raid5.c 174.3 KB
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/*
 * raid5.c : Multiple Devices driver for Linux
 *	   Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
 *	   Copyright (C) 1999, 2000 Ingo Molnar
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 *	   Copyright (C) 2002, 2003 H. Peter Anvin
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 *
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 * RAID-4/5/6 management functions.
 * Thanks to Penguin Computing for making the RAID-6 development possible
 * by donating a test server!
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 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * You should have received a copy of the GNU General Public License
 * (for example /usr/src/linux/COPYING); if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

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/*
 * BITMAP UNPLUGGING:
 *
 * The sequencing for updating the bitmap reliably is a little
 * subtle (and I got it wrong the first time) so it deserves some
 * explanation.
 *
 * We group bitmap updates into batches.  Each batch has a number.
 * We may write out several batches at once, but that isn't very important.
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 * conf->seq_write is the number of the last batch successfully written.
 * conf->seq_flush is the number of the last batch that was closed to
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 *    new additions.
 * When we discover that we will need to write to any block in a stripe
 * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
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 * the number of the batch it will be in. This is seq_flush+1.
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 * When we are ready to do a write, if that batch hasn't been written yet,
 *   we plug the array and queue the stripe for later.
 * When an unplug happens, we increment bm_flush, thus closing the current
 *   batch.
 * When we notice that bm_flush > bm_write, we write out all pending updates
 * to the bitmap, and advance bm_write to where bm_flush was.
 * This may occasionally write a bit out twice, but is sure never to
 * miss any bits.
 */
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#include <linux/blkdev.h>
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#include <linux/kthread.h>
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#include <linux/raid/pq.h>
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#include <linux/async_tx.h>
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#include <linux/module.h>
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#include <linux/async.h>
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#include <linux/seq_file.h>
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#include <linux/cpu.h>
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#include <linux/slab.h>
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#include <linux/ratelimit.h>
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#include "md.h"
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#include "raid5.h"
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#include "raid0.h"
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#include "bitmap.h"
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/*
 * Stripe cache
 */

#define NR_STRIPES		256
#define STRIPE_SIZE		PAGE_SIZE
#define STRIPE_SHIFT		(PAGE_SHIFT - 9)
#define STRIPE_SECTORS		(STRIPE_SIZE>>9)
#define	IO_THRESHOLD		1
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#define BYPASS_THRESHOLD	1
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#define NR_HASH			(PAGE_SIZE / sizeof(struct hlist_head))
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#define HASH_MASK		(NR_HASH - 1)

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static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
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{
	int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
	return &conf->stripe_hashtbl[hash];
}
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/* bio's attached to a stripe+device for I/O are linked together in bi_sector
 * order without overlap.  There may be several bio's per stripe+device, and
 * a bio could span several devices.
 * When walking this list for a particular stripe+device, we must never proceed
 * beyond a bio that extends past this device, as the next bio might no longer
 * be valid.
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 * This function is used to determine the 'next' bio in the list, given the sector
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 * of the current stripe+device
 */
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static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector)
{
	int sectors = bio->bi_size >> 9;
	if (bio->bi_sector + sectors < sector + STRIPE_SECTORS)
		return bio->bi_next;
	else
		return NULL;
}
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/*
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 * We maintain a biased count of active stripes in the bottom 16 bits of
 * bi_phys_segments, and a count of processed stripes in the upper 16 bits
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 */
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static inline int raid5_bi_processed_stripes(struct bio *bio)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	return (atomic_read(segments) >> 16) & 0xffff;
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}

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

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

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

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static inline void raid5_set_bi_stripes(struct bio *bio, unsigned int cnt)
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{
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	atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
	atomic_set(segments, cnt);
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}

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

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

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

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

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

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static void release_stripe(struct stripe_head *sh)
{
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	struct r5conf *conf = sh->raid_conf;
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	unsigned long flags;
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	local_irq_save(flags);
	if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
		do_release_stripe(conf, sh);
		spin_unlock(&conf->device_lock);
	}
	local_irq_restore(flags);
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}

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

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


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

	if (list_empty(&conf->inactive_list))
		goto out;
	first = conf->inactive_list.next;
	sh = list_entry(first, struct stripe_head, lru);
	list_del_init(first);
	remove_hash(sh);
	atomic_inc(&conf->active_stripes);
out:
	return sh;
}

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

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

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

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

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

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

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

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

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

	rcu_read_lock();
	degraded = 0;
	for (i = 0; i < conf->previous_raid_disks; i++) {
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		struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
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		if (rdev && test_bit(Faulty, &rdev->flags))
			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, /* nothing */);
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		sh = __find_stripe(conf, sector, conf->generation - previous);
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		if (!sh) {
			if (!conf->inactive_blocked)
				sh = get_free_stripe(conf);
			if (noblock && sh == NULL)
				break;
			if (!sh) {
				conf->inactive_blocked = 1;
				wait_event_lock_irq(conf->wait_for_stripe,
						    !list_empty(&conf->inactive_list) &&
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						    (atomic_read(&conf->active_stripes)
						     < (conf->max_nr_stripes *3/4)
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						     || !conf->inactive_blocked),
						    conf->device_lock,
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						    );
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				conf->inactive_blocked = 0;
			} else
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				init_stripe(sh, sector, previous);
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		} else {
			if (atomic_read(&sh->count)) {
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				BUG_ON(!list_empty(&sh->lru)
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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;
		} else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
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			rw = READ;
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		else if (test_and_clear_bit(R5_WantReplace,
					    &sh->dev[i].flags)) {
			rw = WRITE;
			replace_only = 1;
		} else
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			continue;
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Shaohua Li 已提交
562 563
		if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
			rw |= REQ_SYNC;
564 565

		bi = &sh->dev[i].req;
566
		rbi = &sh->dev[i].rreq; /* For writing to replacement */
567 568

		bi->bi_rw = rw;
569 570
		rbi->bi_rw = rw;
		if (rw & WRITE) {
571
			bi->bi_end_io = raid5_end_write_request;
572 573
			rbi->bi_end_io = raid5_end_write_request;
		} else
574 575 576
			bi->bi_end_io = raid5_end_read_request;

		rcu_read_lock();
577
		rrdev = rcu_dereference(conf->disks[i].replacement);
578 579 580 581 582 583
		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;
		}
584 585 586
		if (rw & WRITE) {
			if (replace_only)
				rdev = NULL;
587 588 589
			if (rdev == rrdev)
				/* We raced and saw duplicates */
				rrdev = NULL;
590
		} else {
591
			if (test_bit(R5_ReadRepl, &sh->dev[i].flags) && rrdev)
592 593 594
				rdev = rrdev;
			rrdev = NULL;
		}
595

596 597 598 599
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
		if (rdev)
			atomic_inc(&rdev->nr_pending);
600 601 602 603
		if (rrdev && test_bit(Faulty, &rrdev->flags))
			rrdev = NULL;
		if (rrdev)
			atomic_inc(&rrdev->nr_pending);
604 605
		rcu_read_unlock();

606
		/* We have already checked bad blocks for reads.  Now
607 608
		 * need to check for writes.  We never accept write errors
		 * on the replacement, so we don't to check rrdev.
609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628
		 */
		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);
				}
629 630 631 632 633 634
				/*
				 * Because md_wait_for_blocked_rdev
				 * will dec nr_pending, we must
				 * increment it first.
				 */
				atomic_inc(&rdev->nr_pending);
635 636 637 638 639 640 641 642
				md_wait_for_blocked_rdev(rdev, conf->mddev);
			} else {
				/* Acknowledged bad block - skip the write */
				rdev_dec_pending(rdev, conf->mddev);
				rdev = NULL;
			}
		}

643
		if (rdev) {
644 645
			if (s->syncing || s->expanding || s->expanded
			    || s->replacing)
646 647
				md_sync_acct(rdev->bdev, STRIPE_SECTORS);

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			set_bit(STRIPE_IO_STARTED, &sh->state);

650 651
			bi->bi_bdev = rdev->bdev;
			pr_debug("%s: for %llu schedule op %ld on disc %d\n",
652
				__func__, (unsigned long long)sh->sector,
653 654
				bi->bi_rw, i);
			atomic_inc(&sh->count);
655 656 657 658 659 660
			if (use_new_offset(conf, sh))
				bi->bi_sector = (sh->sector
						 + rdev->new_data_offset);
			else
				bi->bi_sector = (sh->sector
						 + rdev->data_offset);
661 662 663
			if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
				bi->bi_rw |= REQ_FLUSH;

664 665 666 667 668 669
			bi->bi_flags = 1 << BIO_UPTODATE;
			bi->bi_idx = 0;
			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
			bi->bi_io_vec[0].bv_offset = 0;
			bi->bi_size = STRIPE_SIZE;
			bi->bi_next = NULL;
670 671
			if (rrdev)
				set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
672
			generic_make_request(bi);
673 674
		}
		if (rrdev) {
675 676
			if (s->syncing || s->expanding || s->expanded
			    || s->replacing)
677 678 679 680 681 682 683 684 685 686
				md_sync_acct(rrdev->bdev, STRIPE_SECTORS);

			set_bit(STRIPE_IO_STARTED, &sh->state);

			rbi->bi_bdev = rrdev->bdev;
			pr_debug("%s: for %llu schedule op %ld on "
				 "replacement disc %d\n",
				__func__, (unsigned long long)sh->sector,
				rbi->bi_rw, i);
			atomic_inc(&sh->count);
687 688 689 690 691 692
			if (use_new_offset(conf, sh))
				rbi->bi_sector = (sh->sector
						  + rrdev->new_data_offset);
			else
				rbi->bi_sector = (sh->sector
						  + rrdev->data_offset);
693 694 695 696 697 698 699 700 701
			rbi->bi_flags = 1 << BIO_UPTODATE;
			rbi->bi_idx = 0;
			rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
			rbi->bi_io_vec[0].bv_offset = 0;
			rbi->bi_size = STRIPE_SIZE;
			rbi->bi_next = NULL;
			generic_make_request(rbi);
		}
		if (!rdev && !rrdev) {
702
			if (rw & WRITE)
703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719
				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;
720
	struct async_submit_ctl submit;
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	enum async_tx_flags flags = 0;
722 723 724 725 726

	if (bio->bi_sector >= sector)
		page_offset = (signed)(bio->bi_sector - sector) * 512;
	else
		page_offset = (signed)(sector - bio->bi_sector) * -512;
727

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728 729 730 731
	if (frombio)
		flags |= ASYNC_TX_FENCE;
	init_async_submit(&submit, flags, tx, NULL, NULL, NULL);

