raid5.c 181.6 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 <trace/events/block.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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		trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
					 bi, 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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	pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
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	hlist_for_each_entry(sh, 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))
			rdev = rcu_dereference(conf->disks[i].replacement);
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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))
			rdev = rcu_dereference(conf->disks[i].replacement);
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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);
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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),
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						    conf->device_lock);
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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)
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				    && !test_bit(STRIPE_EXPANDING, &sh->state)
				    && !test_bit(STRIPE_ON_UNPLUG_LIST, &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;
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			if (test_bit(R5_Discard, &sh->dev[i].flags))
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				rw |= REQ_DISCARD;
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		} else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
559
			rw = READ;
560 561 562 563 564
		else if (test_and_clear_bit(R5_WantReplace,
					    &sh->dev[i].flags)) {
			rw = WRITE;
			replace_only = 1;
		} else
565
			continue;
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566 567
		if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
			rw |= REQ_SYNC;
568 569

		bi = &sh->dev[i].req;
570
		rbi = &sh->dev[i].rreq; /* For writing to replacement */
571 572

		bi->bi_rw = rw;
573 574
		rbi->bi_rw = rw;
		if (rw & WRITE) {
575
			bi->bi_end_io = raid5_end_write_request;
576 577
			rbi->bi_end_io = raid5_end_write_request;
		} else
578 579 580
			bi->bi_end_io = raid5_end_read_request;

		rcu_read_lock();
581
		rrdev = rcu_dereference(conf->disks[i].replacement);
582 583 584 585 586 587
		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;
		}
588 589 590
		if (rw & WRITE) {
			if (replace_only)
				rdev = NULL;
591 592 593
			if (rdev == rrdev)
				/* We raced and saw duplicates */
				rrdev = NULL;
594
		} else {
595
			if (test_bit(R5_ReadRepl, &sh->dev[i].flags) && rrdev)
596 597 598
				rdev = rrdev;
			rrdev = NULL;
		}
599

600 601 602 603
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
		if (rdev)
			atomic_inc(&rdev->nr_pending);
604 605 606 607
		if (rrdev && test_bit(Faulty, &rrdev->flags))
			rrdev = NULL;
		if (rrdev)
			atomic_inc(&rrdev->nr_pending);
608 609
		rcu_read_unlock();

610
		/* We have already checked bad blocks for reads.  Now
611 612
		 * need to check for writes.  We never accept write errors
		 * on the replacement, so we don't to check rrdev.
613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632
		 */
		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);
				}
633 634 635 636 637 638
				/*
				 * Because md_wait_for_blocked_rdev
				 * will dec nr_pending, we must
				 * increment it first.
				 */
				atomic_inc(&rdev->nr_pending);
639 640 641 642 643 644 645 646
				md_wait_for_blocked_rdev(rdev, conf->mddev);
			} else {
				/* Acknowledged bad block - skip the write */
				rdev_dec_pending(rdev, conf->mddev);
				rdev = NULL;
			}
		}

647
		if (rdev) {
648 649
			if (s->syncing || s->expanding || s->expanded
			    || s->replacing)
650 651
				md_sync_acct(rdev->bdev, STRIPE_SECTORS);

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652 653
			set_bit(STRIPE_IO_STARTED, &sh->state);

654 655
			bi->bi_bdev = rdev->bdev;
			pr_debug("%s: for %llu schedule op %ld on disc %d\n",
656
				__func__, (unsigned long long)sh->sector,
657 658
				bi->bi_rw, i);
			atomic_inc(&sh->count);
659 660 661 662 663 664
			if (use_new_offset(conf, sh))
				bi->bi_sector = (sh->sector
						 + rdev->new_data_offset);
			else
				bi->bi_sector = (sh->sector
						 + rdev->data_offset);
665 666 667
			if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
				bi->bi_rw |= REQ_FLUSH;

668 669 670 671 672 673
			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;
674 675
			if (rrdev)
				set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
676 677 678 679 680

			if (conf->mddev->gendisk)
				trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
						      bi, disk_devt(conf->mddev->gendisk),
						      sh->dev[i].sector);
681
			generic_make_request(bi);
682 683
		}
		if (rrdev) {
684 685
			if (s->syncing || s->expanding || s->expanded
			    || s->replacing)
686 687 688 689 690 691 692 693 694 695
				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);
696 697 698 699 700 701
			if (use_new_offset(conf, sh))
				rbi->bi_sector = (sh->sector
						  + rrdev->new_data_offset);
			else
				rbi->bi_sector = (sh->sector
						  + rrdev->data_offset);
702 703 704 705 706 707
			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;
708 709 710 711
			if (conf->mddev->gendisk)
				trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
						      rbi, disk_devt(conf->mddev->gendisk),
						      sh->dev[i].sector);
712 713 714
			generic_make_request(rbi);
		}
		if (!rdev && !rrdev) {
715
			if (rw & WRITE)
716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732
				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;
733
	struct async_submit_ctl submit;
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	enum async_tx_flags flags = 0;
735 736 737 738 739

	if (bio->bi_sector >= sector)
		page_offset = (signed)(bio->bi_sector - sector) * 512;
	else
		page_offset = (signed)(sector - bio->bi_sector) * -512;
740

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741 742 743 744
	if (frombio)
		flags |= ASYNC_TX_FENCE;
	init_async_submit(&submit, flags, tx, NULL, NULL, NULL);

745
	bio_for_each_segment(bvl, bio, i) {
746
		int len = bvl->bv_len;
747 748 749 750 751 752 753 754 755 756 757 758 759 760 761
		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) {
762 763
			b_offset += bvl->bv_offset;
			bio_page = bvl->bv_page;
764 765
			if (frombio)
				tx = async_memcpy(page, bio_page, page_offset,
766
						  b_offset, clen, &submit);
767 768
			else
				tx = async_memcpy(bio_page, page, b_offset,
769
						  page_offset, clen, &submit);
770
		}
771 772 773
		/* chain the operations */
		submit.depend_tx = tx;

774 775 776 777 778 779 780 781 782 783 784 785
		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;
786
	int i;
787

788
	pr_debug("%s: stripe %llu\n", __func__,
789 790 791 792 793 794 795
		(unsigned long long)sh->sector);

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

		/* acknowledge completion of a biofill operation */
796 797
		/* and check if we need to reply to a read request,
		 * new R5_Wantfill requests are held off until
798
		 * !STRIPE_BIOFILL_RUN
799 800
		 */
		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
801 802 803 804 805 806 807 808
			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);
809
				if (!raid5_dec_bi_active_stripes(rbi)) {
810 811 812 813 814 815 816
					rbi->bi_next = return_bi;
					return_bi = rbi;
				}
				rbi = rbi2;
			}
		}
	}
817
	clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
818 819 820

	return_io(return_bi);

821
	set_bit(STRIPE_HANDLE, &sh->state);
822 823 824 825 826 827
	release_stripe(sh);
}

static void ops_run_biofill(struct stripe_head *sh)
{
	struct dma_async_tx_descriptor *tx = NULL;
828
	struct async_submit_ctl submit;
829 830
	int i;

831
	pr_debug("%s: stripe %llu\n", __func__,
832 833 834 835 836 837
		(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;
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Shaohua Li 已提交
838
			spin_lock_irq(&sh->stripe_lock);
839 840
			dev->read = rbi = dev->toread;
			dev->toread = NULL;
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Shaohua Li 已提交
841
			spin_unlock_irq(&sh->stripe_lock);
842 843 844 845 846 847 848 849 850 851
			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);
852 853
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
	async_trigger_callback(&submit);
854 855
}

856
static void mark_target_uptodate(struct stripe_head *sh, int target)
857
{
858
	struct r5dev *tgt;
859

860 861
	if (target < 0)
		return;
862

863
	tgt = &sh->dev[target];
864 865 866
	set_bit(R5_UPTODATE, &tgt->flags);
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	clear_bit(R5_Wantcompute, &tgt->flags);
867 868
}

869
static void ops_complete_compute(void *stripe_head_ref)
870 871 872
{
	struct stripe_head *sh = stripe_head_ref;

873
	pr_debug("%s: stripe %llu\n", __func__,
874 875
		(unsigned long long)sh->sector);

876
	/* mark the computed target(s) as uptodate */
877
	mark_target_uptodate(sh, sh->ops.target);
878
	mark_target_uptodate(sh, sh->ops.target2);
879

880 881 882
	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
	if (sh->check_state == check_state_compute_run)
		sh->check_state = check_state_compute_result;
883 884 885 886
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

887 888 889 890 891 892 893 894 895
/* 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)
896 897
{
	int disks = sh->disks;
898
	struct page **xor_srcs = percpu->scribble;
899 900 901 902 903
	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;
904
	struct async_submit_ctl submit;
905 906 907
	int i;

	pr_debug("%s: stripe %llu block: %d\n",
908
		__func__, (unsigned long long)sh->sector, target);
909 910 911 912 913 914 915 916
	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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917
	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
918
			  ops_complete_compute, sh, to_addr_conv(sh, percpu));
919
	if (unlikely(count == 1))
920
		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
921
	else
922
		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
923 924 925 926

	return tx;
}

927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944
/* 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++)
945
		srcs[i] = NULL;
946 947 948 949 950 951 952 953 954 955

	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);

956
	return syndrome_disks;
957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976
}

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;
977
	else
978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993
		/* 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,
996 997 998 999 1000 1001 1002 1003 1004 1005 1006
				  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,
1009 1010 1011
				  to_addr_conv(sh, percpu));
		tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
	}
1012 1013 1014 1015

	return tx;
}

1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036
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));

1037
	/* we need to open-code set_syndrome_sources to handle the
1038 1039 1040
	 * slot number conversion for 'faila' and 'failb'
	 */
	for (i = 0; i < disks ; i++)
1041
		blocks[i] = NULL;
1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067
	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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Dan Williams 已提交
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			init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
					  ops_complete_compute, sh,
					  to_addr_conv(sh, percpu));
1071
			return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090
						  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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1091 1092 1093 1094
			init_async_submit(&submit,
					  ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
					  NULL, NULL, NULL,
					  to_addr_conv(sh, percpu));
1095 1096 1097 1098
			tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
				       &submit);

			count = set_syndrome_sources(blocks, sh);
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Dan Williams 已提交
1099 1100 1101
			init_async_submit(&submit, ASYNC_TX_FENCE, tx,
					  ops_complete_compute, sh,
					  to_addr_conv(sh, percpu));
1102 1103 1104 1105
			return async_gen_syndrome(blocks, 0, count+2,
						  STRIPE_SIZE, &submit);
		}
	} else {
1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119
		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);
		}
1120 1121 1122 1123
	}
}


1124 1125 1126 1127
static void ops_complete_prexor(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;

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

static struct dma_async_tx_descriptor *
1133 1134
ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
	       struct dma_async_tx_descriptor *tx)
1135 1136
{
	int disks = sh->disks;
1137
	struct page **xor_srcs = percpu->scribble;
1138
	int count = 0, pd_idx = sh->pd_idx, i;
1139
	struct async_submit_ctl submit;
1140 1141 1142 1143

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

1144
	pr_debug("%s: stripe %llu\n", __func__,
1145 1146 1147 1148 1149
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		/* Only process blocks that are known to be uptodate */
1150
		if (test_bit(R5_Wantdrain, &dev->flags))
1151 1152 1153
			xor_srcs[count++] = dev->page;
	}

D
Dan Williams 已提交
1154
	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1155
			  ops_complete_prexor, sh, to_addr_conv(sh, percpu));
1156
	tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1157 1158 1159 1160 1161

	return tx;
}

static struct dma_async_tx_descriptor *
1162
ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1163 1164
{
	int disks = sh->disks;
1165
	int i;
1166

1167
	pr_debug("%s: stripe %llu\n", __func__,
1168 1169 1170 1171 1172 1173
		(unsigned long long)sh->sector);

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

1174
		if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
1175 1176
			struct bio *wbi;

S
Shaohua Li 已提交
1177
			spin_lock_irq(&sh->stripe_lock);
1178 1179 1180 1181
			chosen = dev->towrite;
			dev->towrite = NULL;
			BUG_ON(dev->written);
			wbi = dev->written = chosen;
S
Shaohua Li 已提交
1182
			spin_unlock_irq(&sh->stripe_lock);
1183 1184 1185

			while (wbi && wbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
T
Tejun Heo 已提交
1186 1187
				if (wbi->bi_rw & REQ_FUA)
					set_bit(R5_WantFUA, &dev->flags);
S
Shaohua Li 已提交
1188 1189
				if (wbi->bi_rw & REQ_SYNC)
					set_bit(R5_SyncIO, &dev->flags);
1190
				if (wbi->bi_rw & REQ_DISCARD)
S
Shaohua Li 已提交
1191
					set_bit(R5_Discard, &dev->flags);
1192
				else
S
Shaohua Li 已提交
1193 1194
					tx = async_copy_data(1, wbi, dev->page,
						dev->sector, tx);
1195 1196 1197 1198 1199 1200 1201 1202
				wbi = r5_next_bio(wbi, dev->sector);
			}
		}
	}

	return tx;
}

1203
static void ops_complete_reconstruct(void *stripe_head_ref)
1204 1205
{
	struct stripe_head *sh = stripe_head_ref;
1206 1207 1208 1209
	int disks = sh->disks;
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	int i;
1210
	bool fua = false, sync = false, discard = false;
1211

1212
	pr_debug("%s: stripe %llu\n", __func__,
1213 1214
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
1215
	for (i = disks; i--; ) {
T
Tejun Heo 已提交
1216
		fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
S
Shaohua Li 已提交
1217
		sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1218
		discard |= test_bit(R5_Discard, &sh->dev[i].flags);
S
Shaohua Li 已提交
1219
	}
T
Tejun Heo 已提交
1220

1221 1222
	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
1223

T
Tejun Heo 已提交
1224
		if (dev->written || i == pd_idx || i == qd_idx) {
1225 1226
			if (!discard)
				set_bit(R5_UPTODATE, &dev->flags);
T
Tejun Heo 已提交
1227 1228
			if (fua)
				set_bit(R5_WantFUA, &dev->flags);
S
Shaohua Li 已提交
1229 1230
			if (sync)
				set_bit(R5_SyncIO, &dev->flags);
T
Tejun Heo 已提交
1231
		}
1232 1233
	}

1234 1235 1236 1237 1238 1239 1240 1241
	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;
	}
1242 1243 1244 1245 1246 1247

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

static void
1248 1249
ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
		     struct dma_async_tx_descriptor *tx)
1250 1251
{
	int disks = sh->disks;
1252
	struct page **xor_srcs = percpu->scribble;
1253
	struct async_submit_ctl submit;
1254 1255
	int count = 0, pd_idx = sh->pd_idx, i;
	struct page *xor_dest;
1256
	int prexor = 0;
1257 1258
	unsigned long flags;

1259
	pr_debug("%s: stripe %llu\n", __func__,
1260 1261
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273
	for (i = 0; i < sh->disks; i++) {
		if (pd_idx == i)
			continue;
		if (!test_bit(R5_Discard, &sh->dev[i].flags))
			break;
	}
	if (i >= sh->disks) {
		atomic_inc(&sh->count);
		set_bit(R5_Discard, &sh->dev[pd_idx].flags);
		ops_complete_reconstruct(sh);
		return;
	}
1274 1275 1276
	/* check if prexor is active which means only process blocks
	 * that are part of a read-modify-write (written)
	 */
1277 1278
	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
		prexor = 1;
1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298
		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
	 */
1299
	flags = ASYNC_TX_ACK |
1300 1301 1302 1303
		(prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);

	atomic_inc(&sh->count);

1304
	init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh,
1305
			  to_addr_conv(sh, percpu));
1306 1307 1308 1309
	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);
1310 1311
}

1312 1313 1314 1315 1316 1317
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;
S
Shaohua Li 已提交
1318
	int count, i;
1319 1320 1321

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

S
Shaohua Li 已提交
1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335
	for (i = 0; i < sh->disks; i++) {
		if (sh->pd_idx == i || sh->qd_idx == i)
			continue;
		if (!test_bit(R5_Discard, &sh->dev[i].flags))
			break;
	}
	if (i >= sh->disks) {
		atomic_inc(&sh->count);
		set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
		set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
		ops_complete_reconstruct(sh);
		return;
	}

1336 1337 1338 1339 1340 1341 1342
	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);
1343 1344 1345 1346 1347 1348
}

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

1349
	pr_debug("%s: stripe %llu\n", __func__,
1350 1351
		(unsigned long long)sh->sector);

1352
	sh->check_state = check_state_check_result;
1353 1354 1355 1356
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1357
static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1358 1359
{
	int disks = sh->disks;
1360 1361 1362
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	struct page *xor_dest;
1363
	struct page **xor_srcs = percpu->scribble;
1364
	struct dma_async_tx_descriptor *tx;
1365
	struct async_submit_ctl submit;
1366 1367
	int count;
	int i;
1368

1369
	pr_debug("%s: stripe %llu\n", __func__,
1370 1371
		(unsigned long long)sh->sector);

1372 1373 1374
	count = 0;
	xor_dest = sh->dev[pd_idx].page;
	xor_srcs[count++] = xor_dest;
1375
	for (i = disks; i--; ) {
1376 1377 1378
		if (i == pd_idx || i == qd_idx)
			continue;
		xor_srcs[count++] = sh->dev[i].page;
1379 1380
	}

1381 1382
	init_async_submit(&submit, 0, NULL, NULL, NULL,
			  to_addr_conv(sh, percpu));
D
Dan Williams 已提交
1383
	tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
1384
			   &sh->ops.zero_sum_result, &submit);
1385 1386

	atomic_inc(&sh->count);
1387 1388
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
	tx = async_trigger_callback(&submit);
1389 1390
}

1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402
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;
1403 1404

	atomic_inc(&sh->count);
1405 1406 1407 1408
	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);
1409 1410
}

N
NeilBrown 已提交
1411
static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
1412 1413 1414
{
	int overlap_clear = 0, i, disks = sh->disks;
	struct dma_async_tx_descriptor *tx = NULL;
1415
	struct r5conf *conf = sh->raid_conf;
1416
	int level = conf->level;
1417 1418
	struct raid5_percpu *percpu;
	unsigned long cpu;
1419

1420 1421
	cpu = get_cpu();
	percpu = per_cpu_ptr(conf->percpu, cpu);
1422
	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
1423 1424 1425 1426
		ops_run_biofill(sh);
		overlap_clear++;
	}

