	if (!rdev)
1732
		rdev = conf->disks[i].rdev;
L
Linus Torvalds 已提交
1733

1734 1735 1736 1737
	if (use_new_offset(conf, sh))
		s = sh->sector + rdev->new_data_offset;
	else
		s = sh->sector + rdev->data_offset;
L
Linus Torvalds 已提交
1738 1739
	if (uptodate) {
		set_bit(R5_UPTODATE, &sh->dev[i].flags);
1740
		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1741 1742 1743 1744
			/* Note that this cannot happen on a
			 * replacement device.  We just fail those on
			 * any error
			 */
1745 1746 1747 1748 1749
			printk_ratelimited(
				KERN_INFO
				"md/raid:%s: read error corrected"
				" (%lu sectors at %llu on %s)\n",
				mdname(conf->mddev), STRIPE_SECTORS,
1750
				(unsigned long long)s,
1751
				bdevname(rdev->bdev, b));
1752
			atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1753 1754 1755
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
		}
1756 1757
		if (atomic_read(&rdev->read_errors))
			atomic_set(&rdev->read_errors, 0);
L
Linus Torvalds 已提交
1758
	} else {
1759
		const char *bdn = bdevname(rdev->bdev, b);
1760
		int retry = 0;
1761
		int set_bad = 0;
1762

L
Linus Torvalds 已提交
1763
		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
1764
		atomic_inc(&rdev->read_errors);
1765 1766 1767 1768 1769 1770
		if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error on replacement device "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1771
				(unsigned long long)s,
1772
				bdn);
1773 1774
		else if (conf->mddev->degraded >= conf->max_degraded) {
			set_bad = 1;
1775 1776 1777 1778 1779
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error not correctable "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1780
				(unsigned long long)s,
1781
				bdn);
1782
		} else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
1783
			/* Oh, no!!! */
1784
			set_bad = 1;
1785 1786 1787 1788 1789
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error NOT corrected!! "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1790
				(unsigned long long)s,
1791
				bdn);
1792
		} else if (atomic_read(&rdev->read_errors)
1793
			 > conf->max_nr_stripes)
N
NeilBrown 已提交
1794
			printk(KERN_WARNING
1795
			       "md/raid:%s: Too many read errors, failing device %s.\n",
1796
			       mdname(conf->mddev), bdn);
1797 1798 1799 1800 1801
		else
			retry = 1;
		if (retry)
			set_bit(R5_ReadError, &sh->dev[i].flags);
		else {
1802 1803
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1804 1805 1806 1807 1808
			if (!(set_bad
			      && test_bit(In_sync, &rdev->flags)
			      && rdev_set_badblocks(
				      rdev, sh->sector, STRIPE_SECTORS, 0)))
				md_error(conf->mddev, rdev);
1809
		}
L
Linus Torvalds 已提交
1810
	}
1811
	rdev_dec_pending(rdev, conf->mddev);
L
Linus Torvalds 已提交
1812 1813 1814 1815 1816
	clear_bit(R5_LOCKED, &sh->dev[i].flags);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1817
static void raid5_end_write_request(struct bio *bi, int error)
L
Linus Torvalds 已提交
1818
{
1819
	struct stripe_head *sh = bi->bi_private;
1820
	struct r5conf *conf = sh->raid_conf;
1821
	int disks = sh->disks, i;
1822
	struct md_rdev *uninitialized_var(rdev);
L
Linus Torvalds 已提交
1823
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1824 1825
	sector_t first_bad;
	int bad_sectors;
1826
	int replacement = 0;
L
Linus Torvalds 已提交
1827

1828 1829 1830
	for (i = 0 ; i < disks; i++) {
		if (bi == &sh->dev[i].req) {
			rdev = conf->disks[i].rdev;
L
Linus Torvalds 已提交
1831
			break;
1832 1833 1834
		}
		if (bi == &sh->dev[i].rreq) {
			rdev = conf->disks[i].replacement;
1835 1836 1837 1838 1839 1840 1841 1842
			if (rdev)
				replacement = 1;
			else
				/* rdev was removed and 'replacement'
				 * replaced it.  rdev is not removed
				 * until all requests are finished.
				 */
				rdev = conf->disks[i].rdev;
1843 1844 1845
			break;
		}
	}
1846
	pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
L
Linus Torvalds 已提交
1847 1848 1849 1850
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
		uptodate);
	if (i == disks) {
		BUG();
1851
		return;
L
Linus Torvalds 已提交
1852 1853
	}

1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864
	if (replacement) {
		if (!uptodate)
			md_error(conf->mddev, rdev);
		else if (is_badblock(rdev, sh->sector,
				     STRIPE_SECTORS,
				     &first_bad, &bad_sectors))
			set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
	} else {
		if (!uptodate) {
			set_bit(WriteErrorSeen, &rdev->flags);
			set_bit(R5_WriteError, &sh->dev[i].flags);
1865 1866 1867
			if (!test_and_set_bit(WantReplacement, &rdev->flags))
				set_bit(MD_RECOVERY_NEEDED,
					&rdev->mddev->recovery);
1868 1869 1870 1871 1872 1873
		} else if (is_badblock(rdev, sh->sector,
				       STRIPE_SECTORS,
				       &first_bad, &bad_sectors))
			set_bit(R5_MadeGood, &sh->dev[i].flags);
	}
	rdev_dec_pending(rdev, conf->mddev);
L
Linus Torvalds 已提交
1874

1875 1876
	if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
		clear_bit(R5_LOCKED, &sh->dev[i].flags);
L
Linus Torvalds 已提交
1877
	set_bit(STRIPE_HANDLE, &sh->state);
1878
	release_stripe(sh);
L
Linus Torvalds 已提交
1879 1880
}

1881
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
L
Linus Torvalds 已提交
1882
	
1883
static void raid5_build_block(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
1884 1885 1886 1887 1888 1889 1890 1891
{
	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->req.bi_private = sh;
1892
	dev->vec.bv_page = dev->page;
L
Linus Torvalds 已提交
1893

1894 1895 1896 1897 1898 1899 1900
	bio_init(&dev->rreq);
	dev->rreq.bi_io_vec = &dev->rvec;
	dev->rreq.bi_vcnt++;
	dev->rreq.bi_max_vecs++;
	dev->rreq.bi_private = sh;
	dev->rvec.bv_page = dev->page;

L
Linus Torvalds 已提交
1901
	dev->flags = 0;
1902
	dev->sector = compute_blocknr(sh, i, previous);
L
Linus Torvalds 已提交
1903 1904
}

1905
static void error(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
1906 1907
{
	char b[BDEVNAME_SIZE];
1908
	struct r5conf *conf = mddev->private;
1909
	unsigned long flags;
1910
	pr_debug("raid456: error called\n");
L
Linus Torvalds 已提交
1911

1912 1913 1914 1915 1916 1917
	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);

1918
	set_bit(Blocked, &rdev->flags);
1919 1920 1921 1922 1923 1924 1925 1926 1927
	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);
1928
}
L
Linus Torvalds 已提交
1929 1930 1931 1932 1933

/*
 * Input: a 'big' sector number,
 * Output: index of the data and parity disk, and the sector # in them.
 */
1934
static sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
1935 1936
				     int previous, int *dd_idx,
				     struct stripe_head *sh)
L
Linus Torvalds 已提交
1937
{
N
NeilBrown 已提交
1938
	sector_t stripe, stripe2;
1939
	sector_t chunk_number;
L
Linus Torvalds 已提交
1940
	unsigned int chunk_offset;
1941
	int pd_idx, qd_idx;
1942
	int ddf_layout = 0;
L
Linus Torvalds 已提交
1943
	sector_t new_sector;
1944 1945
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
1946 1947
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
1948 1949 1950
	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
1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962

	/* 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
	 */
1963 1964
	stripe = chunk_number;
	*dd_idx = sector_div(stripe, data_disks);
N
NeilBrown 已提交
1965
	stripe2 = stripe;
L
Linus Torvalds 已提交
1966 1967 1968
	/*
	 * Select the parity disk based on the user selected algorithm.
	 */
1969
	pd_idx = qd_idx = -1;
1970 1971
	switch(conf->level) {
	case 4:
1972
		pd_idx = data_disks;
1973 1974
		break;
	case 5:
1975
		switch (algorithm) {
L
Linus Torvalds 已提交
1976
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
1977
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
1978
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
1979 1980 1981
				(*dd_idx)++;
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
1982
			pd_idx = sector_div(stripe2, raid_disks);
1983
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
1984 1985 1986
				(*dd_idx)++;
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
1987
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
1988
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
1989 1990
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
1991
			pd_idx = sector_div(stripe2, raid_disks);
1992
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
1993
			break;
1994 1995 1996 1997 1998 1999 2000
		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
2001
		default:
2002
			BUG();
2003 2004 2005 2006
		}
		break;
	case 6:

2007
		switch (algorithm) {
2008
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
2009
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2010 2011
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
2012
				(*dd_idx)++;	/* Q D D D P */
2013 2014
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
2015 2016 2017
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
2018
			pd_idx = sector_div(stripe2, raid_disks);
2019 2020
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
2021
				(*dd_idx)++;	/* Q D D D P */
2022 2023
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
2024 2025 2026
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
2027
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2028 2029
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2030 2031
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
2032
			pd_idx = sector_div(stripe2, raid_disks);
2033 2034
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2035
			break;
2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050

		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
2051
			pd_idx = sector_div(stripe2, raid_disks);
2052 2053 2054 2055 2056 2057
			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 */
2058
			ddf_layout = 1;
2059 2060 2061 2062 2063 2064 2065
			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
2066 2067
			stripe2 += 1;
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2068 2069 2070 2071 2072 2073
			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 */
2074
			ddf_layout = 1;
2075 2076 2077 2078
			break;

		case ALGORITHM_ROTATING_N_CONTINUE:
			/* Same as left_symmetric but Q is before P */
N
NeilBrown 已提交
2079
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2080 2081
			qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2082
			ddf_layout = 1;
2083 2084 2085 2086
			break;

		case ALGORITHM_LEFT_ASYMMETRIC_6:
			/* RAID5 left_asymmetric, with Q on last device */
N
NeilBrown 已提交
2087
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2088 2089 2090 2091 2092 2093
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_RIGHT_ASYMMETRIC_6:
N
NeilBrown 已提交
2094
			pd_idx = sector_div(stripe2, raid_disks-1);
2095 2096 2097 2098 2099 2100
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_LEFT_SYMMETRIC_6:
N
NeilBrown 已提交
2101
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2102 2103 2104 2105 2106
			*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
2107
			pd_idx = sector_div(stripe2, raid_disks-1);
2108 2109 2110 2111 2112 2113 2114 2115 2116 2117
			*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;

2118
		default:
2119
			BUG();
2120 2121
		}
		break;
L
Linus Torvalds 已提交
2122 2123
	}

2124 2125 2126
	if (sh) {
		sh->pd_idx = pd_idx;
		sh->qd_idx = qd_idx;
2127
		sh->ddf_layout = ddf_layout;
2128
	}
L
Linus Torvalds 已提交
2129 2130 2131 2132 2133 2134 2135 2136
	/*
	 * Finally, compute the new sector number
	 */
	new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
	return new_sector;
}


2137
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
2138
{
2139
	struct r5conf *conf = sh->raid_conf;
2140 2141
	int raid_disks = sh->disks;
	int data_disks = raid_disks - conf->max_degraded;
L
Linus Torvalds 已提交
2142
	sector_t new_sector = sh->sector, check;
2143 2144
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
2145 2146
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
L
Linus Torvalds 已提交
2147 2148
	sector_t stripe;
	int chunk_offset;
2149 2150
	sector_t chunk_number;
	int dummy1, dd_idx = i;
L
Linus Torvalds 已提交
2151
	sector_t r_sector;
2152
	struct stripe_head sh2;
L
Linus Torvalds 已提交
2153

2154

L
Linus Torvalds 已提交
2155 2156 2157
	chunk_offset = sector_div(new_sector, sectors_per_chunk);
	stripe = new_sector;

2158 2159 2160 2161 2162
	if (i == sh->pd_idx)
		return 0;
	switch(conf->level) {
	case 4: break;
	case 5:
2163
		switch (algorithm) {
L
Linus Torvalds 已提交
2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174
		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;
2175 2176 2177 2178 2179
		case ALGORITHM_PARITY_0:
			i -= 1;
			break;
		case ALGORITHM_PARITY_N:
			break;
L
Linus Torvalds 已提交
2180
		default:
2181
			BUG();
2182 2183 2184
		}
		break;
	case 6:
2185
		if (i == sh->qd_idx)
2186
			return 0; /* It is the Q disk */
2187
		switch (algorithm) {
2188 2189
		case ALGORITHM_LEFT_ASYMMETRIC:
		case ALGORITHM_RIGHT_ASYMMETRIC:
2190 2191 2192 2193
		case ALGORITHM_ROTATING_ZERO_RESTART:
		case ALGORITHM_ROTATING_N_RESTART:
			if (sh->pd_idx == raid_disks-1)
				i--;	/* Q D D D P */
2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207
			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;
2208 2209 2210 2211 2212 2213
		case ALGORITHM_PARITY_0:
			i -= 2;
			break;
		case ALGORITHM_PARITY_N:
			break;
		case ALGORITHM_ROTATING_N_CONTINUE:
2214
			/* Like left_symmetric, but P is before Q */
2215 2216
			if (sh->pd_idx == 0)
				i--;	/* P D D D Q */
2217 2218 2219 2220 2221 2222
			else {
				/* D D Q P D */
				if (i < sh->pd_idx)
					i += raid_disks;
				i -= (sh->pd_idx + 1);
			}
2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237
			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;
2238
		default:
2239
			BUG();
2240 2241
		}
		break;
L
Linus Torvalds 已提交
2242 2243 2244
	}

	chunk_number = stripe * data_disks + i;
2245
	r_sector = chunk_number * sectors_per_chunk + chunk_offset;
L
Linus Torvalds 已提交
2246

2247
	check = raid5_compute_sector(conf, r_sector,
2248
				     previous, &dummy1, &sh2);
2249 2250
	if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
		|| sh2.qd_idx != sh->qd_idx) {
2251 2252
		printk(KERN_ERR "md/raid:%s: compute_blocknr: map not correct\n",
		       mdname(conf->mddev));
L
Linus Torvalds 已提交
2253 2254 2255 2256 2257 2258
		return 0;
	}
	return r_sector;
}


2259
static void
2260
schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
2261
			 int rcw, int expand)
2262 2263
{
	int i, pd_idx = sh->pd_idx, disks = sh->disks;
2264
	struct r5conf *conf = sh->raid_conf;
2265
	int level = conf->level;
2266 2267 2268 2269 2270 2271 2272