732
	bio_for_each_segment(bvl, bio, i) {
733
		int len = bvl->bv_len;
734 735 736 737 738 739 740 741 742 743 744 745 746 747 748
		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) {
749 750
			b_offset += bvl->bv_offset;
			bio_page = bvl->bv_page;
751 752
			if (frombio)
				tx = async_memcpy(page, bio_page, page_offset,
753
						  b_offset, clen, &submit);
754 755
			else
				tx = async_memcpy(bio_page, page, b_offset,
756
						  page_offset, clen, &submit);
757
		}
758 759 760
		/* chain the operations */
		submit.depend_tx = tx;

761 762 763 764 765 766 767 768 769 770 771 772
		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;
773
	int i;
774

775
	pr_debug("%s: stripe %llu\n", __func__,
776 777 778 779 780 781 782
		(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 */
783 784
		/* and check if we need to reply to a read request,
		 * new R5_Wantfill requests are held off until
785
		 * !STRIPE_BIOFILL_RUN
786 787
		 */
		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
788 789 790 791 792 793 794 795
			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);
796
				if (!raid5_dec_bi_active_stripes(rbi)) {
797 798 799 800 801 802 803
					rbi->bi_next = return_bi;
					return_bi = rbi;
				}
				rbi = rbi2;
			}
		}
	}
804
	clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
805 806 807

	return_io(return_bi);

808
	set_bit(STRIPE_HANDLE, &sh->state);
809 810 811 812 813 814
	release_stripe(sh);
}

static void ops_run_biofill(struct stripe_head *sh)
{
	struct dma_async_tx_descriptor *tx = NULL;
815
	struct async_submit_ctl submit;
816 817
	int i;

818
	pr_debug("%s: stripe %llu\n", __func__,
819 820 821 822 823 824
		(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);
826 827
			dev->read = rbi = dev->toread;
			dev->toread = NULL;
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Shaohua Li 已提交
828
			spin_unlock_irq(&sh->stripe_lock);
829 830 831 832 833 834 835 836 837 838
			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);
839 840
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
	async_trigger_callback(&submit);
841 842
}

843
static void mark_target_uptodate(struct stripe_head *sh, int target)
844
{
845
	struct r5dev *tgt;
846

847 848
	if (target < 0)
		return;
849

850
	tgt = &sh->dev[target];
851 852 853
	set_bit(R5_UPTODATE, &tgt->flags);
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
	clear_bit(R5_Wantcompute, &tgt->flags);
854 855
}

856
static void ops_complete_compute(void *stripe_head_ref)
857 858 859
{
	struct stripe_head *sh = stripe_head_ref;

860
	pr_debug("%s: stripe %llu\n", __func__,
861 862
		(unsigned long long)sh->sector);

863
	/* mark the computed target(s) as uptodate */
864
	mark_target_uptodate(sh, sh->ops.target);
865
	mark_target_uptodate(sh, sh->ops.target2);
866

867 868 869
	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
	if (sh->check_state == check_state_compute_run)
		sh->check_state = check_state_compute_result;
870 871 872 873
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

874 875 876 877 878 879 880 881 882
/* 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)
883 884
{
	int disks = sh->disks;
885
	struct page **xor_srcs = percpu->scribble;
886 887 888 889 890
	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;
891
	struct async_submit_ctl submit;
892 893 894
	int i;

	pr_debug("%s: stripe %llu block: %d\n",
895
		__func__, (unsigned long long)sh->sector, target);
896 897 898 899 900 901 902 903
	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));

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

	atomic_inc(&sh->count);

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	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
905
			  ops_complete_compute, sh, to_addr_conv(sh, percpu));
906
	if (unlikely(count == 1))
907
		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
908
	else
909
		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
910 911 912 913

	return tx;
}

914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931
/* 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++)
932
		srcs[i] = NULL;
933 934 935 936 937 938 939 940 941 942

	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);

943
	return syndrome_disks;
944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963
}

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;
964
	else
965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980
		/* 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,
983 984 985 986 987 988 989 990 991 992 993
				  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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Dan Williams 已提交
994 995
		init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
				  NULL, ops_complete_compute, sh,
996 997 998
				  to_addr_conv(sh, percpu));
		tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
	}
999 1000 1001 1002

	return tx;
}

1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023
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));

1024
	/* we need to open-code set_syndrome_sources to handle the
1025 1026 1027
	 * slot number conversion for 'faila' and 'failb'
	 */
	for (i = 0; i < disks ; i++)
1028
		blocks[i] = NULL;
1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054
	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
1055 1056 1057
			init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
					  ops_complete_compute, sh,
					  to_addr_conv(sh, percpu));
1058
			return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077
						  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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1078 1079 1080 1081
			init_async_submit(&submit,
					  ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
					  NULL, NULL, NULL,
					  to_addr_conv(sh, percpu));
1082 1083 1084 1085
			tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
				       &submit);

			count = set_syndrome_sources(blocks, sh);
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1086 1087 1088
			init_async_submit(&submit, ASYNC_TX_FENCE, tx,
					  ops_complete_compute, sh,
					  to_addr_conv(sh, percpu));
1089 1090 1091 1092
			return async_gen_syndrome(blocks, 0, count+2,
						  STRIPE_SIZE, &submit);
		}
	} else {
1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106
		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);
		}
1107 1108 1109 1110
	}
}


1111 1112 1113 1114
static void ops_complete_prexor(void *stripe_head_ref)
{
	struct stripe_head *sh = stripe_head_ref;

1115
	pr_debug("%s: stripe %llu\n", __func__,
1116 1117 1118 1119
		(unsigned long long)sh->sector);
}

static struct dma_async_tx_descriptor *
1120 1121
ops_run_prexor(struct stripe_head *sh, struct raid5_percpu *percpu,
	       struct dma_async_tx_descriptor *tx)
1122 1123
{
	int disks = sh->disks;
1124
	struct page **xor_srcs = percpu->scribble;
1125
	int count = 0, pd_idx = sh->pd_idx, i;
1126
	struct async_submit_ctl submit;
1127 1128 1129 1130

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

1131
	pr_debug("%s: stripe %llu\n", __func__,
1132 1133 1134 1135 1136
		(unsigned long long)sh->sector);

	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
		/* Only process blocks that are known to be uptodate */
1137
		if (test_bit(R5_Wantdrain, &dev->flags))
1138 1139 1140
			xor_srcs[count++] = dev->page;
	}

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Dan Williams 已提交
1141
	init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1142
			  ops_complete_prexor, sh, to_addr_conv(sh, percpu));
1143
	tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1144 1145 1146 1147 1148

	return tx;
}

static struct dma_async_tx_descriptor *
1149
ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1150 1151
{
	int disks = sh->disks;
1152
	int i;
1153

1154
	pr_debug("%s: stripe %llu\n", __func__,
1155 1156 1157 1158 1159 1160
		(unsigned long long)sh->sector);

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

1161
		if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
1162 1163
			struct bio *wbi;

S
Shaohua Li 已提交
1164
			spin_lock_irq(&sh->stripe_lock);
1165 1166 1167 1168
			chosen = dev->towrite;
			dev->towrite = NULL;
			BUG_ON(dev->written);
			wbi = dev->written = chosen;
S
Shaohua Li 已提交
1169
			spin_unlock_irq(&sh->stripe_lock);
1170 1171 1172

			while (wbi && wbi->bi_sector <
				dev->sector + STRIPE_SECTORS) {
T
Tejun Heo 已提交
1173 1174
				if (wbi->bi_rw & REQ_FUA)
					set_bit(R5_WantFUA, &dev->flags);
S
Shaohua Li 已提交
1175 1176
				if (wbi->bi_rw & REQ_SYNC)
					set_bit(R5_SyncIO, &dev->flags);
1177 1178 1179 1180 1181 1182 1183 1184 1185 1186
				tx = async_copy_data(1, wbi, dev->page,
					dev->sector, tx);
				wbi = r5_next_bio(wbi, dev->sector);
			}
		}
	}

	return tx;
}

1187
static void ops_complete_reconstruct(void *stripe_head_ref)
1188 1189
{
	struct stripe_head *sh = stripe_head_ref;
1190 1191 1192 1193
	int disks = sh->disks;
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	int i;
S
Shaohua Li 已提交
1194
	bool fua = false, sync = false;
1195

1196
	pr_debug("%s: stripe %llu\n", __func__,
1197 1198
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
1199
	for (i = disks; i--; ) {
T
Tejun Heo 已提交
1200
		fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
S
Shaohua Li 已提交
1201 1202
		sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
	}
T
Tejun Heo 已提交
1203

1204 1205
	for (i = disks; i--; ) {
		struct r5dev *dev = &sh->dev[i];
1206

T
Tejun Heo 已提交
1207
		if (dev->written || i == pd_idx || i == qd_idx) {
1208
			set_bit(R5_UPTODATE, &dev->flags);
T
Tejun Heo 已提交
1209 1210
			if (fua)
				set_bit(R5_WantFUA, &dev->flags);
S
Shaohua Li 已提交
1211 1212
			if (sync)
				set_bit(R5_SyncIO, &dev->flags);
T
Tejun Heo 已提交
1213
		}
1214 1215
	}

1216 1217 1218 1219 1220 1221 1222 1223
	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;
	}
1224 1225 1226 1227 1228 1229

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

static void
1230 1231
ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
		     struct dma_async_tx_descriptor *tx)
1232 1233
{
	int disks = sh->disks;
1234
	struct page **xor_srcs = percpu->scribble;
1235
	struct async_submit_ctl submit;
1236 1237
	int count = 0, pd_idx = sh->pd_idx, i;
	struct page *xor_dest;
1238
	int prexor = 0;
1239 1240
	unsigned long flags;

1241
	pr_debug("%s: stripe %llu\n", __func__,
1242 1243 1244 1245 1246
		(unsigned long long)sh->sector);

	/* check if prexor is active which means only process blocks
	 * that are part of a read-modify-write (written)
	 */
1247 1248
	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
		prexor = 1;
1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268
		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
	 */
1269
	flags = ASYNC_TX_ACK |
1270 1271 1272 1273
		(prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);

	atomic_inc(&sh->count);

1274
	init_async_submit(&submit, flags, tx, ops_complete_reconstruct, sh,
1275
			  to_addr_conv(sh, percpu));
1276 1277 1278 1279
	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);
1280 1281
}

1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298
static void
ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
		     struct dma_async_tx_descriptor *tx)
{
	struct async_submit_ctl submit;
	struct page **blocks = percpu->scribble;
	int count;