1427
	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
1428 1429 1430 1431 1432 1433 1434 1435 1436 1437
		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))
1438 1439
			async_tx_ack(tx);
	}
1440

1441
	if (test_bit(STRIPE_OP_PREXOR, &ops_request))
1442
		tx = ops_run_prexor(sh, percpu, tx);
1443

1444
	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
1445
		tx = ops_run_biodrain(sh, tx);
1446 1447 1448
		overlap_clear++;
	}

1449 1450 1451 1452 1453 1454
	if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
		if (level < 6)
			ops_run_reconstruct5(sh, percpu, tx);
		else
			ops_run_reconstruct6(sh, percpu, tx);
	}
1455

1456 1457 1458 1459 1460 1461 1462 1463 1464 1465
	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();
	}
1466 1467 1468 1469 1470 1471 1472

	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);
		}
1473
	put_cpu();
1474 1475
}

1476
static int grow_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1477 1478
{
	struct stripe_head *sh;
N
Namhyung Kim 已提交
1479
	sh = kmem_cache_zalloc(conf->slab_cache, GFP_KERNEL);
1480 1481
	if (!sh)
		return 0;
N
Namhyung Kim 已提交
1482

1483 1484
	sh->raid_conf = conf;

S
Shaohua Li 已提交
1485 1486
	spin_lock_init(&sh->stripe_lock);

1487 1488
	if (grow_buffers(sh)) {
		shrink_buffers(sh);
1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499
		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;
}

1500
static int grow_stripes(struct r5conf *conf, int num)
1501
{
1502
	struct kmem_cache *sc;
1503
	int devs = max(conf->raid_disks, conf->previous_raid_disks);
L
Linus Torvalds 已提交
1504

1505 1506 1507 1508 1509 1510 1511 1512
	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]);

1513 1514
	conf->active_name = 0;
	sc = kmem_cache_create(conf->cache_name[conf->active_name],
L
Linus Torvalds 已提交
1515
			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
1516
			       0, 0, NULL);
L
Linus Torvalds 已提交
1517 1518 1519
	if (!sc)
		return 1;
	conf->slab_cache = sc;
1520
	conf->pool_size = devs;
1521
	while (num--)
1522
		if (!grow_one_stripe(conf))
L
Linus Torvalds 已提交
1523 1524 1525
			return 1;
	return 0;
}
1526

1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548
/**
 * 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;
}

1549
static int resize_stripes(struct r5conf *conf, int newsize)
1550 1551 1552 1553 1554 1555 1556
{
	/* 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.
M
Masanari Iida 已提交
1557
	 * 2/ gather all the old stripe_heads and transfer the pages across
1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
	 *    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;
1577
	unsigned long cpu;
1578
	int err;
1579
	struct kmem_cache *sc;
1580 1581 1582 1583 1584
	int i;

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

1585 1586 1587
	err = md_allow_write(conf->mddev);
	if (err)
		return err;
1588

1589 1590 1591
	/* Step 1 */
	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
1592
			       0, 0, NULL);
1593 1594 1595 1596
	if (!sc)
		return -ENOMEM;

	for (i = conf->max_nr_stripes; i; i--) {
N
Namhyung Kim 已提交
1597
		nsh = kmem_cache_zalloc(sc, GFP_KERNEL);
1598 1599 1600 1601
		if (!nsh)
			break;

		nsh->raid_conf = conf;
1602
		spin_lock_init(&nsh->stripe_lock);
1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623

		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),
1624
				    conf->device_lock);
1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638
		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
1639
	 * conf->disks and the scribble region
1640 1641 1642 1643 1644 1645 1646 1647 1648 1649
	 */
	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;

1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668
	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();

1669 1670 1671 1672
	/* 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);
1673

1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689
		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
1690

1691
static int drop_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1692 1693 1694
{
	struct stripe_head *sh;

1695 1696 1697 1698 1699
	spin_lock_irq(&conf->device_lock);
	sh = get_free_stripe(conf);
	spin_unlock_irq(&conf->device_lock);
	if (!sh)
		return 0;
1700
	BUG_ON(atomic_read(&sh->count));
1701
	shrink_buffers(sh);
1702 1703 1704 1705 1706
	kmem_cache_free(conf->slab_cache, sh);
	atomic_dec(&conf->active_stripes);
	return 1;
}

1707
static void shrink_stripes(struct r5conf *conf)
1708 1709 1710 1711
{
	while (drop_one_stripe(conf))
		;

N
NeilBrown 已提交
1712 1713
	if (conf->slab_cache)
		kmem_cache_destroy(conf->slab_cache);
L
Linus Torvalds 已提交
1714 1715 1716
	conf->slab_cache = NULL;
}

1717
static void raid5_end_read_request(struct bio * bi, int error)
L
Linus Torvalds 已提交
1718
{
1719
	struct stripe_head *sh = bi->bi_private;
1720
	struct r5conf *conf = sh->raid_conf;
1721
	int disks = sh->disks, i;
L
Linus Torvalds 已提交
1722
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1723
	char b[BDEVNAME_SIZE];
1724
	struct md_rdev *rdev = NULL;
1725
	sector_t s;
L
Linus Torvalds 已提交
1726 1727 1728 1729 1730

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

1731 1732
	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
1733 1734 1735
		uptodate);
	if (i == disks) {
		BUG();
1736
		return;
L
Linus Torvalds 已提交
1737
	}
1738
	if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
1739 1740 1741 1742 1743
		/* 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.
		 */
1744
		rdev = conf->disks[i].replacement;
1745
	if (!rdev)
1746
		rdev = conf->disks[i].rdev;
L
Linus Torvalds 已提交
1747

1748 1749 1750 1751
	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
1752 1753
	if (uptodate) {
		set_bit(R5_UPTODATE, &sh->dev[i].flags);
1754
		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1755 1756 1757 1758
			/* Note that this cannot happen on a
			 * replacement device.  We just fail those on
			 * any error
			 */
1759 1760 1761 1762 1763
			printk_ratelimited(
				KERN_INFO
				"md/raid:%s: read error corrected"
				" (%lu sectors at %llu on %s)\n",
				mdname(conf->mddev), STRIPE_SECTORS,
1764
				(unsigned long long)s,
1765
				bdevname(rdev->bdev, b));
1766
			atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1767 1768
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1769 1770 1771
		} else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
			clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);

1772 1773
		if (atomic_read(&rdev->read_errors))
			atomic_set(&rdev->read_errors, 0);
L
Linus Torvalds 已提交
1774
	} else {
1775
		const char *bdn = bdevname(rdev->bdev, b);
1776
		int retry = 0;
1777
		int set_bad = 0;
1778

L
Linus Torvalds 已提交
1779
		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
1780
		atomic_inc(&rdev->read_errors);
1781 1782 1783 1784 1785 1786
		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),
1787
				(unsigned long long)s,
1788
				bdn);
1789 1790
		else if (conf->mddev->degraded >= conf->max_degraded) {
			set_bad = 1;
1791 1792 1793 1794 1795
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error not correctable "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1796
				(unsigned long long)s,
1797
				bdn);
1798
		} else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
1799
			/* Oh, no!!! */
1800
			set_bad = 1;
1801 1802 1803 1804 1805
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error NOT corrected!! "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1806
				(unsigned long long)s,
1807
				bdn);
1808
		} else if (atomic_read(&rdev->read_errors)
1809
			 > conf->max_nr_stripes)
N
NeilBrown 已提交
1810
			printk(KERN_WARNING
1811
			       "md/raid:%s: Too many read errors, failing device %s.\n",
1812
			       mdname(conf->mddev), bdn);
1813 1814 1815
		else
			retry = 1;
		if (retry)
1816 1817 1818 1819 1820
			if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
				set_bit(R5_ReadError, &sh->dev[i].flags);
				clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
			} else
				set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
1821
		else {
1822 1823
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1824 1825 1826 1827 1828
			if (!(set_bad
			      && test_bit(In_sync, &rdev->flags)
			      && rdev_set_badblocks(
				      rdev, sh->sector, STRIPE_SECTORS, 0)))
				md_error(conf->mddev, rdev);
1829
		}
L
Linus Torvalds 已提交
1830
	}
1831
	rdev_dec_pending(rdev, conf->mddev);
L
Linus Torvalds 已提交
1832 1833 1834 1835 1836
	clear_bit(R5_LOCKED, &sh->dev[i].flags);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1837
static void raid5_end_write_request(struct bio *bi, int error)
L
Linus Torvalds 已提交
1838
{
1839
	struct stripe_head *sh = bi->bi_private;
1840
	struct r5conf *conf = sh->raid_conf;
1841
	int disks = sh->disks, i;
1842
	struct md_rdev *uninitialized_var(rdev);
L
Linus Torvalds 已提交
1843
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1844 1845
	sector_t first_bad;
	int bad_sectors;
1846
	int replacement = 0;
L
Linus Torvalds 已提交
1847

1848 1849 1850
	for (i = 0 ; i < disks; i++) {
		if (bi == &sh->dev[i].req) {
			rdev = conf->disks[i].rdev;
L
Linus Torvalds 已提交
1851
			break;
1852 1853 1854
		}
		if (bi == &sh->dev[i].rreq) {
			rdev = conf->disks[i].replacement;
1855 1856 1857 1858 1859 1860 1861 1862
			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;
1863 1864 1865
			break;
		}
	}
1866
	pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
L
Linus Torvalds 已提交
1867 1868 1869 1870
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
		uptodate);
	if (i == disks) {
		BUG();
1871
		return;
L
Linus Torvalds 已提交
1872 1873
	}

1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884
	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);
1885 1886 1887
			if (!test_and_set_bit(WantReplacement, &rdev->flags))
				set_bit(MD_RECOVERY_NEEDED,
					&rdev->mddev->recovery);
1888 1889 1890 1891 1892 1893
		} 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
1894

1895 1896
	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
1897
	set_bit(STRIPE_HANDLE, &sh->state);
1898
	release_stripe(sh);
L
Linus Torvalds 已提交
1899 1900
}

1901
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
L
Linus Torvalds 已提交
1902
	
1903
static void raid5_build_block(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
1904 1905 1906 1907 1908 1909 1910 1911
{
	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;
1912
	dev->vec.bv_page = dev->page;
L
Linus Torvalds 已提交
1913

1914 1915 1916 1917 1918 1919 1920
	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
1921
	dev->flags = 0;
1922
	dev->sector = compute_blocknr(sh, i, previous);
L
Linus Torvalds 已提交
1923 1924
}

1925
static void error(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
1926 1927
{
	char b[BDEVNAME_SIZE];
1928
	struct r5conf *conf = mddev->private;
1929
	unsigned long flags;
1930
	pr_debug("raid456: error called\n");
L
Linus Torvalds 已提交
1931

1932 1933 1934 1935 1936 1937
	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);

1938
	set_bit(Blocked, &rdev->flags);
1939 1940 1941 1942 1943 1944 1945 1946 1947
	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);
1948
}
L
Linus Torvalds 已提交
1949 1950 1951 1952 1953

/*
 * Input: a 'big' sector number,
 * Output: index of the data and parity disk, and the sector # in them.
 */
1954
static sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
1955 1956
				     int previous, int *dd_idx,
				     struct stripe_head *sh)
L
Linus Torvalds 已提交
1957
{
N
NeilBrown 已提交
1958
	sector_t stripe, stripe2;
1959
	sector_t chunk_number;
L
Linus Torvalds 已提交
1960
	unsigned int chunk_offset;
1961
	int pd_idx, qd_idx;
1962
	int ddf_layout = 0;
L
Linus Torvalds 已提交
1963
	sector_t new_sector;
1964 1965
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
1966 1967
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
1968 1969 1970
	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
1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982

	/* 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
	 */
1983 1984
	stripe = chunk_number;
	*dd_idx = sector_div(stripe, data_disks);
N
NeilBrown 已提交
1985
	stripe2 = stripe;
L
Linus Torvalds 已提交
1986 1987 1988
	/*
	 * Select the parity disk based on the user selected algorithm.
	 */
1989
	pd_idx = qd_idx = -1;
1990 1991
	switch(conf->level) {
	case 4:
1992
		pd_idx = data_disks;
1993 1994
		break;
	case 5:
1995
		switch (algorithm) {
L
Linus Torvalds 已提交
1996
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
1997
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
1998
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
1999 2000 2001
				(*dd_idx)++;
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
2002
			pd_idx = sector_div(stripe2, raid_disks);
2003
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
2004 2005 2006
				(*dd_idx)++;
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
2007
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
2008
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
2009 2010
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
2011
			pd_idx = sector_div(stripe2, raid_disks);
2012
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
2013
			break;
2014 2015 2016 2017 2018 2019 2020
		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
2021
		default:
2022
			BUG();
2023 2024 2025 2026
		}
		break;
	case 6:

2027
		switch (algorithm) {
2028
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
2029
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2030 2031
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
2032
				(*dd_idx)++;	/* Q D D D P */
2033 2034
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
2035 2036 2037
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
2038
			pd_idx = sector_div(stripe2, raid_disks);
2039 2040
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
2041
				(*dd_idx)++;	/* Q D D D P */
2042 2043
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
2044 2045 2046
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
2047
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2048 2049
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2050 2051
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
2052
			pd_idx = sector_div(stripe2, raid_disks);
2053 2054
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2055
			break;
2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070

		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
2071
			pd_idx = sector_div(stripe2, raid_disks);
2072 2073 2074 2075 2076 2077
			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 */
2078
			ddf_layout = 1;
2079 2080 2081 2082 2083 2084 2085
			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
2086 2087
			stripe2 += 1;
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2088 2089 2090 2091 2092 2093
			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 */
2094
			ddf_layout = 1;
2095 2096 2097 2098
			break;

		case ALGORITHM_ROTATING_N_CONTINUE:
			/* Same as left_symmetric but Q is before P */
N
NeilBrown 已提交
2099
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2100 2101
			qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2102
			ddf_layout = 1;
2103 2104 2105 2106
			break;

		case ALGORITHM_LEFT_ASYMMETRIC_6:
			/* RAID5 left_asymmetric, with Q on last device */
N
NeilBrown 已提交
2107
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2108 2109 2110 2111 2112 2113
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_RIGHT_ASYMMETRIC_6:
N
NeilBrown 已提交
2114
			pd_idx = sector_div(stripe2, raid_disks-1);
2115 2116 2117 2118 2119 2120
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_LEFT_SYMMETRIC_6:
N
NeilBrown 已提交
2121
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2122 2123 2124 2125 2126
			*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
2127
			pd_idx = sector_div(stripe2, raid_disks-1);
2128 2129 2130 2131 2132 2133 2134 2135 2136 2137
			*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;

2138
		default:
2139
			BUG();
2140 2141
		}
		break;
L
Linus Torvalds 已提交
2142 2143
	}

2144 2145 2146
	if (sh) {
		sh->pd_idx = pd_idx;
		sh->qd_idx = qd_idx;
2147
		sh->ddf_layout = ddf_layout;
2148
	}
L
Linus Torvalds 已提交
2149 2150 2151 2152 2153 2154 2155 2156
	/*
	 * Finally, compute the new sector number
	 */
	new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
	return new_sector;
}


2157
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
2158
{
2159
	struct r5conf *conf = sh->raid_conf;
2160 2161
	int raid_disks = sh->disks;
	int data_disks = raid_disks - conf->max_degraded;
L
Linus Torvalds 已提交
2162
	sector_t new_sector = sh->sector, check;
2163 2164
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
2165 2166
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
L
Linus Torvalds 已提交
2167 2168
	sector_t stripe;
	int chunk_offset;
2169 2170
	sector_t chunk_number;
	int dummy1, dd_idx = i;
L
Linus Torvalds 已提交
2171
	sector_t r_sector;
2172
	struct stripe_head sh2;
L
Linus Torvalds 已提交
2173

2174

L
Linus Torvalds 已提交
2175 2176 2177
	chunk_offset = sector_div(new_sector, sectors_per_chunk);
	stripe = new_sector;

2178 2179 2180 2181 2182
	if (i == sh->pd_idx)
		return 0;
	switch(conf->level) {
	case 4: break;
	case 5:
2183
		switch (algorithm) {
L
Linus Torvalds 已提交
2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194
		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;
2195 2196 2197 2198 2199
		case ALGORITHM_PARITY_0:
			i -= 1;
			break;
		case ALGORITHM_PARITY_N:
			break;
L
Linus Torvalds 已提交
2200
		default:
2201
			BUG();
2202 2203 2204
		}
		break;
	case 6:
2205
		if (i == sh->qd_idx)
2206
			return 0; /* It is the Q disk */
2207
		switch (algorithm) {
2208 2209
		case ALGORITHM_LEFT_ASYMMETRIC:
		case ALGORITHM_RIGHT_ASYMMETRIC:
2210 2211 2212 2213
		case ALGORITHM_ROTATING_ZERO_RESTART:
		case ALGORITHM_ROTATING_N_RESTART:
			if (sh->pd_idx == raid_disks-1)
				i--;	/* Q D D D P */
2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227
			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;
2228 2229 2230 2231 2232 2233
		case ALGORITHM_PARITY_0:
			i -= 2;
			break;
		case ALGORITHM_PARITY_N:
			break;
		case ALGORITHM_ROTATING_N_CONTINUE:
2234
			/* Like left_symmetric, but P is before Q */
2235 2236
			if (sh->pd_idx == 0)
				i--;	/* P D D D Q */
2237 2238 2239 2240 2241 2242
			else {
				/* D D Q P D */
				if (i < sh->pd_idx)
					i += raid_disks;
				i -= (sh->pd_idx + 1);
			}
2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257
			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;
2258
		default:
2259
			BUG();
2260 2261
		}
		break;
L
Linus Torvalds 已提交
2262 2263 2264
	}

	chunk_number = stripe * data_disks + i;
2265
	r_sector = chunk_number * sectors_per_chunk + chunk_offset;
L
Linus Torvalds 已提交
2266

2267
	check = raid5_compute_sector(conf, r_sector,
2268
				     previous, &dummy1, &sh2);
2269 2270
	if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
		|| sh2.qd_idx != sh->qd_idx) {
2271 2272
		printk(KERN_ERR "md/raid:%s: compute_blocknr: map not correct\n",
		       mdname(conf->mddev));
L
Linus Torvalds 已提交
2273 2274 2275 2276 2277 2278
		return 0;
	}
	return r_sector;
}


