raid5.c 181.7 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)
{
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	int sectors = bio_sectors(bio);
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	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

		rcu_read_lock();
573
		rrdev = rcu_dereference(conf->disks[i].replacement);
574 575 576 577 578 579
		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;
		}
580 581 582
		if (rw & WRITE) {
			if (replace_only)
				rdev = NULL;
583 584 585
			if (rdev == rrdev)
				/* We raced and saw duplicates */
				rrdev = NULL;
586
		} else {
587
			if (test_bit(R5_ReadRepl, &sh->dev[i].flags) && rrdev)
588 589 590
				rdev = rrdev;
			rrdev = NULL;
		}
591

592 593 594 595
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
		if (rdev)
			atomic_inc(&rdev->nr_pending);
596 597 598 599
		if (rrdev && test_bit(Faulty, &rrdev->flags))
			rrdev = NULL;
		if (rrdev)
			atomic_inc(&rrdev->nr_pending);
600 601
		rcu_read_unlock();

602
		/* We have already checked bad blocks for reads.  Now
603 604
		 * need to check for writes.  We never accept write errors
		 * on the replacement, so we don't to check rrdev.
605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624
		 */
		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);
				}
625 626 627 628 629 630
				/*
				 * Because md_wait_for_blocked_rdev
				 * will dec nr_pending, we must
				 * increment it first.
				 */
				atomic_inc(&rdev->nr_pending);
631 632 633 634 635 636 637 638
				md_wait_for_blocked_rdev(rdev, conf->mddev);
			} else {
				/* Acknowledged bad block - skip the write */
				rdev_dec_pending(rdev, conf->mddev);
				rdev = NULL;
			}
		}

639
		if (rdev) {
640 641
			if (s->syncing || s->expanding || s->expanded
			    || s->replacing)
642 643
				md_sync_acct(rdev->bdev, STRIPE_SECTORS);

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644 645
			set_bit(STRIPE_IO_STARTED, &sh->state);

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646
			bio_reset(bi);
647
			bi->bi_bdev = rdev->bdev;
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648 649 650 651 652 653
			bi->bi_rw = rw;
			bi->bi_end_io = (rw & WRITE)
				? raid5_end_write_request
				: raid5_end_read_request;
			bi->bi_private = sh;

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

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667
			bi->bi_vcnt = 1;
668 669 670
			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
			bi->bi_io_vec[0].bv_offset = 0;
			bi->bi_size = STRIPE_SIZE;
671 672
			if (rrdev)
				set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
673 674 675 676 677

			if (conf->mddev->gendisk)
				trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
						      bi, disk_devt(conf->mddev->gendisk),
						      sh->dev[i].sector);
678
			generic_make_request(bi);
679 680
		}
		if (rrdev) {
681 682
			if (s->syncing || s->expanding || s->expanded
			    || s->replacing)
683 684 685 686
				md_sync_acct(rrdev->bdev, STRIPE_SECTORS);

			set_bit(STRIPE_IO_STARTED, &sh->state);

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687
			bio_reset(rbi);
688
			rbi->bi_bdev = rrdev->bdev;
K
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689 690 691 692 693
			rbi->bi_rw = rw;
			BUG_ON(!(rw & WRITE));
			rbi->bi_end_io = raid5_end_write_request;
			rbi->bi_private = sh;

694 695 696 697 698
			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);
699 700 701 702 703 704
			if (use_new_offset(conf, sh))
				rbi->bi_sector = (sh->sector
						  + rrdev->new_data_offset);
			else
				rbi->bi_sector = (sh->sector
						  + rrdev->data_offset);
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705
			rbi->bi_vcnt = 1;
706 707 708
			rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
			rbi->bi_io_vec[0].bv_offset = 0;
			rbi->bi_size = STRIPE_SIZE;
709 710 711 712
			if (conf->mddev->gendisk)
				trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
						      rbi, disk_devt(conf->mddev->gendisk),
						      sh->dev[i].sector);
713 714 715
			generic_make_request(rbi);
		}
		if (!rdev && !rrdev) {
716
			if (rw & WRITE)
717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733
				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;
734
	struct async_submit_ctl submit;
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	enum async_tx_flags flags = 0;
736 737 738 739 740

	if (bio->bi_sector >= sector)
		page_offset = (signed)(bio->bi_sector - sector) * 512;
	else
		page_offset = (signed)(sector - bio->bi_sector) * -512;
741

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742 743 744 745
	if (frombio)
		flags |= ASYNC_TX_FENCE;
	init_async_submit(&submit, flags, tx, NULL, NULL, NULL);

746
	bio_for_each_segment(bvl, bio, i) {
747
		int len = bvl->bv_len;
748 749 750 751 752 753 754 755 756 757 758 759 760 761 762
		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) {
763 764
			b_offset += bvl->bv_offset;
			bio_page = bvl->bv_page;
765 766
			if (frombio)
				tx = async_memcpy(page, bio_page, page_offset,
767
						  b_offset, clen, &submit);
768 769
			else
				tx = async_memcpy(bio_page, page, b_offset,
770
						  page_offset, clen, &submit);
771
		}
772 773 774
		/* chain the operations */
		submit.depend_tx = tx;

775 776 777 778 779 780 781 782 783 784 785 786
		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;
787
	int i;
788

789
	pr_debug("%s: stripe %llu\n", __func__,
790 791 792 793 794 795 796
		(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 */
797 798
		/* and check if we need to reply to a read request,
		 * new R5_Wantfill requests are held off until
799
		 * !STRIPE_BIOFILL_RUN
800 801
		 */
		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
802 803 804 805 806 807 808 809
			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);
810
				if (!raid5_dec_bi_active_stripes(rbi)) {
811 812 813 814 815 816 817
					rbi->bi_next = return_bi;
					return_bi = rbi;
				}
				rbi = rbi2;
			}
		}
	}
818
	clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
819 820 821

	return_io(return_bi);

822
	set_bit(STRIPE_HANDLE, &sh->state);
823 824 825 826 827 828
	release_stripe(sh);
}

static void ops_run_biofill(struct stripe_head *sh)
{
	struct dma_async_tx_descriptor *tx = NULL;
829
	struct async_submit_ctl submit;
830 831
	int i;

832
	pr_debug("%s: stripe %llu\n", __func__,
833 834 835 836 837 838
		(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
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			spin_lock_irq(&sh->stripe_lock);
840 841
			dev->read = rbi = dev->toread;
			dev->toread = NULL;
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Shaohua Li 已提交
842
			spin_unlock_irq(&sh->stripe_lock);
843 844 845 846 847 848 849 850 851 852
			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);
853 854
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
	async_trigger_callback(&submit);
855 856
}

857
static void mark_target_uptodate(struct stripe_head *sh, int target)
858
{
859
	struct r5dev *tgt;
860

861 862
	if (target < 0)
		return;
863

864
	tgt = &sh->dev[target];
865 866 867
	set_bit(R5_UPTODATE, &tgt->flags);
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	clear_bit(R5_Wantcompute, &tgt->flags);
868 869
}

870
static void ops_complete_compute(void *stripe_head_ref)
871 872 873
{
	struct stripe_head *sh = stripe_head_ref;

874
	pr_debug("%s: stripe %llu\n", __func__,
875 876
		(unsigned long long)sh->sector);

877
	/* mark the computed target(s) as uptodate */
878
	mark_target_uptodate(sh, sh->ops.target);
879
	mark_target_uptodate(sh, sh->ops.target2);
880

881 882 883
	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
	if (sh->check_state == check_state_compute_run)
		sh->check_state = check_state_compute_result;
884 885 886 887
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

888 889 890 891 892 893 894 895 896
/* 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)
897 898
{
	int disks = sh->disks;
899
	struct page **xor_srcs = percpu->scribble;
900 901 902 903 904
	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;
905
	struct async_submit_ctl submit;
906 907 908
	int i;

	pr_debug("%s: stripe %llu block: %d\n",
909
		__func__, (unsigned long long)sh->sector, target);
910 911 912 913 914 915 916 917
	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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918
	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
919
			  ops_complete_compute, sh, to_addr_conv(sh, percpu));
920
	if (unlikely(count == 1))
921
		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
922
	else
923
		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
924 925 926 927

	return tx;
}

928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945
/* 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++)
946
		srcs[i] = NULL;
947 948 949 950 951 952 953 954 955 956

	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);

957
	return syndrome_disks;
958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977
}

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;
978
	else
979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994
		/* 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,
997 998 999 1000 1001 1002 1003 1004 1005 1006 1007
				  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,
1010 1011 1012
				  to_addr_conv(sh, percpu));
		tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
	}
1013 1014 1015 1016

	return tx;
}

1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037
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));

1038
	/* we need to open-code set_syndrome_sources to handle the
1039 1040 1041
	 * slot number conversion for 'faila' and 'failb'
	 */
	for (i = 0; i < disks ; i++)
1042
		blocks[i] = NULL;
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 1068
	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));
1072
			return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091
						  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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1092 1093 1094 1095
			init_async_submit(&submit,
					  ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
					  NULL, NULL, NULL,
					  to_addr_conv(sh, percpu));
1096 1097 1098 1099
			tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
				       &submit);

			count = set_syndrome_sources(blocks, sh);
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1100 1101 1102
			init_async_submit(&submit, ASYNC_TX_FENCE, tx,
					  ops_complete_compute, sh,
					  to_addr_conv(sh, percpu));
1103 1104 1105 1106
			return async_gen_syndrome(blocks, 0, count+2,
						  STRIPE_SIZE, &submit);
		}
	} else {
1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120
		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);
		}
1121 1122 1123 1124
	}
}


1125 1126 1127 1128
static void ops_complete_prexor(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;

1129
	pr_debug("%s: stripe %llu\n", __func__,
1130 1131 1132 1133
		(unsigned long long)sh->sector);
}

static struct dma_async_tx_descriptor *
1134 1135
ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
	       struct dma_async_tx_descriptor *tx)
1136 1137
{
	int disks = sh->disks;
1138
	struct page **xor_srcs = percpu->scribble;
1139
	int count = 0, pd_idx = sh->pd_idx, i;
1140
	struct async_submit_ctl submit;
1141 1142 1143 1144

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

1145
	pr_debug("%s: stripe %llu\n", __func__,
1146 1147 1148 1149 1150
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		/* Only process blocks that are known to be uptodate */
1151
		if (test_bit(R5_Wantdrain, &dev->flags))
1152 1153 1154
			xor_srcs[count++] = dev->page;
	}

D
Dan Williams 已提交
1155
	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1156
			  ops_complete_prexor, sh, to_addr_conv(sh, percpu));
1157
	tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1158 1159 1160 1161 1162

	return tx;
}

static struct dma_async_tx_descriptor *
1163
ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1164 1165
{
	int disks = sh->disks;
1166
	int i;
1167

1168
	pr_debug("%s: stripe %llu\n", __func__,
1169 1170 1171 1172 1173 1174
		(unsigned long long)sh->sector);

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

1175
		if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
1176 1177
			struct bio *wbi;

S
Shaohua Li 已提交
1178
			spin_lock_irq(&sh->stripe_lock);
1179 1180 1181 1182
			chosen = dev->towrite;
			dev->towrite = NULL;
			BUG_ON(dev->written);
			wbi = dev->written = chosen;
S
Shaohua Li 已提交
1183
			spin_unlock_irq(&sh->stripe_lock);
1184 1185 1186

			while (wbi && wbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
T
Tejun Heo 已提交
1187 1188
				if (wbi->bi_rw & REQ_FUA)
					set_bit(R5_WantFUA, &dev->flags);
S
Shaohua Li 已提交
1189 1190
				if (wbi->bi_rw & REQ_SYNC)
					set_bit(R5_SyncIO, &dev->flags);
1191
				if (wbi->bi_rw & REQ_DISCARD)
S
Shaohua Li 已提交
1192
					set_bit(R5_Discard, &dev->flags);
1193
				else
S
Shaohua Li 已提交
1194 1195
					tx = async_copy_data(1, wbi, dev->page,
						dev->sector, tx);
1196 1197 1198 1199 1200 1201 1202 1203
				wbi = r5_next_bio(wbi, dev->sector);
			}
		}
	}

	return tx;
}

1204
static void ops_complete_reconstruct(void *stripe_head_ref)
1205 1206
{
	struct stripe_head *sh = stripe_head_ref;
1207 1208 1209 1210
	int disks = sh->disks;
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	int i;
1211
	bool fua = false, sync = false, discard = false;
1212

1213
	pr_debug("%s: stripe %llu\n", __func__,
1214 1215
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
1216
	for (i = disks; i--; ) {
T
Tejun Heo 已提交
1217
		fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
S
Shaohua Li 已提交
1218
		sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1219
		discard |= test_bit(R5_Discard, &sh->dev[i].flags);
S
Shaohua Li 已提交
1220
	}
T
Tejun Heo 已提交
1221

1222 1223
	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
1224

T
Tejun Heo 已提交
1225
		if (dev->written || i == pd_idx || i == qd_idx) {
1226 1227
			if (!discard)
				set_bit(R5_UPTODATE, &dev->flags);
T
Tejun Heo 已提交
1228 1229
			if (fua)
				set_bit(R5_WantFUA, &dev->flags);
S
Shaohua Li 已提交
1230 1231
			if (sync)
				set_bit(R5_SyncIO, &dev->flags);
T
Tejun Heo 已提交
1232
		}
1233 1234
	}

1235 1236 1237 1238 1239 1240 1241 1242
	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;
	}
1243 1244 1245 1246 1247 1248

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

static void
1249 1250
ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
		     struct dma_async_tx_descriptor *tx)
1251 1252
{
	int disks = sh->disks;
1253
	struct page **xor_srcs = percpu->scribble;
1254
	struct async_submit_ctl submit;
1255 1256
	int count = 0, pd_idx = sh->pd_idx, i;
	struct page *xor_dest;
1257
	int prexor = 0;
1258 1259
	unsigned long flags;

1260
	pr_debug("%s: stripe %llu\n", __func__,
1261 1262
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274
	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;
	}
1275 1276 1277
	/* check if prexor is active which means only process blocks
	 * that are part of a read-modify-write (written)
	 */
1278 1279
	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
		prexor = 1;
1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299
		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
	 */
1300
	flags = ASYNC_TX_ACK |
1301 1302 1303 1304
		(prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);

	atomic_inc(&sh->count);

1305
	init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh,
1306
			  to_addr_conv(sh, percpu));
1307 1308 1309 1310
	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);
1311 1312
}

1313 1314 1315 1316 1317 1318
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
1319
	int count, i;
1320 1321 1322

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

S
Shaohua Li 已提交
1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336
	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;
	}

1337 1338 1339 1340 1341 1342 1343
	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);
1344 1345 1346 1347 1348 1349
}

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

1350
	pr_debug("%s: stripe %llu\n", __func__,
1351 1352
		(unsigned long long)sh->sector);

1353
	sh->check_state = check_state_check_result;
1354 1355 1356 1357
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1358
static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1359 1360
{
	int disks = sh->disks;
1361 1362 1363
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	struct page *xor_dest;
1364
	struct page **xor_srcs = percpu->scribble;
1365
	struct dma_async_tx_descriptor *tx;
1366
	struct async_submit_ctl submit;
1367 1368
	int count;
	int i;
1369

1370
	pr_debug("%s: stripe %llu\n", __func__,
1371 1372
		(unsigned long long)sh->sector);

1373 1374 1375
	count = 0;
	xor_dest = sh->dev[pd_idx].page;
	xor_srcs[count++] = xor_dest;
1376
	for (i = disks; i--; ) {
1377 1378 1379
		if (i == pd_idx || i == qd_idx)
			continue;
		xor_srcs[count++] = sh->dev[i].page;
1380 1381
	}

1382 1383
	init_async_submit(&submit, 0, NULL, NULL, NULL,
			  to_addr_conv(sh, percpu));
D
Dan Williams 已提交
1384
	tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
1385
			   &sh->ops.zero_sum_result, &submit);
1386 1387

	atomic_inc(&sh->count);
1388 1389
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
	tx = async_trigger_callback(&submit);
1390 1391
}

1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403
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;
1404 1405

	atomic_inc(&sh->count);
1406 1407 1408 1409
	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);
1410 1411
}

N
NeilBrown 已提交
1412
static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
1413 1414 1415
{
	int overlap_clear = 0, i, disks = sh->disks;
	struct dma_async_tx_descriptor *tx = NULL;
1416
	struct r5conf *conf = sh->raid_conf;
1417
	int level = conf->level;
1418 1419
	struct raid5_percpu *percpu;
	unsigned long cpu;
1420

1421 1422
	cpu = get_cpu();
	percpu = per_cpu_ptr(conf->percpu, cpu);
1423
	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
1424 1425 1426 1427
		ops_run_biofill(sh);
		overlap_clear++;
	}

1428
	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
1429 1430 1431 1432 1433 1434 1435 1436 1437 1438
		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))
1439 1440
			async_tx_ack(tx);
	}
1441

1442
	if (test_bit(STRIPE_OP_PREXOR, &ops_request))
1443
		tx = ops_run_prexor(sh, percpu, tx);
1444