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

	count = set_syndrome_sources(blocks, sh);

	atomic_inc(&sh->count);

	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_reconstruct,
			  sh, to_addr_conv(sh, percpu));
	async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1299 1300 1301 1302 1303 1304
}

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

1305
	pr_debug("%s: stripe %llu\n", __func__,
1306 1307
		(unsigned long long)sh->sector);

1308
	sh->check_state = check_state_check_result;
1309 1310 1311 1312
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1313
static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1314 1315
{
	int disks = sh->disks;
1316 1317 1318
	int pd_idx = sh->pd_idx;
	int qd_idx = sh->qd_idx;
	struct page *xor_dest;
1319
	struct page **xor_srcs = percpu->scribble;
1320
	struct dma_async_tx_descriptor *tx;
1321
	struct async_submit_ctl submit;
1322 1323
	int count;
	int i;
1324

1325
	pr_debug("%s: stripe %llu\n", __func__,
1326 1327
		(unsigned long long)sh->sector);

1328 1329 1330
	count = 0;
	xor_dest = sh->dev[pd_idx].page;
	xor_srcs[count++] = xor_dest;
1331
	for (i = disks; i--; ) {
1332 1333 1334
		if (i == pd_idx || i == qd_idx)
			continue;
		xor_srcs[count++] = sh->dev[i].page;
1335 1336
	}

1337 1338
	init_async_submit(&submit, 0, NULL, NULL, NULL,
			  to_addr_conv(sh, percpu));
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Dan Williams 已提交
1339
	tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
1340
			   &sh->ops.zero_sum_result, &submit);
1341 1342

	atomic_inc(&sh->count);
1343 1344
	init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
	tx = async_trigger_callback(&submit);
1345 1346
}

1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358
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;
1359 1360

	atomic_inc(&sh->count);
1361 1362 1363 1364
	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);
1365 1366
}

1367
static void __raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
1368 1369 1370
{
	int overlap_clear = 0, i, disks = sh->disks;
	struct dma_async_tx_descriptor *tx = NULL;
1371
	struct r5conf *conf = sh->raid_conf;
1372
	int level = conf->level;
1373 1374
	struct raid5_percpu *percpu;
	unsigned long cpu;
1375

1376 1377
	cpu = get_cpu();
	percpu = per_cpu_ptr(conf->percpu, cpu);
1378
	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
1379 1380 1381 1382
		ops_run_biofill(sh);
		overlap_clear++;
	}

1383
	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
1384 1385 1386 1387 1388 1389 1390 1391 1392 1393
		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))
1394 1395
			async_tx_ack(tx);
	}
1396

1397
	if (test_bit(STRIPE_OP_PREXOR, &ops_request))
1398
		tx = ops_run_prexor(sh, percpu, tx);
1399

1400
	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
1401
		tx = ops_run_biodrain(sh, tx);
1402 1403 1404
		overlap_clear++;
	}

1405 1406 1407 1408 1409 1410
	if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
		if (level < 6)
			ops_run_reconstruct5(sh, percpu, tx);
		else
			ops_run_reconstruct6(sh, percpu, tx);
	}
1411

1412 1413 1414 1415 1416 1417 1418 1419 1420 1421
	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();
	}
1422 1423 1424 1425 1426 1427 1428

	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);
		}
1429
	put_cpu();
1430 1431
}

1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461
#ifdef CONFIG_MULTICORE_RAID456
static void async_run_ops(void *param, async_cookie_t cookie)
{
	struct stripe_head *sh = param;
	unsigned long ops_request = sh->ops.request;

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

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

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

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

1462
static int grow_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1463 1464
{
	struct stripe_head *sh;
N
Namhyung Kim 已提交
1465
	sh = kmem_cache_zalloc(conf->slab_cache, GFP_KERNEL);
1466 1467
	if (!sh)
		return 0;
N
Namhyung Kim 已提交
1468

1469
	sh->raid_conf = conf;
1470 1471 1472
	#ifdef CONFIG_MULTICORE_RAID456
	init_waitqueue_head(&sh->ops.wait_for_ops);
	#endif
1473

S
Shaohua Li 已提交
1474 1475
	spin_lock_init(&sh->stripe_lock);

1476 1477
	if (grow_buffers(sh)) {
		shrink_buffers(sh);
1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488
		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;
}

1489
static int grow_stripes(struct r5conf *conf, int num)
1490
{
1491
	struct kmem_cache *sc;
1492
	int devs = max(conf->raid_disks, conf->previous_raid_disks);
L
Linus Torvalds 已提交
1493

1494 1495 1496 1497 1498 1499 1500 1501
	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]);

1502 1503
	conf->active_name = 0;
	sc = kmem_cache_create(conf->cache_name[conf->active_name],
L
Linus Torvalds 已提交
1504
			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
1505
			       0, 0, NULL);
L
Linus Torvalds 已提交
1506 1507 1508
	if (!sc)
		return 1;
	conf->slab_cache = sc;
1509
	conf->pool_size = devs;
1510
	while (num--)
1511
		if (!grow_one_stripe(conf))
L
Linus Torvalds 已提交
1512 1513 1514
			return 1;
	return 0;
}
1515

1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537
/**
 * 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;
}

1538
static int resize_stripes(struct r5conf *conf, int newsize)
1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565
{
	/* Make all the stripes able to hold 'newsize' devices.
	 * New slots in each stripe get 'page' set to a new page.
	 *
	 * This happens in stages:
	 * 1/ create a new kmem_cache and allocate the required number of
	 *    stripe_heads.
	 * 2/ gather all the old stripe_heads and tranfer the pages across
	 *    to the new stripe_heads.  This will have the side effect of
	 *    freezing the array as once all stripe_heads have been collected,
	 *    no IO will be possible.  Old stripe heads are freed once their
	 *    pages have been transferred over, and the old kmem_cache is
	 *    freed when all stripes are done.
	 * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
	 *    we simple return a failre status - no need to clean anything up.
	 * 4/ allocate new pages for the new slots in the new stripe_heads.
	 *    If this fails, we don't bother trying the shrink the
	 *    stripe_heads down again, we just leave them as they are.
	 *    As each stripe_head is processed the new one is released into
	 *    active service.
	 *
	 * Once step2 is started, we cannot afford to wait for a write,
	 * so we use GFP_NOIO allocations.
	 */
	struct stripe_head *osh, *nsh;
	LIST_HEAD(newstripes);
	struct disk_info *ndisks;
1566
	unsigned long cpu;
1567
	int err;
1568
	struct kmem_cache *sc;
1569 1570 1571 1572 1573
	int i;

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

1574 1575 1576
	err = md_allow_write(conf->mddev);
	if (err)
		return err;
1577

1578 1579 1580
	/* Step 1 */
	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
1581
			       0, 0, NULL);
1582 1583 1584 1585
	if (!sc)
		return -ENOMEM;

	for (i = conf->max_nr_stripes; i; i--) {
N
Namhyung Kim 已提交
1586
		nsh = kmem_cache_zalloc(sc, GFP_KERNEL);
1587 1588 1589 1590
		if (!nsh)
			break;

		nsh->raid_conf = conf;
1591 1592 1593
		#ifdef CONFIG_MULTICORE_RAID456
		init_waitqueue_head(&nsh->ops.wait_for_ops);
		#endif
1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615

		list_add(&nsh->lru, &newstripes);
	}
	if (i) {
		/* didn't get enough, give up */
		while (!list_empty(&newstripes)) {
			nsh = list_entry(newstripes.next, struct stripe_head, lru);
			list_del(&nsh->lru);
			kmem_cache_free(sc, nsh);
		}
		kmem_cache_destroy(sc);
		return -ENOMEM;
	}
	/* Step 2 - Must use GFP_NOIO now.
	 * OK, we have enough stripes, start collecting inactive
	 * stripes and copying them over
	 */
	list_for_each_entry(nsh, &newstripes, lru) {
		spin_lock_irq(&conf->device_lock);
		wait_event_lock_irq(conf->wait_for_stripe,
				    !list_empty(&conf->inactive_list),
				    conf->device_lock,
N
NeilBrown 已提交
1616
				    );
1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630
		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
1631
	 * conf->disks and the scribble region
1632 1633 1634 1635 1636 1637 1638 1639 1640 1641
	 */
	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;

1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660
	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();

1661 1662 1663 1664
	/* 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);
1665

1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681
		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
1682

1683
static int drop_one_stripe(struct r5conf *conf)
L
Linus Torvalds 已提交
1684 1685 1686
{
	struct stripe_head *sh;

1687 1688 1689 1690 1691
	spin_lock_irq(&conf->device_lock);
	sh = get_free_stripe(conf);
	spin_unlock_irq(&conf->device_lock);
	if (!sh)
		return 0;
1692
	BUG_ON(atomic_read(&sh->count));
1693
	shrink_buffers(sh);
1694 1695 1696 1697 1698
	kmem_cache_free(conf->slab_cache, sh);
	atomic_dec(&conf->active_stripes);
	return 1;
}

1699
static void shrink_stripes(struct r5conf *conf)
1700 1701 1702 1703
{
	while (drop_one_stripe(conf))
		;

N
NeilBrown 已提交
1704 1705
	if (conf->slab_cache)
		kmem_cache_destroy(conf->slab_cache);
L
Linus Torvalds 已提交
1706 1707 1708
	conf->slab_cache = NULL;
}

1709
static void raid5_end_read_request(struct bio * bi, int error)
L
Linus Torvalds 已提交
1710
{
1711
	struct stripe_head *sh = bi->bi_private;
1712
	struct r5conf *conf = sh->raid_conf;
1713
	int disks = sh->disks, i;
L
Linus Torvalds 已提交
1714
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1715
	char b[BDEVNAME_SIZE];
1716
	struct md_rdev *rdev = NULL;
1717
	sector_t s;
L
Linus Torvalds 已提交
1718 1719 1720 1721 1722

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

1723 1724
	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
1725 1726 1727
		uptodate);
	if (i == disks) {
		BUG();
1728
		return;
L
Linus Torvalds 已提交
1729
	}
1730
	if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
1731 1732 1733 1734 1735
		/* 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.
		 */
1736
		rdev = conf->disks[i].replacement;
1737
	if (!rdev)
1738
		rdev = conf->disks[i].rdev;
L
Linus Torvalds 已提交
1739