2279
static void
2280
schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
2281
			 int rcw, int expand)
2282 2283
{
	int i, pd_idx = sh->pd_idx, disks = sh->disks;
2284
	struct r5conf *conf = sh->raid_conf;
2285
	int level = conf->level;
2286 2287 2288 2289 2290 2291 2292 2293

	if (rcw) {

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

			if (dev->towrite) {
				set_bit(R5_LOCKED, &dev->flags);
2294
				set_bit(R5_Wantdrain, &dev->flags);
2295 2296
				if (!expand)
					clear_bit(R5_UPTODATE, &dev->flags);
2297
				s->locked++;
2298 2299
			}
		}
2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314
		/* 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) {
			if (!s->locked)
				/* False alarm, nothing to do */
				return;
			sh->reconstruct_state = reconstruct_state_drain_run;
			set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
		} else
			sh->reconstruct_state = reconstruct_state_run;

		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);

2315
		if (s->locked + conf->max_degraded == disks)
2316
			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
2317
				atomic_inc(&conf->pending_full_writes);
2318
	} else {
2319
		BUG_ON(level == 6);
2320 2321 2322 2323 2324 2325 2326 2327 2328 2329
		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));

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

			if (dev->towrite &&
			    (test_bit(R5_UPTODATE, &dev->flags) ||
2330 2331
			     test_bit(R5_Wantcompute, &dev->flags))) {
				set_bit(R5_Wantdrain, &dev->flags);
2332 2333
				set_bit(R5_LOCKED, &dev->flags);
				clear_bit(R5_UPTODATE, &dev->flags);
2334
				s->locked++;
2335 2336
			}
		}
2337 2338 2339 2340 2341 2342 2343
		if (!s->locked)
			/* False alarm - nothing to do */
			return;
		sh->reconstruct_state = reconstruct_state_prexor_drain_run;
		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2344 2345
	}

2346
	/* keep the parity disk(s) locked while asynchronous operations
2347 2348 2349 2350
	 * are in flight
	 */
	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
2351
	s->locked++;
2352

2353 2354 2355 2356 2357 2358 2359 2360 2361
	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++;
	}

2362
	pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
2363
		__func__, (unsigned long long)sh->sector,
2364
		s->locked, s->ops_request);
2365
}
2366

L
Linus Torvalds 已提交
2367 2368
/*
 * Each stripe/dev can have one or more bion attached.
2369
 * toread/towrite point to the first in a chain.
L
Linus Torvalds 已提交
2370 2371 2372 2373 2374
 * 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;
2375
	struct r5conf *conf = sh->raid_conf;
2376
	int firstwrite=0;
L
Linus Torvalds 已提交
2377

2378
	pr_debug("adding bi b#%llu to stripe s#%llu\n",
L
Linus Torvalds 已提交
2379 2380 2381
		(unsigned long long)bi->bi_sector,
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
2382 2383 2384 2385 2386 2387 2388 2389 2390
	/*
	 * If several bio share a stripe. The bio bi_phys_segments acts as a
	 * reference count to avoid race. The reference count should already be
	 * increased before this function is called (for example, in
	 * make_request()), so other bio sharing this stripe will not free the
	 * stripe. If a stripe is owned by one stripe, the stripe lock will
	 * protect it.
	 */
	spin_lock_irq(&sh->stripe_lock);
2391
	if (forwrite) {
L
Linus Torvalds 已提交
2392
		bip = &sh->dev[dd_idx].towrite;
2393
		if (*bip == NULL)
2394 2395
			firstwrite = 1;
	} else
L
Linus Torvalds 已提交
2396 2397 2398 2399 2400 2401 2402 2403 2404
		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;

2405
	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
L
Linus Torvalds 已提交
2406 2407 2408
	if (*bip)
		bi->bi_next = *bip;
	*bip = bi;
2409
	raid5_inc_bi_active_stripes(bi);
2410

L
Linus Torvalds 已提交
2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423
	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);
	}
2424 2425 2426 2427

	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);
2428
	spin_unlock_irq(&sh->stripe_lock);
2429 2430 2431 2432 2433 2434 2435

	if (conf->mddev->bitmap && firstwrite) {
		bitmap_startwrite(conf->mddev->bitmap, sh->sector,
				  STRIPE_SECTORS, 0);
		sh->bm_seq = conf->seq_flush+1;
		set_bit(STRIPE_BIT_DELAY, &sh->state);
	}
L
Linus Torvalds 已提交
2436 2437 2438 2439
	return 1;

 overlap:
	set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
S
Shaohua Li 已提交
2440
	spin_unlock_irq(&sh->stripe_lock);
L
Linus Torvalds 已提交
2441 2442 2443
	return 0;
}

2444
static void end_reshape(struct r5conf *conf);
2445

2446
static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
2447
			    struct stripe_head *sh)
2448
{
2449
	int sectors_per_chunk =
2450
		previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
2451
	int dd_idx;
2452
	int chunk_offset = sector_div(stripe, sectors_per_chunk);
2453
	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
2454

2455 2456
	raid5_compute_sector(conf,
			     stripe * (disks - conf->max_degraded)
2457
			     *sectors_per_chunk + chunk_offset,
2458
			     previous,
2459
			     &dd_idx, sh);
2460 2461
}

2462
static void
2463
handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
2464 2465 2466 2467 2468 2469 2470 2471 2472
				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)) {
2473
			struct md_rdev *rdev;
2474 2475 2476
			rcu_read_lock();
			rdev = rcu_dereference(conf->disks[i].rdev);
			if (rdev && test_bit(In_sync, &rdev->flags))
2477 2478 2479
				atomic_inc(&rdev->nr_pending);
			else
				rdev = NULL;
2480
			rcu_read_unlock();
2481 2482 2483 2484 2485 2486 2487 2488
			if (rdev) {
				if (!rdev_set_badblocks(
					    rdev,
					    sh->sector,
					    STRIPE_SECTORS, 0))
					md_error(conf->mddev, rdev);
				rdev_dec_pending(rdev, conf->mddev);
			}
2489
		}
S
Shaohua Li 已提交
2490
		spin_lock_irq(&sh->stripe_lock);
2491 2492 2493
		/* fail all writes first */
		bi = sh->dev[i].towrite;
		sh->dev[i].towrite = NULL;
S
Shaohua Li 已提交
2494
		spin_unlock_irq(&sh->stripe_lock);
2495
		if (bi)
2496 2497 2498 2499 2500 2501 2502 2503 2504
			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);
2505
			if (!raid5_dec_bi_active_stripes(bi)) {
2506 2507 2508 2509 2510 2511
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = nextbi;
		}
2512 2513 2514 2515
		if (bitmap_end)
			bitmap_endwrite(conf->mddev->bitmap, sh->sector,
				STRIPE_SECTORS, 0, 0);
		bitmap_end = 0;
2516 2517 2518 2519 2520 2521 2522 2523
		/* 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);
2524
			if (!raid5_dec_bi_active_stripes(bi)) {
2525 2526 2527 2528 2529 2530 2531
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = bi2;
		}

2532 2533 2534 2535 2536 2537
		/* 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))) {
2538
			spin_lock_irq(&sh->stripe_lock);
2539 2540
			bi = sh->dev[i].toread;
			sh->dev[i].toread = NULL;
2541
			spin_unlock_irq(&sh->stripe_lock);
2542 2543 2544 2545 2546 2547 2548
			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);
2549
				if (!raid5_dec_bi_active_stripes(bi)) {
2550 2551 2552 2553 2554 2555 2556 2557 2558
					bi->bi_next = *return_bi;
					*return_bi = bi;
				}
				bi = nextbi;
			}
		}
		if (bitmap_end)
			bitmap_endwrite(conf->mddev->bitmap, sh->sector,
					STRIPE_SECTORS, 0, 0);
2559 2560 2561 2562
		/* 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);
2563 2564
	}

2565 2566 2567
	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);
2568 2569
}

2570
static void
2571
handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
2572 2573 2574 2575 2576 2577
		   struct stripe_head_state *s)
{
	int abort = 0;
	int i;

	clear_bit(STRIPE_SYNCING, &sh->state);
2578 2579
	if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
		wake_up(&conf->wait_for_overlap);
2580
	s->syncing = 0;
2581
	s->replacing = 0;
2582
	/* There is nothing more to do for sync/check/repair.
2583 2584 2585
	 * 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.
2586
	 * For recover/replace we need to record a bad block on all
2587 2588
	 * non-sync devices, or abort the recovery
	 */
2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611
	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;
2612
	}
2613
	md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
2614 2615
}

2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631
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;
}

2632
/* fetch_block - checks the given member device to see if its data needs
2633 2634 2635
 * to be read or computed to satisfy a request.
 *
 * Returns 1 when no more member devices need to be checked, otherwise returns
2636
 * 0 to tell the loop in handle_stripe_fill to continue
2637
 */
2638 2639
static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
		       int disk_idx, int disks)
2640
{
2641
	struct r5dev *dev = &sh->dev[disk_idx];
2642 2643
	struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
				  &sh->dev[s->failed_num[1]] };
2644

2645
	/* is the data in this block needed, and can we get it? */
2646 2647 2648 2649 2650
	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 ||
2651
	     (s->replacing && want_replace(sh, disk_idx)) ||
2652 2653
	     (s->failed >= 1 && fdev[0]->toread) ||
	     (s->failed >= 2 && fdev[1]->toread) ||
2654 2655 2656
	     (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))) {
2657 2658 2659 2660 2661 2662
		/* 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) &&
2663 2664
		    (s->failed && (disk_idx == s->failed_num[0] ||
				   disk_idx == s->failed_num[1]))) {
2665 2666
			/* have disk failed, and we're requested to fetch it;
			 * do compute it
2667
			 */
2668 2669 2670 2671 2672 2673 2674 2675
			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;
2676 2677 2678 2679 2680 2681
			/* 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.
			 */
2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694
			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;
2695
			}
2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714
			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);
2715 2716
		}
	}
2717 2718 2719 2720 2721

	return 0;
}

/**
2722
 * handle_stripe_fill - read or compute data to satisfy pending requests.
2723
 */
2724 2725 2726
static void handle_stripe_fill(struct stripe_head *sh,
			       struct stripe_head_state *s,
			       int disks)
2727 2728 2729 2730 2731 2732 2733 2734 2735 2736
{
	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--; )
2737
			if (fetch_block(sh, s, i, disks))
2738
				break;
2739 2740 2741 2742
	set_bit(STRIPE_HANDLE, &sh->state);
}


2743
/* handle_stripe_clean_event
2744 2745 2746 2747
 * 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.
 */
2748
static void handle_stripe_clean_event(struct r5conf *conf,
2749 2750 2751 2752
	struct stripe_head *sh, int disks, struct bio **return_bi)
{
	int i;
	struct r5dev *dev;
2753
	int discard_pending = 0;
2754 2755 2756 2757 2758

	for (i = disks; i--; )
		if (sh->dev[i].written) {
			dev = &sh->dev[i];
			if (!test_bit(R5_LOCKED, &dev->flags) &&
2759
			    (test_bit(R5_UPTODATE, &dev->flags) ||
2760
			     test_bit(R5_Discard, &dev->flags))) {
2761 2762
				/* We can return any write requests */
				struct bio *wbi, *wbi2;
2763
				pr_debug("Return write for disc %d\n", i);
2764 2765
				if (test_and_clear_bit(R5_Discard, &dev->flags))
					clear_bit(R5_UPTODATE, &dev->flags);
2766 2767 2768 2769 2770
				wbi = dev->written;
				dev->written = NULL;
				while (wbi && wbi->bi_sector <
					dev->sector + STRIPE_SECTORS) {
					wbi2 = r5_next_bio(wbi, dev->sector);
2771
					if (!raid5_dec_bi_active_stripes(wbi)) {
2772 2773 2774 2775 2776 2777
						md_write_end(conf->mddev);
						wbi->bi_next = *return_bi;
						*return_bi = wbi;
					}
					wbi = wbi2;
				}
2778 2779
				bitmap_endwrite(conf->mddev->bitmap, sh->sector,
						STRIPE_SECTORS,
2780
					 !test_bit(STRIPE_DEGRADED, &sh->state),
2781
						0);
2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798
			} else if (test_bit(R5_Discard, &dev->flags))
				discard_pending = 1;
		}
	if (!discard_pending &&
	    test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
		clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
		clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
		if (sh->qd_idx >= 0) {
			clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
			clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
		}
		/* now that discard is done we can proceed with any sync */
		clear_bit(STRIPE_DISCARD, &sh->state);
		if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
			set_bit(STRIPE_HANDLE, &sh->state);

	}
2799 2800 2801 2802

	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);
2803 2804
}

2805
static void handle_stripe_dirtying(struct r5conf *conf,
2806 2807 2808
				   struct stripe_head *sh,
				   struct stripe_head_state *s,
				   int disks)
2809 2810
{
	int rmw = 0, rcw = 0, i;
2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823
	sector_t recovery_cp = conf->mddev->recovery_cp;

	/* RAID6 requires 'rcw' in current implementation.
	 * Otherwise, check whether resync is now happening or should start.
	 * If yes, then the array is dirty (after unclean shutdown or
	 * initial creation), so parity in some stripes might be inconsistent.
	 * In this case, we need to always do reconstruct-write, to ensure
	 * that in case of drive failure or read-error correction, we
	 * generate correct data from the parity.
	 */
	if (conf->max_degraded == 2 ||
	    (recovery_cp < MaxSector && sh->sector >= recovery_cp)) {
		/* Calculate the real rcw later - for now make it
2824 2825 2826
		 * look like rcw is cheaper
		 */
		rcw = 1; rmw = 2;
2827 2828 2829
		pr_debug("force RCW max_degraded=%u, recovery_cp=%llu sh->sector=%llu\n",
			 conf->max_degraded, (unsigned long long)recovery_cp,
			 (unsigned long long)sh->sector);
2830
	} else for (i = disks; i--; ) {
2831 2832 2833 2834
		/* 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) &&
2835 2836
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		      test_bit(R5_Wantcompute, &dev->flags))) {
2837 2838 2839 2840 2841 2842 2843 2844
			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) &&
2845 2846 2847
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		    test_bit(R5_Wantcompute, &dev->flags))) {
			if (test_bit(R5_Insync, &dev->flags)) rcw++;
2848 2849 2850 2851
			else
				rcw += 2*disks;
		}
	}
2852
	pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2853 2854
		(unsigned long long)sh->sector, rmw, rcw);
	set_bit(STRIPE_HANDLE, &sh->state);
N
NeilBrown 已提交
2855
	if (rmw < rcw && rmw > 0) {
2856
		/* prefer read-modify-write, but need to get some data */
2857 2858 2859 2860
		if (conf->mddev->queue)
			blk_add_trace_msg(conf->mddev->queue,
					  "raid5 rmw %llu %d",
					  (unsigned long long)sh->sector, rmw);
2861 2862 2863 2864
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if ((dev->towrite || i == sh->pd_idx) &&
			    !test_bit(R5_LOCKED, &dev->flags) &&
2865 2866
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
			    test_bit(R5_Wantcompute, &dev->flags)) &&
2867 2868 2869
			    test_bit(R5_Insync, &dev->flags)) {
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2870
					pr_debug("Read_old block "
N
NeilBrown 已提交
2871
						 "%d for r-m-w\n", i);
2872 2873 2874 2875 2876 2877 2878 2879 2880
					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);
				}
			}
		}
N
NeilBrown 已提交
2881
	}
2882
	if (rcw <= rmw && rcw > 0) {
2883
		/* want reconstruct write, but need to get some data */
N
NeilBrown 已提交
2884
		int qread =0;
2885
		rcw = 0;
2886 2887 2888
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (!test_bit(R5_OVERWRITE, &dev->flags) &&
2889
			    i != sh->pd_idx && i != sh->qd_idx &&
2890
			    !test_bit(R5_LOCKED, &dev->flags) &&
2891
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
2892 2893 2894 2895
			      test_bit(R5_Wantcompute, &dev->flags))) {
				rcw++;
				if (!test_bit(R5_Insync, &dev->flags))
					continue; /* it's a failed drive */
2896 2897
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2898
					pr_debug("Read_old block "
2899 2900 2901 2902
						"%d for Reconstruct\n", i);
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
					s->locked++;
N
NeilBrown 已提交
2903
					qread++;
2904 2905 2906 2907 2908 2909
				} else {
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
2910
		if (rcw && conf->mddev->queue)
N
NeilBrown 已提交
2911 2912 2913
			blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
					  (unsigned long long)sh->sector,
					  rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
2914
	}
2915 2916 2917
	/* now if nothing is locked, and if we have enough data,
	 * we can start a write request
	 */
2918 2919
	/* 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
2920 2921
	 * subsequent call wants to start a write request.  raid_run_ops only
	 * handles the case where compute block and reconstruct are requested
2922 2923 2924
	 * simultaneously.  If this is not the case then new writes need to be
	 * held off until the compute completes.
	 */
2925 2926 2927
	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)))
2928
		schedule_reconstruction(sh, s, rcw == 0, 0);
2929 2930
}

2931
static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
2932 2933
				struct stripe_head_state *s, int disks)
{
2934
	struct r5dev *dev = NULL;
2935

2936
	set_bit(STRIPE_HANDLE, &sh->state);
2937

2938 2939 2940
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are no failures */
2941 2942
		if (s->failed == 0) {
			BUG_ON(s->uptodate != disks);
2943 2944
			sh->check_state = check_state_run;
			set_bit(STRIPE_OP_CHECK, &s->ops_request);
2945 2946
			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
			s->uptodate--;
2947
			break;
2948
		}
2949
		dev = &sh->dev[s->failed_num[0]];
2950 2951 2952 2953 2954 2955 2956 2957 2958
		/* 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
2959

2960 2961 2962 2963 2964
		/* 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);
2965
		s->locked++;
2966
		set_bit(R5_Wantwrite, &dev->flags);
2967

2968 2969
		clear_bit(STRIPE_DEGRADED, &sh->state);
		set_bit(STRIPE_INSYNC, &sh->state);
2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985
		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
2986
		if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
2987 2988 2989 2990 2991
			/* parity is correct (on disc,
			 * not in buffer any more)
			 */
			set_bit(STRIPE_INSYNC, &sh->state);
		else {
2992
			atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
2993 2994 2995 2996 2997
			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;
2998
				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2999 3000 3001 3002
				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;
3003
				sh->ops.target2 = -1;
3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014
				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();
3015 3016 3017 3018
	}
}