1445
	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
1446
		tx = ops_run_biodrain(sh, tx);
1447 1448 1449
		overlap_clear++;
	}

1450 1451 1452 1453 1454 1455
	if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
		if (level < 6)
			ops_run_reconstruct5(sh, percpu, tx);
		else
			ops_run_reconstruct6(sh, percpu, tx);
	}
1456

1457 1458 1459 1460 1461 1462 1463 1464 1465 1466
	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();
	}
1467 1468 1469 1470 1471 1472 1473

	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);
		}
1474
	put_cpu();
1475 1476
}

1477
static int grow_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1478 1479
{
	struct stripe_head *sh;
N
Namhyung Kim 已提交
1480
	sh = kmem_cache_zalloc(conf->slab_cache, GFP_KERNEL);
1481 1482
	if (!sh)
		return 0;
N
Namhyung Kim 已提交
1483

1484 1485
	sh->raid_conf = conf;

S
Shaohua Li 已提交
1486 1487
	spin_lock_init(&sh->stripe_lock);

1488 1489
	if (grow_buffers(sh)) {
		shrink_buffers(sh);
1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500
		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;
}

1501
static int grow_stripes(struct r5conf *conf, int num)
1502
{
1503
	struct kmem_cache *sc;
1504
	int devs = max(conf->raid_disks, conf->previous_raid_disks);
L
Linus Torvalds 已提交
1505

1506 1507 1508 1509 1510 1511 1512 1513
	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]);

1514 1515
	conf->active_name = 0;
	sc = kmem_cache_create(conf->cache_name[conf->active_name],
L
Linus Torvalds 已提交
1516
			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
1517
			       0, 0, NULL);
L
Linus Torvalds 已提交
1518 1519 1520
	if (!sc)
		return 1;
	conf->slab_cache = sc;
1521
	conf->pool_size = devs;
1522
	while (num--)
1523
		if (!grow_one_stripe(conf))
L
Linus Torvalds 已提交
1524 1525 1526
			return 1;
	return 0;
}
1527

1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549
/**
 * 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;
}

1550
static int resize_stripes(struct r5conf *conf, int newsize)
1551 1552 1553 1554 1555 1556 1557
{
	/* 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
1558
	 * 2/ gather all the old stripe_heads and transfer the pages across
1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577
	 *    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;
1578
	unsigned long cpu;
1579
	int err;
1580
	struct kmem_cache *sc;
1581 1582 1583 1584 1585
	int i;

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

1586 1587 1588
	err = md_allow_write(conf->mddev);
	if (err)
		return err;
1589

1590 1591 1592
	/* Step 1 */
	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
1593
			       0, 0, NULL);
1594 1595 1596 1597
	if (!sc)
		return -ENOMEM;

	for (i = conf->max_nr_stripes; i; i--) {
N
Namhyung Kim 已提交
1598
		nsh = kmem_cache_zalloc(sc, GFP_KERNEL);
1599 1600 1601 1602
		if (!nsh)
			break;

		nsh->raid_conf = conf;
1603
		spin_lock_init(&nsh->stripe_lock);
1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624

		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),
1625
				    conf->device_lock);
1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639
		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
1640
	 * conf->disks and the scribble region
1641 1642 1643 1644 1645 1646 1647 1648 1649 1650
	 */
	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;

1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669
	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();

1670 1671 1672 1673
	/* 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);
1674

1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690
		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
1691

1692
static int drop_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1693 1694 1695
{
	struct stripe_head *sh;

1696 1697 1698 1699 1700
	spin_lock_irq(&conf->device_lock);
	sh = get_free_stripe(conf);
	spin_unlock_irq(&conf->device_lock);
	if (!sh)
		return 0;
1701
	BUG_ON(atomic_read(&sh->count));
1702
	shrink_buffers(sh);
1703 1704 1705 1706 1707
	kmem_cache_free(conf->slab_cache, sh);
	atomic_dec(&conf->active_stripes);
	return 1;
}

1708
static void shrink_stripes(struct r5conf *conf)
1709 1710 1711 1712
{
	while (drop_one_stripe(conf))
		;

N
NeilBrown 已提交
1713 1714
	if (conf->slab_cache)
		kmem_cache_destroy(conf->slab_cache);
L
Linus Torvalds 已提交
1715 1716 1717
	conf->slab_cache = NULL;
}

1718
static void raid5_end_read_request(struct bio * bi, int error)
L
Linus Torvalds 已提交
1719
{
1720
	struct stripe_head *sh = bi->bi_private;
1721
	struct r5conf *conf = sh->raid_conf;
1722
	int disks = sh->disks, i;
L
Linus Torvalds 已提交
1723
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1724
	char b[BDEVNAME_SIZE];
1725
	struct md_rdev *rdev = NULL;
1726
	sector_t s;
L
Linus Torvalds 已提交
1727 1728 1729 1730 1731

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

1732 1733
	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
1734 1735 1736
		uptodate);
	if (i == disks) {
		BUG();
1737
		return;
L
Linus Torvalds 已提交
1738
	}
1739
	if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
1740 1741 1742 1743 1744
		/* 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.
		 */
1745
		rdev = conf->disks[i].replacement;
1746
	if (!rdev)
1747
		rdev = conf->disks[i].rdev;
L
Linus Torvalds 已提交
1748

1749 1750 1751 1752
	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
1753 1754
	if (uptodate) {
		set_bit(R5_UPTODATE, &sh->dev[i].flags);
1755
		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1756 1757 1758 1759
			/* Note that this cannot happen on a
			 * replacement device.  We just fail those on
			 * any error
			 */
1760 1761 1762 1763 1764
			printk_ratelimited(
				KERN_INFO
				"md/raid:%s: read error corrected"
				" (%lu sectors at %llu on %s)\n",
				mdname(conf->mddev), STRIPE_SECTORS,
1765
				(unsigned long long)s,
1766
				bdevname(rdev->bdev, b));
1767
			atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1768 1769
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1770 1771 1772
		} else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
			clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);

1773 1774
		if (atomic_read(&rdev->read_errors))
			atomic_set(&rdev->read_errors, 0);
L
Linus Torvalds 已提交
1775
	} else {
1776
		const char *bdn = bdevname(rdev->bdev, b);
1777
		int retry = 0;
1778
		int set_bad = 0;
1779

L
Linus Torvalds 已提交
1780
		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
1781
		atomic_inc(&rdev->read_errors);
1782 1783 1784 1785 1786 1787
		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),
1788
				(unsigned long long)s,
1789
				bdn);
1790 1791
		else if (conf->mddev->degraded >= conf->max_degraded) {
			set_bad = 1;
1792 1793 1794 1795 1796
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error not correctable "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1797
				(unsigned long long)s,
1798
				bdn);
1799
		} else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
1800
			/* Oh, no!!! */
1801
			set_bad = 1;
1802 1803 1804 1805 1806
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error NOT corrected!! "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1807
				(unsigned long long)s,
1808
				bdn);
1809
		} else if (atomic_read(&rdev->read_errors)
1810
			 > conf->max_nr_stripes)
N
NeilBrown 已提交
1811
			printk(KERN_WARNING
1812
			       "md/raid:%s: Too many read errors, failing device %s.\n",
1813
			       mdname(conf->mddev), bdn);
1814 1815 1816
		else
			retry = 1;
		if (retry)
1817 1818 1819 1820 1821
			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);
1822
		else {
1823 1824
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1825 1826 1827 1828 1829
			if (!(set_bad
			      && test_bit(In_sync, &rdev->flags)
			      && rdev_set_badblocks(
				      rdev, sh->sector, STRIPE_SECTORS, 0)))
				md_error(conf->mddev, rdev);
1830
		}
L
Linus Torvalds 已提交
1831
	}
1832
	rdev_dec_pending(rdev, conf->mddev);
L
Linus Torvalds 已提交
1833 1834 1835 1836 1837
	clear_bit(R5_LOCKED, &sh->dev[i].flags);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1838
static void raid5_end_write_request(struct bio *bi, int error)
L
Linus Torvalds 已提交
1839
{
1840
	struct stripe_head *sh = bi->bi_private;
1841
	struct r5conf *conf = sh->raid_conf;
1842
	int disks = sh->disks, i;
1843
	struct md_rdev *uninitialized_var(rdev);
L
Linus Torvalds 已提交
1844
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1845 1846
	sector_t first_bad;
	int bad_sectors;
1847
	int replacement = 0;
L
Linus Torvalds 已提交
1848

1849 1850 1851
	for (i = 0 ; i < disks; i++) {
		if (bi == &sh->dev[i].req) {
			rdev = conf->disks[i].rdev;
L
Linus Torvalds 已提交
1852
			break;
1853 1854 1855
		}
		if (bi == &sh->dev[i].rreq) {
			rdev = conf->disks[i].replacement;
1856 1857 1858 1859 1860 1861 1862 1863
			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;
1864 1865 1866
			break;
		}
	}
1867
	pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
L
Linus Torvalds 已提交
1868 1869 1870 1871
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
		uptodate);
	if (i == disks) {
		BUG();
1872
		return;
L
Linus Torvalds 已提交
1873 1874
	}

1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885
	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);
1886 1887 1888
			if (!test_and_set_bit(WantReplacement, &rdev->flags))
				set_bit(MD_RECOVERY_NEEDED,
					&rdev->mddev->recovery);
1889 1890
		} else if (is_badblock(rdev, sh->sector,
				       STRIPE_SECTORS,
1891
				       &first_bad, &bad_sectors)) {
1892
			set_bit(R5_MadeGood, &sh->dev[i].flags);
1893 1894 1895 1896 1897 1898 1899
			if (test_bit(R5_ReadError, &sh->dev[i].flags))
				/* That was a successful write so make
				 * sure it looks like we already did
				 * a re-write.
				 */
				set_bit(R5_ReWrite, &sh->dev[i].flags);
		}
1900 1901
	}
	rdev_dec_pending(rdev, conf->mddev);
L
Linus Torvalds 已提交
1902

1903 1904
	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
1905
	set_bit(STRIPE_HANDLE, &sh->state);
1906
	release_stripe(sh);
L
Linus Torvalds 已提交
1907 1908
}

1909
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
L
Linus Torvalds 已提交
1910
	
1911
static void raid5_build_block(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
1912 1913 1914 1915 1916 1917 1918 1919
{
	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;
1920
	dev->vec.bv_page = dev->page;
L
Linus Torvalds 已提交
1921

1922 1923 1924 1925 1926 1927 1928
	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
1929
	dev->flags = 0;
1930
	dev->sector = compute_blocknr(sh, i, previous);
L
Linus Torvalds 已提交
1931 1932
}

1933
static void error(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
1934 1935
{
	char b[BDEVNAME_SIZE];
1936
	struct r5conf *conf = mddev->private;
1937
	unsigned long flags;
1938
	pr_debug("raid456: error called\n");
L
Linus Torvalds 已提交
1939

1940 1941 1942 1943 1944 1945
	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);

1946
	set_bit(Blocked, &rdev->flags);
1947 1948 1949 1950 1951 1952 1953 1954 1955
	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);
1956
}
L
Linus Torvalds 已提交
1957 1958 1959 1960 1961

/*
 * Input: a 'big' sector number,
 * Output: index of the data and parity disk, and the sector # in them.
 */
1962
static sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
1963 1964
				     int previous, int *dd_idx,
				     struct stripe_head *sh)
L
Linus Torvalds 已提交
1965
{
N
NeilBrown 已提交
1966
	sector_t stripe, stripe2;
1967
	sector_t chunk_number;
L
Linus Torvalds 已提交
1968
	unsigned int chunk_offset;
1969
	int pd_idx, qd_idx;
1970
	int ddf_layout = 0;
L
Linus Torvalds 已提交
1971
	sector_t new_sector;
1972 1973
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
1974 1975
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
1976 1977 1978
	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
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990

	/* 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
	 */
1991 1992
	stripe = chunk_number;
	*dd_idx = sector_div(stripe, data_disks);
N
NeilBrown 已提交
1993
	stripe2 = stripe;
L
Linus Torvalds 已提交
1994 1995 1996
	/*
	 * Select the parity disk based on the user selected algorithm.
	 */
1997
	pd_idx = qd_idx = -1;
1998 1999
	switch(conf->level) {
	case 4:
2000
		pd_idx = data_disks;
2001 2002
		break;
	case 5:
2003
		switch (algorithm) {
L
Linus Torvalds 已提交
2004
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
2005
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
2006
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
2007 2008 2009
				(*dd_idx)++;
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
2010
			pd_idx = sector_div(stripe2, raid_disks);
2011
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
2012 2013 2014
				(*dd_idx)++;
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
2015
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
2016
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
2017 2018
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
2019
			pd_idx = sector_div(stripe2, raid_disks);
2020
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
2021
			break;
2022 2023 2024 2025 2026 2027 2028
		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
2029
		default:
2030
			BUG();
2031 2032 2033 2034
		}
		break;
	case 6:

2035
		switch (algorithm) {
2036
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
2037
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2038 2039
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
2040
				(*dd_idx)++;	/* Q D D D P */
2041 2042
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
2043 2044 2045
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
2046
			pd_idx = sector_div(stripe2, raid_disks);
2047 2048
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
2049
				(*dd_idx)++;	/* Q D D D P */
2050 2051
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
2052 2053 2054
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
2055
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2056 2057
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2058 2059
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
2060
			pd_idx = sector_div(stripe2, raid_disks);
2061 2062
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2063
			break;
2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078

		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
2079
			pd_idx = sector_div(stripe2, raid_disks);
2080 2081 2082 2083 2084 2085
			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 */
2086
			ddf_layout = 1;
2087 2088 2089 2090 2091 2092 2093
			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
2094 2095
			stripe2 += 1;
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2096 2097 2098 2099 2100 2101
			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 */
2102
			ddf_layout = 1;
2103 2104 2105 2106
			break;

		case ALGORITHM_ROTATING_N_CONTINUE:
			/* Same as left_symmetric but Q is before P */
N
NeilBrown 已提交
2107
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2108 2109
			qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2110
			ddf_layout = 1;
2111 2112 2113 2114
			break;

		case ALGORITHM_LEFT_ASYMMETRIC_6:
			/* RAID5 left_asymmetric, with Q on last device */
N
NeilBrown 已提交
2115
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2116 2117 2118 2119 2120 2121
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_RIGHT_ASYMMETRIC_6:
N
NeilBrown 已提交
2122
			pd_idx = sector_div(stripe2, raid_disks-1);
2123 2124 2125 2126 2127 2128
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_LEFT_SYMMETRIC_6:
N
NeilBrown 已提交
2129
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2130 2131 2132 2133 2134
			*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
2135
			pd_idx = sector_div(stripe2, raid_disks-1);
2136 2137 2138 2139 2140 2141 2142 2143 2144 2145
			*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;

2146
		default:
2147
			BUG();
2148 2149
		}
		break;
L
Linus Torvalds 已提交
2150 2151
	}

2152 2153 2154
	if (sh) {
		sh->pd_idx = pd_idx;
		sh->qd_idx = qd_idx;
2155
		sh->ddf_layout = ddf_layout;
2156
	}
L
Linus Torvalds 已提交
2157 2158 2159 2160 2161 2162 2163 2164
	/*
	 * Finally, compute the new sector number
	 */
	new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
	return new_sector;
}


2165
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
2166
{
2167
	struct r5conf *conf = sh->raid_conf;
2168 2169
	int raid_disks = sh->disks;
	int data_disks = raid_disks - conf->max_degraded;
L
Linus Torvalds 已提交
2170
	sector_t new_sector = sh->sector, check;
2171 2172
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
2173 2174
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
L
Linus Torvalds 已提交
2175 2176
	sector_t stripe;
	int chunk_offset;
2177 2178
	sector_t chunk_number;
	int dummy1, dd_idx = i;
L
Linus Torvalds 已提交
2179
	sector_t r_sector;
2180
	struct stripe_head sh2;
L
Linus Torvalds 已提交
2181

2182

L
Linus Torvalds 已提交
2183 2184 2185
	chunk_offset = sector_div(new_sector, sectors_per_chunk);
	stripe = new_sector;

2186 2187 2188 2189 2190
	if (i == sh->pd_idx)
		return 0;
	switch(conf->level) {
	case 4: break;
	case 5:
2191
		switch (algorithm) {
L
Linus Torvalds 已提交
2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202
		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;
2203 2204 2205 2206 2207
		case ALGORITHM_PARITY_0:
			i -= 1;
			break;
		case ALGORITHM_PARITY_N:
			break;
L
Linus Torvalds 已提交
2208
		default:
2209
			BUG();
2210 2211 2212
		}
		break;
	case 6:
2213
		if (i == sh->qd_idx)
2214
			return 0; /* It is the Q disk */
2215
		switch (algorithm) {
2216 2217
		case ALGORITHM_LEFT_ASYMMETRIC:
		case ALGORITHM_RIGHT_ASYMMETRIC:
2218 2219 2220 2221
		case ALGORITHM_ROTATING_ZERO_RESTART:
		case ALGORITHM_ROTATING_N_RESTART:
			if (sh->pd_idx == raid_disks-1)
				i--;	/* Q D D D P */
2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235
			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;
2236 2237 2238 2239 2240 2241
		case ALGORITHM_PARITY_0:
			i -= 2;
			break;
		case ALGORITHM_PARITY_N:
			break;
		case ALGORITHM_ROTATING_N_CONTINUE:
2242
			/* Like left_symmetric, but P is before Q */
2243 2244
			if (sh->pd_idx == 0)
				i--;	/* P D D D Q */
2245 2246 2247 2248 2249 2250
			else {
				/* D D Q P D */
				if (i < sh->pd_idx)
					i += raid_disks;
				i -= (sh->pd_idx + 1);
			}
2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265
			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;
2266
		default:
2267
			BUG();
2268 2269
		}
		break;
L
Linus Torvalds 已提交
2270 2271 2272
	}

	chunk_number = stripe * data_disks + i;
2273
	r_sector = chunk_number * sectors_per_chunk + chunk_offset;
L
Linus Torvalds 已提交
2274