1740 1741 1742 1743
	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
1744 1745
	if (uptodate) {
		set_bit(R5_UPTODATE, &sh->dev[i].flags);
1746
		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
1747 1748 1749 1750
			/* Note that this cannot happen on a
			 * replacement device.  We just fail those on
			 * any error
			 */
1751 1752 1753 1754 1755
			printk_ratelimited(
				KERN_INFO
				"md/raid:%s: read error corrected"
				" (%lu sectors at %llu on %s)\n",
				mdname(conf->mddev), STRIPE_SECTORS,
1756
				(unsigned long long)s,
1757
				bdevname(rdev->bdev, b));
1758
			atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
1759 1760
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1761 1762 1763
		} else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
			clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);

1764 1765
		if (atomic_read(&rdev->read_errors))
			atomic_set(&rdev->read_errors, 0);
L
Linus Torvalds 已提交
1766
	} else {
1767
		const char *bdn = bdevname(rdev->bdev, b);
1768
		int retry = 0;
1769
		int set_bad = 0;
1770

L
Linus Torvalds 已提交
1771
		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
1772
		atomic_inc(&rdev->read_errors);
1773 1774 1775 1776 1777 1778
		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),
1779
				(unsigned long long)s,
1780
				bdn);
1781 1782
		else if (conf->mddev->degraded >= conf->max_degraded) {
			set_bad = 1;
1783 1784 1785 1786 1787
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error not correctable "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1788
				(unsigned long long)s,
1789
				bdn);
1790
		} else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
1791
			/* Oh, no!!! */
1792
			set_bad = 1;
1793 1794 1795 1796 1797
			printk_ratelimited(
				KERN_WARNING
				"md/raid:%s: read error NOT corrected!! "
				"(sector %llu on %s).\n",
				mdname(conf->mddev),
1798
				(unsigned long long)s,
1799
				bdn);
1800
		} else if (atomic_read(&rdev->read_errors)
1801
			 > conf->max_nr_stripes)
N
NeilBrown 已提交
1802
			printk(KERN_WARNING
1803
			       "md/raid:%s: Too many read errors, failing device %s.\n",
1804
			       mdname(conf->mddev), bdn);
1805 1806 1807
		else
			retry = 1;
		if (retry)
1808 1809 1810 1811 1812
			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);
1813
		else {
1814 1815
			clear_bit(R5_ReadError, &sh->dev[i].flags);
			clear_bit(R5_ReWrite, &sh->dev[i].flags);
1816 1817 1818 1819 1820
			if (!(set_bad
			      && test_bit(In_sync, &rdev->flags)
			      && rdev_set_badblocks(
				      rdev, sh->sector, STRIPE_SECTORS, 0)))
				md_error(conf->mddev, rdev);
1821
		}
L
Linus Torvalds 已提交
1822
	}
1823
	rdev_dec_pending(rdev, conf->mddev);
L
Linus Torvalds 已提交
1824 1825 1826 1827 1828
	clear_bit(R5_LOCKED, &sh->dev[i].flags);
	set_bit(STRIPE_HANDLE, &sh->state);
	release_stripe(sh);
}

1829
static void raid5_end_write_request(struct bio *bi, int error)
L
Linus Torvalds 已提交
1830
{
1831
	struct stripe_head *sh = bi->bi_private;
1832
	struct r5conf *conf = sh->raid_conf;
1833
	int disks = sh->disks, i;
1834
	struct md_rdev *uninitialized_var(rdev);
L
Linus Torvalds 已提交
1835
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
1836 1837
	sector_t first_bad;
	int bad_sectors;
1838
	int replacement = 0;
L
Linus Torvalds 已提交
1839

1840 1841 1842
	for (i = 0 ; i < disks; i++) {
		if (bi == &sh->dev[i].req) {
			rdev = conf->disks[i].rdev;
L
Linus Torvalds 已提交
1843
			break;
1844 1845 1846
		}
		if (bi == &sh->dev[i].rreq) {
			rdev = conf->disks[i].replacement;
1847 1848 1849 1850 1851 1852 1853 1854
			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;
1855 1856 1857
			break;
		}
	}
1858
	pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
L
Linus Torvalds 已提交
1859 1860 1861 1862
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),
		uptodate);
	if (i == disks) {
		BUG();
1863
		return;
L
Linus Torvalds 已提交
1864 1865
	}

1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876
	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);
1877 1878 1879
			if (!test_and_set_bit(WantReplacement, &rdev->flags))
				set_bit(MD_RECOVERY_NEEDED,
					&rdev->mddev->recovery);
1880 1881 1882 1883 1884 1885
		} else if (is_badblock(rdev, sh->sector,
				       STRIPE_SECTORS,
				       &first_bad, &bad_sectors))
			set_bit(R5_MadeGood, &sh->dev[i].flags);
	}
	rdev_dec_pending(rdev, conf->mddev);
L
Linus Torvalds 已提交
1886

1887 1888
	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
1889
	set_bit(STRIPE_HANDLE, &sh->state);
1890
	release_stripe(sh);
L
Linus Torvalds 已提交
1891 1892
}

1893
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
L
Linus Torvalds 已提交
1894
	
1895
static void raid5_build_block(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
1896 1897 1898 1899 1900 1901 1902 1903
{
	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;
1904
	dev->vec.bv_page = dev->page;
L
Linus Torvalds 已提交
1905

1906 1907 1908 1909 1910 1911 1912
	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
1913
	dev->flags = 0;
1914
	dev->sector = compute_blocknr(sh, i, previous);
L
Linus Torvalds 已提交
1915 1916
}

1917
static void error(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
1918 1919
{
	char b[BDEVNAME_SIZE];
1920
	struct r5conf *conf = mddev->private;
1921
	unsigned long flags;
1922
	pr_debug("raid456: error called\n");
L
Linus Torvalds 已提交
1923

1924 1925 1926 1927 1928 1929
	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);

1930
	set_bit(Blocked, &rdev->flags);
1931 1932 1933 1934 1935 1936 1937 1938 1939
	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);
1940
}
L
Linus Torvalds 已提交
1941 1942 1943 1944 1945

/*
 * Input: a 'big' sector number,
 * Output: index of the data and parity disk, and the sector # in them.
 */
1946
static sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
1947 1948
				     int previous, int *dd_idx,
				     struct stripe_head *sh)
L
Linus Torvalds 已提交
1949
{
N
NeilBrown 已提交
1950
	sector_t stripe, stripe2;
1951
	sector_t chunk_number;
L
Linus Torvalds 已提交
1952
	unsigned int chunk_offset;
1953
	int pd_idx, qd_idx;
1954
	int ddf_layout = 0;
L
Linus Torvalds 已提交
1955
	sector_t new_sector;
1956 1957
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
1958 1959
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
1960 1961 1962
	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
1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974

	/* 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
	 */
1975 1976
	stripe = chunk_number;
	*dd_idx = sector_div(stripe, data_disks);
N
NeilBrown 已提交
1977
	stripe2 = stripe;
L
Linus Torvalds 已提交
1978 1979 1980
	/*
	 * Select the parity disk based on the user selected algorithm.
	 */
1981
	pd_idx = qd_idx = -1;
1982 1983
	switch(conf->level) {
	case 4:
1984
		pd_idx = data_disks;
1985 1986
		break;
	case 5:
1987
		switch (algorithm) {
L
Linus Torvalds 已提交
1988
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
1989
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
1990
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
1991 1992 1993
				(*dd_idx)++;
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
1994
			pd_idx = sector_div(stripe2, raid_disks);
1995
			if (*dd_idx >= pd_idx)
L
Linus Torvalds 已提交
1996 1997 1998
				(*dd_idx)++;
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
1999
			pd_idx = data_disks - sector_div(stripe2, raid_disks);
2000
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
2001 2002
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
2003
			pd_idx = sector_div(stripe2, raid_disks);
2004
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
L
Linus Torvalds 已提交
2005
			break;
2006 2007 2008 2009 2010 2011 2012
		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
2013
		default:
2014
			BUG();
2015 2016 2017 2018
		}
		break;
	case 6:

2019
		switch (algorithm) {
2020
		case ALGORITHM_LEFT_ASYMMETRIC:
N
NeilBrown 已提交
2021
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2022 2023
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
2024
				(*dd_idx)++;	/* Q D D D P */
2025 2026
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
2027 2028 2029
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_RIGHT_ASYMMETRIC:
N
NeilBrown 已提交
2030
			pd_idx = sector_div(stripe2, raid_disks);
2031 2032
			qd_idx = pd_idx + 1;
			if (pd_idx == raid_disks-1) {
2033
				(*dd_idx)++;	/* Q D D D P */
2034 2035
				qd_idx = 0;
			} else if (*dd_idx >= pd_idx)
2036 2037 2038
				(*dd_idx) += 2; /* D D P Q D */
			break;
		case ALGORITHM_LEFT_SYMMETRIC:
N
NeilBrown 已提交
2039
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2040 2041
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2042 2043
			break;
		case ALGORITHM_RIGHT_SYMMETRIC:
N
NeilBrown 已提交
2044
			pd_idx = sector_div(stripe2, raid_disks);
2045 2046
			qd_idx = (pd_idx + 1) % raid_disks;
			*dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2047
			break;
2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062

		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
2063
			pd_idx = sector_div(stripe2, raid_disks);
2064 2065 2066 2067 2068 2069
			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 */
2070
			ddf_layout = 1;
2071 2072 2073 2074 2075 2076 2077
			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
2078 2079
			stripe2 += 1;
			pd_idx = raid_disks - 1 - 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
			break;

		case ALGORITHM_ROTATING_N_CONTINUE:
			/* Same as left_symmetric but Q is before P */
N
NeilBrown 已提交
2091
			pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2092 2093
			qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
			*dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2094
			ddf_layout = 1;
2095 2096 2097 2098
			break;

		case ALGORITHM_LEFT_ASYMMETRIC_6:
			/* RAID5 left_asymmetric, with Q on last device */
N
NeilBrown 已提交
2099
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2100 2101 2102 2103 2104 2105
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_RIGHT_ASYMMETRIC_6:
N
NeilBrown 已提交
2106
			pd_idx = sector_div(stripe2, raid_disks-1);
2107 2108 2109 2110 2111 2112
			if (*dd_idx >= pd_idx)
				(*dd_idx)++;
			qd_idx = raid_disks - 1;
			break;

		case ALGORITHM_LEFT_SYMMETRIC_6:
N
NeilBrown 已提交
2113
			pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2114 2115 2116 2117 2118
			*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
2119
			pd_idx = sector_div(stripe2, raid_disks-1);
2120 2121 2122 2123 2124 2125 2126 2127 2128 2129
			*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;

2130
		default:
2131
			BUG();
2132 2133
		}
		break;
L
Linus Torvalds 已提交
2134 2135
	}