3019
static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
3020
				  struct stripe_head_state *s,
3021
				  int disks)
3022 3023
{
	int pd_idx = sh->pd_idx;
N
NeilBrown 已提交
3024
	int qd_idx = sh->qd_idx;
3025
	struct r5dev *dev;
3026 3027 3028 3029

	set_bit(STRIPE_HANDLE, &sh->state);

	BUG_ON(s->failed > 2);
3030

3031 3032 3033 3034 3035 3036
	/* 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
	 */

3037 3038 3039
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are < 2 failures */
3040
		if (s->failed == s->q_failed) {
3041
			/* The only possible failed device holds Q, so it
3042 3043 3044
			 * makes sense to check P (If anything else were failed,
			 * we would have used P to recreate it).
			 */
3045
			sh->check_state = check_state_run;
3046
		}
3047
		if (!s->q_failed && s->failed < 2) {
3048
			/* Q is not failed, and we didn't use it to generate
3049 3050
			 * anything, so it makes sense to check it
			 */
3051 3052 3053 3054
			if (sh->check_state == check_state_run)
				sh->check_state = check_state_run_pq;
			else
				sh->check_state = check_state_run_q;
3055 3056
		}

3057 3058
		/* discard potentially stale zero_sum_result */
		sh->ops.zero_sum_result = 0;
3059

3060 3061 3062 3063
		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--;
3064
		}
3065 3066 3067 3068 3069 3070 3071
		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;
3072 3073
		}

3074 3075 3076 3077 3078
		/* we have 2-disk failure */
		BUG_ON(s->failed != 2);
		/* fall through */
	case check_state_compute_result:
		sh->check_state = check_state_idle;
3079

3080 3081 3082
		/* check that a write has not made the stripe insync */
		if (test_bit(STRIPE_INSYNC, &sh->state))
			break;
3083 3084

		/* now write out any block on a failed drive,
3085
		 * or P or Q if they were recomputed
3086
		 */
3087
		BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
3088
		if (s->failed == 2) {
3089
			dev = &sh->dev[s->failed_num[1]];
3090 3091 3092 3093 3094
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		if (s->failed >= 1) {
3095
			dev = &sh->dev[s->failed_num[0]];
3096 3097 3098 3099
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
3100
		if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
3101 3102 3103 3104 3105
			dev = &sh->dev[pd_idx];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
3106
		if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
3107 3108 3109 3110 3111 3112 3113 3114
			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);
3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143
		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 {
3144
			atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178
			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();
3179 3180 3181
	}
}

3182
static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
3183 3184 3185 3186 3187 3188
{
	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.
	 */
3189
	struct dma_async_tx_descriptor *tx = NULL;
3190 3191
	clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	for (i = 0; i < sh->disks; i++)
N
NeilBrown 已提交
3192
		if (i != sh->pd_idx && i != sh->qd_idx) {
3193
			int dd_idx, j;
3194
			struct stripe_head *sh2;
3195
			struct async_submit_ctl submit;
3196

3197
			sector_t bn = compute_blocknr(sh, i, 1);
3198 3199
			sector_t s = raid5_compute_sector(conf, bn, 0,
							  &dd_idx, NULL);
3200
			sh2 = get_active_stripe(conf, s, 0, 1, 1);
3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212
			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;
			}
3213 3214

			/* place all the copies on one channel */
3215
			init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
3216
			tx = async_memcpy(sh2->dev[dd_idx].page,
3217
					  sh->dev[i].page, 0, 0, STRIPE_SIZE,
3218
					  &submit);
3219

3220 3221 3222 3223
			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 &&
3224
				    j != sh2->qd_idx &&
3225 3226 3227 3228 3229 3230 3231
				    !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);
3232

3233
		}
3234
	/* done submitting copies, wait for them to complete */
3235
	async_tx_quiesce(&tx);
3236
}
L
Linus Torvalds 已提交
3237 3238 3239 3240

/*
 * handle_stripe - do things to a stripe.
 *
3241 3242
 * 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
3243
 * Possible results:
3244 3245
 *    return some read requests which now have data
 *    return some write requests which are safely on storage
L
Linus Torvalds 已提交
3246 3247 3248 3249 3250
 *    schedule a read on some buffers
 *    schedule a write of some buffers
 *    return confirmation of parity correctness
 *
 */
3251

3252
static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
L
Linus Torvalds 已提交
3253
{
3254
	struct r5conf *conf = sh->raid_conf;
3255
	int disks = sh->disks;
3256 3257
	struct r5dev *dev;
	int i;
3258
	int do_recovery = 0;
L
Linus Torvalds 已提交
3259

3260 3261 3262 3263 3264 3265
	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
3266

3267
	/* Now to look around and see what can be done */
L
Linus Torvalds 已提交
3268
	rcu_read_lock();
3269
	for (i=disks; i--; ) {
3270
		struct md_rdev *rdev;
3271 3272 3273
		sector_t first_bad;
		int bad_sectors;
		int is_bad = 0;
3274

3275
		dev = &sh->dev[i];
L
Linus Torvalds 已提交
3276

3277
		pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
3278 3279
			 i, dev->flags,
			 dev->toread, dev->towrite, dev->written);
3280 3281 3282 3283 3284 3285 3286 3287
		/* 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
3288

3289
		/* now count some things */
3290 3291 3292 3293
		if (test_bit(R5_LOCKED, &dev->flags))
			s->locked++;
		if (test_bit(R5_UPTODATE, &dev->flags))
			s->uptodate++;
3294
		if (test_bit(R5_Wantcompute, &dev->flags)) {
3295 3296
			s->compute++;
			BUG_ON(s->compute > 2);
3297
		}
L
Linus Torvalds 已提交
3298

3299
		if (test_bit(R5_Wantfill, &dev->flags))
3300
			s->to_fill++;
3301
		else if (dev->toread)
3302
			s->to_read++;
3303
		if (dev->towrite) {
3304
			s->to_write++;
3305
			if (!test_bit(R5_OVERWRITE, &dev->flags))
3306
				s->non_overwrite++;
3307
		}
3308
		if (dev->written)
3309
			s->written++;
3310 3311 3312 3313 3314 3315 3316 3317 3318 3319
		/* 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 {
3320 3321
			if (rdev)
				set_bit(R5_NeedReplace, &dev->flags);
3322 3323 3324
			rdev = rcu_dereference(conf->disks[i].rdev);
			clear_bit(R5_ReadRepl, &dev->flags);
		}
3325 3326
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338
		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);
			}
3339
		}
3340 3341 3342
		clear_bit(R5_Insync, &dev->flags);
		if (!rdev)
			/* Not in-sync */;
3343 3344
		else if (is_bad) {
			/* also not in-sync */
3345 3346
			if (!test_bit(WriteErrorSeen, &rdev->flags) &&
			    test_bit(R5_UPTODATE, &dev->flags)) {
3347 3348 3349 3350 3351 3352 3353
				/* 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))
3354
			set_bit(R5_Insync, &dev->flags);
3355
		else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
3356
			/* in sync if before recovery_offset */
3357 3358 3359 3360 3361 3362 3363 3364 3365
			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
3366
		if (rdev && test_bit(R5_WriteError, &dev->flags)) {
3367 3368 3369 3370 3371 3372 3373
			/* 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)) {
3374
				s->handle_bad_blocks = 1;
3375
				atomic_inc(&rdev2->nr_pending);
3376 3377 3378
			} else
				clear_bit(R5_WriteError, &dev->flags);
		}
A
Adam Kwolek 已提交
3379
		if (rdev && test_bit(R5_MadeGood, &dev->flags)) {
3380 3381 3382 3383 3384
			/* 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)) {
3385
				s->handle_bad_blocks = 1;
3386
				atomic_inc(&rdev2->nr_pending);
3387 3388 3389
			} else
				clear_bit(R5_MadeGood, &dev->flags);
		}
3390 3391 3392 3393 3394 3395 3396 3397 3398
		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);
		}
3399
		if (!test_bit(R5_Insync, &dev->flags)) {
3400 3401 3402
			/* 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
3403
		}
3404 3405 3406
		if (test_bit(R5_ReadError, &dev->flags))
			clear_bit(R5_Insync, &dev->flags);
		if (!test_bit(R5_Insync, &dev->flags)) {
3407 3408 3409
			if (s->failed < 2)
				s->failed_num[s->failed] = i;
			s->failed++;
3410 3411
			if (rdev && !test_bit(Faulty, &rdev->flags))
				do_recovery = 1;
3412
		}
L
Linus Torvalds 已提交
3413
	}
3414 3415 3416 3417
	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
3418
		 * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
3419 3420 3421 3422 3423
		 * else we can only be replacing
		 * sync and recovery both need to read all devices, and so
		 * use the same flag.
		 */
		if (do_recovery ||
3424 3425
		    sh->sector >= conf->mddev->recovery_cp ||
		    test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
3426 3427 3428 3429
			s->syncing = 1;
		else
			s->replacing = 1;
	}
L
Linus Torvalds 已提交
3430
	rcu_read_unlock();
3431 3432 3433 3434 3435
}

static void handle_stripe(struct stripe_head *sh)
{
	struct stripe_head_state s;
3436
	struct r5conf *conf = sh->raid_conf;
3437
	int i;
3438 3439
	int prexor;
	int disks = sh->disks;
3440
	struct r5dev *pdev, *qdev;
3441 3442

	clear_bit(STRIPE_HANDLE, &sh->state);
3443
	if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
3444 3445 3446 3447 3448 3449
		/* already being handled, ensure it gets handled
		 * again when current action finishes */
		set_bit(STRIPE_HANDLE, &sh->state);
		return;
	}

3450 3451 3452 3453 3454 3455 3456 3457 3458
	if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
		spin_lock(&sh->stripe_lock);
		/* Cannot process 'sync' concurrently with 'discard' */
		if (!test_bit(STRIPE_DISCARD, &sh->state) &&
		    test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
			set_bit(STRIPE_SYNCING, &sh->state);
			clear_bit(STRIPE_INSYNC, &sh->state);
		}
		spin_unlock(&sh->stripe_lock);
3459 3460 3461 3462 3463 3464 3465 3466
	}
	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);
3467

3468
	analyse_stripe(sh, &s);
3469

3470 3471 3472 3473 3474
	if (s.handle_bad_blocks) {
		set_bit(STRIPE_HANDLE, &sh->state);
		goto finish;
	}

3475 3476
	if (unlikely(s.blocked_rdev)) {
		if (s.syncing || s.expanding || s.expanded ||
3477
		    s.replacing || s.to_write || s.written) {
3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497
			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.
	 */
3498 3499 3500 3501 3502
	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);
3503
		if (s.syncing + s.replacing)
3504 3505
			handle_failed_sync(conf, sh, &s);
	}
3506

3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519
	/* 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
		 */
3520 3521
		BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
		       !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
3522
		BUG_ON(sh->qd_idx >= 0 &&
3523 3524
		       !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
		       !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543
		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;
	}

3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577
	/*
	 * 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) ||
				 test_bit(R5_Discard, &pdev->flags))))) &&
	    (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
			     && !test_bit(R5_LOCKED, &qdev->flags)
			     && (test_bit(R5_UPTODATE, &qdev->flags) ||
				 test_bit(R5_Discard, &qdev->flags))))))
		handle_stripe_clean_event(conf, sh, disks, &s.return_bi);

	/* Now we might consider reading some blocks, either to check/generate
	 * parity, or to satisfy requests
	 * or to load a block that is being partially written.
	 */
	if (s.to_read || s.non_overwrite
	    || (conf->level == 6 && s.to_write && s.failed)
	    || (s.syncing && (s.uptodate + s.compute < disks))
	    || s.replacing
	    || s.expanding)
		handle_stripe_fill(sh, &s, disks);

3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600
	/* 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);
	}
3601

3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615
	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)) {
3616 3617
		md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
		clear_bit(STRIPE_SYNCING, &sh->state);
3618 3619
		if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
			wake_up(&conf->wait_for_overlap);
3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646
	}

	/* 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++;
				}
			}
		}


3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673
	/* 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++;
		}
	}
3674

3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690
	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);
3691

3692
finish:
3693
	/* wait for this device to become unblocked */
3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705
	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);
	}
3706

3707 3708
	if (s.handle_bad_blocks)
		for (i = disks; i--; ) {
3709
			struct md_rdev *rdev;
3710 3711 3712 3713 3714 3715 3716 3717 3718
			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);
			}
3719 3720 3721
			if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
				rdev = conf->disks[i].rdev;
				rdev_clear_badblocks(rdev, sh->sector,
3722
						     STRIPE_SECTORS, 0);
3723 3724
				rdev_dec_pending(rdev, conf->mddev);
			}
3725 3726
			if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
				rdev = conf->disks[i].replacement;
3727 3728 3729
				if (!rdev)
					/* rdev have been moved down */
					rdev = conf->disks[i].rdev;
3730
				rdev_clear_badblocks(rdev, sh->sector,
3731
						     STRIPE_SECTORS, 0);
3732 3733
				rdev_dec_pending(rdev, conf->mddev);
			}
3734 3735
		}

3736 3737 3738
	if (s.ops_request)
		raid_run_ops(sh, s.ops_request);

D
Dan Williams 已提交
3739
	ops_run_io(sh, &s);
3740

3741
	if (s.dec_preread_active) {
3742
		/* We delay this until after ops_run_io so that if make_request
T
Tejun Heo 已提交
3743
		 * is waiting on a flush, it won't continue until the writes
3744 3745 3746 3747 3748 3749 3750 3751
		 * 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);
	}

3752
	return_io(s.return_bi);
3753

3754
	clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
3755 3756
}

3757
static void raid5_activate_delayed(struct r5conf *conf)
3758 3759 3760 3761 3762 3763 3764 3765 3766 3767
{
	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);
3768
			list_add_tail(&sh->lru, &conf->hold_list);
3769
		}
N
NeilBrown 已提交
3770
	}
3771 3772
}

3773
static void activate_bit_delay(struct r5conf *conf)
3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786
{
	/* 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);
	}
}

3787
int md_raid5_congested(struct mddev *mddev, int bits)
3788
{
3789
	struct r5conf *conf = mddev->private;
3790 3791 3792 3793

	/* No difference between reads and writes.  Just check
	 * how busy the stripe_cache is
	 */
3794

3795 3796 3797 3798 3799 3800 3801 3802 3803
	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
3804 3805 3806 3807
EXPORT_SYMBOL_GPL(md_raid5_congested);

static int raid5_congested(void *data, int bits)
{
3808
	struct mddev *mddev = data;
N
NeilBrown 已提交
3809 3810 3811 3812

	return mddev_congested(mddev, bits) ||
		md_raid5_congested(mddev, bits);
}
3813

3814 3815 3816
/* We want read requests to align with chunks where possible,
 * but write requests don't need to.
 */
3817 3818 3819
static int raid5_mergeable_bvec(struct request_queue *q,
				struct bvec_merge_data *bvm,
				struct bio_vec *biovec)
3820
{
3821
	struct mddev *mddev = q->queuedata;
3822
	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
3823
	int max;
3824
	unsigned int chunk_sectors = mddev->chunk_sectors;
3825
	unsigned int bio_sectors = bvm->bi_size >> 9;
3826

3827
	if ((bvm->bi_rw & 1) == WRITE)
3828 3829
		return biovec->bv_len; /* always allow writes to be mergeable */

3830 3831
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3832 3833 3834 3835 3836 3837 3838 3839
	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;
}

3840

3841
static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
3842 3843
{
	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3844
	unsigned int chunk_sectors = mddev->chunk_sectors;
3845 3846
	unsigned int bio_sectors = bio->bi_size >> 9;

3847 3848
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3849 3850 3851 3852
	return  chunk_sectors >=
		((sector & (chunk_sectors - 1)) + bio_sectors);
}

3853 3854 3855 3856
/*
 *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
 *  later sampled by raid5d.
 */
3857
static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870
{
	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);
}


3871
static struct bio *remove_bio_from_retry(struct r5conf *conf)
3872 3873 3874 3875 3876 3877 3878 3879 3880 3881
{
	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) {
3882
		conf->retry_read_aligned_list = bi->bi_next;
3883
		bi->bi_next = NULL;
3884 3885 3886 3887
		/*
		 * this sets the active strip count to 1 and the processed
		 * strip count to zero (upper 8 bits)
		 */
3888
		raid5_set_bi_stripes(bi, 1); /* biased count of active stripes */
3889 3890 3891 3892 3893 3894
	}

	return bi;
}


3895 3896 3897 3898 3899 3900
/*
 *  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..
 */
3901
static void raid5_align_endio(struct bio *bi, int error)
3902 3903
{
	struct bio* raid_bi  = bi->bi_private;
3904
	struct mddev *mddev;
3905
	struct r5conf *conf;
3906
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
3907
	struct md_rdev *rdev;
3908

3909
	bio_put(bi);
3910 3911 3912

	rdev = (void*)raid_bi->bi_next;
	raid_bi->bi_next = NULL;
3913 3914
	mddev = rdev->mddev;
	conf = mddev->private;
3915 3916 3917 3918

	rdev_dec_pending(rdev, conf->mddev);

	if (!error && uptodate) {
3919 3920
		trace_block_bio_complete(bdev_get_queue(raid_bi->bi_bdev),
					 raid_bi, 0);
3921
		bio_endio(raid_bi, 0);
3922 3923
		if (atomic_dec_and_test(&conf->active_aligned_reads))
			wake_up(&conf->wait_for_stripe);
3924
		return;
3925 3926 3927
	}


3928
	pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
3929 3930

	add_bio_to_retry(raid_bi, conf);
3931 3932
}

3933 3934
static int bio_fits_rdev(struct bio *bi)
{
3935
	struct request_queue *q = bdev_get_queue(bi->bi_bdev);
3936

3937
	if ((bi->bi_size>>9) > queue_max_sectors(q))
3938 3939
		return 0;
	blk_recount_segments(q, bi);
3940
	if (bi->bi_phys_segments > queue_max_segments(q))
3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952
		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;
}