2275
	check = raid5_compute_sector(conf, r_sector,
2276
				     previous, &dummy1, &sh2);
2277 2278
	if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
		|| sh2.qd_idx != sh->qd_idx) {
2279 2280
		printk(KERN_ERR "md/raid:%s: compute_blocknr: map not correct\n",
		       mdname(conf->mddev));
L
Linus Torvalds 已提交
2281 2282 2283 2284 2285 2286
		return 0;
	}
	return r_sector;
}


2287
static void
2288
schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
2289
			 int rcw, int expand)
2290 2291
{
	int i, pd_idx = sh->pd_idx, disks = sh->disks;
2292
	struct r5conf *conf = sh->raid_conf;
2293
	int level = conf->level;
2294 2295 2296 2297 2298 2299 2300 2301

	if (rcw) {

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

			if (dev->towrite) {
				set_bit(R5_LOCKED, &dev->flags);
2302
				set_bit(R5_Wantdrain, &dev->flags);
2303 2304
				if (!expand)
					clear_bit(R5_UPTODATE, &dev->flags);
2305
				s->locked++;
2306 2307
			}
		}
2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322
		/* 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);

2323
		if (s->locked + conf->max_degraded == disks)
2324
			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
2325
				atomic_inc(&conf->pending_full_writes);
2326
	} else {
2327
		BUG_ON(level == 6);
2328 2329 2330 2331 2332 2333 2334 2335 2336 2337
		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) ||
2338 2339
			     test_bit(R5_Wantcompute, &dev->flags))) {
				set_bit(R5_Wantdrain, &dev->flags);
2340 2341
				set_bit(R5_LOCKED, &dev->flags);
				clear_bit(R5_UPTODATE, &dev->flags);
2342
				s->locked++;
2343 2344
			}
		}
2345 2346 2347 2348 2349 2350 2351
		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);
2352 2353
	}

2354
	/* keep the parity disk(s) locked while asynchronous operations
2355 2356 2357 2358
	 * are in flight
	 */
	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
2359
	s->locked++;
2360

2361 2362 2363 2364 2365 2366 2367 2368 2369
	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++;
	}

2370
	pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
2371
		__func__, (unsigned long long)sh->sector,
2372
		s->locked, s->ops_request);
2373
}
2374

L
Linus Torvalds 已提交
2375 2376
/*
 * Each stripe/dev can have one or more bion attached.
2377
 * toread/towrite point to the first in a chain.
L
Linus Torvalds 已提交
2378 2379 2380 2381 2382
 * 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;
2383
	struct r5conf *conf = sh->raid_conf;
2384
	int firstwrite=0;
L
Linus Torvalds 已提交
2385

2386
	pr_debug("adding bi b#%llu to stripe s#%llu\n",
L
Linus Torvalds 已提交
2387 2388 2389
		(unsigned long long)bi->bi_sector,
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
2390 2391 2392 2393 2394 2395 2396 2397 2398
	/*
	 * 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);
2399
	if (forwrite) {
L
Linus Torvalds 已提交
2400
		bip = &sh->dev[dd_idx].towrite;
2401
		if (*bip == NULL)
2402 2403
			firstwrite = 1;
	} else
L
Linus Torvalds 已提交
2404 2405
		bip = &sh->dev[dd_idx].toread;
	while (*bip && (*bip)->bi_sector < bi->bi_sector) {
K
Kent Overstreet 已提交
2406
		if (bio_end_sector(*bip) > bi->bi_sector)
L
Linus Torvalds 已提交
2407 2408 2409
			goto overlap;
		bip = & (*bip)->bi_next;
	}
K
Kent Overstreet 已提交
2410
	if (*bip && (*bip)->bi_sector < bio_end_sector(bi))
L
Linus Torvalds 已提交
2411 2412
		goto overlap;

2413
	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
L
Linus Torvalds 已提交
2414 2415 2416
	if (*bip)
		bi->bi_next = *bip;
	*bip = bi;
2417
	raid5_inc_bi_active_stripes(bi);
2418

L
Linus Torvalds 已提交
2419 2420 2421 2422 2423 2424 2425
	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)) {
K
Kent Overstreet 已提交
2426 2427
			if (bio_end_sector(bi) >= sector)
				sector = bio_end_sector(bi);
L
Linus Torvalds 已提交
2428 2429 2430 2431
		}
		if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
			set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
	}
2432 2433 2434 2435

	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);
2436
	spin_unlock_irq(&sh->stripe_lock);
2437 2438 2439 2440 2441 2442 2443

	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
2444 2445 2446 2447
	return 1;

 overlap:
	set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
S
Shaohua Li 已提交
2448
	spin_unlock_irq(&sh->stripe_lock);
L
Linus Torvalds 已提交
2449 2450 2451
	return 0;
}

2452
static void end_reshape(struct r5conf *conf);
2453

2454
static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
2455
			    struct stripe_head *sh)
2456
{
2457
	int sectors_per_chunk =
2458
		previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
2459
	int dd_idx;
2460
	int chunk_offset = sector_div(stripe, sectors_per_chunk);
2461
	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
2462

2463 2464
	raid5_compute_sector(conf,
			     stripe * (disks - conf->max_degraded)
2465
			     *sectors_per_chunk + chunk_offset,
2466
			     previous,
2467
			     &dd_idx, sh);
2468 2469
}

2470
static void
2471
handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
2472 2473 2474 2475 2476 2477 2478 2479 2480
				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)) {
2481
			struct md_rdev *rdev;
2482 2483 2484
			rcu_read_lock();
			rdev = rcu_dereference(conf->disks[i].rdev);
			if (rdev && test_bit(In_sync, &rdev->flags))
2485 2486 2487
				atomic_inc(&rdev->nr_pending);
			else
				rdev = NULL;
2488
			rcu_read_unlock();
2489 2490 2491 2492 2493 2494 2495 2496
			if (rdev) {
				if (!rdev_set_badblocks(
					    rdev,
					    sh->sector,
					    STRIPE_SECTORS, 0))
					md_error(conf->mddev, rdev);
				rdev_dec_pending(rdev, conf->mddev);
			}
2497
		}
S
Shaohua Li 已提交
2498
		spin_lock_irq(&sh->stripe_lock);
2499 2500 2501
		/* fail all writes first */
		bi = sh->dev[i].towrite;
		sh->dev[i].towrite = NULL;
S
Shaohua Li 已提交
2502
		spin_unlock_irq(&sh->stripe_lock);
2503
		if (bi)
2504 2505 2506 2507 2508 2509 2510 2511 2512
			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);
2513
			if (!raid5_dec_bi_active_stripes(bi)) {
2514 2515 2516 2517 2518 2519
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = nextbi;
		}
2520 2521 2522 2523
		if (bitmap_end)
			bitmap_endwrite(conf->mddev->bitmap, sh->sector,
				STRIPE_SECTORS, 0, 0);
		bitmap_end = 0;
2524 2525 2526 2527 2528 2529 2530 2531
		/* 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);
2532
			if (!raid5_dec_bi_active_stripes(bi)) {
2533 2534 2535 2536 2537 2538 2539
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = bi2;
		}

2540 2541 2542 2543 2544 2545
		/* 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))) {
2546
			spin_lock_irq(&sh->stripe_lock);
2547 2548
			bi = sh->dev[i].toread;
			sh->dev[i].toread = NULL;
2549
			spin_unlock_irq(&sh->stripe_lock);
2550 2551 2552 2553 2554 2555 2556
			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);
2557
				if (!raid5_dec_bi_active_stripes(bi)) {
2558 2559 2560 2561 2562 2563 2564 2565 2566
					bi->bi_next = *return_bi;
					*return_bi = bi;
				}
				bi = nextbi;
			}
		}
		if (bitmap_end)
			bitmap_endwrite(conf->mddev->bitmap, sh->sector,
					STRIPE_SECTORS, 0, 0);
2567 2568 2569 2570
		/* 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);
2571 2572
	}

2573 2574 2575
	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);
2576 2577
}

2578
static void
2579
handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
2580 2581 2582 2583 2584 2585
		   struct stripe_head_state *s)
{
	int abort = 0;
	int i;

	clear_bit(STRIPE_SYNCING, &sh->state);
2586 2587
	if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
		wake_up(&conf->wait_for_overlap);
2588
	s->syncing = 0;
2589
	s->replacing = 0;
2590
	/* There is nothing more to do for sync/check/repair.
2591 2592 2593
	 * 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.
2594
	 * For recover/replace we need to record a bad block on all
2595 2596
	 * non-sync devices, or abort the recovery
	 */
2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619
	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;
2620
	}
2621
	md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
2622 2623
}

2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639
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;
}

2640
/* fetch_block - checks the given member device to see if its data needs
2641 2642 2643
 * to be read or computed to satisfy a request.
 *
 * Returns 1 when no more member devices need to be checked, otherwise returns
2644
 * 0 to tell the loop in handle_stripe_fill to continue
2645
 */
2646 2647
static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
		       int disk_idx, int disks)
2648
{
2649
	struct r5dev *dev = &sh->dev[disk_idx];
2650 2651
	struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
				  &sh->dev[s->failed_num[1]] };
2652

2653
	/* is the data in this block needed, and can we get it? */
2654 2655 2656 2657 2658
	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 ||
2659
	     (s->replacing && want_replace(sh, disk_idx)) ||
2660 2661
	     (s->failed >= 1 && fdev[0]->toread) ||
	     (s->failed >= 2 && fdev[1]->toread) ||
2662 2663 2664
	     (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))) {
2665 2666 2667 2668 2669 2670
		/* 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) &&
2671 2672
		    (s->failed && (disk_idx == s->failed_num[0] ||
				   disk_idx == s->failed_num[1]))) {
2673 2674
			/* have disk failed, and we're requested to fetch it;
			 * do compute it
2675
			 */
2676 2677 2678 2679 2680 2681 2682 2683
			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;
2684 2685 2686 2687 2688 2689
			/* 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.
			 */
2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702
			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;
2703
			}
2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722
			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);
2723 2724
		}
	}
2725 2726 2727 2728 2729

	return 0;
}

/**
2730
 * handle_stripe_fill - read or compute data to satisfy pending requests.
2731
 */
2732 2733 2734
static void handle_stripe_fill(struct stripe_head *sh,
			       struct stripe_head_state *s,
			       int disks)
2735 2736 2737 2738 2739 2740 2741 2742 2743 2744
{
	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--; )
2745
			if (fetch_block(sh, s, i, disks))
2746
				break;
2747 2748 2749 2750
	set_bit(STRIPE_HANDLE, &sh->state);
}


2751
/* handle_stripe_clean_event
2752 2753 2754 2755
 * 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.
 */
2756
static void handle_stripe_clean_event(struct r5conf *conf,
2757 2758 2759 2760
	struct stripe_head *sh, int disks, struct bio **return_bi)
{
	int i;
	struct r5dev *dev;
2761
	int discard_pending = 0;
2762 2763 2764 2765 2766

	for (i = disks; i--; )
		if (sh->dev[i].written) {
			dev = &sh->dev[i];
			if (!test_bit(R5_LOCKED, &dev->flags) &&
2767
			    (test_bit(R5_UPTODATE, &dev->flags) ||
2768
			     test_bit(R5_Discard, &dev->flags))) {
2769 2770
				/* We can return any write requests */
				struct bio *wbi, *wbi2;
2771
				pr_debug("Return write for disc %d\n", i);
2772 2773
				if (test_and_clear_bit(R5_Discard, &dev->flags))
					clear_bit(R5_UPTODATE, &dev->flags);
2774 2775 2776 2777 2778
				wbi = dev->written;
				dev->written = NULL;
				while (wbi && wbi->bi_sector <
					dev->sector + STRIPE_SECTORS) {
					wbi2 = r5_next_bio(wbi, dev->sector);
2779
					if (!raid5_dec_bi_active_stripes(wbi)) {
2780 2781 2782 2783 2784 2785
						md_write_end(conf->mddev);
						wbi->bi_next = *return_bi;
						*return_bi = wbi;
					}
					wbi = wbi2;
				}
2786 2787
				bitmap_endwrite(conf->mddev->bitmap, sh->sector,
						STRIPE_SECTORS,
2788
					 !test_bit(STRIPE_DEGRADED, &sh->state),
2789
						0);
2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806
			} 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);

	}
2807 2808 2809 2810

	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);
2811 2812
}

2813
static void handle_stripe_dirtying(struct r5conf *conf,
2814 2815 2816
				   struct stripe_head *sh,
				   struct stripe_head_state *s,
				   int disks)
2817 2818
{
	int rmw = 0, rcw = 0, i;
2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831
	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
2832 2833 2834
		 * look like rcw is cheaper
		 */
		rcw = 1; rmw = 2;
2835 2836 2837
		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);
2838
	} else for (i = disks; i--; ) {
2839 2840 2841 2842
		/* 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) &&
2843 2844
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		      test_bit(R5_Wantcompute, &dev->flags))) {
2845 2846 2847 2848 2849 2850 2851 2852
			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) &&
2853 2854 2855
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		    test_bit(R5_Wantcompute, &dev->flags))) {
			if (test_bit(R5_Insync, &dev->flags)) rcw++;
2856 2857 2858 2859
			else
				rcw += 2*disks;
		}
	}
2860
	pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2861 2862
		(unsigned long long)sh->sector, rmw, rcw);
	set_bit(STRIPE_HANDLE, &sh->state);
N
NeilBrown 已提交
2863
	if (rmw < rcw && rmw > 0) {
2864
		/* prefer read-modify-write, but need to get some data */
2865 2866 2867 2868
		if (conf->mddev->queue)
			blk_add_trace_msg(conf->mddev->queue,
					  "raid5 rmw %llu %d",
					  (unsigned long long)sh->sector, rmw);
2869 2870 2871 2872
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if ((dev->towrite || i == sh->pd_idx) &&
			    !test_bit(R5_LOCKED, &dev->flags) &&
2873 2874
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
			    test_bit(R5_Wantcompute, &dev->flags)) &&
2875 2876 2877
			    test_bit(R5_Insync, &dev->flags)) {
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2878
					pr_debug("Read_old block "
N
NeilBrown 已提交
2879
						 "%d for r-m-w\n", i);
2880 2881 2882 2883 2884 2885 2886 2887 2888
					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
2889
	}
2890
	if (rcw <= rmw && rcw > 0) {
2891
		/* want reconstruct write, but need to get some data */
N
NeilBrown 已提交
2892
		int qread =0;
2893
		rcw = 0;
2894 2895 2896
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (!test_bit(R5_OVERWRITE, &dev->flags) &&
2897
			    i != sh->pd_idx && i != sh->qd_idx &&
2898
			    !test_bit(R5_LOCKED, &dev->flags) &&
2899
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
2900 2901 2902 2903
			      test_bit(R5_Wantcompute, &dev->flags))) {
				rcw++;
				if (!test_bit(R5_Insync, &dev->flags))
					continue; /* it's a failed drive */
2904 2905
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2906
					pr_debug("Read_old block "
2907 2908 2909 2910
						"%d for Reconstruct\n", i);
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
					s->locked++;
N
NeilBrown 已提交
2911
					qread++;
2912 2913 2914 2915 2916 2917
				} else {
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
2918
		if (rcw && conf->mddev->queue)
N
NeilBrown 已提交
2919 2920 2921
			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));
2922
	}
2923 2924 2925
	/* now if nothing is locked, and if we have enough data,
	 * we can start a write request
	 */
2926 2927
	/* 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
2928 2929
	 * subsequent call wants to start a write request.  raid_run_ops only
	 * handles the case where compute block and reconstruct are requested
2930 2931 2932
	 * simultaneously.  If this is not the case then new writes need to be
	 * held off until the compute completes.
	 */
2933 2934 2935
	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)))
2936
		schedule_reconstruction(sh, s, rcw == 0, 0);
2937 2938
}

2939
static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
2940 2941
				struct stripe_head_state *s, int disks)
{
2942
	struct r5dev *dev = NULL;
2943

2944
	set_bit(STRIPE_HANDLE, &sh->state);
2945

2946 2947 2948
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are no failures */
2949 2950
		if (s->failed == 0) {
			BUG_ON(s->uptodate != disks);
2951 2952
			sh->check_state = check_state_run;
			set_bit(STRIPE_OP_CHECK, &s->ops_request);
2953 2954
			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
			s->uptodate--;
2955
			break;
2956
		}
2957
		dev = &sh->dev[s->failed_num[0]];
2958 2959 2960 2961 2962 2963 2964 2965 2966
		/* 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
2967