2136 2137 2138
	if (sh) {
		sh->pd_idx = pd_idx;
		sh->qd_idx = qd_idx;
2139
		sh->ddf_layout = ddf_layout;
2140
	}
L
Linus Torvalds 已提交
2141 2142 2143 2144 2145 2146 2147 2148
	/*
	 * Finally, compute the new sector number
	 */
	new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
	return new_sector;
}


2149
static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
L
Linus Torvalds 已提交
2150
{
2151
	struct r5conf *conf = sh->raid_conf;
2152 2153
	int raid_disks = sh->disks;
	int data_disks = raid_disks - conf->max_degraded;
L
Linus Torvalds 已提交
2154
	sector_t new_sector = sh->sector, check;
2155 2156
	int sectors_per_chunk = previous ? conf->prev_chunk_sectors
					 : conf->chunk_sectors;
2157 2158
	int algorithm = previous ? conf->prev_algo
				 : conf->algorithm;
L
Linus Torvalds 已提交
2159 2160
	sector_t stripe;
	int chunk_offset;
2161 2162
	sector_t chunk_number;
	int dummy1, dd_idx = i;
L
Linus Torvalds 已提交
2163
	sector_t r_sector;
2164
	struct stripe_head sh2;
L
Linus Torvalds 已提交
2165

2166

L
Linus Torvalds 已提交
2167 2168 2169
	chunk_offset = sector_div(new_sector, sectors_per_chunk);
	stripe = new_sector;

2170 2171 2172 2173 2174
	if (i == sh->pd_idx)
		return 0;
	switch(conf->level) {
	case 4: break;
	case 5:
2175
		switch (algorithm) {
L
Linus Torvalds 已提交
2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186
		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;
2187 2188 2189 2190 2191
		case ALGORITHM_PARITY_0:
			i -= 1;
			break;
		case ALGORITHM_PARITY_N:
			break;
L
Linus Torvalds 已提交
2192
		default:
2193
			BUG();
2194 2195 2196
		}
		break;
	case 6:
2197
		if (i == sh->qd_idx)
2198
			return 0; /* It is the Q disk */
2199
		switch (algorithm) {
2200 2201
		case ALGORITHM_LEFT_ASYMMETRIC:
		case ALGORITHM_RIGHT_ASYMMETRIC:
2202 2203 2204 2205
		case ALGORITHM_ROTATING_ZERO_RESTART:
		case ALGORITHM_ROTATING_N_RESTART:
			if (sh->pd_idx == raid_disks-1)
				i--;	/* Q D D D P */
2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219
			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;
2220 2221 2222 2223 2224 2225
		case ALGORITHM_PARITY_0:
			i -= 2;
			break;
		case ALGORITHM_PARITY_N:
			break;
		case ALGORITHM_ROTATING_N_CONTINUE:
2226
			/* Like left_symmetric, but P is before Q */
2227 2228
			if (sh->pd_idx == 0)
				i--;	/* P D D D Q */
2229 2230 2231 2232 2233 2234
			else {
				/* D D Q P D */
				if (i < sh->pd_idx)
					i += raid_disks;
				i -= (sh->pd_idx + 1);
			}
2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249
			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;
2250
		default:
2251
			BUG();
2252 2253
		}
		break;
L
Linus Torvalds 已提交
2254 2255 2256
	}

	chunk_number = stripe * data_disks + i;
2257
	r_sector = chunk_number * sectors_per_chunk + chunk_offset;
L
Linus Torvalds 已提交
2258

2259
	check = raid5_compute_sector(conf, r_sector,
2260
				     previous, &dummy1, &sh2);
2261 2262
	if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
		|| sh2.qd_idx != sh->qd_idx) {
2263 2264
		printk(KERN_ERR "md/raid:%s: compute_blocknr: map not correct\n",
		       mdname(conf->mddev));
L
Linus Torvalds 已提交
2265 2266 2267 2268 2269 2270
		return 0;
	}
	return r_sector;
}


2271
static void
2272
schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
2273
			 int rcw, int expand)
2274 2275
{
	int i, pd_idx = sh->pd_idx, disks = sh->disks;
2276
	struct r5conf *conf = sh->raid_conf;
2277
	int level = conf->level;
2278 2279 2280 2281 2282 2283 2284

	if (rcw) {
		/* if we are not expanding this is a proper write request, and
		 * there will be bios with new data to be drained into the
		 * stripe cache
		 */
		if (!expand) {
2285 2286 2287 2288
			sh->reconstruct_state = reconstruct_state_drain_run;
			set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
		} else
			sh->reconstruct_state = reconstruct_state_run;
2289

2290
		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2291 2292 2293 2294 2295 2296

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

			if (dev->towrite) {
				set_bit(R5_LOCKED, &dev->flags);
2297
				set_bit(R5_Wantdrain, &dev->flags);
2298 2299
				if (!expand)
					clear_bit(R5_UPTODATE, &dev->flags);
2300
				s->locked++;
2301 2302
			}
		}
2303
		if (s->locked + conf->max_degraded == disks)
2304
			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
2305
				atomic_inc(&conf->pending_full_writes);
2306
	} else {
2307
		BUG_ON(level == 6);
2308 2309 2310
		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));

2311
		sh->reconstruct_state = reconstruct_state_prexor_drain_run;
2312 2313
		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
2314
		set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
2315 2316 2317 2318 2319 2320 2321 2322

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

			if (dev->towrite &&
			    (test_bit(R5_UPTODATE, &dev->flags) ||
2323 2324
			     test_bit(R5_Wantcompute, &dev->flags))) {
				set_bit(R5_Wantdrain, &dev->flags);
2325 2326
				set_bit(R5_LOCKED, &dev->flags);
				clear_bit(R5_UPTODATE, &dev->flags);
2327
				s->locked++;
2328 2329 2330 2331
			}
		}
	}

2332
	/* keep the parity disk(s) locked while asynchronous operations
2333 2334 2335 2336
	 * are in flight
	 */
	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
2337
	s->locked++;
2338

2339 2340 2341 2342 2343 2344 2345 2346 2347
	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++;
	}

2348
	pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
2349
		__func__, (unsigned long long)sh->sector,
2350
		s->locked, s->ops_request);
2351
}
2352

L
Linus Torvalds 已提交
2353 2354
/*
 * Each stripe/dev can have one or more bion attached.
2355
 * toread/towrite point to the first in a chain.
L
Linus Torvalds 已提交
2356 2357 2358 2359 2360
 * 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;
2361
	struct r5conf *conf = sh->raid_conf;
2362
	int firstwrite=0;
L
Linus Torvalds 已提交
2363

2364
	pr_debug("adding bi b#%llu to stripe s#%llu\n",
L
Linus Torvalds 已提交
2365 2366 2367
		(unsigned long long)bi->bi_sector,
		(unsigned long long)sh->sector);

S
Shaohua Li 已提交
2368 2369 2370 2371 2372 2373 2374 2375 2376
	/*
	 * 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);
2377
	if (forwrite) {
L
Linus Torvalds 已提交
2378
		bip = &sh->dev[dd_idx].towrite;
2379
		if (*bip == NULL)
2380 2381
			firstwrite = 1;
	} else
L
Linus Torvalds 已提交
2382 2383 2384 2385 2386 2387 2388 2389 2390
		bip = &sh->dev[dd_idx].toread;
	while (*bip && (*bip)->bi_sector < bi->bi_sector) {
		if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
			goto overlap;
		bip = & (*bip)->bi_next;
	}
	if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
		goto overlap;

2391
	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
L
Linus Torvalds 已提交
2392 2393 2394
	if (*bip)
		bi->bi_next = *bip;
	*bip = bi;
2395
	raid5_inc_bi_active_stripes(bi);
2396

L
Linus Torvalds 已提交
2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409
	if (forwrite) {
		/* check if page is covered */
		sector_t sector = sh->dev[dd_idx].sector;
		for (bi=sh->dev[dd_idx].towrite;
		     sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
			     bi && bi->bi_sector <= sector;
		     bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
			if (bi->bi_sector + (bi->bi_size>>9) >= sector)
				sector = bi->bi_sector + (bi->bi_size>>9);
		}
		if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
			set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
	}
S
Shaohua Li 已提交
2410
	spin_unlock_irq(&sh->stripe_lock);
2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421

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

	if (conf->mddev->bitmap && firstwrite) {
		bitmap_startwrite(conf->mddev->bitmap, sh->sector,
				  STRIPE_SECTORS, 0);
		sh->bm_seq = conf->seq_flush+1;
		set_bit(STRIPE_BIT_DELAY, &sh->state);
	}
L
Linus Torvalds 已提交
2422 2423 2424 2425
	return 1;

 overlap:
	set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
S
Shaohua Li 已提交
2426
	spin_unlock_irq(&sh->stripe_lock);
L
Linus Torvalds 已提交
2427 2428 2429
	return 0;
}

2430
static void end_reshape(struct r5conf *conf);
2431

2432
static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
2433
			    struct stripe_head *sh)
2434
{
2435
	int sectors_per_chunk =
2436
		previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
2437
	int dd_idx;
2438
	int chunk_offset = sector_div(stripe, sectors_per_chunk);
2439
	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
2440

2441 2442
	raid5_compute_sector(conf,
			     stripe * (disks - conf->max_degraded)
2443
			     *sectors_per_chunk + chunk_offset,
2444
			     previous,
2445
			     &dd_idx, sh);
2446 2447
}

2448
static void
2449
handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
2450 2451 2452 2453 2454 2455 2456 2457 2458
				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)) {
2459
			struct md_rdev *rdev;
2460 2461 2462
			rcu_read_lock();
			rdev = rcu_dereference(conf->disks[i].rdev);
			if (rdev && test_bit(In_sync, &rdev->flags))
2463 2464 2465
				atomic_inc(&rdev->nr_pending);
			else
				rdev = NULL;
2466
			rcu_read_unlock();
2467 2468 2469 2470 2471 2472 2473 2474
			if (rdev) {
				if (!rdev_set_badblocks(
					    rdev,
					    sh->sector,
					    STRIPE_SECTORS, 0))
					md_error(conf->mddev, rdev);
				rdev_dec_pending(rdev, conf->mddev);
			}
2475
		}
S
Shaohua Li 已提交
2476
		spin_lock_irq(&sh->stripe_lock);
2477 2478 2479
		/* fail all writes first */
		bi = sh->dev[i].towrite;
		sh->dev[i].towrite = NULL;
S
Shaohua Li 已提交
2480
		spin_unlock_irq(&sh->stripe_lock);
2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492
		if (bi) {
			s->to_write--;
			bitmap_end = 1;
		}