3953
static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
3954
{
3955
	struct r5conf *conf = mddev->private;
N
NeilBrown 已提交
3956
	int dd_idx;
3957
	struct bio* align_bi;
3958
	struct md_rdev *rdev;
3959
	sector_t end_sector;
3960 3961

	if (!in_chunk_boundary(mddev, raid_bio)) {
3962
		pr_debug("chunk_aligned_read : non aligned\n");
3963 3964 3965
		return 0;
	}
	/*
3966
	 * use bio_clone_mddev to make a copy of the bio
3967
	 */
3968
	align_bi = bio_clone_mddev(raid_bio, GFP_NOIO, mddev);
3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979
	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
	 */
3980 3981
	align_bi->bi_sector =  raid5_compute_sector(conf, raid_bio->bi_sector,
						    0,
3982
						    &dd_idx, NULL);
3983

3984
	end_sector = align_bi->bi_sector + (align_bi->bi_size >> 9);
3985
	rcu_read_lock();
3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996
	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) {
3997 3998 3999
		sector_t first_bad;
		int bad_sectors;

4000 4001
		atomic_inc(&rdev->nr_pending);
		rcu_read_unlock();
4002 4003 4004 4005
		raid_bio->bi_next = (void*)rdev;
		align_bi->bi_bdev =  rdev->bdev;
		align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);

4006 4007 4008 4009
		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 */
4010 4011 4012 4013 4014
			bio_put(align_bi);
			rdev_dec_pending(rdev, mddev);
			return 0;
		}

4015 4016 4017
		/* No reshape active, so we can trust rdev->data_offset */
		align_bi->bi_sector += rdev->data_offset;

4018 4019 4020
		spin_lock_irq(&conf->device_lock);
		wait_event_lock_irq(conf->wait_for_stripe,
				    conf->quiesce == 0,
4021
				    conf->device_lock);
4022 4023 4024
		atomic_inc(&conf->active_aligned_reads);
		spin_unlock_irq(&conf->device_lock);

4025 4026 4027 4028
		if (mddev->gendisk)
			trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev),
					      align_bi, disk_devt(mddev->gendisk),
					      raid_bio->bi_sector);
4029 4030 4031 4032
		generic_make_request(align_bi);
		return 1;
	} else {
		rcu_read_unlock();
4033
		bio_put(align_bi);
4034 4035 4036 4037
		return 0;
	}
}

4038 4039 4040 4041 4042 4043 4044 4045 4046 4047
/* __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.
 */
4048
static struct stripe_head *__get_priority_stripe(struct r5conf *conf)
4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089
{
	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;
}
4090

4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102
struct raid5_plug_cb {
	struct blk_plug_cb	cb;
	struct list_head	list;
};

static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
{
	struct raid5_plug_cb *cb = container_of(
		blk_cb, struct raid5_plug_cb, cb);
	struct stripe_head *sh;
	struct mddev *mddev = cb->cb.data;
	struct r5conf *conf = mddev->private;
N
NeilBrown 已提交
4103
	int cnt = 0;
4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117

	if (cb->list.next && !list_empty(&cb->list)) {
		spin_lock_irq(&conf->device_lock);
		while (!list_empty(&cb->list)) {
			sh = list_first_entry(&cb->list, struct stripe_head, lru);
			list_del_init(&sh->lru);
			/*
			 * avoid race release_stripe_plug() sees
			 * STRIPE_ON_UNPLUG_LIST clear but the stripe
			 * is still in our list
			 */
			smp_mb__before_clear_bit();
			clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
			__release_stripe(conf, sh);
N
NeilBrown 已提交
4118
			cnt++;
4119 4120 4121
		}
		spin_unlock_irq(&conf->device_lock);
	}
4122 4123
	if (mddev->queue)
		trace_block_unplug(mddev->queue, cnt, !from_schedule);
4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150
	kfree(cb);
}

static void release_stripe_plug(struct mddev *mddev,
				struct stripe_head *sh)
{
	struct blk_plug_cb *blk_cb = blk_check_plugged(
		raid5_unplug, mddev,
		sizeof(struct raid5_plug_cb));
	struct raid5_plug_cb *cb;

	if (!blk_cb) {
		release_stripe(sh);
		return;
	}

	cb = container_of(blk_cb, struct raid5_plug_cb, cb);

	if (cb->list.next == NULL)
		INIT_LIST_HEAD(&cb->list);

	if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
		list_add_tail(&sh->lru, &cb->list);
	else
		release_stripe(sh);
}

S
Shaohua Li 已提交
4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185
static void make_discard_request(struct mddev *mddev, struct bio *bi)
{
	struct r5conf *conf = mddev->private;
	sector_t logical_sector, last_sector;
	struct stripe_head *sh;
	int remaining;
	int stripe_sectors;

	if (mddev->reshape_position != MaxSector)
		/* Skip discard while reshape is happening */
		return;

	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 */

	stripe_sectors = conf->chunk_sectors *
		(conf->raid_disks - conf->max_degraded);
	logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
					       stripe_sectors);
	sector_div(last_sector, stripe_sectors);

	logical_sector *= conf->chunk_sectors;
	last_sector *= conf->chunk_sectors;

	for (; logical_sector < last_sector;
	     logical_sector += STRIPE_SECTORS) {
		DEFINE_WAIT(w);
		int d;
	again:
		sh = get_active_stripe(conf, logical_sector, 0, 0, 0);
		prepare_to_wait(&conf->wait_for_overlap, &w,
				TASK_UNINTERRUPTIBLE);
4186 4187 4188 4189 4190 4191 4192
		set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
		if (test_bit(STRIPE_SYNCING, &sh->state)) {
			release_stripe(sh);
			schedule();
			goto again;
		}
		clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
S
Shaohua Li 已提交
4193 4194 4195 4196 4197 4198 4199 4200 4201 4202 4203 4204
		spin_lock_irq(&sh->stripe_lock);
		for (d = 0; d < conf->raid_disks; d++) {
			if (d == sh->pd_idx || d == sh->qd_idx)
				continue;
			if (sh->dev[d].towrite || sh->dev[d].toread) {
				set_bit(R5_Overlap, &sh->dev[d].flags);
				spin_unlock_irq(&sh->stripe_lock);
				release_stripe(sh);
				schedule();
				goto again;
			}
		}
4205
		set_bit(STRIPE_DISCARD, &sh->state);
S
Shaohua Li 已提交
4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240
		finish_wait(&conf->wait_for_overlap, &w);
		for (d = 0; d < conf->raid_disks; d++) {
			if (d == sh->pd_idx || d == sh->qd_idx)
				continue;
			sh->dev[d].towrite = bi;
			set_bit(R5_OVERWRITE, &sh->dev[d].flags);
			raid5_inc_bi_active_stripes(bi);
		}
		spin_unlock_irq(&sh->stripe_lock);
		if (conf->mddev->bitmap) {
			for (d = 0;
			     d < conf->raid_disks - conf->max_degraded;
			     d++)
				bitmap_startwrite(mddev->bitmap,
						  sh->sector,
						  STRIPE_SECTORS,
						  0);
			sh->bm_seq = conf->seq_flush + 1;
			set_bit(STRIPE_BIT_DELAY, &sh->state);
		}

		set_bit(STRIPE_HANDLE, &sh->state);
		clear_bit(STRIPE_DELAYED, &sh->state);
		if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
			atomic_inc(&conf->preread_active_stripes);
		release_stripe_plug(mddev, sh);
	}

	remaining = raid5_dec_bi_active_stripes(bi);
	if (remaining == 0) {
		md_write_end(mddev);
		bio_endio(bi, 0);
	}
}

4241
static void make_request(struct mddev *mddev, struct bio * bi)
L
Linus Torvalds 已提交
4242
{
4243
	struct r5conf *conf = mddev->private;
4244
	int dd_idx;
L
Linus Torvalds 已提交
4245 4246 4247
	sector_t new_sector;
	sector_t logical_sector, last_sector;
	struct stripe_head *sh;
4248
	const int rw = bio_data_dir(bi);
4249
	int remaining;
L
Linus Torvalds 已提交
4250

T
Tejun Heo 已提交
4251 4252
	if (unlikely(bi->bi_rw & REQ_FLUSH)) {
		md_flush_request(mddev, bi);
4253
		return;
4254 4255
	}

4256
	md_write_start(mddev, bi);
4257

4258
	if (rw == READ &&
4259
	     mddev->reshape_position == MaxSector &&
4260
	     chunk_aligned_read(mddev,bi))
4261
		return;
4262

S
Shaohua Li 已提交
4263 4264 4265 4266 4267
	if (unlikely(bi->bi_rw & REQ_DISCARD)) {
		make_discard_request(mddev, bi);
		return;
	}

L
Linus Torvalds 已提交
4268 4269 4270 4271
	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 */
4272

L
Linus Torvalds 已提交
4273 4274
	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
		DEFINE_WAIT(w);
4275
		int previous;
4276

4277
	retry:
4278
		previous = 0;
4279
		prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
4280
		if (unlikely(conf->reshape_progress != MaxSector)) {
4281
			/* spinlock is needed as reshape_progress may be
4282 4283
			 * 64bit on a 32bit platform, and so it might be
			 * possible to see a half-updated value
4284
			 * Of course reshape_progress could change after
4285 4286 4287 4288
			 * the lock is dropped, so once we get a reference
			 * to the stripe that we think it is, we will have
			 * to check again.
			 */
4289
			spin_lock_irq(&conf->device_lock);
4290
			if (mddev->reshape_backwards
4291 4292
			    ? logical_sector < conf->reshape_progress
			    : logical_sector >= conf->reshape_progress) {
4293 4294
				previous = 1;
			} else {
4295
				if (mddev->reshape_backwards
4296 4297
				    ? logical_sector < conf->reshape_safe
				    : logical_sector >= conf->reshape_safe) {
4298 4299 4300 4301 4302
					spin_unlock_irq(&conf->device_lock);
					schedule();
					goto retry;
				}
			}
4303 4304
			spin_unlock_irq(&conf->device_lock);
		}
4305

4306 4307
		new_sector = raid5_compute_sector(conf, logical_sector,
						  previous,
4308
						  &dd_idx, NULL);
4309
		pr_debug("raid456: make_request, sector %llu logical %llu\n",
L
Linus Torvalds 已提交
4310 4311 4312
			(unsigned long long)new_sector, 
			(unsigned long long)logical_sector);

4313
		sh = get_active_stripe(conf, new_sector, previous,
4314
				       (bi->bi_rw&RWA_MASK), 0);
L
Linus Torvalds 已提交
4315
		if (sh) {
4316
			if (unlikely(previous)) {
4317
				/* expansion might have moved on while waiting for a
4318 4319 4320 4321 4322 4323
				 * 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.
4324 4325 4326
				 */
				int must_retry = 0;
				spin_lock_irq(&conf->device_lock);
4327
				if (mddev->reshape_backwards
4328 4329
				    ? logical_sector >= conf->reshape_progress
				    : logical_sector < conf->reshape_progress)
4330 4331 4332 4333 4334
					/* mismatch, need to try again */
					must_retry = 1;
				spin_unlock_irq(&conf->device_lock);
				if (must_retry) {
					release_stripe(sh);
4335
					schedule();
4336 4337 4338
					goto retry;
				}
			}
4339

4340
			if (rw == WRITE &&
4341
			    logical_sector >= mddev->suspend_lo &&
4342 4343
			    logical_sector < mddev->suspend_hi) {
				release_stripe(sh);
4344 4345 4346 4347 4348 4349 4350 4351 4352 4353
				/* 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();
4354 4355
				goto retry;
			}
4356 4357

			if (test_bit(STRIPE_EXPANDING, &sh->state) ||
4358
			    !add_stripe_bio(sh, bi, dd_idx, rw)) {
4359 4360
				/* Stripe is busy expanding or
				 * add failed due to overlap.  Flush everything
L
Linus Torvalds 已提交
4361 4362
				 * and wait a while
				 */
N
NeilBrown 已提交
4363
				md_wakeup_thread(mddev->thread);
L
Linus Torvalds 已提交
4364 4365 4366 4367 4368
				release_stripe(sh);
				schedule();
				goto retry;
			}
			finish_wait(&conf->wait_for_overlap, &w);
4369 4370
			set_bit(STRIPE_HANDLE, &sh->state);
			clear_bit(STRIPE_DELAYED, &sh->state);
4371
			if ((bi->bi_rw & REQ_SYNC) &&
4372 4373
			    !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
				atomic_inc(&conf->preread_active_stripes);
4374
			release_stripe_plug(mddev, sh);
L
Linus Torvalds 已提交
4375 4376 4377 4378 4379 4380 4381
		} 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;
		}
	}
4382

4383
	remaining = raid5_dec_bi_active_stripes(bi);
4384
	if (remaining == 0) {
L
Linus Torvalds 已提交
4385

4386
		if ( rw == WRITE )
L
Linus Torvalds 已提交
4387
			md_write_end(mddev);
4388

4389 4390
		trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
					 bi, 0);
4391
		bio_endio(bi, 0);
L
Linus Torvalds 已提交
4392 4393 4394
	}
}

4395
static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
D
Dan Williams 已提交
4396

4397
static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
L
Linus Torvalds 已提交
4398
{
4399 4400 4401 4402 4403 4404 4405 4406 4407
	/* 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.
	 */
4408
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4409
	struct stripe_head *sh;
4410
	sector_t first_sector, last_sector;
4411 4412 4413
	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;
4414 4415
	int i;
	int dd_idx;
4416
	sector_t writepos, readpos, safepos;
4417
	sector_t stripe_addr;
4418
	int reshape_sectors;
4419
	struct list_head stripes;
4420

4421 4422
	if (sector_nr == 0) {
		/* If restarting in the middle, skip the initial sectors */
4423
		if (mddev->reshape_backwards &&
4424 4425 4426
		    conf->reshape_progress < raid5_size(mddev, 0, 0)) {
			sector_nr = raid5_size(mddev, 0, 0)
				- conf->reshape_progress;
4427
		} else if (!mddev->reshape_backwards &&
4428 4429
			   conf->reshape_progress > 0)
			sector_nr = conf->reshape_progress;
4430
		sector_div(sector_nr, new_data_disks);
4431
		if (sector_nr) {
4432 4433
			mddev->curr_resync_completed = sector_nr;
			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4434 4435 4436
			*skipped = 1;
			return sector_nr;
		}
4437 4438
	}

4439 4440 4441 4442
	/* 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
	 */
4443 4444
	if (mddev->new_chunk_sectors > mddev->chunk_sectors)
		reshape_sectors = mddev->new_chunk_sectors;
4445
	else
4446
		reshape_sectors = mddev->chunk_sectors;
4447

4448 4449 4450 4451 4452
	/* 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
4453
	 */
4454
	writepos = conf->reshape_progress;
4455
	sector_div(writepos, new_data_disks);
4456 4457
	readpos = conf->reshape_progress;
	sector_div(readpos, data_disks);
4458
	safepos = conf->reshape_safe;
4459
	sector_div(safepos, data_disks);
4460
	if (mddev->reshape_backwards) {
4461
		writepos -= min_t(sector_t, reshape_sectors, writepos);
4462
		readpos += reshape_sectors;
4463
		safepos += reshape_sectors;
4464
	} else {
4465
		writepos += reshape_sectors;
4466 4467
		readpos -= min_t(sector_t, reshape_sectors, readpos);
		safepos -= min_t(sector_t, reshape_sectors, safepos);
4468
	}
4469

4470 4471 4472 4473 4474 4475 4476 4477 4478 4479 4480 4481 4482 4483 4484
	/* 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;
	}

4485 4486 4487 4488
	/* '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.
4489 4490 4491 4492
	 * 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
4493 4494 4495 4496 4497 4498 4499 4500 4501 4502 4503 4504
	 * 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???
	 */
4505 4506 4507 4508 4509 4510
	if (conf->min_offset_diff < 0) {
		safepos += -conf->min_offset_diff;
		readpos += -conf->min_offset_diff;
	} else
		writepos += conf->min_offset_diff;

4511
	if ((mddev->reshape_backwards
4512 4513 4514
	     ? (safepos > writepos && readpos < writepos)
	     : (safepos < writepos && readpos > writepos)) ||
	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4515 4516 4517
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes)==0);
4518
		mddev->reshape_position = conf->reshape_progress;
4519
		mddev->curr_resync_completed = sector_nr;
4520
		conf->reshape_checkpoint = jiffies;
4521
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
4522
		md_wakeup_thread(mddev->thread);
4523
		wait_event(mddev->sb_wait, mddev->flags == 0 ||
4524 4525
			   kthread_should_stop());
		spin_lock_irq(&conf->device_lock);
4526
		conf->reshape_safe = mddev->reshape_position;
4527 4528
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4529
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4530 4531
	}

4532
	INIT_LIST_HEAD(&stripes);
4533
	for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
4534
		int j;
4535
		int skipped_disk = 0;
4536
		sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
4537 4538 4539 4540 4541 4542 4543 4544 4545
		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;
4546
			if (conf->level == 6 &&
4547
			    j == sh->qd_idx)
4548
				continue;
4549
			s = compute_blocknr(sh, j, 0);
D
Dan Williams 已提交
4550
			if (s < raid5_size(mddev, 0, 0)) {
4551
				skipped_disk = 1;
4552 4553 4554 4555 4556 4557
				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);
		}
4558
		if (!skipped_disk) {
4559 4560 4561
			set_bit(STRIPE_EXPAND_READY, &sh->state);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
4562
		list_add(&sh->lru, &stripes);
4563 4564
	}
	spin_lock_irq(&conf->device_lock);
4565
	if (mddev->reshape_backwards)
4566
		conf->reshape_progress -= reshape_sectors * new_data_disks;
4567
	else
4568
		conf->reshape_progress += reshape_sectors * new_data_disks;
4569 4570 4571 4572 4573 4574 4575
	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 =
4576
		raid5_compute_sector(conf, stripe_addr*(new_data_disks),
4577
				     1, &dd_idx, NULL);
4578
	last_sector =
4579
		raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
4580
					    * new_data_disks - 1),
4581
				     1, &dd_idx, NULL);
A
Andre Noll 已提交
4582 4583
	if (last_sector >= mddev->dev_sectors)
		last_sector = mddev->dev_sectors - 1;
4584
	while (first_sector <= last_sector) {
4585
		sh = get_active_stripe(conf, first_sector, 1, 0, 1);
4586 4587 4588 4589 4590
		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
		set_bit(STRIPE_HANDLE, &sh->state);
		release_stripe(sh);
		first_sector += STRIPE_SECTORS;
	}
4591 4592 4593 4594 4595 4596 4597 4598
	/* 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);
	}
4599 4600 4601
	/* If this takes us to the resync_max point where we have to pause,
	 * then we need to write out the superblock.
	 */
4602
	sector_nr += reshape_sectors;
4603 4604
	if ((sector_nr - mddev->curr_resync_completed) * 2
	    >= mddev->resync_max - mddev->curr_resync_completed) {
4605 4606 4607
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes) == 0);
4608
		mddev->reshape_position = conf->reshape_progress;
4609
		mddev->curr_resync_completed = sector_nr;
4610
		conf->reshape_checkpoint = jiffies;
4611 4612 4613 4614 4615 4616
		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);
4617
		conf->reshape_safe = mddev->reshape_position;
4618 4619
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4620
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4621
	}
4622
	return reshape_sectors;
4623 4624 4625
}