	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) {
2273 2274 2275 2276
			sh->reconstruct_state = reconstruct_state_drain_run;
			set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
		} else
			sh->reconstruct_state = reconstruct_state_run;
2277

2278
		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2279 2280 2281 2282 2283 2284

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

			if (dev->towrite) {
				set_bit(R5_LOCKED, &dev->flags);
2285
				set_bit(R5_Wantdrain, &dev->flags);
2286 2287
				if (!expand)
					clear_bit(R5_UPTODATE, &dev->flags);
2288
				s->locked++;
2289 2290
			}
		}
2291
		if (s->locked + conf->max_degraded == disks)
2292
			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
2293
				atomic_inc(&conf->pending_full_writes);
2294
	} else {
2295
		BUG_ON(level == 6);
2296 2297 2298
		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));

2299
		sh->reconstruct_state = reconstruct_state_prexor_drain_run;
2300 2301
		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
2302
		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2303 2304 2305 2306 2307 2308 2309 2310

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

			if (dev->towrite &&
			    (test_bit(R5_UPTODATE, &dev->flags) ||
2311 2312
			     test_bit(R5_Wantcompute, &dev->flags))) {
				set_bit(R5_Wantdrain, &dev->flags);
2313 2314
				set_bit(R5_LOCKED, &dev->flags);
				clear_bit(R5_UPTODATE, &dev->flags);
2315
				s->locked++;
2316 2317 2318 2319
			}
		}
	}

2320
	/* keep the parity disk(s) locked while asynchronous operations
2321 2322 2323 2324
	 * are in flight
	 */
	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
2325
	s->locked++;
2326

2327 2328 2329 2330 2331 2332 2333 2334 2335
	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++;
	}

2336
	pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
2337
		__func__, (unsigned long long)sh->sector,
2338
		s->locked, s->ops_request);
2339
}
2340

L
Linus Torvalds 已提交
2341 2342
/*
 * Each stripe/dev can have one or more bion attached.
2343
 * toread/towrite point to the first in a chain.
L
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2344 2345 2346 2347 2348
 * 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;
2349
	struct r5conf *conf = sh->raid_conf;
2350
	int firstwrite=0;
L
Linus Torvalds 已提交
2351

2352
	pr_debug("adding bi b#%llu to stripe s#%llu\n",
L
Linus Torvalds 已提交
2353 2354 2355 2356 2357
		(unsigned long long)bi->bi_sector,
		(unsigned long long)sh->sector);


	spin_lock_irq(&conf->device_lock);
2358
	if (forwrite) {
L
Linus Torvalds 已提交
2359
		bip = &sh->dev[dd_idx].towrite;
2360 2361 2362
		if (*bip == NULL && sh->dev[dd_idx].written == NULL)
			firstwrite = 1;
	} else
L
Linus Torvalds 已提交
2363 2364 2365 2366 2367 2368 2369 2370 2371
		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;

2372
	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
L
Linus Torvalds 已提交
2373 2374 2375
	if (*bip)
		bi->bi_next = *bip;
	*bip = bi;
2376
	raid5_inc_bi_active_stripes(bi);
2377

L
Linus Torvalds 已提交
2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390
	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);
	}
2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402
	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
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2403 2404 2405 2406 2407 2408 2409 2410
	return 1;

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

2411
static void end_reshape(struct r5conf *conf);
2412

2413
static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
2414
			    struct stripe_head *sh)
2415
{
2416
	int sectors_per_chunk =
2417
		previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
2418
	int dd_idx;
2419
	int chunk_offset = sector_div(stripe, sectors_per_chunk);
2420
	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
2421

2422 2423
	raid5_compute_sector(conf,
			     stripe * (disks - conf->max_degraded)
2424
			     *sectors_per_chunk + chunk_offset,
2425
			     previous,
2426
			     &dd_idx, sh);
2427 2428
}

2429
static void
2430
handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
2431 2432 2433 2434 2435 2436 2437 2438 2439
				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)) {
2440
			struct md_rdev *rdev;
2441 2442 2443
			rcu_read_lock();
			rdev = rcu_dereference(conf->disks[i].rdev);
			if (rdev && test_bit(In_sync, &rdev->flags))
2444 2445 2446
				atomic_inc(&rdev->nr_pending);
			else
				rdev = NULL;
2447
			rcu_read_unlock();
2448 2449 2450 2451 2452 2453 2454 2455
			if (rdev) {
				if (!rdev_set_badblocks(
					    rdev,
					    sh->sector,
					    STRIPE_SECTORS, 0))
					md_error(conf->mddev, rdev);
				rdev_dec_pending(rdev, conf->mddev);
			}
2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472
		}
		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);
2473
			if (!raid5_dec_bi_active_stripes(bi)) {
2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487
				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);
2488
			if (!raid5_dec_bi_active_stripes(bi)) {
2489 2490 2491 2492 2493 2494 2495
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = bi2;
		}

2496 2497 2498 2499 2500 2501
		/* 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))) {
2502 2503 2504 2505 2506 2507 2508 2509 2510 2511
			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);
2512
				if (!raid5_dec_bi_active_stripes(bi)) {
2513 2514 2515 2516 2517 2518 2519 2520 2521 2522
					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);
2523 2524 2525 2526
		/* 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);
2527 2528
	}

2529 2530 2531
	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);
2532 2533
}

2534
static void
2535
handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
2536 2537 2538 2539 2540 2541 2542
		   struct stripe_head_state *s)
{
	int abort = 0;
	int i;

	clear_bit(STRIPE_SYNCING, &sh->state);
	s->syncing = 0;
2543
	s->replacing = 0;
2544
	/* There is nothing more to do for sync/check/repair.
2545 2546 2547
	 * Don't even need to abort as that is handled elsewhere
	 * if needed, and not always wanted e.g. if there is a known
	 * bad block here.
2548
	 * For recover/replace we need to record a bad block on all
2549 2550
	 * non-sync devices, or abort the recovery
	 */
2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573
	if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
		/* During recovery devices cannot be removed, so
		 * locking and refcounting of rdevs is not needed
		 */
		for (i = 0; i < conf->raid_disks; i++) {
			struct md_rdev *rdev = conf->disks[i].rdev;
			if (rdev
			    && !test_bit(Faulty, &rdev->flags)
			    && !test_bit(In_sync, &rdev->flags)
			    && !rdev_set_badblocks(rdev, sh->sector,
						   STRIPE_SECTORS, 0))
				abort = 1;
			rdev = conf->disks[i].replacement;
			if (rdev
			    && !test_bit(Faulty, &rdev->flags)
			    && !test_bit(In_sync, &rdev->flags)
			    && !rdev_set_badblocks(rdev, sh->sector,
						   STRIPE_SECTORS, 0))
				abort = 1;
		}
		if (abort)
			conf->recovery_disabled =
				conf->mddev->recovery_disabled;
2574
	}
2575
	md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
2576 2577
}

2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593
static int want_replace(struct stripe_head *sh, int disk_idx)
{
	struct md_rdev *rdev;
	int rv = 0;
	/* Doing recovery so rcu locking not required */
	rdev = sh->raid_conf->disks[disk_idx].replacement;
	if (rdev
	    && !test_bit(Faulty, &rdev->flags)
	    && !test_bit(In_sync, &rdev->flags)
	    && (rdev->recovery_offset <= sh->sector
		|| rdev->mddev->recovery_cp <= sh->sector))
		rv = 1;

	return rv;
}

2594
/* fetch_block - checks the given member device to see if its data needs
2595 2596 2597
 * to be read or computed to satisfy a request.
 *
 * Returns 1 when no more member devices need to be checked, otherwise returns
2598
 * 0 to tell the loop in handle_stripe_fill to continue
2599
 */
2600 2601
static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
		       int disk_idx, int disks)
2602
{
2603
	struct r5dev *dev = &sh->dev[disk_idx];
2604 2605
	struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
				  &sh->dev[s->failed_num[1]] };
2606

2607
	/* is the data in this block needed, and can we get it? */
2608 2609 2610 2611 2612
	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 ||
2613
	     (s->replacing && want_replace(sh, disk_idx)) ||
2614 2615
	     (s->failed >= 1 && fdev[0]->toread) ||
	     (s->failed >= 2 && fdev[1]->toread) ||
2616 2617 2618
	     (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))) {
2619 2620 2621 2622 2623 2624
		/* 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) &&
2625 2626
		    (s->failed && (disk_idx == s->failed_num[0] ||
				   disk_idx == s->failed_num[1]))) {
2627 2628
			/* have disk failed, and we're requested to fetch it;
			 * do compute it
2629
			 */
2630 2631 2632 2633 2634 2635 2636 2637
			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;
2638 2639 2640 2641 2642 2643
			/* 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.
			 */
2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656
			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;
2657
			}
2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676
			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);
2677 2678
		}
	}
2679 2680 2681 2682 2683

	return 0;
}

/**
2684
 * handle_stripe_fill - read or compute data to satisfy pending requests.
2685
 */
2686 2687 2688
static void handle_stripe_fill(struct stripe_head *sh,
			       struct stripe_head_state *s,
			       int disks)
2689 2690 2691 2692 2693 2694 2695 2696 2697 2698
{
	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--; )
2699
			if (fetch_block(sh, s, i, disks))
2700
				break;
2701 2702 2703 2704
	set_bit(STRIPE_HANDLE, &sh->state);
}


2705
/* handle_stripe_clean_event
2706 2707 2708 2709
 * 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.
 */
2710
static void handle_stripe_clean_event(struct r5conf *conf,
2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723
	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;
2724
				pr_debug("Return write for disc %d\n", i);
2725 2726 2727 2728 2729 2730
				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);
2731
					if (!raid5_dec_bi_active_stripes(wbi)) {
2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748
						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);
			}
		}
2749 2750 2751 2752

	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);
2753 2754
}

2755
static void handle_stripe_dirtying(struct r5conf *conf,
2756 2757 2758
				   struct stripe_head *sh,
				   struct stripe_head_state *s,
				   int disks)
2759 2760
{
	int rmw = 0, rcw = 0, i;
2761 2762 2763 2764 2765 2766 2767
	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--; ) {
2768 2769 2770 2771
		/* 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) &&
2772 2773
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		      test_bit(R5_Wantcompute, &dev->flags))) {
2774 2775 2776 2777 2778 2779 2780 2781
			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) &&
2782 2783 2784
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		    test_bit(R5_Wantcompute, &dev->flags))) {
			if (test_bit(R5_Insync, &dev->flags)) rcw++;
2785 2786 2787 2788
			else
				rcw += 2*disks;
		}
	}
2789
	pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2790 2791 2792 2793 2794 2795 2796 2797
		(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) &&
2798 2799
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
			    test_bit(R5_Wantcompute, &dev->flags)) &&
2800 2801 2802
			    test_bit(R5_Insync, &dev->flags)) {
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2803
					pr_debug("Read_old block "
2804 2805 2806 2807 2808 2809 2810 2811 2812 2813
						"%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);
				}
			}
		}
2814
	if (rcw <= rmw && rcw > 0) {
2815
		/* want reconstruct write, but need to get some data */
2816
		rcw = 0;
2817 2818 2819
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (!test_bit(R5_OVERWRITE, &dev->flags) &&
2820
			    i != sh->pd_idx && i != sh->qd_idx &&
2821
			    !test_bit(R5_LOCKED, &dev->flags) &&
2822
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
2823 2824 2825 2826
			      test_bit(R5_Wantcompute, &dev->flags))) {
				rcw++;
				if (!test_bit(R5_Insync, &dev->flags))
					continue; /* it's a failed drive */
2827 2828
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2829
					pr_debug("Read_old block "
2830 2831 2832 2833 2834 2835 2836 2837 2838 2839
						"%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);
				}
			}
		}
2840
	}
2841 2842 2843
	/* now if nothing is locked, and if we have enough data,
	 * we can start a write request
	 */
2844 2845
	/* 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
2846 2847
	 * subsequent call wants to start a write request.  raid_run_ops only
	 * handles the case where compute block and reconstruct are requested
2848 2849 2850
	 * simultaneously.  If this is not the case then new writes need to be
	 * held off until the compute completes.
	 */
2851 2852 2853
	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)))
2854
		schedule_reconstruction(sh, s, rcw == 0, 0);
2855 2856
}

2857
static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
2858 2859
				struct stripe_head_state *s, int disks)
{
2860
	struct r5dev *dev = NULL;
2861

2862
	set_bit(STRIPE_HANDLE, &sh->state);
2863

2864 2865 2866
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are no failures */
2867 2868
		if (s->failed == 0) {
			BUG_ON(s->uptodate != disks);
2869 2870
			sh->check_state = check_state_run;
			set_bit(STRIPE_OP_CHECK, &s->ops_request);
2871 2872
			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
			s->uptodate--;
2873
			break;
2874
		}
2875
		dev = &sh->dev[s->failed_num[0]];
2876 2877 2878 2879 2880 2881 2882 2883 2884
		/* 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
2885

2886 2887 2888 2889 2890
		/* 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);
2891
		s->locked++;
2892
		set_bit(R5_Wantwrite, &dev->flags);
2893

2894 2895
		clear_bit(STRIPE_DEGRADED, &sh->state);
		set_bit(STRIPE_INSYNC, &sh->state);
2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911
		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
2912
		if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923
			/* 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;
2924
				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2925 2926 2927 2928
				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;
2929
				sh->ops.target2 = -1;
2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940
				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();
2941 2942 2943 2944
	}
}


2945
static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
2946
				  struct stripe_head_state *s,
2947
				  int disks)
2948 2949
{
	int pd_idx = sh->pd_idx;
N
NeilBrown 已提交
2950
	int qd_idx = sh->qd_idx;
2951
	struct r5dev *dev;
2952 2953 2954 2955

	set_bit(STRIPE_HANDLE, &sh->state);

	BUG_ON(s->failed > 2);
2956

2957 2958 2959 2960 2961 2962
	/* 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
	 */

2963 2964 2965
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are < 2 failures */
2966
		if (s->failed == s->q_failed) {
2967
			/* The only possible failed device holds Q, so it
2968 2969 2970
			 * makes sense to check P (If anything else were failed,
			 * we would have used P to recreate it).
			 */
2971
			sh->check_state = check_state_run;
2972
		}
2973
		if (!s->q_failed && s->failed < 2) {
2974
			/* Q is not failed, and we didn't use it to generate
2975 2976
			 * anything, so it makes sense to check it
			 */
2977 2978 2979 2980
			if (sh->check_state == check_state_run)
				sh->check_state = check_state_run_pq;
			else
				sh->check_state = check_state_run_q;
2981 2982
		}

2983 2984
		/* discard potentially stale zero_sum_result */
		sh->ops.zero_sum_result = 0;
2985

2986 2987 2988 2989
		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--;
2990
		}
2991 2992 2993 2994 2995 2996 2997
		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;
2998 2999
		}