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

		while (bi && bi->bi_sector <
			sh->dev[i].sector + STRIPE_SECTORS) {
			struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
			clear_bit(BIO_UPTODATE, &bi->bi_flags);
2493
			if (!raid5_dec_bi_active_stripes(bi)) {
2494 2495 2496 2497 2498 2499
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = nextbi;
		}
2500 2501 2502 2503
		if (bitmap_end)
			bitmap_endwrite(conf->mddev->bitmap, sh->sector,
				STRIPE_SECTORS, 0, 0);
		bitmap_end = 0;
2504 2505 2506 2507 2508 2509 2510 2511
		/* 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);
2512
			if (!raid5_dec_bi_active_stripes(bi)) {
2513 2514 2515 2516 2517 2518 2519
				md_write_end(conf->mddev);
				bi->bi_next = *return_bi;
				*return_bi = bi;
			}
			bi = bi2;
		}

2520 2521 2522 2523 2524 2525
		/* 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))) {
2526 2527 2528 2529 2530 2531 2532 2533 2534 2535
			bi = sh->dev[i].toread;
			sh->dev[i].toread = NULL;
			if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
				wake_up(&conf->wait_for_overlap);
			if (bi) s->to_read--;
			while (bi && bi->bi_sector <
			       sh->dev[i].sector + STRIPE_SECTORS) {
				struct bio *nextbi =
					r5_next_bio(bi, sh->dev[i].sector);
				clear_bit(BIO_UPTODATE, &bi->bi_flags);
2536
				if (!raid5_dec_bi_active_stripes(bi)) {
2537 2538 2539 2540 2541 2542 2543 2544 2545
					bi->bi_next = *return_bi;
					*return_bi = bi;
				}
				bi = nextbi;
			}
		}
		if (bitmap_end)
			bitmap_endwrite(conf->mddev->bitmap, sh->sector,
					STRIPE_SECTORS, 0, 0);
2546 2547 2548 2549
		/* 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);
2550 2551
	}

2552 2553 2554
	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);
2555 2556
}

2557
static void
2558
handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
2559 2560 2561 2562 2563 2564 2565
		   struct stripe_head_state *s)
{
	int abort = 0;
	int i;

	clear_bit(STRIPE_SYNCING, &sh->state);
	s->syncing = 0;
2566
	s->replacing = 0;
2567
	/* There is nothing more to do for sync/check/repair.
2568 2569 2570
	 * 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.
2571
	 * For recover/replace we need to record a bad block on all
2572 2573
	 * non-sync devices, or abort the recovery
	 */
2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596
	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;
2597
	}
2598
	md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
2599 2600
}

2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616
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;
}

2617
/* fetch_block - checks the given member device to see if its data needs
2618 2619 2620
 * to be read or computed to satisfy a request.
 *
 * Returns 1 when no more member devices need to be checked, otherwise returns
2621
 * 0 to tell the loop in handle_stripe_fill to continue
2622
 */
2623 2624
static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
		       int disk_idx, int disks)
2625
{
2626
	struct r5dev *dev = &sh->dev[disk_idx];
2627 2628
	struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
				  &sh->dev[s->failed_num[1]] };
2629

2630
	/* is the data in this block needed, and can we get it? */
2631 2632 2633 2634 2635
	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 ||
2636
	     (s->replacing && want_replace(sh, disk_idx)) ||
2637 2638
	     (s->failed >= 1 && fdev[0]->toread) ||
	     (s->failed >= 2 && fdev[1]->toread) ||
2639 2640 2641
	     (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))) {
2642 2643 2644 2645 2646 2647
		/* 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) &&
2648 2649
		    (s->failed && (disk_idx == s->failed_num[0] ||
				   disk_idx == s->failed_num[1]))) {
2650 2651
			/* have disk failed, and we're requested to fetch it;
			 * do compute it
2652
			 */
2653 2654 2655 2656 2657 2658 2659 2660
			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;
2661 2662 2663 2664 2665 2666
			/* 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.
			 */
2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679
			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;
2680
			}
2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699
			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);
2700 2701
		}
	}
2702 2703 2704 2705 2706

	return 0;
}

/**
2707
 * handle_stripe_fill - read or compute data to satisfy pending requests.
2708
 */
2709 2710 2711
static void handle_stripe_fill(struct stripe_head *sh,
			       struct stripe_head_state *s,
			       int disks)
2712 2713 2714 2715 2716 2717 2718 2719 2720 2721
{
	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--; )
2722
			if (fetch_block(sh, s, i, disks))
2723
				break;
2724 2725 2726 2727
	set_bit(STRIPE_HANDLE, &sh->state);
}


2728
/* handle_stripe_clean_event
2729 2730 2731 2732
 * 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.
 */
2733
static void handle_stripe_clean_event(struct r5conf *conf,
2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745
	struct stripe_head *sh, int disks, struct bio **return_bi)
{
	int i;
	struct r5dev *dev;

	for (i = disks; i--; )
		if (sh->dev[i].written) {
			dev = &sh->dev[i];
			if (!test_bit(R5_LOCKED, &dev->flags) &&
				test_bit(R5_UPTODATE, &dev->flags)) {
				/* We can return any write requests */
				struct bio *wbi, *wbi2;
2746
				pr_debug("Return write for disc %d\n", i);
2747 2748 2749 2750 2751
				wbi = dev->written;
				dev->written = NULL;
				while (wbi && wbi->bi_sector <
					dev->sector + STRIPE_SECTORS) {
					wbi2 = r5_next_bio(wbi, dev->sector);
2752
					if (!raid5_dec_bi_active_stripes(wbi)) {
2753 2754 2755 2756 2757 2758
						md_write_end(conf->mddev);
						wbi->bi_next = *return_bi;
						*return_bi = wbi;
					}
					wbi = wbi2;
				}
2759 2760
				bitmap_endwrite(conf->mddev->bitmap, sh->sector,
						STRIPE_SECTORS,
2761
					 !test_bit(STRIPE_DEGRADED, &sh->state),
2762
						0);
2763 2764
			}
		}
2765 2766 2767 2768

	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);
2769 2770
}

2771
static void handle_stripe_dirtying(struct r5conf *conf,
2772 2773 2774
				   struct stripe_head *sh,
				   struct stripe_head_state *s,
				   int disks)
2775 2776
{
	int rmw = 0, rcw = 0, i;
2777 2778 2779 2780 2781 2782 2783
	if (conf->max_degraded == 2) {
		/* RAID6 requires 'rcw' in current implementation
		 * Calculate the real rcw later - for now fake it
		 * look like rcw is cheaper
		 */
		rcw = 1; rmw = 2;
	} else for (i = disks; i--; ) {
2784 2785 2786 2787
		/* 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) &&
2788 2789
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		      test_bit(R5_Wantcompute, &dev->flags))) {
2790 2791 2792 2793 2794 2795 2796 2797
			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) &&
2798 2799 2800
		    !(test_bit(R5_UPTODATE, &dev->flags) ||
		    test_bit(R5_Wantcompute, &dev->flags))) {
			if (test_bit(R5_Insync, &dev->flags)) rcw++;
2801 2802 2803 2804
			else
				rcw += 2*disks;
		}
	}
2805
	pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2806 2807 2808 2809 2810 2811 2812 2813
		(unsigned long long)sh->sector, rmw, rcw);
	set_bit(STRIPE_HANDLE, &sh->state);
	if (rmw < rcw && rmw > 0)
		/* prefer read-modify-write, but need to get some data */
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if ((dev->towrite || i == sh->pd_idx) &&
			    !test_bit(R5_LOCKED, &dev->flags) &&
2814 2815
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
			    test_bit(R5_Wantcompute, &dev->flags)) &&
2816 2817 2818
			    test_bit(R5_Insync, &dev->flags)) {
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2819
					pr_debug("Read_old block "
2820 2821 2822 2823 2824 2825 2826 2827 2828 2829
						"%d for r-m-w\n", i);
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
					s->locked++;
				} else {
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
2830
	if (rcw <= rmw && rcw > 0) {
2831
		/* want reconstruct write, but need to get some data */
2832
		rcw = 0;
2833 2834 2835
		for (i = disks; i--; ) {
			struct r5dev *dev = &sh->dev[i];
			if (!test_bit(R5_OVERWRITE, &dev->flags) &&
2836
			    i != sh->pd_idx && i != sh->qd_idx &&
2837
			    !test_bit(R5_LOCKED, &dev->flags) &&
2838
			    !(test_bit(R5_UPTODATE, &dev->flags) ||
2839 2840 2841 2842
			      test_bit(R5_Wantcompute, &dev->flags))) {
				rcw++;
				if (!test_bit(R5_Insync, &dev->flags))
					continue; /* it's a failed drive */
2843 2844
				if (
				  test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
2845
					pr_debug("Read_old block "
2846 2847 2848 2849 2850 2851 2852 2853 2854 2855
						"%d for Reconstruct\n", i);
					set_bit(R5_LOCKED, &dev->flags);
					set_bit(R5_Wantread, &dev->flags);
					s->locked++;
				} else {
					set_bit(STRIPE_DELAYED, &sh->state);
					set_bit(STRIPE_HANDLE, &sh->state);
				}
			}
		}
2856
	}
2857 2858 2859
	/* now if nothing is locked, and if we have enough data,
	 * we can start a write request
	 */
2860 2861
	/* 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
2862 2863
	 * subsequent call wants to start a write request.  raid_run_ops only
	 * handles the case where compute block and reconstruct are requested
2864 2865 2866
	 * simultaneously.  If this is not the case then new writes need to be
	 * held off until the compute completes.
	 */
2867 2868 2869
	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)))
2870
		schedule_reconstruction(sh, s, rcw == 0, 0);
2871 2872
}

2873
static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
2874 2875
				struct stripe_head_state *s, int disks)
{
2876
	struct r5dev *dev = NULL;
2877

2878
	set_bit(STRIPE_HANDLE, &sh->state);
2879

2880 2881 2882
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are no failures */
2883 2884
		if (s->failed == 0) {
			BUG_ON(s->uptodate != disks);
2885 2886
			sh->check_state = check_state_run;
			set_bit(STRIPE_OP_CHECK, &s->ops_request);
2887 2888
			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
			s->uptodate--;
2889
			break;
2890
		}
2891
		dev = &sh->dev[s->failed_num[0]];
2892 2893 2894 2895 2896 2897 2898 2899 2900
		/* 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
2901

2902 2903 2904 2905 2906
		/* 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);
2907
		s->locked++;
2908
		set_bit(R5_Wantwrite, &dev->flags);
2909