/* FIXME go_faster isn't used */
4626
static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
4627
{
4628
	struct r5conf *conf = mddev->private;
4629
	struct stripe_head *sh;
A
Andre Noll 已提交
4630
	sector_t max_sector = mddev->dev_sectors;
N
NeilBrown 已提交
4631
	sector_t sync_blocks;
4632 4633
	int still_degraded = 0;
	int i;
L
Linus Torvalds 已提交
4634

4635
	if (sector_nr >= max_sector) {
L
Linus Torvalds 已提交
4636
		/* just being told to finish up .. nothing much to do */
4637

4638 4639 4640 4641
		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
			end_reshape(conf);
			return 0;
		}
4642 4643 4644 4645

		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
					&sync_blocks, 1);
4646
		else /* completed sync */
4647 4648 4649
			conf->fullsync = 0;
		bitmap_close_sync(mddev->bitmap);

L
Linus Torvalds 已提交
4650 4651
		return 0;
	}
4652

4653 4654 4655
	/* Allow raid5_quiesce to complete */
	wait_event(conf->wait_for_overlap, conf->quiesce != 2);

4656 4657
	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
		return reshape_request(mddev, sector_nr, skipped);
4658

4659 4660 4661 4662 4663 4664
	/* 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
	 */

4665
	/* if there is too many failed drives and we are trying
L
Linus Torvalds 已提交
4666 4667 4668
	 * to resync, then assert that we are finished, because there is
	 * nothing we can do.
	 */
4669
	if (mddev->degraded >= conf->max_degraded &&
4670
	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
A
Andre Noll 已提交
4671
		sector_t rv = mddev->dev_sectors - sector_nr;
4672
		*skipped = 1;
L
Linus Torvalds 已提交
4673 4674
		return rv;
	}
4675
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
4676
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
4677 4678 4679 4680 4681 4682
	    !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
4683

N
NeilBrown 已提交
4684 4685
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);

4686
	sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
L
Linus Torvalds 已提交
4687
	if (sh == NULL) {
4688
		sh = get_active_stripe(conf, sector_nr, 0, 0, 0);
L
Linus Torvalds 已提交
4689
		/* make sure we don't swamp the stripe cache if someone else
4690
		 * is trying to get access
L
Linus Torvalds 已提交
4691
		 */
4692
		schedule_timeout_uninterruptible(1);
L
Linus Torvalds 已提交
4693
	}
4694 4695 4696 4697
	/* 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.
	 */
4698
	for (i = 0; i < conf->raid_disks; i++)
4699 4700 4701 4702 4703
		if (conf->disks[i].rdev == NULL)
			still_degraded = 1;

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

4704
	set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
L
Linus Torvalds 已提交
4705

4706
	handle_stripe(sh);
L
Linus Torvalds 已提交
4707 4708 4709 4710 4711
	release_stripe(sh);

	return STRIPE_SECTORS;
}

4712
static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 4723 4724
{
	/* 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;
4725
	int dd_idx;
4726 4727 4728 4729 4730 4731
	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);
4732
	sector = raid5_compute_sector(conf, logical_sector,
4733
				      0, &dd_idx, NULL);
4734 4735 4736
	last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);

	for (; logical_sector < last_sector;
4737 4738 4739
	     logical_sector += STRIPE_SECTORS,
		     sector += STRIPE_SECTORS,
		     scnt++) {
4740

4741
		if (scnt < raid5_bi_processed_stripes(raid_bio))
4742 4743 4744
			/* already done this stripe */
			continue;

4745
		sh = get_active_stripe(conf, sector, 0, 1, 0);
4746 4747 4748

		if (!sh) {
			/* failed to get a stripe - must wait */
4749
			raid5_set_bi_processed_stripes(raid_bio, scnt);
4750 4751 4752 4753
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4754 4755
		if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
			release_stripe(sh);
4756
			raid5_set_bi_processed_stripes(raid_bio, scnt);
4757 4758 4759 4760
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4761
		set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
4762
		handle_stripe(sh);
4763 4764 4765
		release_stripe(sh);
		handled++;
	}
4766
	remaining = raid5_dec_bi_active_stripes(raid_bio);
4767 4768 4769
	if (remaining == 0) {
		trace_block_bio_complete(bdev_get_queue(raid_bio->bi_bdev),
					 raid_bio, 0);
4770
		bio_endio(raid_bio, 0);
4771
	}
4772 4773 4774 4775 4776
	if (atomic_dec_and_test(&conf->active_aligned_reads))
		wake_up(&conf->wait_for_stripe);
	return handled;
}

4777 4778 4779 4780 4781 4782 4783 4784 4785 4786 4787 4788 4789 4790 4791 4792 4793 4794 4795 4796 4797 4798 4799 4800
#define MAX_STRIPE_BATCH 8
static int handle_active_stripes(struct r5conf *conf)
{
	struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
	int i, batch_size = 0;

	while (batch_size < MAX_STRIPE_BATCH &&
			(sh = __get_priority_stripe(conf)) != NULL)
		batch[batch_size++] = sh;

	if (batch_size == 0)
		return batch_size;
	spin_unlock_irq(&conf->device_lock);

	for (i = 0; i < batch_size; i++)
		handle_stripe(batch[i]);

	cond_resched();

	spin_lock_irq(&conf->device_lock);
	for (i = 0; i < batch_size; i++)
		__release_stripe(conf, batch[i]);
	return batch_size;
}
4801

L
Linus Torvalds 已提交
4802 4803 4804 4805 4806 4807 4808
/*
 * 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.
 */
S
Shaohua Li 已提交
4809
static void raid5d(struct md_thread *thread)
L
Linus Torvalds 已提交
4810
{
S
Shaohua Li 已提交
4811
	struct mddev *mddev = thread->mddev;
4812
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4813
	int handled;
4814
	struct blk_plug plug;
L
Linus Torvalds 已提交
4815

4816
	pr_debug("+++ raid5d active\n");
L
Linus Torvalds 已提交
4817 4818 4819

	md_check_recovery(mddev);

4820
	blk_start_plug(&plug);
L
Linus Torvalds 已提交
4821 4822 4823
	handled = 0;
	spin_lock_irq(&conf->device_lock);
	while (1) {
4824
		struct bio *bio;
4825
		int batch_size;
L
Linus Torvalds 已提交
4826

4827
		if (
4828 4829 4830
		    !list_empty(&conf->bitmap_list)) {
			/* Now is a good time to flush some bitmap updates */
			conf->seq_flush++;
4831
			spin_unlock_irq(&conf->device_lock);
4832
			bitmap_unplug(mddev->bitmap);
4833
			spin_lock_irq(&conf->device_lock);
4834
			conf->seq_write = conf->seq_flush;
4835 4836
			activate_bit_delay(conf);
		}
4837
		raid5_activate_delayed(conf);
4838

4839 4840 4841 4842 4843 4844 4845 4846 4847 4848
		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++;
		}

4849 4850
		batch_size = handle_active_stripes(conf);
		if (!batch_size)
L
Linus Torvalds 已提交
4851
			break;
4852
		handled += batch_size;
L
Linus Torvalds 已提交
4853

4854 4855
		if (mddev->flags & ~(1<<MD_CHANGE_PENDING)) {
			spin_unlock_irq(&conf->device_lock);
4856
			md_check_recovery(mddev);
4857 4858
			spin_lock_irq(&conf->device_lock);
		}
L
Linus Torvalds 已提交
4859
	}
4860
	pr_debug("%d stripes handled\n", handled);
L
Linus Torvalds 已提交
4861 4862 4863

	spin_unlock_irq(&conf->device_lock);

4864
	async_tx_issue_pending_all();
4865
	blk_finish_plug(&plug);
L
Linus Torvalds 已提交
4866

4867
	pr_debug("--- raid5d inactive\n");
L
Linus Torvalds 已提交
4868 4869
}

4870
static ssize_t
4871
raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
4872
{
4873
	struct r5conf *conf = mddev->private;
4874 4875 4876 4877
	if (conf)
		return sprintf(page, "%d\n", conf->max_nr_stripes);
	else
		return 0;
4878 4879
}

4880
int
4881
raid5_set_cache_size(struct mddev *mddev, int size)
4882
{
4883
	struct r5conf *conf = mddev->private;
4884 4885
	int err;

4886
	if (size <= 16 || size > 32768)
4887
		return -EINVAL;
4888
	while (size < conf->max_nr_stripes) {
4889 4890 4891 4892 4893
		if (drop_one_stripe(conf))
			conf->max_nr_stripes--;
		else
			break;
	}
4894 4895 4896
	err = md_allow_write(mddev);
	if (err)
		return err;
4897
	while (size > conf->max_nr_stripes) {
4898 4899 4900 4901
		if (grow_one_stripe(conf))
			conf->max_nr_stripes++;
		else break;
	}
4902 4903 4904 4905 4906
	return 0;
}
EXPORT_SYMBOL(raid5_set_cache_size);

static ssize_t
4907
raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
4908
{
4909
	struct r5conf *conf = mddev->private;
4910 4911 4912 4913 4914 4915 4916 4917 4918 4919 4920 4921 4922
	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;
4923 4924
	return len;
}
4925

4926 4927 4928 4929
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);
4930

4931
static ssize_t
4932
raid5_show_preread_threshold(struct mddev *mddev, char *page)
4933
{
4934
	struct r5conf *conf = mddev->private;
4935 4936 4937 4938 4939 4940 4941
	if (conf)
		return sprintf(page, "%d\n", conf->bypass_threshold);
	else
		return 0;
}

static ssize_t
4942
raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
4943
{
4944
	struct r5conf *conf = mddev->private;
4945
	unsigned long new;
4946 4947 4948 4949 4950
	if (len >= PAGE_SIZE)
		return -EINVAL;
	if (!conf)
		return -ENODEV;

4951
	if (strict_strtoul(page, 10, &new))
4952
		return -EINVAL;
4953
	if (new > conf->max_nr_stripes)
4954 4955 4956 4957 4958 4959 4960 4961 4962 4963 4964
		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);

4965
static ssize_t
4966
stripe_cache_active_show(struct mddev *mddev, char *page)
4967
{
4968
	struct r5conf *conf = mddev->private;
4969 4970 4971 4972
	if (conf)
		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
	else
		return 0;
4973 4974
}

4975 4976
static struct md_sysfs_entry
raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
4977

4978
static struct attribute *raid5_attrs[] =  {
4979 4980
	&raid5_stripecache_size.attr,
	&raid5_stripecache_active.attr,
4981
	&raid5_preread_bypass_threshold.attr,
4982 4983
	NULL,
};
4984 4985 4986
static struct attribute_group raid5_attrs_group = {
	.name = NULL,
	.attrs = raid5_attrs,
4987 4988
};

4989
static sector_t
4990
raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
4991
{
4992
	struct r5conf *conf = mddev->private;
4993 4994 4995

	if (!sectors)
		sectors = mddev->dev_sectors;
4996
	if (!raid_disks)
4997
		/* size is defined by the smallest of previous and new size */
4998
		raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
4999

5000
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5001
	sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
5002 5003 5004
	return sectors * (raid_disks - conf->max_degraded);
}

5005
static void raid5_free_percpu(struct r5conf *conf)
5006 5007 5008 5009 5010 5011 5012 5013 5014 5015 5016
{
	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);
5017
		kfree(percpu->scribble);
5018 5019 5020 5021 5022 5023 5024 5025 5026
	}
#ifdef CONFIG_HOTPLUG_CPU
	unregister_cpu_notifier(&conf->cpu_notify);
#endif
	put_online_cpus();

	free_percpu(conf->percpu);
}

5027
static void free_conf(struct r5conf *conf)
5028 5029
{
	shrink_stripes(conf);
5030
	raid5_free_percpu(conf);
5031 5032 5033 5034 5035
	kfree(conf->disks);
	kfree(conf->stripe_hashtbl);
	kfree(conf);
}

5036 5037 5038 5039
#ifdef CONFIG_HOTPLUG_CPU
static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action,
			      void *hcpu)
{
5040
	struct r5conf *conf = container_of(nfb, struct r5conf, cpu_notify);
5041 5042 5043 5044 5045 5046
	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:
5047
		if (conf->level == 6 && !percpu->spare_page)
5048
			percpu->spare_page = alloc_page(GFP_KERNEL);
5049 5050 5051 5052 5053 5054 5055
		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);
5056 5057
			pr_err("%s: failed memory allocation for cpu%ld\n",
			       __func__, cpu);
5058
			return notifier_from_errno(-ENOMEM);
5059 5060 5061 5062 5063
		}
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		safe_put_page(percpu->spare_page);
5064
		kfree(percpu->scribble);
5065
		percpu->spare_page = NULL;
5066
		percpu->scribble = NULL;
5067 5068 5069 5070 5071 5072 5073 5074
		break;
	default:
		break;
	}
	return NOTIFY_OK;
}
#endif

5075
static int raid5_alloc_percpu(struct r5conf *conf)
5076 5077 5078
{
	unsigned long cpu;
	struct page *spare_page;
5079
	struct raid5_percpu __percpu *allcpus;
5080
	void *scribble;
5081 5082 5083 5084 5085 5086 5087 5088 5089 5090
	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) {
5091 5092 5093 5094 5095 5096 5097 5098
		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;
		}
5099
		scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
5100
		if (!scribble) {
5101 5102 5103
			err = -ENOMEM;
			break;
		}
5104
		per_cpu_ptr(conf->percpu, cpu)->scribble = scribble;
5105 5106 5107 5108 5109 5110 5111 5112 5113 5114 5115 5116
	}
#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;
}

5117
static struct r5conf *setup_conf(struct mddev *mddev)
L
Linus Torvalds 已提交
5118
{
5119
	struct r5conf *conf;
5120
	int raid_disk, memory, max_disks;
5121
	struct md_rdev *rdev;
L
Linus Torvalds 已提交
5122
	struct disk_info *disk;
5123
	char pers_name[6];
L
Linus Torvalds 已提交
5124

N
NeilBrown 已提交
5125 5126 5127
	if (mddev->new_level != 5
	    && mddev->new_level != 4
	    && mddev->new_level != 6) {
5128
		printk(KERN_ERR "md/raid:%s: raid level not set to 4/5/6 (%d)\n",
N
NeilBrown 已提交
5129 5130
		       mdname(mddev), mddev->new_level);
		return ERR_PTR(-EIO);
L
Linus Torvalds 已提交
5131
	}
N
NeilBrown 已提交
5132 5133 5134 5135
	if ((mddev->new_level == 5
	     && !algorithm_valid_raid5(mddev->new_layout)) ||
	    (mddev->new_level == 6
	     && !algorithm_valid_raid6(mddev->new_layout))) {
5136
		printk(KERN_ERR "md/raid:%s: layout %d not supported\n",
N
NeilBrown 已提交
5137 5138
		       mdname(mddev), mddev->new_layout);
		return ERR_PTR(-EIO);
5139
	}
N
NeilBrown 已提交
5140
	if (mddev->new_level == 6 && mddev->raid_disks < 4) {
5141
		printk(KERN_ERR "md/raid:%s: not enough configured devices (%d, minimum 4)\n",
N
NeilBrown 已提交
5142 5143
		       mdname(mddev), mddev->raid_disks);
		return ERR_PTR(-EINVAL);
5144 5145
	}

5146 5147 5148
	if (!mddev->new_chunk_sectors ||
	    (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
	    !is_power_of_2(mddev->new_chunk_sectors)) {
5149 5150
		printk(KERN_ERR "md/raid:%s: invalid chunk size %d\n",
		       mdname(mddev), mddev->new_chunk_sectors << 9);
N
NeilBrown 已提交
5151
		return ERR_PTR(-EINVAL);
5152 5153
	}

5154
	conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
N
NeilBrown 已提交
5155
	if (conf == NULL)
L
Linus Torvalds 已提交
5156
		goto abort;
5157 5158 5159 5160 5161 5162 5163 5164 5165 5166 5167 5168
	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;
5169
	conf->recovery_disabled = mddev->recovery_disabled - 1;
N
NeilBrown 已提交
5170 5171 5172 5173 5174

	conf->raid_disks = mddev->raid_disks;
	if (mddev->reshape_position == MaxSector)
		conf->previous_raid_disks = mddev->raid_disks;
	else
5175
		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
5176 5177
	max_disks = max(conf->raid_disks, conf->previous_raid_disks);
	conf->scribble_len = scribble_len(max_disks);
5178

5179
	conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
5180 5181 5182
			      GFP_KERNEL);
	if (!conf->disks)
		goto abort;
5183

L
Linus Torvalds 已提交
5184 5185
	conf->mddev = mddev;

5186
	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
L
Linus Torvalds 已提交
5187 5188
		goto abort;

5189 5190 5191 5192
	conf->level = mddev->new_level;
	if (raid5_alloc_percpu(conf) != 0)
		goto abort;

5193
	pr_debug("raid456: run(%s) called.\n", mdname(mddev));
L
Linus Torvalds 已提交
5194

N
NeilBrown 已提交
5195
	rdev_for_each(rdev, mddev) {
L
Linus Torvalds 已提交
5196
		raid_disk = rdev->raid_disk;
5197
		if (raid_disk >= max_disks
L
Linus Torvalds 已提交
5198 5199 5200 5201
		    || raid_disk < 0)
			continue;
		disk = conf->disks + raid_disk;