3000 3001 3002 3003 3004
		/* we have 2-disk failure */
		BUG_ON(s->failed != 2);
		/* fall through */
	case check_state_compute_result:
		sh->check_state = check_state_idle;
3005

3006 3007 3008
		/* check that a write has not made the stripe insync */
		if (test_bit(STRIPE_INSYNC, &sh->state))
			break;
3009 3010

		/* now write out any block on a failed drive,
3011
		 * or P or Q if they were recomputed
3012
		 */
3013
		BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
3014
		if (s->failed == 2) {
3015
			dev = &sh->dev[s->failed_num[1]];
3016 3017 3018 3019 3020
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		if (s->failed >= 1) {
3021
			dev = &sh->dev[s->failed_num[0]];
3022 3023 3024 3025
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
3026
		if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
3027 3028 3029 3030 3031
			dev = &sh->dev[pd_idx];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
3032
		if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
3033 3034 3035 3036 3037 3038 3039 3040
			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);
3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104
		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();
3105 3106 3107
	}
}

3108
static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
3109 3110 3111 3112 3113 3114
{
	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.
	 */
3115
	struct dma_async_tx_descriptor *tx = NULL;
3116 3117
	clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	for (i = 0; i < sh->disks; i++)
N
NeilBrown 已提交
3118
		if (i != sh->pd_idx && i != sh->qd_idx) {
3119
			int dd_idx, j;
3120
			struct stripe_head *sh2;
3121
			struct async_submit_ctl submit;
3122

3123
			sector_t bn = compute_blocknr(sh, i, 1);
3124 3125
			sector_t s = raid5_compute_sector(conf, bn, 0,
							  &dd_idx, NULL);
3126
			sh2 = get_active_stripe(conf, s, 0, 1, 1);
3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138
			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;
			}
3139 3140

			/* place all the copies on one channel */
3141
			init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
3142
			tx = async_memcpy(sh2->dev[dd_idx].page,
3143
					  sh->dev[i].page, 0, 0, STRIPE_SIZE,
3144
					  &submit);
3145

3146 3147 3148 3149
			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 &&
3150
				    j != sh2->qd_idx &&
3151 3152 3153 3154 3155 3156 3157
				    !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);
3158

3159
		}
3160 3161 3162 3163 3164
	/* done submitting copies, wait for them to complete */
	if (tx) {
		async_tx_ack(tx);
		dma_wait_for_async_tx(tx);
	}
3165
}
L
Linus Torvalds 已提交
3166 3167 3168 3169

/*
 * handle_stripe - do things to a stripe.
 *
3170 3171
 * We lock the stripe by setting STRIPE_ACTIVE and then examine the
 * state of various bits to see what needs to be done.
L
Linus Torvalds 已提交
3172
 * Possible results:
3173 3174
 *    return some read requests which now have data
 *    return some write requests which are safely on storage
L
Linus Torvalds 已提交
3175 3176 3177 3178 3179
 *    schedule a read on some buffers
 *    schedule a write of some buffers
 *    return confirmation of parity correctness
 *
 */
3180

3181
static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
L
Linus Torvalds 已提交
3182
{
3183
	struct r5conf *conf = sh->raid_conf;
3184
	int disks = sh->disks;
3185 3186
	struct r5dev *dev;
	int i;
3187
	int do_recovery = 0;
L
Linus Torvalds 已提交
3188

3189 3190 3191 3192 3193 3194
	memset(s, 0, sizeof(*s));

	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
3195

3196
	/* Now to look around and see what can be done */
L
Linus Torvalds 已提交
3197
	rcu_read_lock();
3198
	spin_lock_irq(&conf->device_lock);
3199
	for (i=disks; i--; ) {
3200
		struct md_rdev *rdev;
3201 3202 3203
		sector_t first_bad;
		int bad_sectors;
		int is_bad = 0;
3204

3205
		dev = &sh->dev[i];
L
Linus Torvalds 已提交
3206

3207
		pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
3208 3209
			 i, dev->flags,
			 dev->toread, dev->towrite, dev->written);
3210 3211 3212 3213 3214 3215 3216 3217
		/* 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
3218

3219
		/* now count some things */
3220 3221 3222 3223
		if (test_bit(R5_LOCKED, &dev->flags))
			s->locked++;
		if (test_bit(R5_UPTODATE, &dev->flags))
			s->uptodate++;
3224
		if (test_bit(R5_Wantcompute, &dev->flags)) {
3225 3226
			s->compute++;
			BUG_ON(s->compute > 2);
3227
		}
L
Linus Torvalds 已提交
3228

3229
		if (test_bit(R5_Wantfill, &dev->flags))
3230
			s->to_fill++;
3231
		else if (dev->toread)
3232
			s->to_read++;
3233
		if (dev->towrite) {
3234
			s->to_write++;
3235
			if (!test_bit(R5_OVERWRITE, &dev->flags))
3236
				s->non_overwrite++;
3237
		}
3238
		if (dev->written)
3239
			s->written++;
3240 3241 3242 3243 3244 3245 3246 3247 3248 3249
		/* Prefer to use the replacement for reads, but only
		 * if it is recovered enough and has no bad blocks.
		 */
		rdev = rcu_dereference(conf->disks[i].replacement);
		if (rdev && !test_bit(Faulty, &rdev->flags) &&
		    rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
		    !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
				 &first_bad, &bad_sectors))
			set_bit(R5_ReadRepl, &dev->flags);
		else {
3250 3251
			if (rdev)
				set_bit(R5_NeedReplace, &dev->flags);
3252 3253 3254
			rdev = rcu_dereference(conf->disks[i].rdev);
			clear_bit(R5_ReadRepl, &dev->flags);
		}
3255 3256
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268
		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);
			}
3269
		}
3270 3271 3272
		clear_bit(R5_Insync, &dev->flags);
		if (!rdev)
			/* Not in-sync */;
3273 3274
		else if (is_bad) {
			/* also not in-sync */
3275 3276
			if (!test_bit(WriteErrorSeen, &rdev->flags) &&
			    test_bit(R5_UPTODATE, &dev->flags)) {
3277 3278 3279 3280 3281 3282 3283
				/* 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))
3284
			set_bit(R5_Insync, &dev->flags);
3285
		else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
3286
			/* in sync if before recovery_offset */
3287 3288 3289 3290 3291 3292 3293 3294 3295
			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
3296
		if (rdev && test_bit(R5_WriteError, &dev->flags)) {
3297 3298 3299 3300 3301 3302 3303
			/* This flag does not apply to '.replacement'
			 * only to .rdev, so make sure to check that*/
			struct md_rdev *rdev2 = rcu_dereference(
				conf->disks[i].rdev);
			if (rdev2 == rdev)
				clear_bit(R5_Insync, &dev->flags);
			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
3304
				s->handle_bad_blocks = 1;
3305
				atomic_inc(&rdev2->nr_pending);
3306 3307 3308
			} else
				clear_bit(R5_WriteError, &dev->flags);
		}
A
Adam Kwolek 已提交
3309
		if (rdev && test_bit(R5_MadeGood, &dev->flags)) {
3310 3311 3312 3313 3314
			/* This flag does not apply to '.replacement'
			 * only to .rdev, so make sure to check that*/
			struct md_rdev *rdev2 = rcu_dereference(
				conf->disks[i].rdev);
			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
3315
				s->handle_bad_blocks = 1;
3316
				atomic_inc(&rdev2->nr_pending);
3317 3318 3319
			} else
				clear_bit(R5_MadeGood, &dev->flags);
		}
3320 3321 3322 3323 3324 3325 3326 3327 3328
		if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
			struct md_rdev *rdev2 = rcu_dereference(
				conf->disks[i].replacement);
			if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
				s->handle_bad_blocks = 1;
				atomic_inc(&rdev2->nr_pending);
			} else
				clear_bit(R5_MadeGoodRepl, &dev->flags);
		}
3329
		if (!test_bit(R5_Insync, &dev->flags)) {
3330 3331 3332
			/* 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
3333
		}
3334 3335 3336
		if (test_bit(R5_ReadError, &dev->flags))
			clear_bit(R5_Insync, &dev->flags);
		if (!test_bit(R5_Insync, &dev->flags)) {
3337 3338 3339
			if (s->failed < 2)
				s->failed_num[s->failed] = i;
			s->failed++;
3340 3341
			if (rdev && !test_bit(Faulty, &rdev->flags))
				do_recovery = 1;
3342
		}
L
Linus Torvalds 已提交
3343
	}
3344
	spin_unlock_irq(&conf->device_lock);
3345 3346 3347 3348
	if (test_bit(STRIPE_SYNCING, &sh->state)) {
		/* If there is a failed device being replaced,
		 *     we must be recovering.
		 * else if we are after recovery_cp, we must be syncing
3349
		 * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
3350 3351 3352 3353 3354
		 * else we can only be replacing
		 * sync and recovery both need to read all devices, and so
		 * use the same flag.
		 */
		if (do_recovery ||
3355 3356
		    sh->sector >= conf->mddev->recovery_cp ||
		    test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
3357 3358 3359 3360
			s->syncing = 1;
		else
			s->replacing = 1;
	}
L
Linus Torvalds 已提交
3361
	rcu_read_unlock();
3362 3363 3364 3365 3366
}

static void handle_stripe(struct stripe_head *sh)
{
	struct stripe_head_state s;
3367
	struct r5conf *conf = sh->raid_conf;
3368
	int i;
3369 3370
	int prexor;
	int disks = sh->disks;
3371
	struct r5dev *pdev, *qdev;
3372 3373

	clear_bit(STRIPE_HANDLE, &sh->state);
3374
	if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391
		/* 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);
3392

3393
	analyse_stripe(sh, &s);
3394

3395 3396 3397 3398 3399
	if (s.handle_bad_blocks) {
		set_bit(STRIPE_HANDLE, &sh->state);
		goto finish;
	}

3400 3401
	if (unlikely(s.blocked_rdev)) {
		if (s.syncing || s.expanding || s.expanded ||
3402
		    s.replacing || s.to_write || s.written) {
3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422
			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.
	 */
3423 3424 3425 3426 3427
	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);
3428
		if (s.syncing + s.replacing)
3429 3430
			handle_failed_sync(conf, sh, &s);
	}
3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458

	/*
	 * 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)
3459 3460 3461
	    || (s.syncing && (s.uptodate + s.compute < disks))
	    || s.replacing
	    || s.expanding)
3462 3463
		handle_stripe_fill(sh, &s, disks);

3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521
	/* 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);
	}
3522

3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536
	if (s.replacing && s.locked == 0
	    && !test_bit(STRIPE_INSYNC, &sh->state)) {
		/* Write out to replacement devices where possible */
		for (i = 0; i < conf->raid_disks; i++)
			if (test_bit(R5_UPTODATE, &sh->dev[i].flags) &&
			    test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
				set_bit(R5_WantReplace, &sh->dev[i].flags);
				set_bit(R5_LOCKED, &sh->dev[i].flags);
				s.locked++;
			}
		set_bit(STRIPE_INSYNC, &sh->state);
	}
	if ((s.syncing || s.replacing) && s.locked == 0 &&
	    test_bit(STRIPE_INSYNC, &sh->state)) {
3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565
		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++;
				}
			}
		}


3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592
	/* 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++;
		}
	}
3593

3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609
	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);
3610

3611
finish:
3612
	/* wait for this device to become unblocked */
3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624
	if (unlikely(s.blocked_rdev)) {
		if (conf->mddev->external)
			md_wait_for_blocked_rdev(s.blocked_rdev,
						 conf->mddev);
		else
			/* Internal metadata will immediately
			 * be written by raid5d, so we don't
			 * need to wait here.
			 */
			rdev_dec_pending(s.blocked_rdev,
					 conf->mddev);
	}
3625

3626 3627
	if (s.handle_bad_blocks)
		for (i = disks; i--; ) {
3628
			struct md_rdev *rdev;
3629 3630 3631 3632 3633 3634 3635 3636 3637
			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);
			}
3638 3639 3640
			if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
				rdev = conf->disks[i].rdev;
				rdev_clear_badblocks(rdev, sh->sector,
3641
						     STRIPE_SECTORS, 0);
3642 3643
				rdev_dec_pending(rdev, conf->mddev);
			}
3644 3645
			if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
				rdev = conf->disks[i].replacement;
3646 3647 3648
				if (!rdev)
					/* rdev have been moved down */
					rdev = conf->disks[i].rdev;
3649
				rdev_clear_badblocks(rdev, sh->sector,
3650
						     STRIPE_SECTORS, 0);
3651 3652
				rdev_dec_pending(rdev, conf->mddev);
			}
3653 3654
		}

3655 3656 3657
	if (s.ops_request)
		raid_run_ops(sh, s.ops_request);

D
Dan Williams 已提交
3658
	ops_run_io(sh, &s);
3659

3660
	if (s.dec_preread_active) {
3661
		/* We delay this until after ops_run_io so that if make_request
T
Tejun Heo 已提交
3662
		 * is waiting on a flush, it won't continue until the writes
3663 3664 3665 3666 3667 3668 3669 3670
		 * 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);
	}

3671
	return_io(s.return_bi);
3672

3673
	clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
3674 3675
}

3676
static void raid5_activate_delayed(struct r5conf *conf)
3677 3678 3679 3680 3681 3682 3683 3684 3685 3686
{
	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);
3687
			list_add_tail(&sh->lru, &conf->hold_list);
3688
		}
N
NeilBrown 已提交
3689
	}
3690 3691
}

3692
static void activate_bit_delay(struct r5conf *conf)
3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705
{
	/* 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);
	}
}

3706
int md_raid5_congested(struct mddev *mddev, int bits)
3707
{
3708
	struct r5conf *conf = mddev->private;
3709 3710 3711 3712

	/* No difference between reads and writes.  Just check
	 * how busy the stripe_cache is
	 */
3713

3714 3715 3716 3717 3718 3719 3720 3721 3722
	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
3723 3724 3725 3726
EXPORT_SYMBOL_GPL(md_raid5_congested);

static int raid5_congested(void *data, int bits)
{
3727
	struct mddev *mddev = data;
N
NeilBrown 已提交
3728 3729 3730 3731

	return mddev_congested(mddev, bits) ||
		md_raid5_congested(mddev, bits);
}
3732

3733 3734 3735
/* We want read requests to align with chunks where possible,
 * but write requests don't need to.
 */
3736 3737 3738
static int raid5_mergeable_bvec(struct request_queue *q,
				struct bvec_merge_data *bvm,
				struct bio_vec *biovec)
3739
{
3740
	struct mddev *mddev = q->queuedata;
3741
	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
3742
	int max;
3743
	unsigned int chunk_sectors = mddev->chunk_sectors;
3744
	unsigned int bio_sectors = bvm->bi_size >> 9;
3745