2968 2969 2970 2971 2972
		/* 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);
2973
		s->locked++;
2974
		set_bit(R5_Wantwrite, &dev->flags);
2975

2976 2977
		clear_bit(STRIPE_DEGRADED, &sh->state);
		set_bit(STRIPE_INSYNC, &sh->state);
2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993
		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
2994
		if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
2995 2996 2997 2998 2999
			/* parity is correct (on disc,
			 * not in buffer any more)
			 */
			set_bit(STRIPE_INSYNC, &sh->state);
		else {
3000
			atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
3001 3002 3003 3004 3005
			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;
3006
				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3007 3008 3009 3010
				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;
3011
				sh->ops.target2 = -1;
3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022
				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();
3023 3024 3025 3026
	}
}


3027
static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
3028
				  struct stripe_head_state *s,
3029
				  int disks)
3030 3031
{
	int pd_idx = sh->pd_idx;
N
NeilBrown 已提交
3032
	int qd_idx = sh->qd_idx;
3033
	struct r5dev *dev;
3034 3035 3036 3037

	set_bit(STRIPE_HANDLE, &sh->state);

	BUG_ON(s->failed > 2);
3038

3039 3040 3041 3042 3043 3044
	/* 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
	 */

3045 3046 3047
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are < 2 failures */
3048
		if (s->failed == s->q_failed) {
3049
			/* The only possible failed device holds Q, so it
3050 3051 3052
			 * makes sense to check P (If anything else were failed,
			 * we would have used P to recreate it).
			 */
3053
			sh->check_state = check_state_run;
3054
		}
3055
		if (!s->q_failed && s->failed < 2) {
3056
			/* Q is not failed, and we didn't use it to generate
3057 3058
			 * anything, so it makes sense to check it
			 */
3059 3060 3061 3062
			if (sh->check_state == check_state_run)
				sh->check_state = check_state_run_pq;
			else
				sh->check_state = check_state_run_q;
3063 3064
		}

3065 3066
		/* discard potentially stale zero_sum_result */
		sh->ops.zero_sum_result = 0;
3067

3068 3069 3070 3071
		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--;
3072
		}
3073 3074 3075 3076 3077 3078 3079
		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;
3080 3081
		}

3082 3083 3084 3085 3086
		/* we have 2-disk failure */
		BUG_ON(s->failed != 2);
		/* fall through */
	case check_state_compute_result:
		sh->check_state = check_state_idle;
3087

3088 3089 3090
		/* check that a write has not made the stripe insync */
		if (test_bit(STRIPE_INSYNC, &sh->state))
			break;
3091 3092

		/* now write out any block on a failed drive,
3093
		 * or P or Q if they were recomputed
3094
		 */
3095
		BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
3096
		if (s->failed == 2) {
3097
			dev = &sh->dev[s->failed_num[1]];
3098 3099 3100 3101 3102
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		if (s->failed >= 1) {
3103
			dev = &sh->dev[s->failed_num[0]];
3104 3105 3106 3107
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
3108
		if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
3109 3110 3111 3112 3113
			dev = &sh->dev[pd_idx];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
3114
		if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
3115 3116 3117 3118 3119 3120 3121 3122
			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);
3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151
		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 {
3152
			atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
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 3179 3180 3181 3182 3183 3184 3185 3186
			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();
3187 3188 3189
	}
}

3190
static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
3191 3192 3193 3194 3195 3196
{
	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.
	 */
3197
	struct dma_async_tx_descriptor *tx = NULL;
3198 3199
	clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	for (i = 0; i < sh->disks; i++)
N
NeilBrown 已提交
3200
		if (i != sh->pd_idx && i != sh->qd_idx) {
3201
			int dd_idx, j;
3202
			struct stripe_head *sh2;
3203
			struct async_submit_ctl submit;
3204

3205
			sector_t bn = compute_blocknr(sh, i, 1);
3206 3207
			sector_t s = raid5_compute_sector(conf, bn, 0,
							  &dd_idx, NULL);
3208
			sh2 = get_active_stripe(conf, s, 0, 1, 1);
3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220
			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;
			}
3221 3222

			/* place all the copies on one channel */
3223
			init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
3224
			tx = async_memcpy(sh2->dev[dd_idx].page,
3225
					  sh->dev[i].page, 0, 0, STRIPE_SIZE,
3226
					  &submit);
3227

3228 3229 3230 3231
			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 &&
3232
				    j != sh2->qd_idx &&
3233 3234 3235 3236 3237 3238 3239
				    !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);
3240

3241
		}
3242
	/* done submitting copies, wait for them to complete */
3243
	async_tx_quiesce(&tx);
3244
}
L
Linus Torvalds 已提交
3245 3246 3247 3248

/*
 * handle_stripe - do things to a stripe.
 *
3249 3250
 * 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
3251
 * Possible results:
3252 3253
 *    return some read requests which now have data
 *    return some write requests which are safely on storage
L
Linus Torvalds 已提交
3254 3255 3256 3257 3258
 *    schedule a read on some buffers
 *    schedule a write of some buffers
 *    return confirmation of parity correctness
 *
 */
3259

3260
static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
L
Linus Torvalds 已提交
3261
{
3262
	struct r5conf *conf = sh->raid_conf;
3263
	int disks = sh->disks;
3264 3265
	struct r5dev *dev;
	int i;
3266
	int do_recovery = 0;
L
Linus Torvalds 已提交
3267

3268 3269 3270 3271 3272 3273
	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
3274

3275
	/* Now to look around and see what can be done */
L
Linus Torvalds 已提交
3276
	rcu_read_lock();
3277
	for (i=disks; i--; ) {
3278
		struct md_rdev *rdev;
3279 3280 3281
		sector_t first_bad;
		int bad_sectors;
		int is_bad = 0;
3282

3283
		dev = &sh->dev[i];
L
Linus Torvalds 已提交
3284

3285
		pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
3286 3287
			 i, dev->flags,
			 dev->toread, dev->towrite, dev->written);
3288 3289 3290 3291 3292 3293 3294 3295
		/* 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
3296

3297
		/* now count some things */
3298 3299 3300 3301
		if (test_bit(R5_LOCKED, &dev->flags))
			s->locked++;
		if (test_bit(R5_UPTODATE, &dev->flags))
			s->uptodate++;
3302
		if (test_bit(R5_Wantcompute, &dev->flags)) {
3303 3304
			s->compute++;
			BUG_ON(s->compute > 2);
3305
		}
L
Linus Torvalds 已提交
3306

3307
		if (test_bit(R5_Wantfill, &dev->flags))
3308
			s->to_fill++;
3309
		else if (dev->toread)
3310
			s->to_read++;
3311
		if (dev->towrite) {
3312
			s->to_write++;
3313
			if (!test_bit(R5_OVERWRITE, &dev->flags))
3314
				s->non_overwrite++;
3315
		}
3316
		if (dev->written)
3317
			s->written++;
3318 3319 3320 3321 3322 3323 3324 3325 3326 3327
		/* 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 {
3328 3329
			if (rdev)
				set_bit(R5_NeedReplace, &dev->flags);
3330 3331 3332
			rdev = rcu_dereference(conf->disks[i].rdev);
			clear_bit(R5_ReadRepl, &dev->flags);
		}
3333 3334
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346
		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);
			}
3347
		}
3348 3349 3350
		clear_bit(R5_Insync, &dev->flags);
		if (!rdev)
			/* Not in-sync */;
3351 3352
		else if (is_bad) {
			/* also not in-sync */
3353 3354
			if (!test_bit(WriteErrorSeen, &rdev->flags) &&
			    test_bit(R5_UPTODATE, &dev->flags)) {
3355 3356 3357 3358 3359 3360 3361
				/* 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))
3362
			set_bit(R5_Insync, &dev->flags);
3363
		else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
3364
			/* in sync if before recovery_offset */
3365 3366 3367 3368 3369 3370 3371 3372 3373
			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
3374
		if (rdev && test_bit(R5_WriteError, &dev->flags)) {
3375 3376 3377 3378 3379 3380 3381
			/* 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)) {
3382
				s->handle_bad_blocks = 1;
3383
				atomic_inc(&rdev2->nr_pending);
3384 3385 3386
			} else
				clear_bit(R5_WriteError, &dev->flags);
		}
A
Adam Kwolek 已提交
3387
		if (rdev && test_bit(R5_MadeGood, &dev->flags)) {
3388 3389 3390 3391 3392
			/* 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)) {
3393
				s->handle_bad_blocks = 1;
3394
				atomic_inc(&rdev2->nr_pending);
3395 3396 3397
			} else
				clear_bit(R5_MadeGood, &dev->flags);
		}
3398 3399 3400 3401 3402 3403 3404 3405 3406
		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);
		}
3407
		if (!test_bit(R5_Insync, &dev->flags)) {
3408 3409 3410
			/* 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
3411
		}
3412 3413 3414
		if (test_bit(R5_ReadError, &dev->flags))
			clear_bit(R5_Insync, &dev->flags);
		if (!test_bit(R5_Insync, &dev->flags)) {
3415 3416 3417
			if (s->failed < 2)
				s->failed_num[s->failed] = i;
			s->failed++;
3418 3419
			if (rdev && !test_bit(Faulty, &rdev->flags))
				do_recovery = 1;
3420
		}
L
Linus Torvalds 已提交
3421
	}
3422 3423 3424 3425
	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
3426
		 * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
3427 3428 3429 3430 3431
		 * else we can only be replacing
		 * sync and recovery both need to read all devices, and so
		 * use the same flag.
		 */
		if (do_recovery ||
3432 3433
		    sh->sector >= conf->mddev->recovery_cp ||
		    test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
3434 3435 3436 3437
			s->syncing = 1;
		else
			s->replacing = 1;
	}
L
Linus Torvalds 已提交
3438
	rcu_read_unlock();
3439 3440 3441 3442 3443
}

static void handle_stripe(struct stripe_head *sh)
{
	struct stripe_head_state s;
3444
	struct r5conf *conf = sh->raid_conf;
3445
	int i;
3446 3447
	int prexor;
	int disks = sh->disks;
3448
	struct r5dev *pdev, *qdev;
3449 3450

	clear_bit(STRIPE_HANDLE, &sh->state);
3451
	if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
3452 3453 3454 3455 3456 3457
		/* already being handled, ensure it gets handled
		 * again when current action finishes */
		set_bit(STRIPE_HANDLE, &sh->state);
		return;
	}

3458 3459 3460 3461 3462 3463 3464 3465 3466
	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);
3467 3468 3469 3470 3471 3472 3473 3474
	}
	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);
3475

3476
	analyse_stripe(sh, &s);
3477

3478 3479 3480 3481 3482
	if (s.handle_bad_blocks) {
		set_bit(STRIPE_HANDLE, &sh->state);
		goto finish;
	}

3483 3484
	if (unlikely(s.blocked_rdev)) {
		if (s.syncing || s.expanding || s.expanded ||
3485
		    s.replacing || s.to_write || s.written) {
3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505
			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.
	 */
3506 3507 3508 3509 3510
	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);
3511
		if (s.syncing + s.replacing)
3512 3513
			handle_failed_sync(conf, sh, &s);
	}
3514

3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527
	/* 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
		 */
3528 3529
		BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
		       !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
3530
		BUG_ON(sh->qd_idx >= 0 &&
3531 3532
		       !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
		       !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551
		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;
	}

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 3578 3579 3580 3581 3582 3583 3584 3585
	/*
	 * 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);

3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608
	/* 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);
	}
3609

3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623
	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)) {
3624 3625
		md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
		clear_bit(STRIPE_SYNCING, &sh->state);
3626 3627
		if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
			wake_up(&conf->wait_for_overlap);
3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654
	}

	/* 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++;
				}
			}
		}


3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681
	/* 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++;
		}
	}
3682

3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698
	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);
3699

3700
finish:
3701
	/* wait for this device to become unblocked */
3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713
	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);
	}
3714

3715 3716
	if (s.handle_bad_blocks)
		for (i = disks; i--; ) {
3717
			struct md_rdev *rdev;
3718 3719 3720 3721 3722 3723 3724 3725 3726
			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);
			}
3727 3728 3729
			if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
				rdev = conf->disks[i].rdev;
				rdev_clear_badblocks(rdev, sh->sector,
3730
						     STRIPE_SECTORS, 0);
3731 3732
				rdev_dec_pending(rdev, conf->mddev);
			}
3733 3734
			if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
				rdev = conf->disks[i].replacement;
3735 3736 3737
				if (!rdev)
					/* rdev have been moved down */
					rdev = conf->disks[i].rdev;
3738
				rdev_clear_badblocks(rdev, sh->sector,
3739
						     STRIPE_SECTORS, 0);
3740 3741
				rdev_dec_pending(rdev, conf->mddev);
			}
3742 3743
		}

3744 3745 3746
	if (s.ops_request)
		raid_run_ops(sh, s.ops_request);

D
Dan Williams 已提交
3747
	ops_run_io(sh, &s);
3748

3749
	if (s.dec_preread_active) {
3750
		/* We delay this until after ops_run_io so that if make_request
T
Tejun Heo 已提交
3751
		 * is waiting on a flush, it won't continue until the writes
3752 3753 3754 3755 3756 3757 3758 3759
		 * 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);
	}

3760
	return_io(s.return_bi);
3761

3762
	clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
3763 3764
}

3765
static void raid5_activate_delayed(struct r5conf *conf)
3766 3767 3768 3769 3770 3771 3772 3773 3774 3775
{
	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);
3776
			list_add_tail(&sh->lru, &conf->hold_list);
3777
		}
N
NeilBrown 已提交
3778
	}
3779 3780
}

3781
static void activate_bit_delay(struct r5conf *conf)
3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794
{
	/* 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);
	}
}

3795
int md_raid5_congested(struct mddev *mddev, int bits)
3796
{
3797
	struct r5conf *conf = mddev->private;
3798 3799 3800 3801

	/* No difference between reads and writes.  Just check
	 * how busy the stripe_cache is
	 */
3802

3803 3804 3805 3806 3807 3808 3809 3810 3811
	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
3812 3813 3814 3815
EXPORT_SYMBOL_GPL(md_raid5_congested);

static int raid5_congested(void *data, int bits)
{
3816
	struct mddev *mddev = data;
N
NeilBrown 已提交
3817 3818 3819 3820

	return mddev_congested(mddev, bits) ||
		md_raid5_congested(mddev, bits);
}
3821

3822 3823 3824
/* We want read requests to align with chunks where possible,
 * but write requests don't need to.
 */
3825 3826 3827
static int raid5_mergeable_bvec(struct request_queue *q,
				struct bvec_merge_data *bvm,
				struct bio_vec *biovec)
3828
{
3829
	struct mddev *mddev = q->queuedata;
3830
	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
3831
	int max;
3832
	unsigned int chunk_sectors = mddev->chunk_sectors;
3833
	unsigned int bio_sectors = bvm->bi_size >> 9;
3834

3835
	if ((bvm->bi_rw & 1) == WRITE)
3836 3837
		return biovec->bv_len; /* always allow writes to be mergeable */

3838 3839
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3840 3841 3842 3843 3844 3845 3846 3847
	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;
}

3848

3849
static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
3850 3851
{
	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3852
	unsigned int chunk_sectors = mddev->chunk_sectors;
3853
	unsigned int bio_sectors = bio_sectors(bio);
3854

3855 3856
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3857 3858 3859 3860
	return  chunk_sectors >=
		((sector & (chunk_sectors - 1)) + bio_sectors);
}

3861 3862 3863 3864
/*
 *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
 *  later sampled by raid5d.
 */
3865
static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878
{
	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);
}


3879
static struct bio *remove_bio_from_retry(struct r5conf *conf)
3880 3881 3882 3883 3884 3885 3886 3887 3888 3889
{
	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) {
3890
		conf->retry_read_aligned_list = bi->bi_next;
3891
		bi->bi_next = NULL;
3892 3893 3894 3895
		/*
		 * this sets the active strip count to 1 and the processed
		 * strip count to zero (upper 8 bits)
		 */
3896
		raid5_set_bi_stripes(bi, 1); /* biased count of active stripes */
3897 3898 3899 3900 3901 3902
	}

	return bi;
}


3903 3904 3905 3906 3907 3908
/*
 *  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..
 */
3909
static void raid5_align_endio(struct bio *bi, int error)
3910 3911
{
	struct bio* raid_bi  = bi->bi_private;
3912
	struct mddev *mddev;
3913
	struct r5conf *conf;
3914
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
3915
	struct md_rdev *rdev;
3916

3917
	bio_put(bi);
3918 3919 3920

	rdev = (void*)raid_bi->bi_next;
	raid_bi->bi_next = NULL;
3921 3922
	mddev = rdev->mddev;
	conf = mddev->private;
3923 3924 3925 3926

	rdev_dec_pending(rdev, conf->mddev);

	if (!error && uptodate) {
3927 3928
		trace_block_bio_complete(bdev_get_queue(raid_bi->bi_bdev),
					 raid_bi, 0);
3929
		bio_endio(raid_bi, 0);
3930 3931
		if (atomic_dec_and_test(&conf->active_aligned_reads))
			wake_up(&conf->wait_for_stripe);
3932
		return;
3933 3934 3935
	}