5202 5203 5204 5205 5206 5207 5208 5209 5210
		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
5211

5212
		if (test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
5213
			char b[BDEVNAME_SIZE];
5214 5215 5216
			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
5217
		} else if (rdev->saved_raid_disk != raid_disk)
5218 5219
			/* Cannot rely on bitmap to complete recovery */
			conf->fullsync = 1;
L
Linus Torvalds 已提交
5220 5221
	}

5222
	conf->chunk_sectors = mddev->new_chunk_sectors;
N
NeilBrown 已提交
5223
	conf->level = mddev->new_level;
5224 5225 5226 5227
	if (conf->level == 6)
		conf->max_degraded = 2;
	else
		conf->max_degraded = 1;
N
NeilBrown 已提交
5228
	conf->algorithm = mddev->new_layout;
L
Linus Torvalds 已提交
5229
	conf->max_nr_stripes = NR_STRIPES;
5230
	conf->reshape_progress = mddev->reshape_position;
5231
	if (conf->reshape_progress != MaxSector) {
5232
		conf->prev_chunk_sectors = mddev->chunk_sectors;
5233 5234
		conf->prev_algo = mddev->layout;
	}
L
Linus Torvalds 已提交
5235

N
NeilBrown 已提交
5236
	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
5237
		 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
N
NeilBrown 已提交
5238 5239
	if (grow_stripes(conf, conf->max_nr_stripes)) {
		printk(KERN_ERR
5240 5241
		       "md/raid:%s: couldn't allocate %dkB for buffers\n",
		       mdname(mddev), memory);
N
NeilBrown 已提交
5242 5243
		goto abort;
	} else
5244 5245
		printk(KERN_INFO "md/raid:%s: allocated %dkB\n",
		       mdname(mddev), memory);
L
Linus Torvalds 已提交
5246

5247 5248
	sprintf(pers_name, "raid%d", mddev->new_level);
	conf->thread = md_register_thread(raid5d, mddev, pers_name);
N
NeilBrown 已提交
5249 5250
	if (!conf->thread) {
		printk(KERN_ERR
5251
		       "md/raid:%s: couldn't allocate thread.\n",
N
NeilBrown 已提交
5252
		       mdname(mddev));
5253 5254
		goto abort;
	}
N
NeilBrown 已提交
5255 5256 5257 5258 5259

	return conf;

 abort:
	if (conf) {
5260
		free_conf(conf);
N
NeilBrown 已提交
5261 5262 5263 5264 5265
		return ERR_PTR(-EIO);
	} else
		return ERR_PTR(-ENOMEM);
}

5266 5267 5268 5269 5270 5271 5272 5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286 5287 5288 5289 5290 5291 5292

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;
}

5293
static int run(struct mddev *mddev)
N
NeilBrown 已提交
5294
{
5295
	struct r5conf *conf;
5296
	int working_disks = 0;
5297
	int dirty_parity_disks = 0;
5298
	struct md_rdev *rdev;
5299
	sector_t reshape_offset = 0;
5300
	int i;
5301 5302
	long long min_offset_diff = 0;
	int first = 1;
N
NeilBrown 已提交
5303

5304
	if (mddev->recovery_cp != MaxSector)
5305
		printk(KERN_NOTICE "md/raid:%s: not clean"
5306 5307
		       " -- starting background reconstruction\n",
		       mdname(mddev));
5308 5309 5310 5311 5312 5313 5314 5315 5316 5317 5318 5319 5320 5321 5322 5323 5324

	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
5325 5326
	if (mddev->reshape_position != MaxSector) {
		/* Check that we can continue the reshape.
5327 5328 5329 5330 5331 5332 5333 5334 5335 5336
		 * 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
5337 5338 5339
		 */
		sector_t here_new, here_old;
		int old_disks;
5340
		int max_degraded = (mddev->level == 6 ? 2 : 1);
N
NeilBrown 已提交
5341

5342
		if (mddev->new_level != mddev->level) {
5343
			printk(KERN_ERR "md/raid:%s: unsupported reshape "
N
NeilBrown 已提交
5344 5345 5346 5347 5348 5349 5350 5351 5352 5353
			       "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;
5354
		if (sector_div(here_new, mddev->new_chunk_sectors *
N
NeilBrown 已提交
5355
			       (mddev->raid_disks - max_degraded))) {
5356 5357
			printk(KERN_ERR "md/raid:%s: reshape_position not "
			       "on a stripe boundary\n", mdname(mddev));
N
NeilBrown 已提交
5358 5359
			return -EINVAL;
		}
5360
		reshape_offset = here_new * mddev->new_chunk_sectors;
N
NeilBrown 已提交
5361 5362
		/* here_new is the stripe we will write to */
		here_old = mddev->reshape_position;
5363
		sector_div(here_old, mddev->chunk_sectors *
N
NeilBrown 已提交
5364 5365 5366
			   (old_disks-max_degraded));
		/* here_old is the first stripe that we might need to read
		 * from */
5367
		if (mddev->delta_disks == 0) {
5368 5369 5370 5371 5372 5373
			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;
			}
5374
			/* We cannot be sure it is safe to start an in-place
5375
			 * reshape.  It is only safe if user-space is monitoring
5376 5377 5378 5379 5380
			 * 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.
			 */
5381 5382 5383 5384 5385 5386 5387
			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",
5388
				       mdname(mddev));
5389 5390
				return -EINVAL;
			}
5391
		} else if (mddev->reshape_backwards
5392
		    ? (here_new * mddev->new_chunk_sectors + min_offset_diff <=
5393 5394
		       here_old * mddev->chunk_sectors)
		    : (here_new * mddev->new_chunk_sectors >=
5395
		       here_old * mddev->chunk_sectors + (-min_offset_diff))) {
N
NeilBrown 已提交
5396
			/* Reading from the same stripe as writing to - bad */
5397 5398 5399
			printk(KERN_ERR "md/raid:%s: reshape_position too early for "
			       "auto-recovery - aborting.\n",
			       mdname(mddev));
N
NeilBrown 已提交
5400 5401
			return -EINVAL;
		}
5402 5403
		printk(KERN_INFO "md/raid:%s: reshape will continue\n",
		       mdname(mddev));
N
NeilBrown 已提交
5404 5405 5406 5407
		/* OK, we should be able to continue; */
	} else {
		BUG_ON(mddev->level != mddev->new_level);
		BUG_ON(mddev->layout != mddev->new_layout);
5408
		BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
N
NeilBrown 已提交
5409
		BUG_ON(mddev->delta_disks != 0);
L
Linus Torvalds 已提交
5410
	}
N
NeilBrown 已提交
5411

5412 5413 5414 5415 5416
	if (mddev->private == NULL)
		conf = setup_conf(mddev);
	else
		conf = mddev->private;

N
NeilBrown 已提交
5417 5418 5419
	if (IS_ERR(conf))
		return PTR_ERR(conf);

5420
	conf->min_offset_diff = min_offset_diff;
N
NeilBrown 已提交
5421 5422 5423 5424
	mddev->thread = conf->thread;
	conf->thread = NULL;
	mddev->private = conf;

5425 5426 5427 5428 5429 5430 5431 5432 5433 5434 5435
	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)
5436
			continue;
5437 5438 5439 5440 5441 5442 5443
		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;
		}
5444
		if (test_bit(In_sync, &rdev->flags)) {
N
NeilBrown 已提交
5445
			working_disks++;
5446 5447
			continue;
		}
5448 5449 5450 5451 5452 5453 5454 5455 5456 5457 5458 5459 5460 5461 5462 5463 5464 5465 5466 5467 5468 5469 5470 5471 5472 5473 5474 5475
		/* 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
5476

5477 5478 5479
	/*
	 * 0 for a fully functional array, 1 or 2 for a degraded array.
	 */
5480
	mddev->degraded = calc_degraded(conf);
N
NeilBrown 已提交
5481

5482
	if (has_failed(conf)) {
5483
		printk(KERN_ERR "md/raid:%s: not enough operational devices"
L
Linus Torvalds 已提交
5484
			" (%d/%d failed)\n",
5485
			mdname(mddev), mddev->degraded, conf->raid_disks);
L
Linus Torvalds 已提交
5486 5487 5488
		goto abort;
	}

N
NeilBrown 已提交
5489
	/* device size must be a multiple of chunk size */
5490
	mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
N
NeilBrown 已提交
5491 5492
	mddev->resync_max_sectors = mddev->dev_sectors;

5493
	if (mddev->degraded > dirty_parity_disks &&
L
Linus Torvalds 已提交
5494
	    mddev->recovery_cp != MaxSector) {
5495 5496
		if (mddev->ok_start_degraded)
			printk(KERN_WARNING
5497 5498
			       "md/raid:%s: starting dirty degraded array"
			       " - data corruption possible.\n",
5499 5500 5501
			       mdname(mddev));
		else {
			printk(KERN_ERR
5502
			       "md/raid:%s: cannot start dirty degraded array.\n",
5503 5504 5505
			       mdname(mddev));
			goto abort;
		}
L
Linus Torvalds 已提交
5506 5507 5508
	}

	if (mddev->degraded == 0)
5509 5510
		printk(KERN_INFO "md/raid:%s: raid level %d active with %d out of %d"
		       " devices, algorithm %d\n", mdname(mddev), conf->level,
5511 5512
		       mddev->raid_disks-mddev->degraded, mddev->raid_disks,
		       mddev->new_layout);
L
Linus Torvalds 已提交
5513
	else
5514 5515 5516 5517 5518
		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
5519 5520 5521

	print_raid5_conf(conf);

5522 5523
	if (conf->reshape_progress != MaxSector) {
		conf->reshape_safe = conf->reshape_progress;
5524 5525 5526 5527 5528 5529
		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,
5530
							"reshape");
5531 5532
	}

L
Linus Torvalds 已提交
5533 5534

	/* Ok, everything is just fine now */
5535 5536
	if (mddev->to_remove == &raid5_attrs_group)
		mddev->to_remove = NULL;
N
NeilBrown 已提交
5537 5538
	else if (mddev->kobj.sd &&
	    sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
5539
		printk(KERN_WARNING
5540
		       "raid5: failed to create sysfs attributes for %s\n",
5541
		       mdname(mddev));
5542
	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
5543

5544
	if (mddev->queue) {
5545
		int chunk_size;
S
Shaohua Li 已提交
5546
		bool discard_supported = true;
5547 5548 5549 5550 5551 5552 5553 5554 5555
		/* 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
5556

5557
		blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
5558

N
NeilBrown 已提交
5559 5560
		mddev->queue->backing_dev_info.congested_data = mddev;
		mddev->queue->backing_dev_info.congested_fn = raid5_congested;
5561

5562 5563 5564 5565
		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));
S
Shaohua Li 已提交
5566 5567 5568 5569 5570
		/*
		 * We can only discard a whole stripe. It doesn't make sense to
		 * discard data disk but write parity disk
		 */
		stripe = stripe * PAGE_SIZE;
5571 5572 5573 5574
		/* Round up to power of 2, as discard handling
		 * currently assumes that */
		while ((stripe-1) & stripe)
			stripe = (stripe | (stripe-1)) + 1;
S
Shaohua Li 已提交
5575 5576 5577 5578 5579 5580 5581
		mddev->queue->limits.discard_alignment = stripe;
		mddev->queue->limits.discard_granularity = stripe;
		/*
		 * unaligned part of discard request will be ignored, so can't
		 * guarantee discard_zerors_data
		 */
		mddev->queue->limits.discard_zeroes_data = 0;
5582

5583
		rdev_for_each(rdev, mddev) {
5584 5585
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
5586 5587
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->new_data_offset << 9);
S
Shaohua Li 已提交
5588 5589 5590 5591 5592 5593 5594 5595 5596 5597 5598 5599 5600 5601
			/*
			 * discard_zeroes_data is required, otherwise data
			 * could be lost. Consider a scenario: discard a stripe
			 * (the stripe could be inconsistent if
			 * discard_zeroes_data is 0); write one disk of the
			 * stripe (the stripe could be inconsistent again
			 * depending on which disks are used to calculate
			 * parity); the disk is broken; The stripe data of this
			 * disk is lost.
			 */
			if (!blk_queue_discard(bdev_get_queue(rdev->bdev)) ||
			    !bdev_get_queue(rdev->bdev)->
						limits.discard_zeroes_data)
				discard_supported = false;
5602
		}
S
Shaohua Li 已提交
5603 5604 5605 5606 5607 5608 5609 5610 5611

		if (discard_supported &&
		   mddev->queue->limits.max_discard_sectors >= stripe &&
		   mddev->queue->limits.discard_granularity >= stripe)
			queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
						mddev->queue);
		else
			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
						mddev->queue);
5612
	}
5613

L
Linus Torvalds 已提交
5614 5615
	return 0;
abort:
5616
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
5617 5618
	print_raid5_conf(conf);
	free_conf(conf);
L
Linus Torvalds 已提交
5619
	mddev->private = NULL;
5620
	printk(KERN_ALERT "md/raid:%s: failed to run raid set.\n", mdname(mddev));
L
Linus Torvalds 已提交
5621 5622 5623
	return -EIO;
}

5624
static int stop(struct mddev *mddev)
L
Linus Torvalds 已提交
5625
{
5626
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5627

5628
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
5629 5630
	if (mddev->queue)
		mddev->queue->backing_dev_info.congested_fn = NULL;
5631
	free_conf(conf);
5632 5633
	mddev->private = NULL;
	mddev->to_remove = &raid5_attrs_group;
L
Linus Torvalds 已提交
5634 5635 5636
	return 0;
}

5637
static void status(struct seq_file *seq, struct mddev *mddev)
L
Linus Torvalds 已提交
5638
{
5639
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5640 5641
	int i;

5642 5643
	seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
		mddev->chunk_sectors / 2, mddev->layout);
5644
	seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
L
Linus Torvalds 已提交
5645 5646 5647
	for (i = 0; i < conf->raid_disks; i++)
		seq_printf (seq, "%s",
			       conf->disks[i].rdev &&
5648
			       test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
L
Linus Torvalds 已提交
5649 5650 5651
	seq_printf (seq, "]");
}

5652
static void print_raid5_conf (struct r5conf *conf)
L
Linus Torvalds 已提交
5653 5654 5655 5656
{
	int i;
	struct disk_info *tmp;

5657
	printk(KERN_DEBUG "RAID conf printout:\n");
L
Linus Torvalds 已提交
5658 5659 5660 5661
	if (!conf) {
		printk("(conf==NULL)\n");
		return;
	}
5662 5663 5664
	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
5665 5666 5667 5668 5669

	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
		tmp = conf->disks + i;
		if (tmp->rdev)
5670 5671 5672
			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
5673 5674 5675
	}
}

5676
static int raid5_spare_active(struct mddev *mddev)
L
Linus Torvalds 已提交
5677 5678
{
	int i;
5679
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5680
	struct disk_info *tmp;
5681 5682
	int count = 0;
	unsigned long flags;
L
Linus Torvalds 已提交
5683 5684 5685

	for (i = 0; i < conf->raid_disks; i++) {
		tmp = conf->disks + i;
5686 5687 5688 5689 5690 5691 5692 5693 5694 5695 5696 5697 5698 5699 5700 5701 5702 5703 5704
		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
5705
		    && tmp->rdev->recovery_offset == MaxSector
5706
		    && !test_bit(Faulty, &tmp->rdev->flags)
5707
		    && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
5708
			count++;
5709
			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
L
Linus Torvalds 已提交
5710 5711
		}
	}
5712
	spin_lock_irqsave(&conf->device_lock, flags);
5713
	mddev->degraded = calc_degraded(conf);
5714
	spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
5715
	print_raid5_conf(conf);
5716
	return count;
L
Linus Torvalds 已提交
5717 5718
}

5719
static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5720
{
5721
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5722
	int err = 0;
5723
	int number = rdev->raid_disk;
5724
	struct md_rdev **rdevp;
L
Linus Torvalds 已提交
5725 5726 5727
	struct disk_info *p = conf->disks + number;

	print_raid5_conf(conf);
5728 5729 5730 5731 5732 5733 5734 5735 5736 5737 5738 5739 5740 5741 5742 5743 5744 5745 5746 5747 5748 5749
	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) &&
5750
	    (!p->replacement || p->replacement == rdev) &&
5751 5752 5753 5754 5755 5756 5757 5758 5759 5760
	    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;
5761 5762 5763 5764 5765 5766 5767 5768 5769 5770 5771 5772 5773 5774
	} 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
5775 5776 5777 5778 5779 5780
abort:

	print_raid5_conf(conf);
	return err;
}

5781
static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5782
{
5783
	struct r5conf *conf = mddev->private;
5784
	int err = -EEXIST;
L
Linus Torvalds 已提交
5785 5786
	int disk;
	struct disk_info *p;
5787 5788
	int first = 0;
	int last = conf->raid_disks - 1;
L
Linus Torvalds 已提交
5789

5790 5791 5792
	if (mddev->recovery_disabled == conf->recovery_disabled)
		return -EBUSY;

N
NeilBrown 已提交
5793
	if (rdev->saved_raid_disk < 0 && has_failed(conf))
L
Linus Torvalds 已提交
5794
		/* no point adding a device */
5795
		return -EINVAL;
L
Linus Torvalds 已提交
5796

5797 5798
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;
L
Linus Torvalds 已提交
5799 5800

	/*
5801 5802
	 * find the disk ... but prefer rdev->saved_raid_disk
	 * if possible.
L
Linus Torvalds 已提交
5803
	 */
5804
	if (rdev->saved_raid_disk >= 0 &&
5805
	    rdev->saved_raid_disk >= first &&
5806
	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
5807 5808 5809
		first = rdev->saved_raid_disk;

	for (disk = first; disk <= last; disk++) {
5810 5811
		p = conf->disks + disk;
		if (p->rdev == NULL) {
5812
			clear_bit(In_sync, &rdev->flags);
L
Linus Torvalds 已提交
5813
			rdev->raid_disk = disk;
5814
			err = 0;
5815 5816
			if (rdev->saved_raid_disk != disk)
				conf->fullsync = 1;
5817
			rcu_assign_pointer(p->rdev, rdev);
5818
			goto out;
L
Linus Torvalds 已提交
5819
		}
5820 5821 5822
	}
	for (disk = first; disk <= last; disk++) {
		p = conf->disks + disk;
5823 5824 5825 5826 5827 5828 5829 5830 5831 5832 5833
		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;
		}
	}
5834
out:
L
Linus Torvalds 已提交
5835
	print_raid5_conf(conf);
5836
	return err;
L
Linus Torvalds 已提交
5837 5838
}