3746
	if ((bvm->bi_rw & 1) == WRITE)
3747 3748
		return biovec->bv_len; /* always allow writes to be mergeable */

3749 3750
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3751 3752 3753 3754 3755 3756 3757 3758
	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;
}

3759

3760
static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
3761 3762
{
	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3763
	unsigned int chunk_sectors = mddev->chunk_sectors;
3764 3765
	unsigned int bio_sectors = bio->bi_size >> 9;

3766 3767
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3768 3769 3770 3771
	return  chunk_sectors >=
		((sector & (chunk_sectors - 1)) + bio_sectors);
}

3772 3773 3774 3775
/*
 *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
 *  later sampled by raid5d.
 */
3776
static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789
{
	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);
}


3790
static struct bio *remove_bio_from_retry(struct r5conf *conf)
3791 3792 3793 3794 3795 3796 3797 3798 3799 3800
{
	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) {
3801
		conf->retry_read_aligned_list = bi->bi_next;
3802
		bi->bi_next = NULL;
3803 3804 3805 3806
		/*
		 * this sets the active strip count to 1 and the processed
		 * strip count to zero (upper 8 bits)
		 */
3807
		raid5_set_bi_stripes(bi, 1); /* biased count of active stripes */
3808 3809 3810 3811 3812 3813
	}

	return bi;
}


3814 3815 3816 3817 3818 3819
/*
 *  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..
 */
3820
static void raid5_align_endio(struct bio *bi, int error)
3821 3822
{
	struct bio* raid_bi  = bi->bi_private;
3823
	struct mddev *mddev;
3824
	struct r5conf *conf;
3825
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
3826
	struct md_rdev *rdev;
3827

3828
	bio_put(bi);
3829 3830 3831

	rdev = (void*)raid_bi->bi_next;
	raid_bi->bi_next = NULL;
3832 3833
	mddev = rdev->mddev;
	conf = mddev->private;
3834 3835 3836 3837

	rdev_dec_pending(rdev, conf->mddev);

	if (!error && uptodate) {
3838
		bio_endio(raid_bi, 0);
3839 3840
		if (atomic_dec_and_test(&conf->active_aligned_reads))
			wake_up(&conf->wait_for_stripe);
3841
		return;
3842 3843 3844
	}


3845
	pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
3846 3847

	add_bio_to_retry(raid_bi, conf);
3848 3849
}

3850 3851
static int bio_fits_rdev(struct bio *bi)
{
3852
	struct request_queue *q = bdev_get_queue(bi->bi_bdev);
3853

3854
	if ((bi->bi_size>>9) > queue_max_sectors(q))
3855 3856
		return 0;
	blk_recount_segments(q, bi);
3857
	if (bi->bi_phys_segments > queue_max_segments(q))
3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869
		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;
}


3870
static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
3871
{
3872
	struct r5conf *conf = mddev->private;
N
NeilBrown 已提交
3873
	int dd_idx;
3874
	struct bio* align_bi;
3875
	struct md_rdev *rdev;
3876
	sector_t end_sector;
3877 3878

	if (!in_chunk_boundary(mddev, raid_bio)) {
3879
		pr_debug("chunk_aligned_read : non aligned\n");
3880 3881 3882
		return 0;
	}
	/*
3883
	 * use bio_clone_mddev to make a copy of the bio
3884
	 */
3885
	align_bi = bio_clone_mddev(raid_bio, GFP_NOIO, mddev);
3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896
	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
	 */
3897 3898
	align_bi->bi_sector =  raid5_compute_sector(conf, raid_bio->bi_sector,
						    0,
3899
						    &dd_idx, NULL);
3900

3901
	end_sector = align_bi->bi_sector + (align_bi->bi_size >> 9);
3902
	rcu_read_lock();
3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913
	rdev = rcu_dereference(conf->disks[dd_idx].replacement);
	if (!rdev || test_bit(Faulty, &rdev->flags) ||
	    rdev->recovery_offset < end_sector) {
		rdev = rcu_dereference(conf->disks[dd_idx].rdev);
		if (rdev &&
		    (test_bit(Faulty, &rdev->flags) ||
		    !(test_bit(In_sync, &rdev->flags) ||
		      rdev->recovery_offset >= end_sector)))
			rdev = NULL;
	}
	if (rdev) {
3914 3915 3916
		sector_t first_bad;
		int bad_sectors;

3917 3918
		atomic_inc(&rdev->nr_pending);
		rcu_read_unlock();
3919 3920 3921 3922
		raid_bio->bi_next = (void*)rdev;
		align_bi->bi_bdev =  rdev->bdev;
		align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);

3923 3924 3925 3926
		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 */
3927 3928 3929 3930 3931
			bio_put(align_bi);
			rdev_dec_pending(rdev, mddev);
			return 0;
		}

3932 3933 3934
		/* No reshape active, so we can trust rdev->data_offset */
		align_bi->bi_sector += rdev->data_offset;

3935 3936 3937 3938 3939 3940 3941
		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);

3942 3943 3944 3945
		generic_make_request(align_bi);
		return 1;
	} else {
		rcu_read_unlock();
3946
		bio_put(align_bi);
3947 3948 3949 3950
		return 0;
	}
}

3951 3952 3953 3954 3955 3956 3957 3958 3959 3960
/* __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.
 */
3961
static struct stripe_head *__get_priority_stripe(struct r5conf *conf)
3962 3963 3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002
{
	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;
}
4003

4004
static void make_request(struct mddev *mddev, struct bio * bi)
L
Linus Torvalds 已提交
4005
{
4006
	struct r5conf *conf = mddev->private;
4007
	int dd_idx;
L
Linus Torvalds 已提交
4008 4009 4010
	sector_t new_sector;
	sector_t logical_sector, last_sector;
	struct stripe_head *sh;
4011
	const int rw = bio_data_dir(bi);
4012
	int remaining;
L
Linus Torvalds 已提交
4013

T
Tejun Heo 已提交
4014 4015
	if (unlikely(bi->bi_rw & REQ_FLUSH)) {
		md_flush_request(mddev, bi);
4016
		return;
4017 4018
	}

4019
	md_write_start(mddev, bi);
4020

4021
	if (rw == READ &&
4022
	     mddev->reshape_position == MaxSector &&
4023
	     chunk_aligned_read(mddev,bi))
4024
		return;
4025

L
Linus Torvalds 已提交
4026 4027 4028 4029
	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 */
4030

L
Linus Torvalds 已提交
4031 4032
	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
		DEFINE_WAIT(w);
4033
		int previous;
4034

4035
	retry:
4036
		previous = 0;
4037
		prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
4038
		if (unlikely(conf->reshape_progress != MaxSector)) {
4039
			/* spinlock is needed as reshape_progress may be
4040 4041
			 * 64bit on a 32bit platform, and so it might be
			 * possible to see a half-updated value
4042
			 * Of course reshape_progress could change after
4043 4044 4045 4046
			 * the lock is dropped, so once we get a reference
			 * to the stripe that we think it is, we will have
			 * to check again.
			 */
4047
			spin_lock_irq(&conf->device_lock);
4048
			if (mddev->reshape_backwards
4049 4050
			    ? logical_sector < conf->reshape_progress
			    : logical_sector >= conf->reshape_progress) {
4051 4052
				previous = 1;
			} else {
4053
				if (mddev->reshape_backwards
4054 4055
				    ? logical_sector < conf->reshape_safe
				    : logical_sector >= conf->reshape_safe) {
4056 4057 4058 4059 4060
					spin_unlock_irq(&conf->device_lock);
					schedule();
					goto retry;
				}
			}
4061 4062
			spin_unlock_irq(&conf->device_lock);
		}
4063

4064 4065
		new_sector = raid5_compute_sector(conf, logical_sector,
						  previous,
4066
						  &dd_idx, NULL);
4067
		pr_debug("raid456: make_request, sector %llu logical %llu\n",
L
Linus Torvalds 已提交
4068 4069 4070
			(unsigned long long)new_sector, 
			(unsigned long long)logical_sector);

4071
		sh = get_active_stripe(conf, new_sector, previous,
4072
				       (bi->bi_rw&RWA_MASK), 0);
L
Linus Torvalds 已提交
4073
		if (sh) {
4074
			if (unlikely(previous)) {
4075
				/* expansion might have moved on while waiting for a
4076 4077 4078 4079 4080 4081
				 * 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.
4082 4083 4084
				 */
				int must_retry = 0;
				spin_lock_irq(&conf->device_lock);
4085
				if (mddev->reshape_backwards
4086 4087
				    ? logical_sector >= conf->reshape_progress
				    : logical_sector < conf->reshape_progress)
4088 4089 4090 4091 4092
					/* mismatch, need to try again */
					must_retry = 1;
				spin_unlock_irq(&conf->device_lock);
				if (must_retry) {
					release_stripe(sh);
4093
					schedule();
4094 4095 4096
					goto retry;
				}
			}
4097

4098
			if (rw == WRITE &&
4099
			    logical_sector >= mddev->suspend_lo &&
4100 4101
			    logical_sector < mddev->suspend_hi) {
				release_stripe(sh);
4102 4103 4104 4105 4106 4107 4108 4109 4110 4111
				/* 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();
4112 4113
				goto retry;
			}
4114 4115

			if (test_bit(STRIPE_EXPANDING, &sh->state) ||
4116
			    !add_stripe_bio(sh, bi, dd_idx, rw)) {
4117 4118
				/* Stripe is busy expanding or
				 * add failed due to overlap.  Flush everything
L
Linus Torvalds 已提交
4119 4120
				 * and wait a while
				 */
N
NeilBrown 已提交
4121
				md_wakeup_thread(mddev->thread);
L
Linus Torvalds 已提交
4122 4123 4124 4125 4126
				release_stripe(sh);
				schedule();
				goto retry;
			}
			finish_wait(&conf->wait_for_overlap, &w);
4127 4128
			set_bit(STRIPE_HANDLE, &sh->state);
			clear_bit(STRIPE_DELAYED, &sh->state);
T
Tejun Heo 已提交
4129
			if ((bi->bi_rw & REQ_SYNC) &&
4130 4131
			    !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
				atomic_inc(&conf->preread_active_stripes);
N
NeilBrown 已提交
4132
			mddev_check_plugged(mddev);
L
Linus Torvalds 已提交
4133 4134 4135 4136 4137 4138 4139 4140
			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;
		}
	}
4141

4142
	remaining = raid5_dec_bi_active_stripes(bi);
4143
	if (remaining == 0) {
L
Linus Torvalds 已提交
4144

4145
		if ( rw == WRITE )
L
Linus Torvalds 已提交
4146
			md_write_end(mddev);
4147

4148
		bio_endio(bi, 0);
L
Linus Torvalds 已提交
4149 4150 4151
	}
}

4152
static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
D
Dan Williams 已提交
4153

4154
static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
L
Linus Torvalds 已提交
4155
{
4156 4157 4158 4159 4160 4161 4162 4163 4164
	/* 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.
	 */
4165
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4166
	struct stripe_head *sh;
4167
	sector_t first_sector, last_sector;
4168 4169 4170
	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;
4171 4172
	int i;
	int dd_idx;
4173
	sector_t writepos, readpos, safepos;
4174
	sector_t stripe_addr;
4175
	int reshape_sectors;
4176
	struct list_head stripes;
4177

4178 4179
	if (sector_nr == 0) {
		/* If restarting in the middle, skip the initial sectors */
4180
		if (mddev->reshape_backwards &&
4181 4182 4183
		    conf->reshape_progress < raid5_size(mddev, 0, 0)) {
			sector_nr = raid5_size(mddev, 0, 0)
				- conf->reshape_progress;
4184
		} else if (!mddev->reshape_backwards &&
4185 4186
			   conf->reshape_progress > 0)
			sector_nr = conf->reshape_progress;
4187
		sector_div(sector_nr, new_data_disks);
4188
		if (sector_nr) {
4189 4190
			mddev->curr_resync_completed = sector_nr;
			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4191 4192 4193
			*skipped = 1;
			return sector_nr;
		}
4194 4195
	}

4196 4197 4198 4199
	/* 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
	 */
4200 4201
	if (mddev->new_chunk_sectors > mddev->chunk_sectors)
		reshape_sectors = mddev->new_chunk_sectors;
4202
	else
4203
		reshape_sectors = mddev->chunk_sectors;
4204

4205 4206 4207 4208 4209
	/* We update the metadata at least every 10 seconds, or when
	 * the data about to be copied would over-write the source of
	 * the data at the front of the range.  i.e. one new_stripe
	 * along from reshape_progress new_maps to after where
	 * reshape_safe old_maps to
4210
	 */
4211
	writepos = conf->reshape_progress;
4212
	sector_div(writepos, new_data_disks);
4213 4214
	readpos = conf->reshape_progress;
	sector_div(readpos, data_disks);
4215
	safepos = conf->reshape_safe;
4216
	sector_div(safepos, data_disks);
4217
	if (mddev->reshape_backwards) {
4218
		writepos -= min_t(sector_t, reshape_sectors, writepos);
4219
		readpos += reshape_sectors;
4220
		safepos += reshape_sectors;
4221
	} else {
4222
		writepos += reshape_sectors;
4223 4224
		readpos -= min_t(sector_t, reshape_sectors, readpos);
		safepos -= min_t(sector_t, reshape_sectors, safepos);
4225
	}
4226

4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240 4241
	/* Having calculated the 'writepos' possibly use it
	 * to set 'stripe_addr' which is where we will write to.
	 */
	if (mddev->reshape_backwards) {
		BUG_ON(conf->reshape_progress == 0);
		stripe_addr = writepos;
		BUG_ON((mddev->dev_sectors &
			~((sector_t)reshape_sectors - 1))
		       - reshape_sectors - stripe_addr
		       != sector_nr);
	} else {
		BUG_ON(writepos != sector_nr + reshape_sectors);
		stripe_addr = sector_nr;
	}

4242 4243 4244 4245
	/* '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.
4246 4247 4248 4249
	 * If there is a min_offset_diff, these are adjusted either by
	 * increasing the safepos/readpos if diff is negative, or
	 * increasing writepos if diff is positive.
	 * If 'readpos' is then behind 'writepos', there is no way that we can
4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261
	 * 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???
	 */
4262 4263 4264 4265 4266 4267
	if (conf->min_offset_diff < 0) {
		safepos += -conf->min_offset_diff;
		readpos += -conf->min_offset_diff;
	} else
		writepos += conf->min_offset_diff;

4268
	if ((mddev->reshape_backwards
4269 4270 4271
	     ? (safepos > writepos && readpos < writepos)
	     : (safepos < writepos && readpos > writepos)) ||
	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4272 4273 4274
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes)==0);
4275
		mddev->reshape_position = conf->reshape_progress;
4276
		mddev->curr_resync_completed = sector_nr;
4277
		conf->reshape_checkpoint = jiffies;
4278
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
4279
		md_wakeup_thread(mddev->thread);
4280
		wait_event(mddev->sb_wait, mddev->flags == 0 ||
4281 4282
			   kthread_should_stop());
		spin_lock_irq(&conf->device_lock);
4283
		conf->reshape_safe = mddev->reshape_position;
4284 4285
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4286
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4287 4288
	}