3936
	pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
3937 3938

	add_bio_to_retry(raid_bi, conf);
3939 3940
}

3941 3942
static int bio_fits_rdev(struct bio *bi)
{
3943
	struct request_queue *q = bdev_get_queue(bi->bi_bdev);
3944

3945
	if (bio_sectors(bi) > queue_max_sectors(q))
3946 3947
		return 0;
	blk_recount_segments(q, bi);
3948
	if (bi->bi_phys_segments > queue_max_segments(q))
3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960
		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;
}


3961
static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
3962
{
3963
	struct r5conf *conf = mddev->private;
N
NeilBrown 已提交
3964
	int dd_idx;
3965
	struct bio* align_bi;
3966
	struct md_rdev *rdev;
3967
	sector_t end_sector;
3968 3969

	if (!in_chunk_boundary(mddev, raid_bio)) {
3970
		pr_debug("chunk_aligned_read : non aligned\n");
3971 3972 3973
		return 0;
	}
	/*
3974
	 * use bio_clone_mddev to make a copy of the bio
3975
	 */
3976
	align_bi = bio_clone_mddev(raid_bio, GFP_NOIO, mddev);
3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987
	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
	 */
3988 3989
	align_bi->bi_sector =  raid5_compute_sector(conf, raid_bio->bi_sector,
						    0,
3990
						    &dd_idx, NULL);
3991

K
Kent Overstreet 已提交
3992
	end_sector = bio_end_sector(align_bi);
3993
	rcu_read_lock();
3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004
	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) {
4005 4006 4007
		sector_t first_bad;
		int bad_sectors;

4008 4009
		atomic_inc(&rdev->nr_pending);
		rcu_read_unlock();
4010 4011 4012 4013
		raid_bio->bi_next = (void*)rdev;
		align_bi->bi_bdev =  rdev->bdev;
		align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);

4014
		if (!bio_fits_rdev(align_bi) ||
4015
		    is_badblock(rdev, align_bi->bi_sector, bio_sectors(align_bi),
4016 4017
				&first_bad, &bad_sectors)) {
			/* too big in some way, or has a known bad block */
4018 4019 4020 4021 4022
			bio_put(align_bi);
			rdev_dec_pending(rdev, mddev);
			return 0;
		}

4023 4024 4025
		/* No reshape active, so we can trust rdev->data_offset */
		align_bi->bi_sector += rdev->data_offset;

4026 4027 4028
		spin_lock_irq(&conf->device_lock);
		wait_event_lock_irq(conf->wait_for_stripe,
				    conf->quiesce == 0,
4029
				    conf->device_lock);
4030 4031 4032
		atomic_inc(&conf->active_aligned_reads);
		spin_unlock_irq(&conf->device_lock);

4033 4034 4035 4036
		if (mddev->gendisk)
			trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev),
					      align_bi, disk_devt(mddev->gendisk),
					      raid_bio->bi_sector);
4037 4038 4039 4040
		generic_make_request(align_bi);
		return 1;
	} else {
		rcu_read_unlock();
4041
		bio_put(align_bi);
4042 4043 4044 4045
		return 0;
	}
}

4046 4047 4048 4049 4050 4051 4052 4053 4054 4055
/* __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.
 */
4056
static struct stripe_head *__get_priority_stripe(struct r5conf *conf)
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 4090 4091 4092 4093 4094 4095 4096 4097
{
	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;
}
4098

4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110
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
4111
	int cnt = 0;
4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125

	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
4126
			cnt++;
4127 4128 4129
		}
		spin_unlock_irq(&conf->device_lock);
	}
4130 4131
	if (mddev->queue)
		trace_block_unplug(mddev->queue, cnt, !from_schedule);
4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158
	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
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 4186 4187 4188 4189 4190 4191 4192 4193
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);
4194 4195 4196 4197 4198 4199 4200
		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
4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212
		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;
			}
		}
4213
		set_bit(STRIPE_DISCARD, &sh->state);
S
Shaohua Li 已提交
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 4241 4242 4243 4244 4245 4246 4247 4248
		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);
	}
}

4249
static void make_request(struct mddev *mddev, struct bio * bi)
L
Linus Torvalds 已提交
4250
{
4251
	struct r5conf *conf = mddev->private;
4252
	int dd_idx;
L
Linus Torvalds 已提交
4253 4254 4255
	sector_t new_sector;
	sector_t logical_sector, last_sector;
	struct stripe_head *sh;
4256
	const int rw = bio_data_dir(bi);
4257
	int remaining;
L
Linus Torvalds 已提交
4258

T
Tejun Heo 已提交
4259 4260
	if (unlikely(bi->bi_rw & REQ_FLUSH)) {
		md_flush_request(mddev, bi);
4261
		return;
4262 4263
	}

4264
	md_write_start(mddev, bi);
4265

4266
	if (rw == READ &&
4267
	     mddev->reshape_position == MaxSector &&
4268
	     chunk_aligned_read(mddev,bi))
4269
		return;
4270

S
Shaohua Li 已提交
4271 4272 4273 4274 4275
	if (unlikely(bi->bi_rw & REQ_DISCARD)) {
		make_discard_request(mddev, bi);
		return;
	}

L
Linus Torvalds 已提交
4276
	logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
K
Kent Overstreet 已提交
4277
	last_sector = bio_end_sector(bi);
L
Linus Torvalds 已提交
4278 4279
	bi->bi_next = NULL;
	bi->bi_phys_segments = 1;	/* over-loaded to count active stripes */
4280

L
Linus Torvalds 已提交
4281 4282
	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
		DEFINE_WAIT(w);
4283
		int previous;
4284

4285
	retry:
4286
		previous = 0;
4287
		prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
4288
		if (unlikely(conf->reshape_progress != MaxSector)) {
4289
			/* spinlock is needed as reshape_progress may be
4290 4291
			 * 64bit on a 32bit platform, and so it might be
			 * possible to see a half-updated value
4292
			 * Of course reshape_progress could change after
4293 4294 4295 4296
			 * the lock is dropped, so once we get a reference
			 * to the stripe that we think it is, we will have
			 * to check again.
			 */
4297
			spin_lock_irq(&conf->device_lock);
4298
			if (mddev->reshape_backwards
4299 4300
			    ? logical_sector < conf->reshape_progress
			    : logical_sector >= conf->reshape_progress) {
4301 4302
				previous = 1;
			} else {
4303
				if (mddev->reshape_backwards
4304 4305
				    ? logical_sector < conf->reshape_safe
				    : logical_sector >= conf->reshape_safe) {
4306 4307 4308 4309 4310
					spin_unlock_irq(&conf->device_lock);
					schedule();
					goto retry;
				}
			}
4311 4312
			spin_unlock_irq(&conf->device_lock);
		}
4313

4314 4315
		new_sector = raid5_compute_sector(conf, logical_sector,
						  previous,
4316
						  &dd_idx, NULL);
4317
		pr_debug("raid456: make_request, sector %llu logical %llu\n",
L
Linus Torvalds 已提交
4318 4319 4320
			(unsigned long long)new_sector, 
			(unsigned long long)logical_sector);

4321
		sh = get_active_stripe(conf, new_sector, previous,
4322
				       (bi->bi_rw&RWA_MASK), 0);
L
Linus Torvalds 已提交
4323
		if (sh) {
4324
			if (unlikely(previous)) {
4325
				/* expansion might have moved on while waiting for a
4326 4327 4328 4329 4330 4331
				 * 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.
4332 4333 4334
				 */
				int must_retry = 0;
				spin_lock_irq(&conf->device_lock);
4335
				if (mddev->reshape_backwards
4336 4337
				    ? logical_sector >= conf->reshape_progress
				    : logical_sector < conf->reshape_progress)
4338 4339 4340 4341 4342
					/* mismatch, need to try again */
					must_retry = 1;
				spin_unlock_irq(&conf->device_lock);
				if (must_retry) {
					release_stripe(sh);
4343
					schedule();
4344 4345 4346
					goto retry;
				}
			}
4347

4348
			if (rw == WRITE &&
4349
			    logical_sector >= mddev->suspend_lo &&
4350 4351
			    logical_sector < mddev->suspend_hi) {
				release_stripe(sh);
4352 4353 4354 4355 4356 4357 4358 4359 4360 4361
				/* 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();
4362 4363
				goto retry;
			}
4364 4365

			if (test_bit(STRIPE_EXPANDING, &sh->state) ||
4366
			    !add_stripe_bio(sh, bi, dd_idx, rw)) {
4367 4368
				/* Stripe is busy expanding or
				 * add failed due to overlap.  Flush everything
L
Linus Torvalds 已提交
4369 4370
				 * and wait a while
				 */
N
NeilBrown 已提交
4371
				md_wakeup_thread(mddev->thread);
L
Linus Torvalds 已提交
4372 4373 4374 4375 4376
				release_stripe(sh);
				schedule();
				goto retry;
			}
			finish_wait(&conf->wait_for_overlap, &w);
4377 4378
			set_bit(STRIPE_HANDLE, &sh->state);
			clear_bit(STRIPE_DELAYED, &sh->state);
4379
			if ((bi->bi_rw & REQ_SYNC) &&
4380 4381
			    !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
				atomic_inc(&conf->preread_active_stripes);
4382
			release_stripe_plug(mddev, sh);
L
Linus Torvalds 已提交
4383 4384 4385 4386 4387 4388 4389
		} 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;
		}
	}
4390

4391
	remaining = raid5_dec_bi_active_stripes(bi);
4392
	if (remaining == 0) {
L
Linus Torvalds 已提交
4393

4394
		if ( rw == WRITE )
L
Linus Torvalds 已提交
4395
			md_write_end(mddev);
4396

4397 4398
		trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
					 bi, 0);
4399
		bio_endio(bi, 0);
L
Linus Torvalds 已提交
4400 4401 4402
	}
}

4403
static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
D
Dan Williams 已提交
4404

4405
static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
L
Linus Torvalds 已提交
4406
{
4407 4408 4409 4410 4411 4412 4413 4414 4415
	/* 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.
	 */
4416
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4417
	struct stripe_head *sh;
4418
	sector_t first_sector, last_sector;
4419 4420 4421
	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;
4422 4423
	int i;
	int dd_idx;
4424
	sector_t writepos, readpos, safepos;
4425
	sector_t stripe_addr;
4426
	int reshape_sectors;
4427
	struct list_head stripes;
4428

4429 4430
	if (sector_nr == 0) {
		/* If restarting in the middle, skip the initial sectors */
4431
		if (mddev->reshape_backwards &&
4432 4433 4434
		    conf->reshape_progress < raid5_size(mddev, 0, 0)) {
			sector_nr = raid5_size(mddev, 0, 0)
				- conf->reshape_progress;
4435
		} else if (!mddev->reshape_backwards &&
4436 4437
			   conf->reshape_progress > 0)
			sector_nr = conf->reshape_progress;
4438
		sector_div(sector_nr, new_data_disks);
4439
		if (sector_nr) {
4440 4441
			mddev->curr_resync_completed = sector_nr;
			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4442 4443 4444
			*skipped = 1;
			return sector_nr;
		}
4445 4446
	}

4447 4448 4449 4450
	/* 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
	 */
4451 4452
	if (mddev->new_chunk_sectors > mddev->chunk_sectors)
		reshape_sectors = mddev->new_chunk_sectors;
4453
	else
4454
		reshape_sectors = mddev->chunk_sectors;
4455

4456 4457 4458 4459 4460
	/* 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
4461
	 */
4462
	writepos = conf->reshape_progress;
4463
	sector_div(writepos, new_data_disks);
4464 4465
	readpos = conf->reshape_progress;
	sector_div(readpos, data_disks);
4466
	safepos = conf->reshape_safe;
4467
	sector_div(safepos, data_disks);
4468
	if (mddev->reshape_backwards) {
4469
		writepos -= min_t(sector_t, reshape_sectors, writepos);
4470
		readpos += reshape_sectors;
4471
		safepos += reshape_sectors;
4472
	} else {
4473
		writepos += reshape_sectors;
4474 4475
		readpos -= min_t(sector_t, reshape_sectors, readpos);
		safepos -= min_t(sector_t, reshape_sectors, safepos);
4476
	}
4477

4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490 4491 4492
	/* 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;
	}

4493 4494 4495 4496
	/* '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.
4497 4498 4499 4500
	 * 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
4501 4502 4503 4504 4505 4506 4507 4508 4509 4510 4511 4512
	 * 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???
	 */
4513 4514 4515 4516 4517 4518
	if (conf->min_offset_diff < 0) {
		safepos += -conf->min_offset_diff;
		readpos += -conf->min_offset_diff;
	} else
		writepos += conf->min_offset_diff;

4519
	if ((mddev->reshape_backwards
4520 4521 4522
	     ? (safepos > writepos && readpos < writepos)
	     : (safepos < writepos && readpos > writepos)) ||
	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4523 4524 4525
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes)==0);
4526
		mddev->reshape_position = conf->reshape_progress;
4527
		mddev->curr_resync_completed = sector_nr;
4528
		conf->reshape_checkpoint = jiffies;
4529
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
4530
		md_wakeup_thread(mddev->thread);
4531
		wait_event(mddev->sb_wait, mddev->flags == 0 ||
4532 4533
			   kthread_should_stop());
		spin_lock_irq(&conf->device_lock);
4534
		conf->reshape_safe = mddev->reshape_position;
4535 4536
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4537
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4538 4539
	}

4540
	INIT_LIST_HEAD(&stripes);
4541
	for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
4542
		int j;
4543
		int skipped_disk = 0;
4544
		sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
4545 4546 4547 4548 4549 4550 4551 4552 4553
		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;
4554
			if (conf->level == 6 &&
4555
			    j == sh->qd_idx)
4556
				continue;
4557
			s = compute_blocknr(sh, j, 0);
D
Dan Williams 已提交
4558
			if (s < raid5_size(mddev, 0, 0)) {
4559
				skipped_disk = 1;
4560 4561 4562 4563 4564 4565
				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);
		}
4566
		if (!skipped_disk) {
4567 4568 4569
			set_bit(STRIPE_EXPAND_READY, &sh->state);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
4570
		list_add(&sh->lru, &stripes);
4571 4572
	}
	spin_lock_irq(&conf->device_lock);
4573
	if (mddev->reshape_backwards)
4574
		conf->reshape_progress -= reshape_sectors * new_data_disks;
4575
	else
4576
		conf->reshape_progress += reshape_sectors * new_data_disks;
4577 4578 4579 4580 4581 4582 4583
	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 =
4584
		raid5_compute_sector(conf, stripe_addr*(new_data_disks),
4585
				     1, &dd_idx, NULL);
4586
	last_sector =
4587
		raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
4588
					    * new_data_disks - 1),
4589
				     1, &dd_idx, NULL);
A
Andre Noll 已提交
4590 4591
	if (last_sector >= mddev->dev_sectors)
		last_sector = mddev->dev_sectors - 1;
4592
	while (first_sector <= last_sector) {
4593
		sh = get_active_stripe(conf, first_sector, 1, 0, 1);
4594 4595 4596 4597 4598
		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
		set_bit(STRIPE_HANDLE, &sh->state);
		release_stripe(sh);
		first_sector += STRIPE_SECTORS;
	}
4599 4600 4601 4602 4603 4604 4605 4606
	/* 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);
	}
4607 4608 4609
	/* If this takes us to the resync_max point where we have to pause,
	 * then we need to write out the superblock.
	 */
4610
	sector_nr += reshape_sectors;
4611 4612
	if ((sector_nr - mddev->curr_resync_completed) * 2
	    >= mddev->resync_max - mddev->curr_resync_completed) {
4613 4614 4615
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes) == 0);
4616
		mddev->reshape_position = conf->reshape_progress;
4617
		mddev->curr_resync_completed = sector_nr;
4618
		conf->reshape_checkpoint = jiffies;
4619 4620 4621 4622 4623 4624
		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);
4625
		conf->reshape_safe = mddev->reshape_position;
4626 4627
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4628
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4629
	}
4630
	return reshape_sectors;
4631 4632 4633
}

/* FIXME go_faster isn't used */
4634
static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
4635
{
4636
	struct r5conf *conf = mddev->private;
4637
	struct stripe_head *sh;
A
Andre Noll 已提交
4638
	sector_t max_sector = mddev->dev_sectors;
N
NeilBrown 已提交
4639
	sector_t sync_blocks;
4640 4641
	int still_degraded = 0;
	int i;
L
Linus Torvalds 已提交
4642

4643
	if (sector_nr >= max_sector) {
L
Linus Torvalds 已提交
4644
		/* just being told to finish up .. nothing much to do */
4645

4646 4647 4648 4649
		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
			end_reshape(conf);
			return 0;
		}
4650 4651 4652 4653

		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
					&sync_blocks, 1);
4654
		else /* completed sync */
4655 4656 4657
			conf->fullsync = 0;
		bitmap_close_sync(mddev->bitmap);