2910 2911
		clear_bit(STRIPE_DEGRADED, &sh->state);
		set_bit(STRIPE_INSYNC, &sh->state);
2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927
		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
2928
		if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939
			/* parity is correct (on disc,
			 * not in buffer any more)
			 */
			set_bit(STRIPE_INSYNC, &sh->state);
		else {
			conf->mddev->resync_mismatches += STRIPE_SECTORS;
			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
				/* don't try to repair!! */
				set_bit(STRIPE_INSYNC, &sh->state);
			else {
				sh->check_state = check_state_compute_run;
2940
				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
2941 2942 2943 2944
				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;
2945
				sh->ops.target2 = -1;
2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956
				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();
2957 2958 2959 2960
	}
}


2961
static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
2962
				  struct stripe_head_state *s,
2963
				  int disks)
2964 2965
{
	int pd_idx = sh->pd_idx;
N
NeilBrown 已提交
2966
	int qd_idx = sh->qd_idx;
2967
	struct r5dev *dev;
2968 2969 2970 2971

	set_bit(STRIPE_HANDLE, &sh->state);

	BUG_ON(s->failed > 2);
2972

2973 2974 2975 2976 2977 2978
	/* 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
	 */

2979 2980 2981
	switch (sh->check_state) {
	case check_state_idle:
		/* start a new check operation if there are < 2 failures */
2982
		if (s->failed == s->q_failed) {
2983
			/* The only possible failed device holds Q, so it
2984 2985 2986
			 * makes sense to check P (If anything else were failed,
			 * we would have used P to recreate it).
			 */
2987
			sh->check_state = check_state_run;
2988
		}
2989
		if (!s->q_failed && s->failed < 2) {
2990
			/* Q is not failed, and we didn't use it to generate
2991 2992
			 * anything, so it makes sense to check it
			 */
2993 2994 2995 2996
			if (sh->check_state == check_state_run)
				sh->check_state = check_state_run_pq;
			else
				sh->check_state = check_state_run_q;
2997 2998
		}

2999 3000
		/* discard potentially stale zero_sum_result */
		sh->ops.zero_sum_result = 0;
3001

3002 3003 3004 3005
		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--;
3006
		}
3007 3008 3009 3010 3011 3012 3013
		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;
3014 3015
		}

3016 3017 3018 3019 3020
		/* we have 2-disk failure */
		BUG_ON(s->failed != 2);
		/* fall through */
	case check_state_compute_result:
		sh->check_state = check_state_idle;
3021

3022 3023 3024
		/* check that a write has not made the stripe insync */
		if (test_bit(STRIPE_INSYNC, &sh->state))
			break;
3025 3026

		/* now write out any block on a failed drive,
3027
		 * or P or Q if they were recomputed
3028
		 */
3029
		BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
3030
		if (s->failed == 2) {
3031
			dev = &sh->dev[s->failed_num[1]];
3032 3033 3034 3035 3036
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
		if (s->failed >= 1) {
3037
			dev = &sh->dev[s->failed_num[0]];
3038 3039 3040 3041
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
3042
		if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
3043 3044 3045 3046 3047
			dev = &sh->dev[pd_idx];
			s->locked++;
			set_bit(R5_LOCKED, &dev->flags);
			set_bit(R5_Wantwrite, &dev->flags);
		}
3048
		if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
3049 3050 3051 3052 3053 3054 3055 3056
			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);
3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120
		break;
	case check_state_run:
	case check_state_run_q:
	case check_state_run_pq:
		break; /* we will be called again upon completion */
	case check_state_check_result:
		sh->check_state = check_state_idle;

		/* handle a successful check operation, if parity is correct
		 * we are done.  Otherwise update the mismatch count and repair
		 * parity if !MD_RECOVERY_CHECK
		 */
		if (sh->ops.zero_sum_result == 0) {
			/* both parities are correct */
			if (!s->failed)
				set_bit(STRIPE_INSYNC, &sh->state);
			else {
				/* in contrast to the raid5 case we can validate
				 * parity, but still have a failure to write
				 * back
				 */
				sh->check_state = check_state_compute_result;
				/* Returning at this point means that we may go
				 * off and bring p and/or q uptodate again so
				 * we make sure to check zero_sum_result again
				 * to verify if p or q need writeback
				 */
			}
		} else {
			conf->mddev->resync_mismatches += STRIPE_SECTORS;
			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
				/* don't try to repair!! */
				set_bit(STRIPE_INSYNC, &sh->state);
			else {
				int *target = &sh->ops.target;

				sh->ops.target = -1;
				sh->ops.target2 = -1;
				sh->check_state = check_state_compute_run;
				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
				if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
					set_bit(R5_Wantcompute,
						&sh->dev[pd_idx].flags);
					*target = pd_idx;
					target = &sh->ops.target2;
					s->uptodate++;
				}
				if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
					set_bit(R5_Wantcompute,
						&sh->dev[qd_idx].flags);
					*target = qd_idx;
					s->uptodate++;
				}
			}
		}
		break;
	case check_state_compute_run:
		break;
	default:
		printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
		       __func__, sh->check_state,
		       (unsigned long long) sh->sector);
		BUG();
3121 3122 3123
	}
}

3124
static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
3125 3126 3127 3128 3129 3130
{
	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.
	 */
3131
	struct dma_async_tx_descriptor *tx = NULL;
3132 3133
	clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	for (i = 0; i < sh->disks; i++)
N
NeilBrown 已提交
3134
		if (i != sh->pd_idx && i != sh->qd_idx) {
3135
			int dd_idx, j;
3136
			struct stripe_head *sh2;
3137
			struct async_submit_ctl submit;
3138

3139
			sector_t bn = compute_blocknr(sh, i, 1);
3140 3141
			sector_t s = raid5_compute_sector(conf, bn, 0,
							  &dd_idx, NULL);
3142
			sh2 = get_active_stripe(conf, s, 0, 1, 1);
3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154
			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;
			}
3155 3156

			/* place all the copies on one channel */
3157
			init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
3158
			tx = async_memcpy(sh2->dev[dd_idx].page,
3159
					  sh->dev[i].page, 0, 0, STRIPE_SIZE,
3160
					  &submit);
3161

3162 3163 3164 3165
			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 &&
3166
				    j != sh2->qd_idx &&
3167 3168 3169 3170 3171 3172 3173
				    !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);
3174

3175
		}
3176 3177 3178 3179 3180
	/* done submitting copies, wait for them to complete */
	if (tx) {
		async_tx_ack(tx);
		dma_wait_for_async_tx(tx);
	}
3181
}
L
Linus Torvalds 已提交
3182 3183 3184 3185

/*
 * handle_stripe - do things to a stripe.
 *
3186 3187
 * 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
3188
 * Possible results:
3189 3190
 *    return some read requests which now have data
 *    return some write requests which are safely on storage
L
Linus Torvalds 已提交
3191 3192 3193 3194 3195
 *    schedule a read on some buffers
 *    schedule a write of some buffers
 *    return confirmation of parity correctness
 *
 */
3196

3197
static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
L
Linus Torvalds 已提交
3198
{
3199
	struct r5conf *conf = sh->raid_conf;
3200
	int disks = sh->disks;
3201 3202
	struct r5dev *dev;
	int i;
3203
	int do_recovery = 0;
L
Linus Torvalds 已提交
3204

3205 3206 3207 3208 3209 3210
	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
3211

3212
	/* Now to look around and see what can be done */
L
Linus Torvalds 已提交
3213
	rcu_read_lock();
3214
	for (i=disks; i--; ) {
3215
		struct md_rdev *rdev;
3216 3217 3218
		sector_t first_bad;
		int bad_sectors;
		int is_bad = 0;
3219

3220
		dev = &sh->dev[i];
L
Linus Torvalds 已提交
3221

3222
		pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
3223 3224
			 i, dev->flags,
			 dev->toread, dev->towrite, dev->written);
3225 3226 3227 3228 3229 3230 3231 3232
		/* 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
3233

3234
		/* now count some things */
3235 3236 3237 3238
		if (test_bit(R5_LOCKED, &dev->flags))
			s->locked++;
		if (test_bit(R5_UPTODATE, &dev->flags))
			s->uptodate++;
3239
		if (test_bit(R5_Wantcompute, &dev->flags)) {
3240 3241
			s->compute++;
			BUG_ON(s->compute > 2);
3242
		}
L
Linus Torvalds 已提交
3243

3244
		if (test_bit(R5_Wantfill, &dev->flags))
3245
			s->to_fill++;
3246
		else if (dev->toread)
3247
			s->to_read++;
3248
		if (dev->towrite) {
3249
			s->to_write++;
3250
			if (!test_bit(R5_OVERWRITE, &dev->flags))
3251
				s->non_overwrite++;
3252
		}
3253
		if (dev->written)
3254
			s->written++;
3255 3256 3257 3258 3259 3260 3261 3262 3263 3264
		/* 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 {
3265 3266
			if (rdev)
				set_bit(R5_NeedReplace, &dev->flags);
3267 3268 3269
			rdev = rcu_dereference(conf->disks[i].rdev);
			clear_bit(R5_ReadRepl, &dev->flags);
		}
3270 3271
		if (rdev && test_bit(Faulty, &rdev->flags))
			rdev = NULL;
3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283
		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);
			}
3284
		}
3285 3286 3287
		clear_bit(R5_Insync, &dev->flags);
		if (!rdev)
			/* Not in-sync */;
3288 3289
		else if (is_bad) {
			/* also not in-sync */
3290 3291
			if (!test_bit(WriteErrorSeen, &rdev->flags) &&
			    test_bit(R5_UPTODATE, &dev->flags)) {
3292 3293 3294 3295 3296 3297 3298
				/* 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))
3299
			set_bit(R5_Insync, &dev->flags);
3300
		else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
3301
			/* in sync if before recovery_offset */
3302 3303 3304 3305 3306 3307 3308 3309 3310
			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
3311
		if (rdev && test_bit(R5_WriteError, &dev->flags)) {
3312 3313 3314 3315 3316 3317 3318
			/* 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)) {
3319
				s->handle_bad_blocks = 1;
3320
				atomic_inc(&rdev2->nr_pending);
3321 3322 3323
			} else
				clear_bit(R5_WriteError, &dev->flags);
		}
A
Adam Kwolek 已提交
3324
		if (rdev && test_bit(R5_MadeGood, &dev->flags)) {
3325 3326 3327 3328 3329
			/* 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)) {
3330
				s->handle_bad_blocks = 1;
3331
				atomic_inc(&rdev2->nr_pending);
3332 3333 3334
			} else
				clear_bit(R5_MadeGood, &dev->flags);
		}
3335 3336 3337 3338 3339 3340 3341 3342 3343
		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);
		}
3344
		if (!test_bit(R5_Insync, &dev->flags)) {
3345 3346 3347
			/* 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
3348
		}
3349 3350 3351
		if (test_bit(R5_ReadError, &dev->flags))
			clear_bit(R5_Insync, &dev->flags);
		if (!test_bit(R5_Insync, &dev->flags)) {
3352 3353 3354
			if (s->failed < 2)
				s->failed_num[s->failed] = i;
			s->failed++;
3355 3356
			if (rdev && !test_bit(Faulty, &rdev->flags))
				do_recovery = 1;
3357
		}
L
Linus Torvalds 已提交
3358
	}
3359 3360 3361 3362
	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
3363
		 * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
3364 3365 3366 3367 3368
		 * else we can only be replacing
		 * sync and recovery both need to read all devices, and so
		 * use the same flag.
		 */
		if (do_recovery ||
3369 3370
		    sh->sector >= conf->mddev->recovery_cp ||
		    test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
3371 3372 3373 3374
			s->syncing = 1;
		else
			s->replacing = 1;
	}
L
Linus Torvalds 已提交
3375
	rcu_read_unlock();
3376 3377 3378 3379 3380
}