4289
	INIT_LIST_HEAD(&stripes);
4290
	for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
4291
		int j;
4292
		int skipped_disk = 0;
4293
		sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
4294 4295 4296 4297 4298 4299 4300 4301 4302
		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;
4303
			if (conf->level == 6 &&
4304
			    j == sh->qd_idx)
4305
				continue;
4306
			s = compute_blocknr(sh, j, 0);
D
Dan Williams 已提交
4307
			if (s < raid5_size(mddev, 0, 0)) {
4308
				skipped_disk = 1;
4309 4310 4311 4312 4313 4314
				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);
		}
4315
		if (!skipped_disk) {
4316 4317 4318
			set_bit(STRIPE_EXPAND_READY, &sh->state);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
4319
		list_add(&sh->lru, &stripes);
4320 4321
	}
	spin_lock_irq(&conf->device_lock);
4322
	if (mddev->reshape_backwards)
4323
		conf->reshape_progress -= reshape_sectors * new_data_disks;
4324
	else
4325
		conf->reshape_progress += reshape_sectors * new_data_disks;
4326 4327 4328 4329 4330 4331 4332
	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 =
4333
		raid5_compute_sector(conf, stripe_addr*(new_data_disks),
4334
				     1, &dd_idx, NULL);
4335
	last_sector =
4336
		raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
4337
					    * new_data_disks - 1),
4338
				     1, &dd_idx, NULL);
A
Andre Noll 已提交
4339 4340
	if (last_sector >= mddev->dev_sectors)
		last_sector = mddev->dev_sectors - 1;
4341
	while (first_sector <= last_sector) {
4342
		sh = get_active_stripe(conf, first_sector, 1, 0, 1);
4343 4344 4345 4346 4347
		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
		set_bit(STRIPE_HANDLE, &sh->state);
		release_stripe(sh);
		first_sector += STRIPE_SECTORS;
	}
4348 4349 4350 4351 4352 4353 4354 4355
	/* 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);
	}
4356 4357 4358
	/* If this takes us to the resync_max point where we have to pause,
	 * then we need to write out the superblock.
	 */
4359
	sector_nr += reshape_sectors;
4360 4361
	if ((sector_nr - mddev->curr_resync_completed) * 2
	    >= mddev->resync_max - mddev->curr_resync_completed) {
4362 4363 4364
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes) == 0);
4365
		mddev->reshape_position = conf->reshape_progress;
4366
		mddev->curr_resync_completed = sector_nr;
4367
		conf->reshape_checkpoint = jiffies;
4368 4369 4370 4371 4372 4373
		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);
4374
		conf->reshape_safe = mddev->reshape_position;
4375 4376
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4377
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4378
	}
4379
	return reshape_sectors;
4380 4381 4382
}

/* FIXME go_faster isn't used */
4383
static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
4384
{
4385
	struct r5conf *conf = mddev->private;
4386
	struct stripe_head *sh;
A
Andre Noll 已提交
4387
	sector_t max_sector = mddev->dev_sectors;
N
NeilBrown 已提交
4388
	sector_t sync_blocks;
4389 4390
	int still_degraded = 0;
	int i;
L
Linus Torvalds 已提交
4391

4392
	if (sector_nr >= max_sector) {
L
Linus Torvalds 已提交
4393
		/* just being told to finish up .. nothing much to do */
4394

4395 4396 4397 4398
		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
			end_reshape(conf);
			return 0;
		}
4399 4400 4401 4402

		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
					&sync_blocks, 1);
4403
		else /* completed sync */
4404 4405 4406
			conf->fullsync = 0;
		bitmap_close_sync(mddev->bitmap);

L
Linus Torvalds 已提交
4407 4408
		return 0;
	}
4409

4410 4411 4412
	/* Allow raid5_quiesce to complete */
	wait_event(conf->wait_for_overlap, conf->quiesce != 2);

4413 4414
	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
		return reshape_request(mddev, sector_nr, skipped);
4415

4416 4417 4418 4419 4420 4421
	/* 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
	 */

4422
	/* if there is too many failed drives and we are trying
L
Linus Torvalds 已提交
4423 4424 4425
	 * to resync, then assert that we are finished, because there is
	 * nothing we can do.
	 */
4426
	if (mddev->degraded >= conf->max_degraded &&
4427
	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
A
Andre Noll 已提交
4428
		sector_t rv = mddev->dev_sectors - sector_nr;
4429
		*skipped = 1;
L
Linus Torvalds 已提交
4430 4431
		return rv;
	}
4432
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
4433
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
4434 4435 4436 4437 4438 4439
	    !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
4440

N
NeilBrown 已提交
4441 4442
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);

4443
	sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
L
Linus Torvalds 已提交
4444
	if (sh == NULL) {
4445
		sh = get_active_stripe(conf, sector_nr, 0, 0, 0);
L
Linus Torvalds 已提交
4446
		/* make sure we don't swamp the stripe cache if someone else
4447
		 * is trying to get access
L
Linus Torvalds 已提交
4448
		 */
4449
		schedule_timeout_uninterruptible(1);
L
Linus Torvalds 已提交
4450
	}
4451 4452 4453 4454
	/* 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.
	 */
4455
	for (i = 0; i < conf->raid_disks; i++)
4456 4457 4458 4459 4460
		if (conf->disks[i].rdev == NULL)
			still_degraded = 1;

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

4461
	set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
L
Linus Torvalds 已提交
4462

4463
	handle_stripe(sh);
L
Linus Torvalds 已提交
4464 4465 4466 4467 4468
	release_stripe(sh);

	return STRIPE_SECTORS;
}

4469
static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
4470 4471 4472 4473 4474 4475 4476 4477 4478 4479 4480 4481
{
	/* 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;
4482
	int dd_idx;
4483 4484 4485 4486 4487 4488
	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);
4489
	sector = raid5_compute_sector(conf, logical_sector,
4490
				      0, &dd_idx, NULL);
4491 4492 4493
	last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);

	for (; logical_sector < last_sector;
4494 4495 4496
	     logical_sector += STRIPE_SECTORS,
		     sector += STRIPE_SECTORS,
		     scnt++) {
4497

4498
		if (scnt < raid5_bi_processed_stripes(raid_bio))
4499 4500 4501
			/* already done this stripe */
			continue;

4502
		sh = get_active_stripe(conf, sector, 0, 1, 0);
4503 4504 4505

		if (!sh) {
			/* failed to get a stripe - must wait */
4506
			raid5_set_bi_processed_stripes(raid_bio, scnt);
4507 4508 4509 4510
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4511 4512
		if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
			release_stripe(sh);
4513
			raid5_set_bi_processed_stripes(raid_bio, scnt);
4514 4515 4516 4517
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4518
		handle_stripe(sh);
4519 4520 4521
		release_stripe(sh);
		handled++;
	}
4522
	remaining = raid5_dec_bi_active_stripes(raid_bio);
4523 4524
	if (remaining == 0)
		bio_endio(raid_bio, 0);
4525 4526 4527 4528 4529 4530
	if (atomic_dec_and_test(&conf->active_aligned_reads))
		wake_up(&conf->wait_for_stripe);
	return handled;
}


L
Linus Torvalds 已提交
4531 4532 4533 4534 4535 4536 4537
/*
 * 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.
 */
4538
static void raid5d(struct mddev *mddev)
L
Linus Torvalds 已提交
4539 4540
{
	struct stripe_head *sh;
4541
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4542
	int handled;
4543
	struct blk_plug plug;
L
Linus Torvalds 已提交
4544

4545
	pr_debug("+++ raid5d active\n");
L
Linus Torvalds 已提交
4546 4547 4548

	md_check_recovery(mddev);

4549
	blk_start_plug(&plug);
L
Linus Torvalds 已提交
4550 4551 4552
	handled = 0;
	spin_lock_irq(&conf->device_lock);
	while (1) {
4553
		struct bio *bio;
L
Linus Torvalds 已提交
4554

4555 4556 4557 4558
		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++;
4559
			spin_unlock_irq(&conf->device_lock);
4560
			bitmap_unplug(mddev->bitmap);
4561
			spin_lock_irq(&conf->device_lock);
4562
			conf->seq_write = conf->seq_flush;
4563 4564
			activate_bit_delay(conf);
		}
4565 4566
		if (atomic_read(&mddev->plug_cnt) == 0)
			raid5_activate_delayed(conf);
4567

4568 4569 4570 4571 4572 4573 4574 4575 4576 4577
		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++;
		}

4578 4579
		sh = __get_priority_stripe(conf);

4580
		if (!sh)
L
Linus Torvalds 已提交
4581 4582 4583 4584
			break;
		spin_unlock_irq(&conf->device_lock);
		
		handled++;
4585 4586 4587
		handle_stripe(sh);
		release_stripe(sh);
		cond_resched();
L
Linus Torvalds 已提交
4588

4589 4590 4591
		if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
			md_check_recovery(mddev);

L
Linus Torvalds 已提交
4592 4593
		spin_lock_irq(&conf->device_lock);
	}
4594
	pr_debug("%d stripes handled\n", handled);
L
Linus Torvalds 已提交
4595 4596 4597

	spin_unlock_irq(&conf->device_lock);

4598
	async_tx_issue_pending_all();
4599
	blk_finish_plug(&plug);
L
Linus Torvalds 已提交
4600

4601
	pr_debug("--- raid5d inactive\n");
L
Linus Torvalds 已提交
4602 4603
}

4604
static ssize_t
4605
raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
4606
{
4607
	struct r5conf *conf = mddev->private;
4608 4609 4610 4611
	if (conf)
		return sprintf(page, "%d\n", conf->max_nr_stripes);
	else
		return 0;
4612 4613
}

4614
int
4615
raid5_set_cache_size(struct mddev *mddev, int size)
4616
{
4617
	struct r5conf *conf = mddev->private;
4618 4619
	int err;

4620
	if (size <= 16 || size > 32768)
4621
		return -EINVAL;
4622
	while (size < conf->max_nr_stripes) {
4623 4624 4625 4626 4627
		if (drop_one_stripe(conf))
			conf->max_nr_stripes--;
		else
			break;
	}
4628 4629 4630
	err = md_allow_write(mddev);
	if (err)
		return err;
4631
	while (size > conf->max_nr_stripes) {
4632 4633 4634 4635
		if (grow_one_stripe(conf))
			conf->max_nr_stripes++;
		else break;
	}
4636 4637 4638 4639 4640
	return 0;
}
EXPORT_SYMBOL(raid5_set_cache_size);

static ssize_t
4641
raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
4642
{
4643
	struct r5conf *conf = mddev->private;
4644 4645 4646 4647 4648 4649 4650 4651 4652 4653 4654 4655 4656
	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;
4657 4658
	return len;
}
4659

4660 4661 4662 4663
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);
4664

4665
static ssize_t
4666
raid5_show_preread_threshold(struct mddev *mddev, char *page)
4667
{
4668
	struct r5conf *conf = mddev->private;
4669 4670 4671 4672 4673 4674 4675
	if (conf)
		return sprintf(page, "%d\n", conf->bypass_threshold);
	else
		return 0;
}

static ssize_t
4676
raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
4677
{
4678
	struct r5conf *conf = mddev->private;
4679
	unsigned long new;
4680 4681 4682 4683 4684
	if (len >= PAGE_SIZE)
		return -EINVAL;
	if (!conf)
		return -ENODEV;

4685
	if (strict_strtoul(page, 10, &new))
4686
		return -EINVAL;
4687
	if (new > conf->max_nr_stripes)
4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698
		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);

4699
static ssize_t
4700
stripe_cache_active_show(struct mddev *mddev, char *page)
4701
{
4702
	struct r5conf *conf = mddev->private;
4703 4704 4705 4706
	if (conf)
		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
	else
		return 0;
4707 4708
}

4709 4710
static struct md_sysfs_entry
raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
4711

4712
static struct attribute *raid5_attrs[] =  {
4713 4714
	&raid5_stripecache_size.attr,
	&raid5_stripecache_active.attr,
4715
	&raid5_preread_bypass_threshold.attr,
4716 4717
	NULL,
};
4718 4719 4720
static struct attribute_group raid5_attrs_group = {
	.name = NULL,
	.attrs = raid5_attrs,
4721 4722
};

4723
static sector_t
4724
raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
4725
{
4726
	struct r5conf *conf = mddev->private;
4727 4728 4729

	if (!sectors)
		sectors = mddev->dev_sectors;
4730
	if (!raid_disks)
4731
		/* size is defined by the smallest of previous and new size */
4732
		raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
4733

4734
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
4735
	sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
4736 4737 4738
	return sectors * (raid_disks - conf->max_degraded);
}

4739
static void raid5_free_percpu(struct r5conf *conf)
4740 4741 4742 4743 4744 4745 4746 4747 4748 4749 4750
{
	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);
4751
		kfree(percpu->scribble);
4752 4753 4754 4755 4756 4757 4758 4759 4760
	}
#ifdef CONFIG_HOTPLUG_CPU
	unregister_cpu_notifier(&conf->cpu_notify);
#endif
	put_online_cpus();

	free_percpu(conf->percpu);
}

4761
static void free_conf(struct r5conf *conf)
4762 4763
{
	shrink_stripes(conf);
4764
	raid5_free_percpu(conf);
4765 4766 4767 4768 4769
	kfree(conf->disks);
	kfree(conf->stripe_hashtbl);
	kfree(conf);
}

4770 4771 4772 4773
#ifdef CONFIG_HOTPLUG_CPU
static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action,
			      void *hcpu)
{
4774
	struct r5conf *conf = container_of(nfb, struct r5conf, cpu_notify);
4775 4776 4777 4778 4779 4780
	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:
4781
		if (conf->level == 6 && !percpu->spare_page)
4782
			percpu->spare_page = alloc_page(GFP_KERNEL);
4783 4784 4785 4786 4787 4788 4789
		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);
4790 4791
			pr_err("%s: failed memory allocation for cpu%ld\n",
			       __func__, cpu);
4792
			return notifier_from_errno(-ENOMEM);
4793 4794 4795 4796 4797
		}
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		safe_put_page(percpu->spare_page);
4798
		kfree(percpu->scribble);
4799
		percpu->spare_page = NULL;
4800
		percpu->scribble = NULL;
4801 4802 4803 4804 4805 4806 4807 4808
		break;
	default:
		break;
	}
	return NOTIFY_OK;
}
#endif