5839
static int raid5_resize(struct mddev *mddev, sector_t sectors)
L
Linus Torvalds 已提交
5840 5841 5842 5843 5844 5845 5846 5847
{
	/* 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.
	 */
5848
	sector_t newsize;
5849
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5850 5851 5852
	newsize = raid5_size(mddev, sectors, mddev->raid_disks);
	if (mddev->external_size &&
	    mddev->array_sectors > newsize)
D
Dan Williams 已提交
5853
		return -EINVAL;
5854 5855 5856 5857 5858 5859
	if (mddev->bitmap) {
		int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
		if (ret)
			return ret;
	}
	md_set_array_sectors(mddev, newsize);
5860
	set_capacity(mddev->gendisk, mddev->array_sectors);
5861
	revalidate_disk(mddev->gendisk);
5862 5863
	if (sectors > mddev->dev_sectors &&
	    mddev->recovery_cp > mddev->dev_sectors) {
A
Andre Noll 已提交
5864
		mddev->recovery_cp = mddev->dev_sectors;
L
Linus Torvalds 已提交
5865 5866
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
A
Andre Noll 已提交
5867
	mddev->dev_sectors = sectors;
5868
	mddev->resync_max_sectors = sectors;
L
Linus Torvalds 已提交
5869 5870 5871
	return 0;
}

5872
static int check_stripe_cache(struct mddev *mddev)
5873 5874 5875 5876 5877 5878 5879 5880 5881
{
	/* 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.
	 */
5882
	struct r5conf *conf = mddev->private;
5883 5884 5885 5886
	if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes ||
	    ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes) {
5887 5888
		printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
		       mdname(mddev),
5889 5890 5891 5892 5893 5894 5895
		       ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
			/ STRIPE_SIZE)*4);
		return 0;
	}
	return 1;
}

5896
static int check_reshape(struct mddev *mddev)
5897
{
5898
	struct r5conf *conf = mddev->private;
5899

5900 5901
	if (mddev->delta_disks == 0 &&
	    mddev->new_layout == mddev->layout &&
5902
	    mddev->new_chunk_sectors == mddev->chunk_sectors)
5903
		return 0; /* nothing to do */
5904
	if (has_failed(conf))
5905 5906 5907 5908 5909 5910 5911 5912 5913 5914 5915 5916 5917
		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;
	}
5918

5919
	if (!check_stripe_cache(mddev))
5920 5921
		return -ENOSPC;

5922 5923
	return resize_stripes(conf, (conf->previous_raid_disks
				     + mddev->delta_disks));
5924 5925
}

5926
static int raid5_start_reshape(struct mddev *mddev)
5927
{
5928
	struct r5conf *conf = mddev->private;
5929
	struct md_rdev *rdev;
5930
	int spares = 0;
5931
	unsigned long flags;
5932

5933
	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
5934 5935
		return -EBUSY;

5936 5937 5938
	if (!check_stripe_cache(mddev))
		return -ENOSPC;

5939 5940 5941
	if (has_failed(conf))
		return -EINVAL;

5942
	rdev_for_each(rdev, mddev) {
5943 5944
		if (!test_bit(In_sync, &rdev->flags)
		    && !test_bit(Faulty, &rdev->flags))
5945
			spares++;
5946
	}
5947

5948
	if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
5949 5950 5951 5952 5953
		/* Not enough devices even to make a degraded array
		 * of that size
		 */
		return -EINVAL;

5954 5955 5956 5957 5958 5959
	/* 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) {
5960
		printk(KERN_ERR "md/raid:%s: array size must be reduced "
5961 5962 5963 5964
		       "before number of disks\n", mdname(mddev));
		return -EINVAL;
	}

5965
	atomic_set(&conf->reshape_stripes, 0);
5966 5967
	spin_lock_irq(&conf->device_lock);
	conf->previous_raid_disks = conf->raid_disks;
5968
	conf->raid_disks += mddev->delta_disks;
5969 5970
	conf->prev_chunk_sectors = conf->chunk_sectors;
	conf->chunk_sectors = mddev->new_chunk_sectors;
5971 5972
	conf->prev_algo = conf->algorithm;
	conf->algorithm = mddev->new_layout;
5973 5974 5975 5976 5977
	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();
5978
	if (mddev->reshape_backwards)
5979 5980 5981 5982
		conf->reshape_progress = raid5_size(mddev, 0, 0);
	else
		conf->reshape_progress = 0;
	conf->reshape_safe = conf->reshape_progress;
5983 5984 5985 5986
	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.
5987 5988 5989 5990
	 * 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.
5991
	 */
5992
	if (mddev->delta_disks >= 0) {
N
NeilBrown 已提交
5993
		rdev_for_each(rdev, mddev)
5994 5995 5996 5997
			if (rdev->raid_disk < 0 &&
			    !test_bit(Faulty, &rdev->flags)) {
				if (raid5_add_disk(mddev, rdev) == 0) {
					if (rdev->raid_disk
5998
					    >= conf->previous_raid_disks)
5999
						set_bit(In_sync, &rdev->flags);
6000
					else
6001
						rdev->recovery_offset = 0;
6002 6003

					if (sysfs_link_rdev(mddev, rdev))
6004
						/* Failure here is OK */;
6005
				}
6006 6007 6008 6009 6010
			} 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);
			}
6011

6012 6013 6014 6015
		/* When a reshape changes the number of devices,
		 * ->degraded is measured against the larger of the
		 * pre and post number of devices.
		 */
6016
		spin_lock_irqsave(&conf->device_lock, flags);
6017
		mddev->degraded = calc_degraded(conf);
6018 6019
		spin_unlock_irqrestore(&conf->device_lock, flags);
	}
6020
	mddev->raid_disks = conf->raid_disks;
6021
	mddev->reshape_position = conf->reshape_progress;
6022
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
6023

6024 6025 6026 6027 6028
	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,
6029
						"reshape");
6030 6031 6032 6033
	if (!mddev->sync_thread) {
		mddev->recovery = 0;
		spin_lock_irq(&conf->device_lock);
		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
6034 6035 6036
		rdev_for_each(rdev, mddev)
			rdev->new_data_offset = rdev->data_offset;
		smp_wmb();
6037
		conf->reshape_progress = MaxSector;
6038
		mddev->reshape_position = MaxSector;
6039 6040 6041
		spin_unlock_irq(&conf->device_lock);
		return -EAGAIN;
	}
6042
	conf->reshape_checkpoint = jiffies;
6043 6044 6045 6046 6047
	md_wakeup_thread(mddev->sync_thread);
	md_new_event(mddev);
	return 0;
}

6048 6049 6050
/* This is called from the reshape thread and should make any
 * changes needed in 'conf'
 */
6051
static void end_reshape(struct r5conf *conf)
6052 6053
{

6054
	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
6055
		struct md_rdev *rdev;
6056 6057

		spin_lock_irq(&conf->device_lock);
6058
		conf->previous_raid_disks = conf->raid_disks;
6059 6060 6061
		rdev_for_each(rdev, conf->mddev)
			rdev->data_offset = rdev->new_data_offset;
		smp_wmb();
6062
		conf->reshape_progress = MaxSector;
6063
		spin_unlock_irq(&conf->device_lock);
6064
		wake_up(&conf->wait_for_overlap);
6065 6066 6067 6068

		/* read-ahead size must cover two whole stripes, which is
		 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
		 */
6069
		if (conf->mddev->queue) {
6070
			int data_disks = conf->raid_disks - conf->max_degraded;
6071
			int stripe = data_disks * ((conf->chunk_sectors << 9)
6072
						   / PAGE_SIZE);
6073 6074 6075
			if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
				conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
		}
6076 6077 6078
	}
}

6079 6080 6081
/* This is called from the raid5d thread with mddev_lock held.
 * It makes config changes to the device.
 */
6082
static void raid5_finish_reshape(struct mddev *mddev)
6083
{
6084
	struct r5conf *conf = mddev->private;
6085 6086 6087

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

6088 6089 6090
		if (mddev->delta_disks > 0) {
			md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
			set_capacity(mddev->gendisk, mddev->array_sectors);
6091
			revalidate_disk(mddev->gendisk);
6092 6093
		} else {
			int d;
6094 6095 6096
			spin_lock_irq(&conf->device_lock);
			mddev->degraded = calc_degraded(conf);
			spin_unlock_irq(&conf->device_lock);
6097 6098
			for (d = conf->raid_disks ;
			     d < conf->raid_disks - mddev->delta_disks;
6099
			     d++) {
6100
				struct md_rdev *rdev = conf->disks[d].rdev;
6101 6102 6103 6104 6105
				if (rdev)
					clear_bit(In_sync, &rdev->flags);
				rdev = conf->disks[d].replacement;
				if (rdev)
					clear_bit(In_sync, &rdev->flags);
6106
			}
6107
		}
6108
		mddev->layout = conf->algorithm;
6109
		mddev->chunk_sectors = conf->chunk_sectors;
6110 6111
		mddev->reshape_position = MaxSector;
		mddev->delta_disks = 0;
6112
		mddev->reshape_backwards = 0;
6113 6114 6115
	}
}

6116
static void raid5_quiesce(struct mddev *mddev, int state)
6117
{
6118
	struct r5conf *conf = mddev->private;
6119 6120

	switch(state) {
6121 6122 6123 6124
	case 2: /* resume for a suspend */
		wake_up(&conf->wait_for_overlap);
		break;

6125 6126
	case 1: /* stop all writes */
		spin_lock_irq(&conf->device_lock);
6127 6128 6129 6130
		/* '2' tells resync/reshape to pause so that all
		 * active stripes can drain
		 */
		conf->quiesce = 2;
6131
		wait_event_lock_irq(conf->wait_for_stripe,
6132 6133
				    atomic_read(&conf->active_stripes) == 0 &&
				    atomic_read(&conf->active_aligned_reads) == 0,
6134
				    conf->device_lock);
6135
		conf->quiesce = 1;
6136
		spin_unlock_irq(&conf->device_lock);
6137 6138
		/* allow reshape to continue */
		wake_up(&conf->wait_for_overlap);
6139 6140 6141 6142 6143 6144
		break;

	case 0: /* re-enable writes */
		spin_lock_irq(&conf->device_lock);
		conf->quiesce = 0;
		wake_up(&conf->wait_for_stripe);
6145
		wake_up(&conf->wait_for_overlap);
6146 6147 6148 6149
		spin_unlock_irq(&conf->device_lock);
		break;
	}
}
6150

6151

6152
static void *raid45_takeover_raid0(struct mddev *mddev, int level)
6153
{
6154
	struct r0conf *raid0_conf = mddev->private;
6155
	sector_t sectors;
6156

D
Dan Williams 已提交
6157
	/* for raid0 takeover only one zone is supported */
6158
	if (raid0_conf->nr_strip_zones > 1) {
6159 6160
		printk(KERN_ERR "md/raid:%s: cannot takeover raid0 with more than one zone.\n",
		       mdname(mddev));
D
Dan Williams 已提交
6161 6162 6163
		return ERR_PTR(-EINVAL);
	}

6164 6165
	sectors = raid0_conf->strip_zone[0].zone_end;
	sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
6166
	mddev->dev_sectors = sectors;
D
Dan Williams 已提交
6167
	mddev->new_level = level;
6168 6169 6170 6171 6172 6173 6174 6175 6176 6177 6178
	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);
}


6179
static void *raid5_takeover_raid1(struct mddev *mddev)
6180 6181 6182 6183 6184 6185 6186 6187 6188 6189 6190 6191 6192 6193 6194 6195 6196 6197 6198 6199 6200
{
	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;
6201
	mddev->new_chunk_sectors = chunksect;
6202 6203 6204 6205

	return setup_conf(mddev);
}

6206
static void *raid5_takeover_raid6(struct mddev *mddev)
6207 6208 6209 6210 6211 6212 6213 6214 6215 6216 6217 6218 6219 6220 6221 6222 6223 6224 6225 6226 6227 6228 6229 6230 6231 6232 6233 6234 6235 6236 6237 6238
{
	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);
}

6239

6240
static int raid5_check_reshape(struct mddev *mddev)
6241
{
6242 6243 6244 6245
	/* 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.
6246
	 */
6247
	struct r5conf *conf = mddev->private;
6248
	int new_chunk = mddev->new_chunk_sectors;
6249

6250
	if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
6251 6252
		return -EINVAL;
	if (new_chunk > 0) {
6253
		if (!is_power_of_2(new_chunk))
6254
			return -EINVAL;
6255
		if (new_chunk < (PAGE_SIZE>>9))
6256
			return -EINVAL;
6257
		if (mddev->array_sectors & (new_chunk-1))
6258 6259 6260 6261 6262 6263
			/* not factor of array size */
			return -EINVAL;
	}

	/* They look valid */

6264
	if (mddev->raid_disks == 2) {
6265 6266 6267 6268
		/* can make the change immediately */
		if (mddev->new_layout >= 0) {
			conf->algorithm = mddev->new_layout;
			mddev->layout = mddev->new_layout;
6269 6270
		}
		if (new_chunk > 0) {
6271 6272
			conf->chunk_sectors = new_chunk ;
			mddev->chunk_sectors = new_chunk;
6273 6274 6275
		}
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		md_wakeup_thread(mddev->thread);
6276
	}
6277
	return check_reshape(mddev);
6278 6279
}

6280
static int raid6_check_reshape(struct mddev *mddev)
6281
{
6282
	int new_chunk = mddev->new_chunk_sectors;
6283

6284
	if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
6285
		return -EINVAL;
6286
	if (new_chunk > 0) {
6287
		if (!is_power_of_2(new_chunk))
6288
			return -EINVAL;
6289
		if (new_chunk < (PAGE_SIZE >> 9))
6290
			return -EINVAL;
6291
		if (mddev->array_sectors & (new_chunk-1))
6292 6293
			/* not factor of array size */
			return -EINVAL;
6294
	}
6295 6296

	/* They look valid */
6297
	return check_reshape(mddev);
6298 6299
}

6300
static void *raid5_takeover(struct mddev *mddev)
6301 6302
{
	/* raid5 can take over:
D
Dan Williams 已提交
6303
	 *  raid0 - if there is only one strip zone - make it a raid4 layout
6304 6305 6306 6307
	 *  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
6308 6309
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 5);
6310 6311
	if (mddev->level == 1)
		return raid5_takeover_raid1(mddev);
6312 6313 6314 6315 6316
	if (mddev->level == 4) {
		mddev->new_layout = ALGORITHM_PARITY_N;
		mddev->new_level = 5;
		return setup_conf(mddev);
	}
6317 6318
	if (mddev->level == 6)
		return raid5_takeover_raid6(mddev);
6319 6320 6321 6322

	return ERR_PTR(-EINVAL);
}

6323
static void *raid4_takeover(struct mddev *mddev)
6324
{
D
Dan Williams 已提交
6325 6326 6327
	/* raid4 can take over:
	 *  raid0 - if there is only one strip zone
	 *  raid5 - if layout is right
6328
	 */
D
Dan Williams 已提交
6329 6330
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 4);
6331 6332 6333 6334 6335 6336 6337 6338
	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);
}
6339

6340
static struct md_personality raid5_personality;
6341

6342
static void *raid6_takeover(struct mddev *mddev)
6343 6344 6345 6346 6347 6348 6349 6350 6351 6352 6353 6354 6355 6356 6357 6358 6359 6360 6361 6362 6363 6364 6365 6366 6367 6368 6369 6370 6371 6372 6373 6374 6375 6376 6377 6378 6379 6380 6381 6382 6383 6384 6385 6386 6387 6388
{
	/* 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);
}


6389
static struct md_personality raid6_personality =
6390 6391 6392 6393 6394 6395 6396 6397 6398 6399 6400 6401 6402 6403
{
	.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,
6404
	.size		= raid5_size,
6405
	.check_reshape	= raid6_check_reshape,
6406
	.start_reshape  = raid5_start_reshape,
6407
	.finish_reshape = raid5_finish_reshape,
6408
	.quiesce	= raid5_quiesce,
6409
	.takeover	= raid6_takeover,
6410
};
6411
static struct md_personality raid5_personality =
L
Linus Torvalds 已提交
6412 6413
{
	.name		= "raid5",
6414
	.level		= 5,
L
Linus Torvalds 已提交
6415 6416 6417 6418 6419 6420 6421 6422 6423 6424 6425
	.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,
6426
	.size		= raid5_size,
6427 6428
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
6429
	.finish_reshape = raid5_finish_reshape,
6430
	.quiesce	= raid5_quiesce,
6431
	.takeover	= raid5_takeover,
L
Linus Torvalds 已提交
6432 6433
};

6434
static struct md_personality raid4_personality =
L
Linus Torvalds 已提交
6435
{
6436 6437 6438 6439 6440 6441 6442 6443 6444 6445 6446 6447 6448
	.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,
6449
	.size		= raid5_size,
6450 6451
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
6452
	.finish_reshape = raid5_finish_reshape,
6453
	.quiesce	= raid5_quiesce,
6454
	.takeover	= raid4_takeover,
6455 6456 6457 6458
};

static int __init raid5_init(void)
{
6459
	register_md_personality(&raid6_personality);
6460 6461 6462
	register_md_personality(&raid5_personality);
	register_md_personality(&raid4_personality);
	return 0;
L
Linus Torvalds 已提交
6463 6464
}

6465
static void raid5_exit(void)
L
Linus Torvalds 已提交
6466
{
6467
	unregister_md_personality(&raid6_personality);
6468 6469
	unregister_md_personality(&raid5_personality);
	unregister_md_personality(&raid4_personality);
L
Linus Torvalds 已提交
6470 6471 6472 6473 6474
}

module_init(raid5_init);
module_exit(raid5_exit);
MODULE_LICENSE("GPL");
6475
MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
L
Linus Torvalds 已提交
6476
MODULE_ALIAS("md-personality-4"); /* RAID5 */
6477 6478
MODULE_ALIAS("md-raid5");
MODULE_ALIAS("md-raid4");
6479 6480
MODULE_ALIAS("md-level-5");
MODULE_ALIAS("md-level-4");
6481 6482 6483 6484 6485 6486 6487
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");