L
Linus Torvalds 已提交
4658 4659
		return 0;
	}
4660

4661 4662 4663
	/* Allow raid5_quiesce to complete */
	wait_event(conf->wait_for_overlap, conf->quiesce != 2);

4664 4665
	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
		return reshape_request(mddev, sector_nr, skipped);
4666

4667 4668 4669 4670 4671 4672
	/* 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
	 */

4673
	/* if there is too many failed drives and we are trying
L
Linus Torvalds 已提交
4674 4675 4676
	 * to resync, then assert that we are finished, because there is
	 * nothing we can do.
	 */
4677
	if (mddev->degraded >= conf->max_degraded &&
4678
	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
A
Andre Noll 已提交
4679
		sector_t rv = mddev->dev_sectors - sector_nr;
4680
		*skipped = 1;
L
Linus Torvalds 已提交
4681 4682
		return rv;
	}
4683 4684 4685 4686
	if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
	    !conf->fullsync &&
	    !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
	    sync_blocks >= STRIPE_SECTORS) {
4687 4688 4689 4690 4691
		/* 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
4692

N
NeilBrown 已提交
4693 4694
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);

4695
	sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
L
Linus Torvalds 已提交
4696
	if (sh == NULL) {
4697
		sh = get_active_stripe(conf, sector_nr, 0, 0, 0);
L
Linus Torvalds 已提交
4698
		/* make sure we don't swamp the stripe cache if someone else
4699
		 * is trying to get access
L
Linus Torvalds 已提交
4700
		 */
4701
		schedule_timeout_uninterruptible(1);
L
Linus Torvalds 已提交
4702
	}
4703 4704 4705 4706
	/* 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.
	 */
4707
	for (i = 0; i < conf->raid_disks; i++)
4708 4709 4710 4711 4712
		if (conf->disks[i].rdev == NULL)
			still_degraded = 1;

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

4713
	set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
L
Linus Torvalds 已提交
4714

4715
	handle_stripe(sh);
L
Linus Torvalds 已提交
4716 4717 4718 4719 4720
	release_stripe(sh);

	return STRIPE_SECTORS;
}

4721
static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
4722 4723 4724 4725 4726 4727 4728 4729 4730 4731 4732 4733
{
	/* 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;
4734
	int dd_idx;
4735 4736 4737 4738 4739 4740
	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);
4741
	sector = raid5_compute_sector(conf, logical_sector,
4742
				      0, &dd_idx, NULL);
K
Kent Overstreet 已提交
4743
	last_sector = bio_end_sector(raid_bio);
4744 4745

	for (; logical_sector < last_sector;
4746 4747 4748
	     logical_sector += STRIPE_SECTORS,
		     sector += STRIPE_SECTORS,
		     scnt++) {
4749

4750
		if (scnt < raid5_bi_processed_stripes(raid_bio))
4751 4752 4753
			/* already done this stripe */
			continue;

4754
		sh = get_active_stripe(conf, sector, 0, 1, 0);
4755 4756 4757

		if (!sh) {
			/* failed to get a stripe - must wait */
4758
			raid5_set_bi_processed_stripes(raid_bio, scnt);
4759 4760 4761 4762
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4763 4764
		if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
			release_stripe(sh);
4765
			raid5_set_bi_processed_stripes(raid_bio, scnt);
4766 4767 4768 4769
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4770
		set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
4771
		handle_stripe(sh);
4772 4773 4774
		release_stripe(sh);
		handled++;
	}
4775
	remaining = raid5_dec_bi_active_stripes(raid_bio);
4776 4777 4778
	if (remaining == 0) {
		trace_block_bio_complete(bdev_get_queue(raid_bio->bi_bdev),
					 raid_bio, 0);
4779
		bio_endio(raid_bio, 0);
4780
	}
4781 4782 4783 4784 4785
	if (atomic_dec_and_test(&conf->active_aligned_reads))
		wake_up(&conf->wait_for_stripe);
	return handled;
}

4786 4787 4788 4789 4790 4791 4792 4793 4794 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804 4805 4806 4807 4808 4809
#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;
}
4810

L
Linus Torvalds 已提交
4811 4812 4813 4814 4815 4816 4817
/*
 * 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
4818
static void raid5d(struct md_thread *thread)
L
Linus Torvalds 已提交
4819
{
S
Shaohua Li 已提交
4820
	struct mddev *mddev = thread->mddev;
4821
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4822
	int handled;
4823
	struct blk_plug plug;
L
Linus Torvalds 已提交
4824

4825
	pr_debug("+++ raid5d active\n");
L
Linus Torvalds 已提交
4826 4827 4828

	md_check_recovery(mddev);

4829
	blk_start_plug(&plug);
L
Linus Torvalds 已提交
4830 4831 4832
	handled = 0;
	spin_lock_irq(&conf->device_lock);
	while (1) {
4833
		struct bio *bio;
4834
		int batch_size;
L
Linus Torvalds 已提交
4835

4836
		if (
4837 4838 4839
		    !list_empty(&conf->bitmap_list)) {
			/* Now is a good time to flush some bitmap updates */
			conf->seq_flush++;
4840
			spin_unlock_irq(&conf->device_lock);
4841
			bitmap_unplug(mddev->bitmap);
4842
			spin_lock_irq(&conf->device_lock);
4843
			conf->seq_write = conf->seq_flush;
4844 4845
			activate_bit_delay(conf);
		}
4846
		raid5_activate_delayed(conf);
4847

4848 4849 4850 4851 4852 4853 4854 4855 4856 4857
		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++;
		}

4858 4859
		batch_size = handle_active_stripes(conf);
		if (!batch_size)
L
Linus Torvalds 已提交
4860
			break;
4861
		handled += batch_size;
L
Linus Torvalds 已提交
4862

4863 4864
		if (mddev->flags & ~(1<<MD_CHANGE_PENDING)) {
			spin_unlock_irq(&conf->device_lock);
4865
			md_check_recovery(mddev);
4866 4867
			spin_lock_irq(&conf->device_lock);
		}
L
Linus Torvalds 已提交
4868
	}
4869
	pr_debug("%d stripes handled\n", handled);
L
Linus Torvalds 已提交
4870 4871 4872

	spin_unlock_irq(&conf->device_lock);

4873
	async_tx_issue_pending_all();
4874
	blk_finish_plug(&plug);
L
Linus Torvalds 已提交
4875

4876
	pr_debug("--- raid5d inactive\n");
L
Linus Torvalds 已提交
4877 4878
}

4879
static ssize_t
4880
raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
4881
{
4882
	struct r5conf *conf = mddev->private;
4883 4884 4885 4886
	if (conf)
		return sprintf(page, "%d\n", conf->max_nr_stripes);
	else
		return 0;
4887 4888
}

4889
int
4890
raid5_set_cache_size(struct mddev *mddev, int size)
4891
{
4892
	struct r5conf *conf = mddev->private;
4893 4894
	int err;

4895
	if (size <= 16 || size > 32768)
4896
		return -EINVAL;
4897
	while (size < conf->max_nr_stripes) {
4898 4899 4900 4901 4902
		if (drop_one_stripe(conf))
			conf->max_nr_stripes--;
		else
			break;
	}
4903 4904 4905
	err = md_allow_write(mddev);
	if (err)
		return err;
4906
	while (size > conf->max_nr_stripes) {
4907 4908 4909 4910
		if (grow_one_stripe(conf))
			conf->max_nr_stripes++;
		else break;
	}
4911 4912 4913 4914 4915
	return 0;
}
EXPORT_SYMBOL(raid5_set_cache_size);

static ssize_t
4916
raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
4917
{
4918
	struct r5conf *conf = mddev->private;
4919 4920 4921 4922 4923 4924 4925 4926
	unsigned long new;
	int err;

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

4927
	if (kstrtoul(page, 10, &new))
4928 4929 4930 4931
		return -EINVAL;
	err = raid5_set_cache_size(mddev, new);
	if (err)
		return err;
4932 4933
	return len;
}
4934

4935 4936 4937 4938
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);
4939

4940
static ssize_t
4941
raid5_show_preread_threshold(struct mddev *mddev, char *page)
4942
{
4943
	struct r5conf *conf = mddev->private;
4944 4945 4946 4947 4948 4949 4950
	if (conf)
		return sprintf(page, "%d\n", conf->bypass_threshold);
	else
		return 0;
}

static ssize_t
4951
raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
4952
{
4953
	struct r5conf *conf = mddev->private;
4954
	unsigned long new;
4955 4956 4957 4958 4959
	if (len >= PAGE_SIZE)
		return -EINVAL;
	if (!conf)
		return -ENODEV;

4960
	if (kstrtoul(page, 10, &new))
4961
		return -EINVAL;
4962
	if (new > conf->max_nr_stripes)
4963 4964 4965 4966 4967 4968 4969 4970 4971 4972 4973
		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);

4974
static ssize_t
4975
stripe_cache_active_show(struct mddev *mddev, char *page)
4976
{
4977
	struct r5conf *conf = mddev->private;
4978 4979 4980 4981
	if (conf)
		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
	else
		return 0;
4982 4983
}

4984 4985
static struct md_sysfs_entry
raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
4986

4987
static struct attribute *raid5_attrs[] =  {
4988 4989
	&raid5_stripecache_size.attr,
	&raid5_stripecache_active.attr,
4990
	&raid5_preread_bypass_threshold.attr,
4991 4992
	NULL,
};
4993 4994 4995
static struct attribute_group raid5_attrs_group = {
	.name = NULL,
	.attrs = raid5_attrs,
4996 4997
};

4998
static sector_t
4999
raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
5000
{
5001
	struct r5conf *conf = mddev->private;
5002 5003 5004

	if (!sectors)
		sectors = mddev->dev_sectors;
5005
	if (!raid_disks)
5006
		/* size is defined by the smallest of previous and new size */
5007
		raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
5008

5009
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5010
	sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
5011 5012 5013
	return sectors * (raid_disks - conf->max_degraded);
}

5014
static void raid5_free_percpu(struct r5conf *conf)
5015 5016 5017 5018 5019 5020 5021 5022 5023 5024 5025
{
	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);
5026
		kfree(percpu->scribble);
5027 5028 5029 5030 5031 5032 5033 5034 5035
	}
#ifdef CONFIG_HOTPLUG_CPU
	unregister_cpu_notifier(&conf->cpu_notify);
#endif
	put_online_cpus();

	free_percpu(conf->percpu);
}

5036
static void free_conf(struct r5conf *conf)
5037 5038
{
	shrink_stripes(conf);
5039
	raid5_free_percpu(conf);
5040 5041 5042 5043 5044
	kfree(conf->disks);
	kfree(conf->stripe_hashtbl);
	kfree(conf);
}

5045 5046 5047 5048
#ifdef CONFIG_HOTPLUG_CPU
static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action,
			      void *hcpu)
{
5049
	struct r5conf *conf = container_of(nfb, struct r5conf, cpu_notify);
5050 5051 5052 5053 5054 5055
	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:
5056
		if (conf->level == 6 && !percpu->spare_page)
5057
			percpu->spare_page = alloc_page(GFP_KERNEL);
5058 5059 5060 5061 5062 5063 5064
		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);
5065 5066
			pr_err("%s: failed memory allocation for cpu%ld\n",
			       __func__, cpu);
5067
			return notifier_from_errno(-ENOMEM);
5068 5069 5070 5071 5072
		}
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		safe_put_page(percpu->spare_page);
5073
		kfree(percpu->scribble);
5074
		percpu->spare_page = NULL;
5075
		percpu->scribble = NULL;
5076 5077 5078 5079 5080 5081 5082 5083
		break;
	default:
		break;
	}
	return NOTIFY_OK;
}
#endif

5084
static int raid5_alloc_percpu(struct r5conf *conf)
5085 5086 5087
{
	unsigned long cpu;
	struct page *spare_page;
5088
	struct raid5_percpu __percpu *allcpus;
5089
	void *scribble;
5090 5091 5092 5093 5094 5095 5096 5097 5098 5099
	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) {
5100 5101 5102 5103 5104 5105 5106 5107
		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;
		}
5108
		scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
5109
		if (!scribble) {
5110 5111 5112
			err = -ENOMEM;
			break;
		}
5113
		per_cpu_ptr(conf->percpu, cpu)->scribble = scribble;
5114 5115 5116 5117 5118 5119 5120 5121 5122 5123 5124 5125
	}
#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;
}

5126
static struct r5conf *setup_conf(struct mddev *mddev)
L
Linus Torvalds 已提交
5127
{
5128
	struct r5conf *conf;
5129
	int raid_disk, memory, max_disks;
5130
	struct md_rdev *rdev;
L
Linus Torvalds 已提交
5131
	struct disk_info *disk;
5132
	char pers_name[6];
L
Linus Torvalds 已提交
5133

N
NeilBrown 已提交
5134 5135 5136
	if (mddev->new_level != 5
	    && mddev->new_level != 4
	    && mddev->new_level != 6) {
5137
		printk(KERN_ERR "md/raid:%s: raid level not set to 4/5/6 (%d)\n",
N
NeilBrown 已提交
5138 5139
		       mdname(mddev), mddev->new_level);
		return ERR_PTR(-EIO);
L
Linus Torvalds 已提交
5140
	}
N
NeilBrown 已提交
5141 5142 5143 5144
	if ((mddev->new_level == 5
	     && !algorithm_valid_raid5(mddev->new_layout)) ||
	    (mddev->new_level == 6
	     && !algorithm_valid_raid6(mddev->new_layout))) {
5145
		printk(KERN_ERR "md/raid:%s: layout %d not supported\n",
N
NeilBrown 已提交
5146 5147
		       mdname(mddev), mddev->new_layout);
		return ERR_PTR(-EIO);
5148
	}
N
NeilBrown 已提交
5149
	if (mddev->new_level == 6 && mddev->raid_disks < 4) {
5150
		printk(KERN_ERR "md/raid:%s: not enough configured devices (%d, minimum 4)\n",
N
NeilBrown 已提交
5151 5152
		       mdname(mddev), mddev->raid_disks);
		return ERR_PTR(-EINVAL);
5153 5154
	}

5155 5156 5157
	if (!mddev->new_chunk_sectors ||
	    (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
	    !is_power_of_2(mddev->new_chunk_sectors)) {
5158 5159
		printk(KERN_ERR "md/raid:%s: invalid chunk size %d\n",
		       mdname(mddev), mddev->new_chunk_sectors << 9);
N
NeilBrown 已提交
5160
		return ERR_PTR(-EINVAL);
5161 5162
	}

5163
	conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
N
NeilBrown 已提交
5164
	if (conf == NULL)
L
Linus Torvalds 已提交
5165
		goto abort;
5166 5167 5168 5169 5170 5171 5172 5173 5174 5175 5176 5177
	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;
5178
	conf->recovery_disabled = mddev->recovery_disabled - 1;
N
NeilBrown 已提交
5179 5180 5181 5182 5183

	conf->raid_disks = mddev->raid_disks;
	if (mddev->reshape_position == MaxSector)
		conf->previous_raid_disks = mddev->raid_disks;
	else
5184
		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
5185 5186
	max_disks = max(conf->raid_disks, conf->previous_raid_disks);
	conf->scribble_len = scribble_len(max_disks);
5187

5188
	conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
5189 5190 5191
			      GFP_KERNEL);
	if (!conf->disks)
		goto abort;
5192

L
Linus Torvalds 已提交
5193 5194
	conf->mddev = mddev;

5195
	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
L
Linus Torvalds 已提交
5196 5197
		goto abort;

5198 5199 5200 5201
	conf->level = mddev->new_level;
	if (raid5_alloc_percpu(conf) != 0)
		goto abort;

5202
	pr_debug("raid456: run(%s) called.\n", mdname(mddev));
L
Linus Torvalds 已提交
5203

N
NeilBrown 已提交
5204
	rdev_for_each(rdev, mddev) {
L
Linus Torvalds 已提交
5205
		raid_disk = rdev->raid_disk;
5206
		if (raid_disk >= max_disks
L
Linus Torvalds 已提交
5207 5208 5209 5210
		    || raid_disk < 0)
			continue;
		disk = conf->disks + raid_disk;

5211 5212 5213 5214 5215 5216 5217 5218 5219
		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
5220

5221
		if (test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
5222
			char b[BDEVNAME_SIZE];
5223 5224 5225
			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
5226
		} else if (rdev->saved_raid_disk != raid_disk)
5227 5228
			/* Cannot rely on bitmap to complete recovery */
			conf->fullsync = 1;
L
Linus Torvalds 已提交
5229 5230
	}

5231
	conf->chunk_sectors = mddev->new_chunk_sectors;
N
NeilBrown 已提交
5232
	conf->level = mddev->new_level;
5233 5234 5235 5236
	if (conf->level == 6)
		conf->max_degraded = 2;
	else
		conf->max_degraded = 1;
N
NeilBrown 已提交
5237
	conf->algorithm = mddev->new_layout;
L
Linus Torvalds 已提交
5238
	conf->max_nr_stripes = NR_STRIPES;
5239
	conf->reshape_progress = mddev->reshape_position;
5240
	if (conf->reshape_progress != MaxSector) {
5241
		conf->prev_chunk_sectors = mddev->chunk_sectors;
5242 5243
		conf->prev_algo = mddev->layout;
	}
L
Linus Torvalds 已提交
5244