4809
static int raid5_alloc_percpu(struct r5conf *conf)
4810 4811 4812
{
	unsigned long cpu;
	struct page *spare_page;
4813
	struct raid5_percpu __percpu *allcpus;
4814
	void *scribble;
4815 4816 4817 4818 4819 4820 4821 4822 4823 4824
	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) {
4825 4826 4827 4828 4829 4830 4831 4832
		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;
		}
4833
		scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
4834
		if (!scribble) {
4835 4836 4837
			err = -ENOMEM;
			break;
		}
4838
		per_cpu_ptr(conf->percpu, cpu)->scribble = scribble;
4839 4840 4841 4842 4843 4844 4845 4846 4847 4848 4849 4850
	}
#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;
}

4851
static struct r5conf *setup_conf(struct mddev *mddev)
L
Linus Torvalds 已提交
4852
{
4853
	struct r5conf *conf;
4854
	int raid_disk, memory, max_disks;
4855
	struct md_rdev *rdev;
L
Linus Torvalds 已提交
4856
	struct disk_info *disk;
4857
	char pers_name[6];
L
Linus Torvalds 已提交
4858

N
NeilBrown 已提交
4859 4860 4861
	if (mddev->new_level != 5
	    && mddev->new_level != 4
	    && mddev->new_level != 6) {
4862
		printk(KERN_ERR "md/raid:%s: raid level not set to 4/5/6 (%d)\n",
N
NeilBrown 已提交
4863 4864
		       mdname(mddev), mddev->new_level);
		return ERR_PTR(-EIO);
L
Linus Torvalds 已提交
4865
	}
N
NeilBrown 已提交
4866 4867 4868 4869
	if ((mddev->new_level == 5
	     && !algorithm_valid_raid5(mddev->new_layout)) ||
	    (mddev->new_level == 6
	     && !algorithm_valid_raid6(mddev->new_layout))) {
4870
		printk(KERN_ERR "md/raid:%s: layout %d not supported\n",
N
NeilBrown 已提交
4871 4872
		       mdname(mddev), mddev->new_layout);
		return ERR_PTR(-EIO);
4873
	}
N
NeilBrown 已提交
4874
	if (mddev->new_level == 6 && mddev->raid_disks < 4) {
4875
		printk(KERN_ERR "md/raid:%s: not enough configured devices (%d, minimum 4)\n",
N
NeilBrown 已提交
4876 4877
		       mdname(mddev), mddev->raid_disks);
		return ERR_PTR(-EINVAL);
4878 4879
	}

4880 4881 4882
	if (!mddev->new_chunk_sectors ||
	    (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
	    !is_power_of_2(mddev->new_chunk_sectors)) {
4883 4884
		printk(KERN_ERR "md/raid:%s: invalid chunk size %d\n",
		       mdname(mddev), mddev->new_chunk_sectors << 9);
N
NeilBrown 已提交
4885
		return ERR_PTR(-EINVAL);
4886 4887
	}

4888
	conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
N
NeilBrown 已提交
4889
	if (conf == NULL)
L
Linus Torvalds 已提交
4890
		goto abort;
4891 4892 4893 4894 4895 4896 4897 4898 4899 4900 4901 4902
	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;
4903
	conf->recovery_disabled = mddev->recovery_disabled - 1;
N
NeilBrown 已提交
4904 4905 4906 4907 4908

	conf->raid_disks = mddev->raid_disks;
	if (mddev->reshape_position == MaxSector)
		conf->previous_raid_disks = mddev->raid_disks;
	else
4909
		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
4910 4911
	max_disks = max(conf->raid_disks, conf->previous_raid_disks);
	conf->scribble_len = scribble_len(max_disks);
4912

4913
	conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
4914 4915 4916
			      GFP_KERNEL);
	if (!conf->disks)
		goto abort;
4917

L
Linus Torvalds 已提交
4918 4919
	conf->mddev = mddev;

4920
	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
L
Linus Torvalds 已提交
4921 4922
		goto abort;

4923 4924 4925 4926
	conf->level = mddev->new_level;
	if (raid5_alloc_percpu(conf) != 0)
		goto abort;

4927
	pr_debug("raid456: run(%s) called.\n", mdname(mddev));
L
Linus Torvalds 已提交
4928

N
NeilBrown 已提交
4929
	rdev_for_each(rdev, mddev) {
L
Linus Torvalds 已提交
4930
		raid_disk = rdev->raid_disk;
4931
		if (raid_disk >= max_disks
L
Linus Torvalds 已提交
4932 4933 4934 4935
		    || raid_disk < 0)
			continue;
		disk = conf->disks + raid_disk;

4936 4937 4938 4939 4940 4941 4942 4943 4944
		if (test_bit(Replacement, &rdev->flags)) {
			if (disk->replacement)
				goto abort;
			disk->replacement = rdev;
		} else {
			if (disk->rdev)
				goto abort;
			disk->rdev = rdev;
		}
L
Linus Torvalds 已提交
4945

4946
		if (test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
4947
			char b[BDEVNAME_SIZE];
4948 4949 4950
			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
4951
		} else if (rdev->saved_raid_disk != raid_disk)
4952 4953
			/* Cannot rely on bitmap to complete recovery */
			conf->fullsync = 1;
L
Linus Torvalds 已提交
4954 4955
	}

4956
	conf->chunk_sectors = mddev->new_chunk_sectors;
N
NeilBrown 已提交
4957
	conf->level = mddev->new_level;
4958 4959 4960 4961
	if (conf->level == 6)
		conf->max_degraded = 2;
	else
		conf->max_degraded = 1;
N
NeilBrown 已提交
4962
	conf->algorithm = mddev->new_layout;
L
Linus Torvalds 已提交
4963
	conf->max_nr_stripes = NR_STRIPES;
4964
	conf->reshape_progress = mddev->reshape_position;
4965
	if (conf->reshape_progress != MaxSector) {
4966
		conf->prev_chunk_sectors = mddev->chunk_sectors;
4967 4968
		conf->prev_algo = mddev->layout;
	}
L
Linus Torvalds 已提交
4969

N
NeilBrown 已提交
4970
	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
4971
		 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
N
NeilBrown 已提交
4972 4973
	if (grow_stripes(conf, conf->max_nr_stripes)) {
		printk(KERN_ERR
4974 4975
		       "md/raid:%s: couldn't allocate %dkB for buffers\n",
		       mdname(mddev), memory);
N
NeilBrown 已提交
4976 4977
		goto abort;
	} else
4978 4979
		printk(KERN_INFO "md/raid:%s: allocated %dkB\n",
		       mdname(mddev), memory);
L
Linus Torvalds 已提交
4980

4981 4982
	sprintf(pers_name, "raid%d", mddev->new_level);
	conf->thread = md_register_thread(raid5d, mddev, pers_name);
N
NeilBrown 已提交
4983 4984
	if (!conf->thread) {
		printk(KERN_ERR
4985
		       "md/raid:%s: couldn't allocate thread.\n",
N
NeilBrown 已提交
4986
		       mdname(mddev));
4987 4988
		goto abort;
	}
N
NeilBrown 已提交
4989 4990 4991 4992 4993

	return conf;

 abort:
	if (conf) {
4994
		free_conf(conf);
N
NeilBrown 已提交
4995 4996 4997 4998 4999
		return ERR_PTR(-EIO);
	} else
		return ERR_PTR(-ENOMEM);
}

5000 5001 5002 5003 5004 5005 5006 5007 5008 5009 5010 5011 5012 5013 5014 5015 5016 5017 5018 5019 5020 5021 5022 5023 5024 5025 5026

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;
}

5027
static int run(struct mddev *mddev)
N
NeilBrown 已提交
5028
{
5029
	struct r5conf *conf;
5030
	int working_disks = 0;
5031
	int dirty_parity_disks = 0;
5032
	struct md_rdev *rdev;
5033
	sector_t reshape_offset = 0;
5034
	int i;
5035 5036
	long long min_offset_diff = 0;
	int first = 1;
N
NeilBrown 已提交
5037

5038
	if (mddev->recovery_cp != MaxSector)
5039
		printk(KERN_NOTICE "md/raid:%s: not clean"
5040 5041
		       " -- starting background reconstruction\n",
		       mdname(mddev));
5042 5043 5044 5045 5046 5047 5048 5049 5050 5051 5052 5053 5054 5055 5056 5057 5058

	rdev_for_each(rdev, mddev) {
		long long diff;
		if (rdev->raid_disk < 0)
			continue;
		diff = (rdev->new_data_offset - rdev->data_offset);
		if (first) {
			min_offset_diff = diff;
			first = 0;
		} else if (mddev->reshape_backwards &&
			 diff < min_offset_diff)
			min_offset_diff = diff;
		else if (!mddev->reshape_backwards &&
			 diff > min_offset_diff)
			min_offset_diff = diff;
	}

N
NeilBrown 已提交
5059 5060
	if (mddev->reshape_position != MaxSector) {
		/* Check that we can continue the reshape.
5061 5062 5063 5064 5065 5066 5067 5068 5069 5070
		 * Difficulties arise if the stripe we would write to
		 * next is at or after the stripe we would read from next.
		 * For a reshape that changes the number of devices, this
		 * is only possible for a very short time, and mdadm makes
		 * sure that time appears to have past before assembling
		 * the array.  So we fail if that time hasn't passed.
		 * For a reshape that keeps the number of devices the same
		 * mdadm must be monitoring the reshape can keeping the
		 * critical areas read-only and backed up.  It will start
		 * the array in read-only mode, so we check for that.
N
NeilBrown 已提交
5071 5072 5073
		 */
		sector_t here_new, here_old;
		int old_disks;
5074
		int max_degraded = (mddev->level == 6 ? 2 : 1);
N
NeilBrown 已提交
5075

5076
		if (mddev->new_level != mddev->level) {
5077
			printk(KERN_ERR "md/raid:%s: unsupported reshape "
N
NeilBrown 已提交
5078 5079 5080 5081 5082 5083 5084 5085 5086 5087
			       "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;
5088
		if (sector_div(here_new, mddev->new_chunk_sectors *
N
NeilBrown 已提交
5089
			       (mddev->raid_disks - max_degraded))) {
5090 5091
			printk(KERN_ERR "md/raid:%s: reshape_position not "
			       "on a stripe boundary\n", mdname(mddev));
N
NeilBrown 已提交
5092 5093
			return -EINVAL;
		}
5094
		reshape_offset = here_new * mddev->new_chunk_sectors;
N
NeilBrown 已提交
5095 5096
		/* here_new is the stripe we will write to */
		here_old = mddev->reshape_position;
5097
		sector_div(here_old, mddev->chunk_sectors *
N
NeilBrown 已提交
5098 5099 5100
			   (old_disks-max_degraded));
		/* here_old is the first stripe that we might need to read
		 * from */
5101
		if (mddev->delta_disks == 0) {
5102 5103 5104 5105 5106 5107
			if ((here_new * mddev->new_chunk_sectors !=
			     here_old * mddev->chunk_sectors)) {
				printk(KERN_ERR "md/raid:%s: reshape position is"
				       " confused - aborting\n", mdname(mddev));
				return -EINVAL;
			}
5108
			/* We cannot be sure it is safe to start an in-place
5109
			 * reshape.  It is only safe if user-space is monitoring
5110 5111 5112 5113 5114
			 * 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.
			 */
5115 5116 5117 5118 5119 5120 5121
			if (abs(min_offset_diff) >= mddev->chunk_sectors &&
			    abs(min_offset_diff) >= mddev->new_chunk_sectors)
				/* not really in-place - so OK */;
			else if (mddev->ro == 0) {
				printk(KERN_ERR "md/raid:%s: in-place reshape "
				       "must be started in read-only mode "
				       "- aborting\n",
5122
				       mdname(mddev));
5123 5124
				return -EINVAL;
			}
5125
		} else if (mddev->reshape_backwards
5126
		    ? (here_new * mddev->new_chunk_sectors + min_offset_diff <=
5127 5128
		       here_old * mddev->chunk_sectors)
		    : (here_new * mddev->new_chunk_sectors >=
5129
		       here_old * mddev->chunk_sectors + (-min_offset_diff))) {
N
NeilBrown 已提交
5130
			/* Reading from the same stripe as writing to - bad */
5131 5132 5133
			printk(KERN_ERR "md/raid:%s: reshape_position too early for "
			       "auto-recovery - aborting.\n",
			       mdname(mddev));
N
NeilBrown 已提交
5134 5135
			return -EINVAL;
		}
5136 5137
		printk(KERN_INFO "md/raid:%s: reshape will continue\n",
		       mdname(mddev));
N
NeilBrown 已提交
5138 5139 5140 5141
		/* OK, we should be able to continue; */
	} else {
		BUG_ON(mddev->level != mddev->new_level);
		BUG_ON(mddev->layout != mddev->new_layout);
5142
		BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
N
NeilBrown 已提交
5143
		BUG_ON(mddev->delta_disks != 0);
L
Linus Torvalds 已提交
5144
	}
N
NeilBrown 已提交
5145

5146 5147 5148 5149 5150
	if (mddev->private == NULL)
		conf = setup_conf(mddev);
	else
		conf = mddev->private;

N
NeilBrown 已提交
5151 5152 5153
	if (IS_ERR(conf))
		return PTR_ERR(conf);

5154
	conf->min_offset_diff = min_offset_diff;
N
NeilBrown 已提交
5155 5156 5157 5158
	mddev->thread = conf->thread;
	conf->thread = NULL;
	mddev->private = conf;

5159 5160 5161 5162 5163 5164 5165 5166 5167 5168 5169
	for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
	     i++) {
		rdev = conf->disks[i].rdev;
		if (!rdev && conf->disks[i].replacement) {
			/* The replacement is all we have yet */
			rdev = conf->disks[i].replacement;
			conf->disks[i].replacement = NULL;
			clear_bit(Replacement, &rdev->flags);
			conf->disks[i].rdev = rdev;
		}
		if (!rdev)
5170
			continue;
5171 5172 5173 5174 5175 5176 5177
		if (conf->disks[i].replacement &&
		    conf->reshape_progress != MaxSector) {
			/* replacements and reshape simply do not mix. */
			printk(KERN_ERR "md: cannot handle concurrent "
			       "replacement and reshape.\n");
			goto abort;
		}
5178
		if (test_bit(In_sync, &rdev->flags)) {
N
NeilBrown 已提交
5179
			working_disks++;
5180 5181
			continue;
		}
5182 5183 5184 5185 5186 5187 5188 5189 5190 5191 5192 5193 5194 5195 5196 5197 5198 5199 5200 5201 5202 5203 5204 5205 5206 5207 5208 5209
		/* 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
5210

5211 5212 5213
	/*
	 * 0 for a fully functional array, 1 or 2 for a degraded array.
	 */
5214
	mddev->degraded = calc_degraded(conf);
N
NeilBrown 已提交
5215

5216
	if (has_failed(conf)) {
5217
		printk(KERN_ERR "md/raid:%s: not enough operational devices"
L
Linus Torvalds 已提交
5218
			" (%d/%d failed)\n",
5219
			mdname(mddev), mddev->degraded, conf->raid_disks);
L
Linus Torvalds 已提交
5220 5221 5222
		goto abort;
	}

N
NeilBrown 已提交
5223
	/* device size must be a multiple of chunk size */
5224
	mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
N
NeilBrown 已提交
5225 5226
	mddev->resync_max_sectors = mddev->dev_sectors;

5227
	if (mddev->degraded > dirty_parity_disks &&
L
Linus Torvalds 已提交
5228
	    mddev->recovery_cp != MaxSector) {
5229 5230
		if (mddev->ok_start_degraded)
			printk(KERN_WARNING
5231 5232
			       "md/raid:%s: starting dirty degraded array"
			       " - data corruption possible.\n",
5233 5234 5235
			       mdname(mddev));
		else {
			printk(KERN_ERR
5236
			       "md/raid:%s: cannot start dirty degraded array.\n",
5237 5238 5239
			       mdname(mddev));
			goto abort;
		}
L
Linus Torvalds 已提交
5240 5241 5242
	}

	if (mddev->degraded == 0)
5243 5244
		printk(KERN_INFO "md/raid:%s: raid level %d active with %d out of %d"
		       " devices, algorithm %d\n", mdname(mddev), conf->level,
5245 5246
		       mddev->raid_disks-mddev->degraded, mddev->raid_disks,
		       mddev->new_layout);
L
Linus Torvalds 已提交
5247
	else
5248 5249 5250 5251 5252
		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
5253 5254 5255

	print_raid5_conf(conf);

5256 5257
	if (conf->reshape_progress != MaxSector) {
		conf->reshape_safe = conf->reshape_progress;
5258 5259 5260 5261 5262 5263
		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,
5264
							"reshape");
5265 5266
	}

L
Linus Torvalds 已提交
5267 5268

	/* Ok, everything is just fine now */
5269 5270
	if (mddev->to_remove == &raid5_attrs_group)
		mddev->to_remove = NULL;
N
NeilBrown 已提交
5271 5272
	else if (mddev->kobj.sd &&
	    sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
5273
		printk(KERN_WARNING
5274
		       "raid5: failed to create sysfs attributes for %s\n",
5275
		       mdname(mddev));
5276
	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
5277

5278
	if (mddev->queue) {
5279
		int chunk_size;
5280 5281 5282 5283 5284 5285 5286 5287 5288
		/* 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
5289

5290
		blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
5291

N
NeilBrown 已提交
5292 5293
		mddev->queue->backing_dev_info.congested_data = mddev;
		mddev->queue->backing_dev_info.congested_fn = raid5_congested;
5294

5295 5296 5297 5298
		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));
5299

5300
		rdev_for_each(rdev, mddev) {
5301 5302
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
5303 5304 5305
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->new_data_offset << 9);
		}
5306
	}
5307

L
Linus Torvalds 已提交
5308 5309
	return 0;
abort:
5310
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
5311 5312
	print_raid5_conf(conf);
	free_conf(conf);
L
Linus Torvalds 已提交
5313
	mddev->private = NULL;
5314
	printk(KERN_ALERT "md/raid:%s: failed to run raid set.\n", mdname(mddev));
L
Linus Torvalds 已提交
5315 5316 5317
	return -EIO;
}

5318
static int stop(struct mddev *mddev)
L
Linus Torvalds 已提交
5319
{
5320
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5321

5322
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
5323 5324
	if (mddev->queue)
		mddev->queue->backing_dev_info.congested_fn = NULL;
5325
	free_conf(conf);
5326 5327
	mddev->private = NULL;
	mddev->to_remove = &raid5_attrs_group;
L
Linus Torvalds 已提交
5328 5329 5330
	return 0;
}

5331
static void status(struct seq_file *seq, struct mddev *mddev)
L
Linus Torvalds 已提交
5332
{
5333
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5334 5335
	int i;

5336 5337
	seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
		mddev->chunk_sectors / 2, mddev->layout);
5338
	seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
L
Linus Torvalds 已提交
5339 5340 5341
	for (i = 0; i < conf->raid_disks; i++)
		seq_printf (seq, "%s",
			       conf->disks[i].rdev &&
5342
			       test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
L
Linus Torvalds 已提交
5343 5344 5345
	seq_printf (seq, "]");
}

5346
static void print_raid5_conf (struct r5conf *conf)
L
Linus Torvalds 已提交
5347 5348 5349 5350
{
	int i;
	struct disk_info *tmp;

5351
	printk(KERN_DEBUG "RAID conf printout:\n");
L
Linus Torvalds 已提交
5352 5353 5354 5355
	if (!conf) {
		printk("(conf==NULL)\n");
		return;
	}
5356 5357 5358
	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
5359 5360 5361 5362 5363

	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
		tmp = conf->disks + i;
		if (tmp->rdev)
5364 5365 5366
			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
5367 5368 5369
	}
}

5370
static int raid5_spare_active(struct mddev *mddev)
L
Linus Torvalds 已提交
5371 5372
{
	int i;
5373
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5374
	struct disk_info *tmp;
5375 5376
	int count = 0;
	unsigned long flags;
L
Linus Torvalds 已提交
5377 5378 5379

	for (i = 0; i < conf->raid_disks; i++) {
		tmp = conf->disks + i;
5380 5381 5382 5383 5384 5385 5386 5387 5388 5389 5390 5391 5392 5393 5394 5395 5396 5397 5398
		if (tmp->replacement
		    && tmp->replacement->recovery_offset == MaxSector
		    && !test_bit(Faulty, &tmp->replacement->flags)
		    && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
			/* Replacement has just become active. */
			if (!tmp->rdev
			    || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
				count++;
			if (tmp->rdev) {
				/* Replaced device not technically faulty,
				 * but we need to be sure it gets removed
				 * and never re-added.
				 */
				set_bit(Faulty, &tmp->rdev->flags);
				sysfs_notify_dirent_safe(
					tmp->rdev->sysfs_state);
			}
			sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
		} else if (tmp->rdev
5399
		    && tmp->rdev->recovery_offset == MaxSector
5400
		    && !test_bit(Faulty, &tmp->rdev->flags)
5401
		    && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
5402
			count++;
5403
			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
L
Linus Torvalds 已提交
5404 5405
		}
	}
5406
	spin_lock_irqsave(&conf->device_lock, flags);
5407
	mddev->degraded = calc_degraded(conf);
5408
	spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
5409
	print_raid5_conf(conf);
5410
	return count;
L
Linus Torvalds 已提交
5411 5412
}

5413
static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5414
{
5415
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5416
	int err = 0;
5417
	int number = rdev->raid_disk;
5418
	struct md_rdev **rdevp;
L
Linus Torvalds 已提交
5419 5420 5421
	struct disk_info *p = conf->disks + number;

	print_raid5_conf(conf);
5422 5423 5424 5425 5426 5427 5428 5429 5430 5431 5432 5433 5434 5435 5436 5437 5438 5439 5440 5441 5442 5443
	if (rdev == p->rdev)
		rdevp = &p->rdev;
	else if (rdev == p->replacement)
		rdevp = &p->replacement;
	else
		return 0;

	if (number >= conf->raid_disks &&
	    conf->reshape_progress == MaxSector)
		clear_bit(In_sync, &rdev->flags);

	if (test_bit(In_sync, &rdev->flags) ||
	    atomic_read(&rdev->nr_pending)) {
		err = -EBUSY;
		goto abort;
	}
	/* Only remove non-faulty devices if recovery
	 * isn't possible.
	 */
	if (!test_bit(Faulty, &rdev->flags) &&
	    mddev->recovery_disabled != conf->recovery_disabled &&
	    !has_failed(conf) &&
5444
	    (!p->replacement || p->replacement == rdev) &&
5445 5446 5447 5448 5449 5450 5451 5452 5453 5454
	    number < conf->raid_disks) {
		err = -EBUSY;
		goto abort;
	}
	*rdevp = NULL;
	synchronize_rcu();
	if (atomic_read(&rdev->nr_pending)) {
		/* lost the race, try later */
		err = -EBUSY;
		*rdevp = rdev;
5455 5456 5457 5458 5459 5460 5461 5462 5463 5464 5465 5466 5467 5468
	} else if (p->replacement) {
		/* We must have just cleared 'rdev' */
		p->rdev = p->replacement;
		clear_bit(Replacement, &p->replacement->flags);
		smp_mb(); /* Make sure other CPUs may see both as identical
			   * but will never see neither - if they are careful
			   */
		p->replacement = NULL;
		clear_bit(WantReplacement, &rdev->flags);
	} else
		/* We might have just removed the Replacement as faulty-
		 * clear the bit just in case
		 */
		clear_bit(WantReplacement, &rdev->flags);
L
Linus Torvalds 已提交
5469 5470 5471 5472 5473 5474
abort:

	print_raid5_conf(conf);
	return err;
}

5475
static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5476
{
5477
	struct r5conf *conf = mddev->private;
5478
	int err = -EEXIST;
L
Linus Torvalds 已提交
5479 5480
	int disk;
	struct disk_info *p;
5481 5482
	int first = 0;
	int last = conf->raid_disks - 1;
L
Linus Torvalds 已提交
5483

5484 5485 5486
	if (mddev->recovery_disabled == conf->recovery_disabled)
		return -EBUSY;

N
NeilBrown 已提交
5487
	if (rdev->saved_raid_disk < 0 && has_failed(conf))
L
Linus Torvalds 已提交
5488
		/* no point adding a device */
5489
		return -EINVAL;
L
Linus Torvalds 已提交
5490

5491 5492
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;
L
Linus Torvalds 已提交
5493 5494

	/*
5495 5496
	 * find the disk ... but prefer rdev->saved_raid_disk
	 * if possible.
L
Linus Torvalds 已提交
5497
	 */
5498
	if (rdev->saved_raid_disk >= 0 &&
5499
	    rdev->saved_raid_disk >= first &&
5500
	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
5501 5502 5503
		first = rdev->saved_raid_disk;

	for (disk = first; disk <= last; disk++) {
5504 5505
		p = conf->disks + disk;
		if (p->rdev == NULL) {
5506
			clear_bit(In_sync, &rdev->flags);
L
Linus Torvalds 已提交
5507
			rdev->raid_disk = disk;
5508
			err = 0;
5509 5510
			if (rdev->saved_raid_disk != disk)
				conf->fullsync = 1;
5511
			rcu_assign_pointer(p->rdev, rdev);
5512
			goto out;
L
Linus Torvalds 已提交
5513
		}
5514 5515 5516
	}
	for (disk = first; disk <= last; disk++) {
		p = conf->disks + disk;
5517 5518 5519 5520 5521 5522 5523 5524 5525 5526 5527
		if (test_bit(WantReplacement, &p->rdev->flags) &&
		    p->replacement == NULL) {
			clear_bit(In_sync, &rdev->flags);
			set_bit(Replacement, &rdev->flags);
			rdev->raid_disk = disk;
			err = 0;
			conf->fullsync = 1;
			rcu_assign_pointer(p->replacement, rdev);
			break;
		}
	}
5528
out:
L
Linus Torvalds 已提交
5529
	print_raid5_conf(conf);
5530
	return err;
L
Linus Torvalds 已提交
5531 5532
}

5533
static int raid5_resize(struct mddev *mddev, sector_t sectors)
L
Linus Torvalds 已提交
5534 5535 5536 5537 5538 5539 5540 5541
{
	/* 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.
	 */
5542
	sector_t newsize;
5543
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5544 5545 5546
	newsize = raid5_size(mddev, sectors, mddev->raid_disks);
	if (mddev->external_size &&
	    mddev->array_sectors > newsize)
D
Dan Williams 已提交
5547
		return -EINVAL;
5548 5549 5550 5551 5552 5553
	if (mddev->bitmap) {
		int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
		if (ret)
			return ret;
	}
	md_set_array_sectors(mddev, newsize);
5554
	set_capacity(mddev->gendisk, mddev->array_sectors);
5555
	revalidate_disk(mddev->gendisk);
5556 5557
	if (sectors > mddev->dev_sectors &&
	    mddev->recovery_cp > mddev->dev_sectors) {
A
Andre Noll 已提交
5558
		mddev->recovery_cp = mddev->dev_sectors;
L
Linus Torvalds 已提交
5559 5560
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
A
Andre Noll 已提交
5561
	mddev->dev_sectors = sectors;
5562
	mddev->resync_max_sectors = sectors;
L
Linus Torvalds 已提交
5563 5564 5565
	return 0;
}

5566
static int check_stripe_cache(struct mddev *mddev)
5567 5568 5569 5570 5571 5572 5573 5574 5575
{
	/* 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.
	 */
5576
	struct r5conf *conf = mddev->private;
5577 5578 5579 5580
	if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes ||
	    ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes) {
5581 5582
		printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
		       mdname(mddev),
5583 5584 5585 5586 5587 5588 5589
		       ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
			/ STRIPE_SIZE)*4);
		return 0;
	}
	return 1;
}

5590
static int check_reshape(struct mddev *mddev)
5591
{
5592
	struct r5conf *conf = mddev->private;
5593

5594 5595
	if (mddev->delta_disks == 0 &&
	    mddev->new_layout == mddev->layout &&
5596
	    mddev->new_chunk_sectors == mddev->chunk_sectors)
5597
		return 0; /* nothing to do */
5598
	if (has_failed(conf))
5599 5600 5601 5602 5603 5604 5605 5606 5607 5608 5609 5610 5611
		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;
	}
5612

5613
	if (!check_stripe_cache(mddev))
5614 5615
		return -ENOSPC;

5616
	return resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
5617 5618
}

5619
static int raid5_start_reshape(struct mddev *mddev)
5620
{
5621
	struct r5conf *conf = mddev->private;
5622
	struct md_rdev *rdev;
5623
	int spares = 0;
5624
	unsigned long flags;
5625

5626
	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
5627 5628
		return -EBUSY;

5629 5630 5631
	if (!check_stripe_cache(mddev))
		return -ENOSPC;

5632 5633 5634
	if (has_failed(conf))
		return -EINVAL;

5635
	rdev_for_each(rdev, mddev) {
5636 5637
		if (!test_bit(In_sync, &rdev->flags)
		    && !test_bit(Faulty, &rdev->flags))
5638
			spares++;
5639
	}
5640

5641
	if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
5642 5643 5644 5645 5646
		/* Not enough devices even to make a degraded array
		 * of that size
		 */
		return -EINVAL;

5647 5648 5649 5650 5651 5652
	/* 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) {
5653
		printk(KERN_ERR "md/raid:%s: array size must be reduced "
5654 5655 5656 5657
		       "before number of disks\n", mdname(mddev));
		return -EINVAL;
	}