N
NeilBrown 已提交
5245
	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
5246
		 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
N
NeilBrown 已提交
5247 5248
	if (grow_stripes(conf, conf->max_nr_stripes)) {
		printk(KERN_ERR
5249 5250
		       "md/raid:%s: couldn't allocate %dkB for buffers\n",
		       mdname(mddev), memory);
N
NeilBrown 已提交
5251 5252
		goto abort;
	} else
5253 5254
		printk(KERN_INFO "md/raid:%s: allocated %dkB\n",
		       mdname(mddev), memory);
L
Linus Torvalds 已提交
5255

5256 5257
	sprintf(pers_name, "raid%d", mddev->new_level);
	conf->thread = md_register_thread(raid5d, mddev, pers_name);
N
NeilBrown 已提交
5258 5259
	if (!conf->thread) {
		printk(KERN_ERR
5260
		       "md/raid:%s: couldn't allocate thread.\n",
N
NeilBrown 已提交
5261
		       mdname(mddev));
5262 5263
		goto abort;
	}
N
NeilBrown 已提交
5264 5265 5266 5267 5268

	return conf;

 abort:
	if (conf) {
5269
		free_conf(conf);
N
NeilBrown 已提交
5270 5271 5272 5273 5274
		return ERR_PTR(-EIO);
	} else
		return ERR_PTR(-ENOMEM);
}

5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286 5287 5288 5289 5290 5291 5292 5293 5294 5295 5296 5297 5298 5299 5300 5301

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;
}

5302
static int run(struct mddev *mddev)
N
NeilBrown 已提交
5303
{
5304
	struct r5conf *conf;
5305
	int working_disks = 0;
5306
	int dirty_parity_disks = 0;
5307
	struct md_rdev *rdev;
5308
	sector_t reshape_offset = 0;
5309
	int i;
5310 5311
	long long min_offset_diff = 0;
	int first = 1;
N
NeilBrown 已提交
5312

5313
	if (mddev->recovery_cp != MaxSector)
5314
		printk(KERN_NOTICE "md/raid:%s: not clean"
5315 5316
		       " -- starting background reconstruction\n",
		       mdname(mddev));
5317 5318 5319 5320 5321 5322 5323 5324 5325 5326 5327 5328 5329 5330 5331 5332 5333

	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
5334 5335
	if (mddev->reshape_position != MaxSector) {
		/* Check that we can continue the reshape.
5336 5337 5338 5339 5340 5341 5342 5343 5344 5345
		 * 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
5346 5347 5348
		 */
		sector_t here_new, here_old;
		int old_disks;
5349
		int max_degraded = (mddev->level == 6 ? 2 : 1);
N
NeilBrown 已提交
5350

5351
		if (mddev->new_level != mddev->level) {
5352
			printk(KERN_ERR "md/raid:%s: unsupported reshape "
N
NeilBrown 已提交
5353 5354 5355 5356 5357 5358 5359 5360 5361 5362
			       "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;
5363
		if (sector_div(here_new, mddev->new_chunk_sectors *
N
NeilBrown 已提交
5364
			       (mddev->raid_disks - max_degraded))) {
5365 5366
			printk(KERN_ERR "md/raid:%s: reshape_position not "
			       "on a stripe boundary\n", mdname(mddev));
N
NeilBrown 已提交
5367 5368
			return -EINVAL;
		}
5369
		reshape_offset = here_new * mddev->new_chunk_sectors;
N
NeilBrown 已提交
5370 5371
		/* here_new is the stripe we will write to */
		here_old = mddev->reshape_position;
5372
		sector_div(here_old, mddev->chunk_sectors *
N
NeilBrown 已提交
5373 5374 5375
			   (old_disks-max_degraded));
		/* here_old is the first stripe that we might need to read
		 * from */
5376
		if (mddev->delta_disks == 0) {
5377 5378 5379 5380 5381 5382
			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;
			}
5383
			/* We cannot be sure it is safe to start an in-place
5384
			 * reshape.  It is only safe if user-space is monitoring
5385 5386 5387 5388 5389
			 * 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.
			 */
5390 5391 5392 5393 5394 5395 5396
			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",
5397
				       mdname(mddev));
5398 5399
				return -EINVAL;
			}
5400
		} else if (mddev->reshape_backwards
5401
		    ? (here_new * mddev->new_chunk_sectors + min_offset_diff <=
5402 5403
		       here_old * mddev->chunk_sectors)
		    : (here_new * mddev->new_chunk_sectors >=
5404
		       here_old * mddev->chunk_sectors + (-min_offset_diff))) {
N
NeilBrown 已提交
5405
			/* Reading from the same stripe as writing to - bad */
5406 5407 5408
			printk(KERN_ERR "md/raid:%s: reshape_position too early for "
			       "auto-recovery - aborting.\n",
			       mdname(mddev));
N
NeilBrown 已提交
5409 5410
			return -EINVAL;
		}
5411 5412
		printk(KERN_INFO "md/raid:%s: reshape will continue\n",
		       mdname(mddev));
N
NeilBrown 已提交
5413 5414 5415 5416
		/* OK, we should be able to continue; */
	} else {
		BUG_ON(mddev->level != mddev->new_level);
		BUG_ON(mddev->layout != mddev->new_layout);
5417
		BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
N
NeilBrown 已提交
5418
		BUG_ON(mddev->delta_disks != 0);
L
Linus Torvalds 已提交
5419
	}
N
NeilBrown 已提交
5420

5421 5422 5423 5424 5425
	if (mddev->private == NULL)
		conf = setup_conf(mddev);
	else
		conf = mddev->private;

N
NeilBrown 已提交
5426 5427 5428
	if (IS_ERR(conf))
		return PTR_ERR(conf);

5429
	conf->min_offset_diff = min_offset_diff;
N
NeilBrown 已提交
5430 5431 5432 5433
	mddev->thread = conf->thread;
	conf->thread = NULL;
	mddev->private = conf;

5434 5435 5436 5437 5438 5439 5440 5441 5442 5443 5444
	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)
5445
			continue;
5446 5447 5448 5449 5450 5451 5452
		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;
		}
5453
		if (test_bit(In_sync, &rdev->flags)) {
N
NeilBrown 已提交
5454
			working_disks++;
5455 5456
			continue;
		}
5457 5458 5459 5460 5461 5462 5463 5464 5465 5466 5467 5468
		/* 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;
5469

5470 5471 5472 5473 5474 5475 5476 5477 5478 5479 5480 5481 5482 5483 5484
		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
5485

5486 5487 5488
	/*
	 * 0 for a fully functional array, 1 or 2 for a degraded array.
	 */
5489
	mddev->degraded = calc_degraded(conf);
N
NeilBrown 已提交
5490

5491
	if (has_failed(conf)) {
5492
		printk(KERN_ERR "md/raid:%s: not enough operational devices"
L
Linus Torvalds 已提交
5493
			" (%d/%d failed)\n",
5494
			mdname(mddev), mddev->degraded, conf->raid_disks);
L
Linus Torvalds 已提交
5495 5496 5497
		goto abort;
	}

N
NeilBrown 已提交
5498
	/* device size must be a multiple of chunk size */
5499
	mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
N
NeilBrown 已提交
5500 5501
	mddev->resync_max_sectors = mddev->dev_sectors;

5502
	if (mddev->degraded > dirty_parity_disks &&
L
Linus Torvalds 已提交
5503
	    mddev->recovery_cp != MaxSector) {
5504 5505
		if (mddev->ok_start_degraded)
			printk(KERN_WARNING
5506 5507
			       "md/raid:%s: starting dirty degraded array"
			       " - data corruption possible.\n",
5508 5509 5510
			       mdname(mddev));
		else {
			printk(KERN_ERR
5511
			       "md/raid:%s: cannot start dirty degraded array.\n",
5512 5513 5514
			       mdname(mddev));
			goto abort;
		}
L
Linus Torvalds 已提交
5515 5516 5517
	}

	if (mddev->degraded == 0)
5518 5519
		printk(KERN_INFO "md/raid:%s: raid level %d active with %d out of %d"
		       " devices, algorithm %d\n", mdname(mddev), conf->level,
5520 5521
		       mddev->raid_disks-mddev->degraded, mddev->raid_disks,
		       mddev->new_layout);
L
Linus Torvalds 已提交
5522
	else
5523 5524 5525 5526 5527
		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
5528 5529 5530

	print_raid5_conf(conf);

5531 5532
	if (conf->reshape_progress != MaxSector) {
		conf->reshape_safe = conf->reshape_progress;
5533 5534 5535 5536 5537 5538
		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,
5539
							"reshape");
5540 5541
	}

L
Linus Torvalds 已提交
5542 5543

	/* Ok, everything is just fine now */
5544 5545
	if (mddev->to_remove == &raid5_attrs_group)
		mddev->to_remove = NULL;
N
NeilBrown 已提交
5546 5547
	else if (mddev->kobj.sd &&
	    sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
5548
		printk(KERN_WARNING
5549
		       "raid5: failed to create sysfs attributes for %s\n",
5550
		       mdname(mddev));
5551
	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
5552

5553
	if (mddev->queue) {
5554
		int chunk_size;
S
Shaohua Li 已提交
5555
		bool discard_supported = true;
5556 5557 5558 5559 5560 5561 5562 5563 5564
		/* 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
5565

5566
		blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
5567

N
NeilBrown 已提交
5568 5569
		mddev->queue->backing_dev_info.congested_data = mddev;
		mddev->queue->backing_dev_info.congested_fn = raid5_congested;
5570

5571 5572 5573 5574
		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
5575 5576 5577 5578 5579
		/*
		 * We can only discard a whole stripe. It doesn't make sense to
		 * discard data disk but write parity disk
		 */
		stripe = stripe * PAGE_SIZE;
5580 5581 5582 5583
		/* 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
5584 5585 5586 5587 5588 5589 5590
		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;
5591

5592 5593
		blk_queue_max_write_same_sectors(mddev->queue, 0);

5594
		rdev_for_each(rdev, mddev) {
5595 5596
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
5597 5598
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->new_data_offset << 9);
S
Shaohua Li 已提交
5599 5600 5601 5602 5603 5604 5605 5606 5607 5608 5609 5610 5611 5612
			/*
			 * 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;
5613
		}
S
Shaohua Li 已提交
5614 5615 5616 5617 5618 5619 5620 5621 5622

		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);
5623
	}
5624

L
Linus Torvalds 已提交
5625 5626
	return 0;
abort:
5627
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
5628 5629
	print_raid5_conf(conf);
	free_conf(conf);
L
Linus Torvalds 已提交
5630
	mddev->private = NULL;
5631
	printk(KERN_ALERT "md/raid:%s: failed to run raid set.\n", mdname(mddev));
L
Linus Torvalds 已提交
5632 5633 5634
	return -EIO;
}

5635
static int stop(struct mddev *mddev)
L
Linus Torvalds 已提交
5636
{
5637
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5638

5639
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
5640 5641
	if (mddev->queue)
		mddev->queue->backing_dev_info.congested_fn = NULL;
5642
	free_conf(conf);
5643 5644
	mddev->private = NULL;
	mddev->to_remove = &raid5_attrs_group;
L
Linus Torvalds 已提交
5645 5646 5647
	return 0;
}

5648
static void status(struct seq_file *seq, struct mddev *mddev)
L
Linus Torvalds 已提交
5649
{
5650
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5651 5652
	int i;

5653 5654
	seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
		mddev->chunk_sectors / 2, mddev->layout);
5655
	seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
L
Linus Torvalds 已提交
5656 5657 5658
	for (i = 0; i < conf->raid_disks; i++)
		seq_printf (seq, "%s",
			       conf->disks[i].rdev &&
5659
			       test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
L
Linus Torvalds 已提交
5660 5661 5662
	seq_printf (seq, "]");
}

5663
static void print_raid5_conf (struct r5conf *conf)
L
Linus Torvalds 已提交
5664 5665 5666 5667
{
	int i;
	struct disk_info *tmp;

5668
	printk(KERN_DEBUG "RAID conf printout:\n");
L
Linus Torvalds 已提交
5669 5670 5671 5672
	if (!conf) {
		printk("(conf==NULL)\n");
		return;
	}
5673 5674 5675
	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
5676 5677 5678 5679 5680

	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
		tmp = conf->disks + i;
		if (tmp->rdev)
5681 5682 5683
			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
5684 5685 5686
	}
}

5687
static int raid5_spare_active(struct mddev *mddev)
L
Linus Torvalds 已提交
5688 5689
{
	int i;
5690
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5691
	struct disk_info *tmp;
5692 5693
	int count = 0;
	unsigned long flags;
L
Linus Torvalds 已提交
5694 5695 5696

	for (i = 0; i < conf->raid_disks; i++) {
		tmp = conf->disks + i;
5697 5698 5699 5700 5701 5702 5703 5704 5705 5706 5707 5708 5709 5710 5711 5712 5713 5714 5715
		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
5716
		    && tmp->rdev->recovery_offset == MaxSector
5717
		    && !test_bit(Faulty, &tmp->rdev->flags)
5718
		    && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
5719
			count++;
5720
			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
L
Linus Torvalds 已提交
5721 5722
		}
	}
5723
	spin_lock_irqsave(&conf->device_lock, flags);
5724
	mddev->degraded = calc_degraded(conf);
5725
	spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
5726
	print_raid5_conf(conf);
5727
	return count;
L
Linus Torvalds 已提交
5728 5729
}

5730
static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5731
{
5732
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5733
	int err = 0;
5734
	int number = rdev->raid_disk;
5735
	struct md_rdev **rdevp;
L
Linus Torvalds 已提交
5736 5737 5738
	struct disk_info *p = conf->disks + number;

	print_raid5_conf(conf);
5739 5740 5741 5742 5743 5744 5745 5746 5747 5748 5749 5750 5751 5752 5753 5754 5755 5756 5757 5758 5759 5760
	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) &&
5761
	    (!p->replacement || p->replacement == rdev) &&
5762 5763 5764 5765 5766 5767 5768 5769 5770 5771
	    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;
5772 5773 5774 5775 5776 5777 5778 5779 5780 5781 5782 5783 5784 5785
	} 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
5786 5787 5788 5789 5790 5791
abort:

	print_raid5_conf(conf);
	return err;
}

5792
static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5793
{
5794
	struct r5conf *conf = mddev->private;
5795
	int err = -EEXIST;
L
Linus Torvalds 已提交
5796 5797
	int disk;
	struct disk_info *p;
5798 5799
	int first = 0;
	int last = conf->raid_disks - 1;
L
Linus Torvalds 已提交
5800

5801 5802 5803
	if (mddev->recovery_disabled == conf->recovery_disabled)
		return -EBUSY;

N
NeilBrown 已提交
5804
	if (rdev->saved_raid_disk < 0 && has_failed(conf))
L
Linus Torvalds 已提交
5805
		/* no point adding a device */
5806
		return -EINVAL;
L
Linus Torvalds 已提交
5807

5808 5809
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;
L
Linus Torvalds 已提交
5810 5811

	/*
5812 5813
	 * find the disk ... but prefer rdev->saved_raid_disk
	 * if possible.
L
Linus Torvalds 已提交
5814
	 */
5815
	if (rdev->saved_raid_disk >= 0 &&
5816
	    rdev->saved_raid_disk >= first &&
5817
	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
5818 5819 5820
		first = rdev->saved_raid_disk;

	for (disk = first; disk <= last; disk++) {
5821 5822
		p = conf->disks + disk;
		if (p->rdev == NULL) {
5823
			clear_bit(In_sync, &rdev->flags);
L
Linus Torvalds 已提交
5824
			rdev->raid_disk = disk;
5825
			err = 0;
5826 5827
			if (rdev->saved_raid_disk != disk)
				conf->fullsync = 1;
5828
			rcu_assign_pointer(p->rdev, rdev);
5829
			goto out;
L
Linus Torvalds 已提交
5830
		}
5831 5832 5833
	}
	for (disk = first; disk <= last; disk++) {
		p = conf->disks + disk;
5834 5835 5836 5837 5838 5839 5840 5841 5842 5843 5844
		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;
		}
	}
5845
out:
L
Linus Torvalds 已提交
5846
	print_raid5_conf(conf);
5847
	return err;
L
Linus Torvalds 已提交
5848 5849
}

5850
static int raid5_resize(struct mddev *mddev, sector_t sectors)
L
Linus Torvalds 已提交
5851 5852 5853 5854 5855 5856 5857 5858
{
	/* 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.
	 */
5859
	sector_t newsize;
5860
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5861 5862 5863
	newsize = raid5_size(mddev, sectors, mddev->raid_disks);
	if (mddev->external_size &&
	    mddev->array_sectors > newsize)
D
Dan Williams 已提交
5864
		return -EINVAL;
5865 5866 5867 5868 5869 5870
	if (mddev->bitmap) {
		int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
		if (ret)
			return ret;
	}
	md_set_array_sectors(mddev, newsize);
5871
	set_capacity(mddev->gendisk, mddev->array_sectors);
5872
	revalidate_disk(mddev->gendisk);
5873 5874
	if (sectors > mddev->dev_sectors &&
	    mddev->recovery_cp > mddev->dev_sectors) {
A
Andre Noll 已提交
5875
		mddev->recovery_cp = mddev->dev_sectors;
L
Linus Torvalds 已提交
5876 5877
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
A
Andre Noll 已提交
5878
	mddev->dev_sectors = sectors;
5879
	mddev->resync_max_sectors = sectors;
L
Linus Torvalds 已提交
5880 5881 5882
	return 0;
}