5658
	atomic_set(&conf->reshape_stripes, 0);
5659 5660
	spin_lock_irq(&conf->device_lock);
	conf->previous_raid_disks = conf->raid_disks;
5661
	conf->raid_disks += mddev->delta_disks;
5662 5663
	conf->prev_chunk_sectors = conf->chunk_sectors;
	conf->chunk_sectors = mddev->new_chunk_sectors;
5664 5665
	conf->prev_algo = conf->algorithm;
	conf->algorithm = mddev->new_layout;
5666 5667 5668 5669 5670
	conf->generation++;
	/* Code that selects data_offset needs to see the generation update
	 * if reshape_progress has been set - so a memory barrier needed.
	 */
	smp_mb();
5671
	if (mddev->reshape_backwards)
5672 5673 5674 5675
		conf->reshape_progress = raid5_size(mddev, 0, 0);
	else
		conf->reshape_progress = 0;
	conf->reshape_safe = conf->reshape_progress;
5676 5677 5678 5679
	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.
5680 5681 5682 5683
	 * 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.
5684
	 */
5685
	if (mddev->delta_disks >= 0) {
N
NeilBrown 已提交
5686
		rdev_for_each(rdev, mddev)
5687 5688 5689 5690
			if (rdev->raid_disk < 0 &&
			    !test_bit(Faulty, &rdev->flags)) {
				if (raid5_add_disk(mddev, rdev) == 0) {
					if (rdev->raid_disk
5691
					    >= conf->previous_raid_disks)
5692
						set_bit(In_sync, &rdev->flags);
5693
					else
5694
						rdev->recovery_offset = 0;
5695 5696

					if (sysfs_link_rdev(mddev, rdev))
5697
						/* Failure here is OK */;
5698
				}
5699 5700 5701 5702 5703
			} 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);
			}
5704

5705 5706 5707 5708
		/* When a reshape changes the number of devices,
		 * ->degraded is measured against the larger of the
		 * pre and post number of devices.
		 */
5709
		spin_lock_irqsave(&conf->device_lock, flags);
5710
		mddev->degraded = calc_degraded(conf);
5711 5712
		spin_unlock_irqrestore(&conf->device_lock, flags);
	}
5713
	mddev->raid_disks = conf->raid_disks;
5714
	mddev->reshape_position = conf->reshape_progress;
5715
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
5716

5717 5718 5719 5720 5721
	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,
5722
						"reshape");
5723 5724 5725 5726
	if (!mddev->sync_thread) {
		mddev->recovery = 0;
		spin_lock_irq(&conf->device_lock);
		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
5727 5728 5729
		rdev_for_each(rdev, mddev)
			rdev->new_data_offset = rdev->data_offset;
		smp_wmb();
5730
		conf->reshape_progress = MaxSector;
5731
		mddev->reshape_position = MaxSector;
5732 5733 5734
		spin_unlock_irq(&conf->device_lock);
		return -EAGAIN;
	}
5735
	conf->reshape_checkpoint = jiffies;
5736 5737 5738 5739 5740
	md_wakeup_thread(mddev->sync_thread);
	md_new_event(mddev);
	return 0;
}

5741 5742 5743
/* This is called from the reshape thread and should make any
 * changes needed in 'conf'
 */
5744
static void end_reshape(struct r5conf *conf)
5745 5746
{

5747
	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
5748
		struct md_rdev *rdev;
5749 5750

		spin_lock_irq(&conf->device_lock);
5751
		conf->previous_raid_disks = conf->raid_disks;
5752 5753 5754
		rdev_for_each(rdev, conf->mddev)
			rdev->data_offset = rdev->new_data_offset;
		smp_wmb();
5755
		conf->reshape_progress = MaxSector;
5756
		spin_unlock_irq(&conf->device_lock);
5757
		wake_up(&conf->wait_for_overlap);
5758 5759 5760 5761

		/* read-ahead size must cover two whole stripes, which is
		 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
		 */
5762
		if (conf->mddev->queue) {
5763
			int data_disks = conf->raid_disks - conf->max_degraded;
5764
			int stripe = data_disks * ((conf->chunk_sectors << 9)
5765
						   / PAGE_SIZE);
5766 5767 5768
			if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
				conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
		}
5769 5770 5771
	}
}

5772 5773 5774
/* This is called from the raid5d thread with mddev_lock held.
 * It makes config changes to the device.
 */
5775
static void raid5_finish_reshape(struct mddev *mddev)
5776
{
5777
	struct r5conf *conf = mddev->private;
5778 5779 5780

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

5781 5782 5783
		if (mddev->delta_disks > 0) {
			md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
			set_capacity(mddev->gendisk, mddev->array_sectors);
5784
			revalidate_disk(mddev->gendisk);
5785 5786
		} else {
			int d;
5787 5788 5789
			spin_lock_irq(&conf->device_lock);
			mddev->degraded = calc_degraded(conf);
			spin_unlock_irq(&conf->device_lock);
5790 5791
			for (d = conf->raid_disks ;
			     d < conf->raid_disks - mddev->delta_disks;
5792
			     d++) {
5793
				struct md_rdev *rdev = conf->disks[d].rdev;
5794 5795 5796 5797 5798
				if (rdev)
					clear_bit(In_sync, &rdev->flags);
				rdev = conf->disks[d].replacement;
				if (rdev)
					clear_bit(In_sync, &rdev->flags);
5799
			}
5800
		}
5801
		mddev->layout = conf->algorithm;
5802
		mddev->chunk_sectors = conf->chunk_sectors;
5803 5804
		mddev->reshape_position = MaxSector;
		mddev->delta_disks = 0;
5805
		mddev->reshape_backwards = 0;
5806 5807 5808
	}
}

5809
static void raid5_quiesce(struct mddev *mddev, int state)
5810
{
5811
	struct r5conf *conf = mddev->private;
5812 5813

	switch(state) {
5814 5815 5816 5817
	case 2: /* resume for a suspend */
		wake_up(&conf->wait_for_overlap);
		break;

5818 5819
	case 1: /* stop all writes */
		spin_lock_irq(&conf->device_lock);
5820 5821 5822 5823
		/* '2' tells resync/reshape to pause so that all
		 * active stripes can drain
		 */
		conf->quiesce = 2;
5824
		wait_event_lock_irq(conf->wait_for_stripe,
5825 5826
				    atomic_read(&conf->active_stripes) == 0 &&
				    atomic_read(&conf->active_aligned_reads) == 0,
5827
				    conf->device_lock, /* nothing */);
5828
		conf->quiesce = 1;
5829
		spin_unlock_irq(&conf->device_lock);
5830 5831
		/* allow reshape to continue */
		wake_up(&conf->wait_for_overlap);
5832 5833 5834 5835 5836 5837
		break;

	case 0: /* re-enable writes */
		spin_lock_irq(&conf->device_lock);
		conf->quiesce = 0;
		wake_up(&conf->wait_for_stripe);
5838
		wake_up(&conf->wait_for_overlap);
5839 5840 5841 5842
		spin_unlock_irq(&conf->device_lock);
		break;
	}
}
5843

5844

5845
static void *raid45_takeover_raid0(struct mddev *mddev, int level)
5846
{
5847
	struct r0conf *raid0_conf = mddev->private;
5848
	sector_t sectors;
5849

D
Dan Williams 已提交
5850
	/* for raid0 takeover only one zone is supported */
5851
	if (raid0_conf->nr_strip_zones > 1) {
5852 5853
		printk(KERN_ERR "md/raid:%s: cannot takeover raid0 with more than one zone.\n",
		       mdname(mddev));
D
Dan Williams 已提交
5854 5855 5856
		return ERR_PTR(-EINVAL);
	}

5857 5858
	sectors = raid0_conf->strip_zone[0].zone_end;
	sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
5859
	mddev->dev_sectors = sectors;
D
Dan Williams 已提交
5860
	mddev->new_level = level;
5861 5862 5863 5864 5865 5866 5867 5868 5869 5870 5871
	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);
}


5872
static void *raid5_takeover_raid1(struct mddev *mddev)
5873 5874 5875 5876 5877 5878 5879 5880 5881 5882 5883 5884 5885 5886 5887 5888 5889 5890 5891 5892 5893
{
	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;
5894
	mddev->new_chunk_sectors = chunksect;
5895 5896 5897 5898

	return setup_conf(mddev);
}

5899
static void *raid5_takeover_raid6(struct mddev *mddev)
5900 5901 5902 5903 5904 5905 5906 5907 5908 5909 5910 5911 5912 5913 5914 5915 5916 5917 5918 5919 5920 5921 5922 5923 5924 5925 5926 5927 5928 5929 5930 5931
{
	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);
}

5932

5933
static int raid5_check_reshape(struct mddev *mddev)
5934
{
5935 5936 5937 5938
	/* 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.
5939
	 */
5940
	struct r5conf *conf = mddev->private;
5941
	int new_chunk = mddev->new_chunk_sectors;
5942

5943
	if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
5944 5945
		return -EINVAL;
	if (new_chunk > 0) {
5946
		if (!is_power_of_2(new_chunk))
5947
			return -EINVAL;
5948
		if (new_chunk < (PAGE_SIZE>>9))
5949
			return -EINVAL;
5950
		if (mddev->array_sectors & (new_chunk-1))
5951 5952 5953 5954 5955 5956
			/* not factor of array size */
			return -EINVAL;
	}

	/* They look valid */

5957
	if (mddev->raid_disks == 2) {
5958 5959 5960 5961
		/* can make the change immediately */
		if (mddev->new_layout >= 0) {
			conf->algorithm = mddev->new_layout;
			mddev->layout = mddev->new_layout;
5962 5963
		}
		if (new_chunk > 0) {
5964 5965
			conf->chunk_sectors = new_chunk ;
			mddev->chunk_sectors = new_chunk;
5966 5967 5968
		}
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		md_wakeup_thread(mddev->thread);
5969
	}
5970
	return check_reshape(mddev);
5971 5972
}

5973
static int raid6_check_reshape(struct mddev *mddev)
5974
{
5975
	int new_chunk = mddev->new_chunk_sectors;
5976

5977
	if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
5978
		return -EINVAL;
5979
	if (new_chunk > 0) {
5980
		if (!is_power_of_2(new_chunk))
5981
			return -EINVAL;
5982
		if (new_chunk < (PAGE_SIZE >> 9))
5983
			return -EINVAL;
5984
		if (mddev->array_sectors & (new_chunk-1))
5985 5986
			/* not factor of array size */
			return -EINVAL;
5987
	}
5988 5989

	/* They look valid */
5990
	return check_reshape(mddev);
5991 5992
}

5993
static void *raid5_takeover(struct mddev *mddev)
5994 5995
{
	/* raid5 can take over:
D
Dan Williams 已提交
5996
	 *  raid0 - if there is only one strip zone - make it a raid4 layout
5997 5998 5999 6000
	 *  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
6001 6002
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 5);
6003 6004
	if (mddev->level == 1)
		return raid5_takeover_raid1(mddev);
6005 6006 6007 6008 6009
	if (mddev->level == 4) {
		mddev->new_layout = ALGORITHM_PARITY_N;
		mddev->new_level = 5;
		return setup_conf(mddev);
	}
6010 6011
	if (mddev->level == 6)
		return raid5_takeover_raid6(mddev);
6012 6013 6014 6015

	return ERR_PTR(-EINVAL);
}

6016
static void *raid4_takeover(struct mddev *mddev)
6017
{
D
Dan Williams 已提交
6018 6019 6020
	/* raid4 can take over:
	 *  raid0 - if there is only one strip zone
	 *  raid5 - if layout is right
6021
	 */
D
Dan Williams 已提交
6022 6023
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 4);
6024 6025 6026 6027 6028 6029 6030 6031
	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);
}
6032

6033
static struct md_personality raid5_personality;
6034

6035
static void *raid6_takeover(struct mddev *mddev)
6036 6037 6038 6039 6040 6041 6042 6043 6044 6045 6046 6047 6048 6049 6050 6051 6052 6053 6054 6055 6056 6057 6058 6059 6060 6061 6062 6063 6064 6065 6066 6067 6068 6069 6070 6071 6072 6073 6074 6075 6076 6077 6078 6079 6080 6081
{
	/* 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);
}


6082
static struct md_personality raid6_personality =
6083 6084 6085 6086 6087 6088 6089 6090 6091 6092 6093 6094 6095 6096
{
	.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,
6097
	.size		= raid5_size,
6098
	.check_reshape	= raid6_check_reshape,
6099
	.start_reshape  = raid5_start_reshape,
6100
	.finish_reshape = raid5_finish_reshape,
6101
	.quiesce	= raid5_quiesce,
6102
	.takeover	= raid6_takeover,
6103
};
6104
static struct md_personality raid5_personality =
L
Linus Torvalds 已提交
6105 6106
{
	.name		= "raid5",
6107
	.level		= 5,
L
Linus Torvalds 已提交
6108 6109 6110 6111 6112 6113 6114 6115 6116 6117 6118
	.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,
6119
	.size		= raid5_size,
6120 6121
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
6122
	.finish_reshape = raid5_finish_reshape,
6123
	.quiesce	= raid5_quiesce,
6124
	.takeover	= raid5_takeover,
L
Linus Torvalds 已提交
6125 6126
};

6127
static struct md_personality raid4_personality =
L
Linus Torvalds 已提交
6128
{
6129 6130 6131 6132 6133 6134 6135 6136 6137 6138 6139 6140 6141
	.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,
6142
	.size		= raid5_size,
6143 6144
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
6145
	.finish_reshape = raid5_finish_reshape,
6146
	.quiesce	= raid5_quiesce,
6147
	.takeover	= raid4_takeover,
6148 6149 6150 6151
};

static int __init raid5_init(void)
{
6152
	register_md_personality(&raid6_personality);
6153 6154 6155
	register_md_personality(&raid5_personality);
	register_md_personality(&raid4_personality);
	return 0;
L
Linus Torvalds 已提交
6156 6157
}

6158
static void raid5_exit(void)
L
Linus Torvalds 已提交
6159
{
6160
	unregister_md_personality(&raid6_personality);
6161 6162
	unregister_md_personality(&raid5_personality);
	unregister_md_personality(&raid4_personality);
L
Linus Torvalds 已提交
6163 6164 6165 6166 6167
}

module_init(raid5_init);
module_exit(raid5_exit);
MODULE_LICENSE("GPL");
6168
MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
L
Linus Torvalds 已提交
6169
MODULE_ALIAS("md-personality-4"); /* RAID5 */
6170 6171
MODULE_ALIAS("md-raid5");
MODULE_ALIAS("md-raid4");
6172 6173
MODULE_ALIAS("md-level-5");
MODULE_ALIAS("md-level-4");
6174 6175 6176 6177 6178 6179 6180
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");