5883
static int check_stripe_cache(struct mddev *mddev)
5884 5885 5886 5887 5888 5889 5890 5891 5892
{
	/* 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.
	 */
5893
	struct r5conf *conf = mddev->private;
5894 5895 5896 5897
	if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes ||
	    ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes) {
5898 5899
		printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
		       mdname(mddev),
5900 5901 5902 5903 5904 5905 5906
		       ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
			/ STRIPE_SIZE)*4);
		return 0;
	}
	return 1;
}

5907
static int check_reshape(struct mddev *mddev)
5908
{
5909
	struct r5conf *conf = mddev->private;
5910

5911 5912
	if (mddev->delta_disks == 0 &&
	    mddev->new_layout == mddev->layout &&
5913
	    mddev->new_chunk_sectors == mddev->chunk_sectors)
5914
		return 0; /* nothing to do */
5915
	if (has_failed(conf))
5916 5917 5918 5919 5920 5921 5922 5923 5924 5925 5926 5927 5928
		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;
	}
5929

5930
	if (!check_stripe_cache(mddev))
5931 5932
		return -ENOSPC;

5933 5934
	return resize_stripes(conf, (conf->previous_raid_disks
				     + mddev->delta_disks));
5935 5936
}

5937
static int raid5_start_reshape(struct mddev *mddev)
5938
{
5939
	struct r5conf *conf = mddev->private;
5940
	struct md_rdev *rdev;
5941
	int spares = 0;
5942
	unsigned long flags;
5943

5944
	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
5945 5946
		return -EBUSY;

5947 5948 5949
	if (!check_stripe_cache(mddev))
		return -ENOSPC;

5950 5951 5952
	if (has_failed(conf))
		return -EINVAL;

5953
	rdev_for_each(rdev, mddev) {
5954 5955
		if (!test_bit(In_sync, &rdev->flags)
		    && !test_bit(Faulty, &rdev->flags))
5956
			spares++;
5957
	}
5958

5959
	if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
5960 5961 5962 5963 5964
		/* Not enough devices even to make a degraded array
		 * of that size
		 */
		return -EINVAL;

5965 5966 5967 5968 5969 5970
	/* 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) {
5971
		printk(KERN_ERR "md/raid:%s: array size must be reduced "
5972 5973 5974 5975
		       "before number of disks\n", mdname(mddev));
		return -EINVAL;
	}

5976
	atomic_set(&conf->reshape_stripes, 0);
5977 5978
	spin_lock_irq(&conf->device_lock);
	conf->previous_raid_disks = conf->raid_disks;
5979
	conf->raid_disks += mddev->delta_disks;
5980 5981
	conf->prev_chunk_sectors = conf->chunk_sectors;
	conf->chunk_sectors = mddev->new_chunk_sectors;
5982 5983
	conf->prev_algo = conf->algorithm;
	conf->algorithm = mddev->new_layout;
5984 5985 5986 5987 5988
	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();
5989
	if (mddev->reshape_backwards)
5990 5991 5992 5993
		conf->reshape_progress = raid5_size(mddev, 0, 0);
	else
		conf->reshape_progress = 0;
	conf->reshape_safe = conf->reshape_progress;
5994 5995 5996 5997
	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.
5998 5999 6000 6001
	 * 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.
6002
	 */
6003
	if (mddev->delta_disks >= 0) {
N
NeilBrown 已提交
6004
		rdev_for_each(rdev, mddev)
6005 6006 6007 6008
			if (rdev->raid_disk < 0 &&
			    !test_bit(Faulty, &rdev->flags)) {
				if (raid5_add_disk(mddev, rdev) == 0) {
					if (rdev->raid_disk
6009
					    >= conf->previous_raid_disks)
6010
						set_bit(In_sync, &rdev->flags);
6011
					else
6012
						rdev->recovery_offset = 0;
6013 6014

					if (sysfs_link_rdev(mddev, rdev))
6015
						/* Failure here is OK */;
6016
				}
6017 6018 6019 6020 6021
			} 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);
			}
6022

6023 6024 6025 6026
		/* When a reshape changes the number of devices,
		 * ->degraded is measured against the larger of the
		 * pre and post number of devices.
		 */
6027
		spin_lock_irqsave(&conf->device_lock, flags);
6028
		mddev->degraded = calc_degraded(conf);
6029 6030
		spin_unlock_irqrestore(&conf->device_lock, flags);
	}
6031
	mddev->raid_disks = conf->raid_disks;
6032
	mddev->reshape_position = conf->reshape_progress;
6033
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
6034

6035 6036 6037 6038 6039
	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,
6040
						"reshape");
6041 6042 6043 6044
	if (!mddev->sync_thread) {
		mddev->recovery = 0;
		spin_lock_irq(&conf->device_lock);
		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
6045 6046 6047
		rdev_for_each(rdev, mddev)
			rdev->new_data_offset = rdev->data_offset;
		smp_wmb();
6048
		conf->reshape_progress = MaxSector;
6049
		mddev->reshape_position = MaxSector;
6050 6051 6052
		spin_unlock_irq(&conf->device_lock);
		return -EAGAIN;
	}
6053
	conf->reshape_checkpoint = jiffies;
6054 6055 6056 6057 6058
	md_wakeup_thread(mddev->sync_thread);
	md_new_event(mddev);
	return 0;
}

6059 6060 6061
/* This is called from the reshape thread and should make any
 * changes needed in 'conf'
 */
6062
static void end_reshape(struct r5conf *conf)
6063 6064
{

6065
	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
6066
		struct md_rdev *rdev;
6067 6068

		spin_lock_irq(&conf->device_lock);
6069
		conf->previous_raid_disks = conf->raid_disks;
6070 6071 6072
		rdev_for_each(rdev, conf->mddev)
			rdev->data_offset = rdev->new_data_offset;
		smp_wmb();
6073
		conf->reshape_progress = MaxSector;
6074
		spin_unlock_irq(&conf->device_lock);
6075
		wake_up(&conf->wait_for_overlap);
6076 6077 6078 6079

		/* read-ahead size must cover two whole stripes, which is
		 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
		 */
6080
		if (conf->mddev->queue) {
6081
			int data_disks = conf->raid_disks - conf->max_degraded;
6082
			int stripe = data_disks * ((conf->chunk_sectors << 9)
6083
						   / PAGE_SIZE);
6084 6085 6086
			if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
				conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
		}
6087 6088 6089
	}
}

6090 6091 6092
/* This is called from the raid5d thread with mddev_lock held.
 * It makes config changes to the device.
 */
6093
static void raid5_finish_reshape(struct mddev *mddev)
6094
{
6095
	struct r5conf *conf = mddev->private;
6096 6097 6098

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

6099 6100 6101
		if (mddev->delta_disks > 0) {
			md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
			set_capacity(mddev->gendisk, mddev->array_sectors);
6102
			revalidate_disk(mddev->gendisk);
6103 6104
		} else {
			int d;
6105 6106 6107
			spin_lock_irq(&conf->device_lock);
			mddev->degraded = calc_degraded(conf);
			spin_unlock_irq(&conf->device_lock);
6108 6109
			for (d = conf->raid_disks ;
			     d < conf->raid_disks - mddev->delta_disks;
6110
			     d++) {
6111
				struct md_rdev *rdev = conf->disks[d].rdev;
6112 6113 6114 6115 6116
				if (rdev)
					clear_bit(In_sync, &rdev->flags);
				rdev = conf->disks[d].replacement;
				if (rdev)
					clear_bit(In_sync, &rdev->flags);
6117
			}
6118
		}
6119
		mddev->layout = conf->algorithm;
6120
		mddev->chunk_sectors = conf->chunk_sectors;
6121 6122
		mddev->reshape_position = MaxSector;
		mddev->delta_disks = 0;
6123
		mddev->reshape_backwards = 0;
6124 6125 6126
	}
}

6127
static void raid5_quiesce(struct mddev *mddev, int state)
6128
{
6129
	struct r5conf *conf = mddev->private;
6130 6131

	switch(state) {
6132 6133 6134 6135
	case 2: /* resume for a suspend */
		wake_up(&conf->wait_for_overlap);
		break;

6136 6137
	case 1: /* stop all writes */
		spin_lock_irq(&conf->device_lock);
6138 6139 6140 6141
		/* '2' tells resync/reshape to pause so that all
		 * active stripes can drain
		 */
		conf->quiesce = 2;
6142
		wait_event_lock_irq(conf->wait_for_stripe,
6143 6144
				    atomic_read(&conf->active_stripes) == 0 &&
				    atomic_read(&conf->active_aligned_reads) == 0,
6145
				    conf->device_lock);
6146
		conf->quiesce = 1;
6147
		spin_unlock_irq(&conf->device_lock);
6148 6149
		/* allow reshape to continue */
		wake_up(&conf->wait_for_overlap);
6150 6151 6152 6153 6154 6155
		break;

	case 0: /* re-enable writes */
		spin_lock_irq(&conf->device_lock);
		conf->quiesce = 0;
		wake_up(&conf->wait_for_stripe);
6156
		wake_up(&conf->wait_for_overlap);
6157 6158 6159 6160
		spin_unlock_irq(&conf->device_lock);
		break;
	}
}
6161

6162

6163
static void *raid45_takeover_raid0(struct mddev *mddev, int level)
6164
{
6165
	struct r0conf *raid0_conf = mddev->private;
6166
	sector_t sectors;
6167

D
Dan Williams 已提交
6168
	/* for raid0 takeover only one zone is supported */
6169
	if (raid0_conf->nr_strip_zones > 1) {
6170 6171
		printk(KERN_ERR "md/raid:%s: cannot takeover raid0 with more than one zone.\n",
		       mdname(mddev));
D
Dan Williams 已提交
6172 6173 6174
		return ERR_PTR(-EINVAL);
	}

6175 6176
	sectors = raid0_conf->strip_zone[0].zone_end;
	sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
6177
	mddev->dev_sectors = sectors;
D
Dan Williams 已提交
6178
	mddev->new_level = level;
6179 6180 6181 6182 6183 6184 6185 6186 6187 6188 6189
	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);
}


6190
static void *raid5_takeover_raid1(struct mddev *mddev)
6191 6192 6193 6194 6195 6196 6197 6198 6199 6200 6201 6202 6203 6204 6205 6206 6207 6208 6209 6210 6211
{
	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;
6212
	mddev->new_chunk_sectors = chunksect;
6213 6214 6215 6216

	return setup_conf(mddev);
}

6217
static void *raid5_takeover_raid6(struct mddev *mddev)
6218 6219 6220 6221 6222 6223 6224 6225 6226 6227 6228 6229 6230 6231 6232 6233 6234 6235 6236 6237 6238 6239 6240 6241 6242 6243 6244 6245 6246 6247 6248 6249
{
	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);
}

6250

6251
static int raid5_check_reshape(struct mddev *mddev)
6252
{
6253 6254 6255 6256
	/* 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.
6257
	 */
6258
	struct r5conf *conf = mddev->private;
6259
	int new_chunk = mddev->new_chunk_sectors;
6260

6261
	if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
6262 6263
		return -EINVAL;
	if (new_chunk > 0) {
6264
		if (!is_power_of_2(new_chunk))
6265
			return -EINVAL;
6266
		if (new_chunk < (PAGE_SIZE>>9))
6267
			return -EINVAL;
6268
		if (mddev->array_sectors & (new_chunk-1))
6269 6270 6271 6272 6273 6274
			/* not factor of array size */
			return -EINVAL;
	}

	/* They look valid */

6275
	if (mddev->raid_disks == 2) {
6276 6277 6278 6279
		/* can make the change immediately */
		if (mddev->new_layout >= 0) {
			conf->algorithm = mddev->new_layout;
			mddev->layout = mddev->new_layout;
6280 6281
		}
		if (new_chunk > 0) {
6282 6283
			conf->chunk_sectors = new_chunk ;
			mddev->chunk_sectors = new_chunk;
6284 6285 6286
		}
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		md_wakeup_thread(mddev->thread);
6287
	}
6288
	return check_reshape(mddev);
6289 6290
}

6291
static int raid6_check_reshape(struct mddev *mddev)
6292
{
6293
	int new_chunk = mddev->new_chunk_sectors;
6294

6295
	if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
6296
		return -EINVAL;
6297
	if (new_chunk > 0) {
6298
		if (!is_power_of_2(new_chunk))
6299
			return -EINVAL;
6300
		if (new_chunk < (PAGE_SIZE >> 9))
6301
			return -EINVAL;
6302
		if (mddev->array_sectors & (new_chunk-1))
6303 6304
			/* not factor of array size */
			return -EINVAL;
6305
	}
6306 6307

	/* They look valid */
6308
	return check_reshape(mddev);
6309 6310
}

6311
static void *raid5_takeover(struct mddev *mddev)
6312 6313
{
	/* raid5 can take over:
D
Dan Williams 已提交
6314
	 *  raid0 - if there is only one strip zone - make it a raid4 layout
6315 6316 6317 6318
	 *  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
6319 6320
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 5);
6321 6322
	if (mddev->level == 1)
		return raid5_takeover_raid1(mddev);
6323 6324 6325 6326 6327
	if (mddev->level == 4) {
		mddev->new_layout = ALGORITHM_PARITY_N;
		mddev->new_level = 5;
		return setup_conf(mddev);
	}
6328 6329
	if (mddev->level == 6)
		return raid5_takeover_raid6(mddev);
6330 6331 6332 6333

	return ERR_PTR(-EINVAL);
}

6334
static void *raid4_takeover(struct mddev *mddev)
6335
{
D
Dan Williams 已提交
6336 6337 6338
	/* raid4 can take over:
	 *  raid0 - if there is only one strip zone
	 *  raid5 - if layout is right
6339
	 */
D
Dan Williams 已提交
6340 6341
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 4);
6342 6343 6344 6345 6346 6347 6348 6349
	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);
}
6350

6351
static struct md_personality raid5_personality;
6352

6353
static void *raid6_takeover(struct mddev *mddev)
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 6389 6390 6391 6392 6393 6394 6395 6396 6397 6398 6399
{
	/* 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);
}


6400
static struct md_personality raid6_personality =
6401 6402 6403 6404 6405 6406 6407 6408 6409 6410 6411 6412 6413 6414
{
	.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,
6415
	.size		= raid5_size,
6416
	.check_reshape	= raid6_check_reshape,
6417
	.start_reshape  = raid5_start_reshape,
6418
	.finish_reshape = raid5_finish_reshape,
6419
	.quiesce	= raid5_quiesce,
6420
	.takeover	= raid6_takeover,
6421
};
6422
static struct md_personality raid5_personality =
L
Linus Torvalds 已提交
6423 6424
{
	.name		= "raid5",
6425
	.level		= 5,
L
Linus Torvalds 已提交
6426 6427 6428 6429 6430 6431 6432 6433 6434 6435 6436
	.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,
6437
	.size		= raid5_size,
6438 6439
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
6440
	.finish_reshape = raid5_finish_reshape,
6441
	.quiesce	= raid5_quiesce,
6442
	.takeover	= raid5_takeover,
L
Linus Torvalds 已提交
6443 6444
};

6445
static struct md_personality raid4_personality =
L
Linus Torvalds 已提交
6446
{
6447 6448 6449 6450 6451 6452 6453 6454 6455 6456 6457 6458 6459
	.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,
6460
	.size		= raid5_size,
6461 6462
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
6463
	.finish_reshape = raid5_finish_reshape,
6464
	.quiesce	= raid5_quiesce,
6465
	.takeover	= raid4_takeover,
6466 6467 6468 6469
};

static int __init raid5_init(void)
{
6470
	register_md_personality(&raid6_personality);
6471 6472 6473
	register_md_personality(&raid5_personality);
	register_md_personality(&raid4_personality);
	return 0;
L
Linus Torvalds 已提交
6474 6475
}

6476
static void raid5_exit(void)
L
Linus Torvalds 已提交
6477
{
6478
	unregister_md_personality(&raid6_personality);
6479 6480
	unregister_md_personality(&raid5_personality);
	unregister_md_personality(&raid4_personality);
L
Linus Torvalds 已提交
6481 6482 6483 6484 6485
}

module_init(raid5_init);
module_exit(raid5_exit);
MODULE_LICENSE("GPL");
6486
MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
L
Linus Torvalds 已提交
6487
MODULE_ALIAS("md-personality-4"); /* RAID5 */
6488 6489
MODULE_ALIAS("md-raid5");
MODULE_ALIAS("md-raid4");
6490 6491
MODULE_ALIAS("md-level-5");
MODULE_ALIAS("md-level-4");
6492 6493 6494 6495 6496 6497 6498
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");