static void handle_stripe(struct stripe_head *sh)
{
	struct stripe_head_state s;
3381
	struct r5conf *conf = sh->raid_conf;
3382
	int i;
3383 3384
	int prexor;
	int disks = sh->disks;
3385
	struct r5dev *pdev, *qdev;
3386 3387

	clear_bit(STRIPE_HANDLE, &sh->state);
3388
	if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405
		/* already being handled, ensure it gets handled
		 * again when current action finishes */
		set_bit(STRIPE_HANDLE, &sh->state);
		return;
	}

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

	pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
		"pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
	       (unsigned long long)sh->sector, sh->state,
	       atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
	       sh->check_state, sh->reconstruct_state);
3406

3407
	analyse_stripe(sh, &s);
3408

3409 3410 3411 3412 3413
	if (s.handle_bad_blocks) {
		set_bit(STRIPE_HANDLE, &sh->state);
		goto finish;
	}

3414 3415
	if (unlikely(s.blocked_rdev)) {
		if (s.syncing || s.expanding || s.expanded ||
3416
		    s.replacing || s.to_write || s.written) {
3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436
			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.
	 */
3437 3438 3439 3440 3441
	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);
3442
		if (s.syncing + s.replacing)
3443 3444
			handle_failed_sync(conf, sh, &s);
	}
3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472

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

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

	/* Now we might consider reading some blocks, either to check/generate
	 * parity, or to satisfy requests
	 * or to load a block that is being partially written.
	 */
	if (s.to_read || s.non_overwrite
	    || (conf->level == 6 && s.to_write && s.failed)
3473 3474 3475
	    || (s.syncing && (s.uptodate + s.compute < disks))
	    || s.replacing
	    || s.expanding)
3476 3477
		handle_stripe_fill(sh, &s, disks);

3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535
	/* Now we check to see if any write operations have recently
	 * completed
	 */
	prexor = 0;
	if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
		prexor = 1;
	if (sh->reconstruct_state == reconstruct_state_drain_result ||
	    sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
		sh->reconstruct_state = reconstruct_state_idle;

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

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

	/* maybe we need to check and possibly fix the parity for this stripe
	 * Any reads will already have been scheduled, so we just see if enough
	 * data is available.  The parity check is held off while parity
	 * dependent operations are in flight.
	 */
	if (sh->check_state ||
	    (s.syncing && s.locked == 0 &&
	     !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
	     !test_bit(STRIPE_INSYNC, &sh->state))) {
		if (conf->level == 6)
			handle_parity_checks6(conf, sh, &s, disks);
		else
			handle_parity_checks5(conf, sh, &s, disks);
	}
3536

3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550
	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)) {
3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579
		md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
		clear_bit(STRIPE_SYNCING, &sh->state);
	}

	/* If the failed drives are just a ReadError, then we might need
	 * to progress the repair/check process
	 */
	if (s.failed <= conf->max_degraded && !conf->mddev->ro)
		for (i = 0; i < s.failed; i++) {
			struct r5dev *dev = &sh->dev[s.failed_num[i]];
			if (test_bit(R5_ReadError, &dev->flags)
			    && !test_bit(R5_LOCKED, &dev->flags)
			    && test_bit(R5_UPTODATE, &dev->flags)
				) {
				if (!test_bit(R5_ReWrite, &dev->flags)) {
					set_bit(R5_Wantwrite, &dev->flags);
					set_bit(R5_ReWrite, &dev->flags);
					set_bit(R5_LOCKED, &dev->flags);
					s.locked++;
				} else {
					/* let's read it back */
					set_bit(R5_Wantread, &dev->flags);
					set_bit(R5_LOCKED, &dev->flags);
					s.locked++;
				}
			}
		}


3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606
	/* 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++;
		}
	}
3607

3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623
	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);
3624

3625
finish:
3626
	/* wait for this device to become unblocked */
3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638
	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);
	}
3639

3640 3641
	if (s.handle_bad_blocks)
		for (i = disks; i--; ) {
3642
			struct md_rdev *rdev;
3643 3644 3645 3646 3647 3648 3649 3650 3651
			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);
			}
3652 3653 3654
			if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
				rdev = conf->disks[i].rdev;
				rdev_clear_badblocks(rdev, sh->sector,
3655
						     STRIPE_SECTORS, 0);
3656 3657
				rdev_dec_pending(rdev, conf->mddev);
			}
3658 3659
			if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
				rdev = conf->disks[i].replacement;
3660 3661 3662
				if (!rdev)
					/* rdev have been moved down */
					rdev = conf->disks[i].rdev;
3663
				rdev_clear_badblocks(rdev, sh->sector,
3664
						     STRIPE_SECTORS, 0);
3665 3666
				rdev_dec_pending(rdev, conf->mddev);
			}
3667 3668
		}

3669 3670 3671
	if (s.ops_request)
		raid_run_ops(sh, s.ops_request);

D
Dan Williams 已提交
3672
	ops_run_io(sh, &s);
3673

3674
	if (s.dec_preread_active) {
3675
		/* We delay this until after ops_run_io so that if make_request
T
Tejun Heo 已提交
3676
		 * is waiting on a flush, it won't continue until the writes
3677 3678 3679 3680 3681 3682 3683 3684
		 * 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);
	}

3685
	return_io(s.return_bi);
3686

3687
	clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
3688 3689
}

3690
static void raid5_activate_delayed(struct r5conf *conf)
3691 3692 3693 3694 3695 3696 3697 3698 3699 3700
{
	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);
3701
			list_add_tail(&sh->lru, &conf->hold_list);
3702
		}
N
NeilBrown 已提交
3703
	}
3704 3705
}

3706
static void activate_bit_delay(struct r5conf *conf)
3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719
{
	/* 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);
	}
}

3720
int md_raid5_congested(struct mddev *mddev, int bits)
3721
{
3722
	struct r5conf *conf = mddev->private;
3723 3724 3725 3726

	/* No difference between reads and writes.  Just check
	 * how busy the stripe_cache is
	 */
3727

3728 3729 3730 3731 3732 3733 3734 3735 3736
	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
3737 3738 3739 3740
EXPORT_SYMBOL_GPL(md_raid5_congested);

static int raid5_congested(void *data, int bits)
{
3741
	struct mddev *mddev = data;
N
NeilBrown 已提交
3742 3743 3744 3745

	return mddev_congested(mddev, bits) ||
		md_raid5_congested(mddev, bits);
}
3746

3747 3748 3749
/* We want read requests to align with chunks where possible,
 * but write requests don't need to.
 */
3750 3751 3752
static int raid5_mergeable_bvec(struct request_queue *q,
				struct bvec_merge_data *bvm,
				struct bio_vec *biovec)
3753
{
3754
	struct mddev *mddev = q->queuedata;
3755
	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
3756
	int max;
3757
	unsigned int chunk_sectors = mddev->chunk_sectors;
3758
	unsigned int bio_sectors = bvm->bi_size >> 9;
3759

3760
	if ((bvm->bi_rw & 1) == WRITE)
3761 3762
		return biovec->bv_len; /* always allow writes to be mergeable */

3763 3764
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3765 3766 3767 3768 3769 3770 3771 3772
	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;
}

3773

3774
static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
3775 3776
{
	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
3777
	unsigned int chunk_sectors = mddev->chunk_sectors;
3778 3779
	unsigned int bio_sectors = bio->bi_size >> 9;

3780 3781
	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
		chunk_sectors = mddev->new_chunk_sectors;
3782 3783 3784 3785
	return  chunk_sectors >=
		((sector & (chunk_sectors - 1)) + bio_sectors);
}

3786 3787 3788 3789
/*
 *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
 *  later sampled by raid5d.
 */
3790
static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803
{
	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);
}


3804
static struct bio *remove_bio_from_retry(struct r5conf *conf)
3805 3806 3807 3808 3809 3810 3811 3812 3813 3814
{
	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) {
3815
		conf->retry_read_aligned_list = bi->bi_next;
3816
		bi->bi_next = NULL;
3817 3818 3819 3820
		/*
		 * this sets the active strip count to 1 and the processed
		 * strip count to zero (upper 8 bits)
		 */
3821
		raid5_set_bi_stripes(bi, 1); /* biased count of active stripes */
3822 3823 3824 3825 3826 3827
	}

	return bi;
}


3828 3829 3830 3831 3832 3833
/*
 *  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..
 */
3834
static void raid5_align_endio(struct bio *bi, int error)
3835 3836
{
	struct bio* raid_bi  = bi->bi_private;
3837
	struct mddev *mddev;
3838
	struct r5conf *conf;
3839
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
3840
	struct md_rdev *rdev;
3841

3842
	bio_put(bi);
3843 3844 3845

	rdev = (void*)raid_bi->bi_next;
	raid_bi->bi_next = NULL;
3846 3847
	mddev = rdev->mddev;
	conf = mddev->private;
3848 3849 3850 3851

	rdev_dec_pending(rdev, conf->mddev);

	if (!error && uptodate) {
3852
		bio_endio(raid_bi, 0);
3853 3854
		if (atomic_dec_and_test(&conf->active_aligned_reads))
			wake_up(&conf->wait_for_stripe);
3855
		return;
3856 3857 3858
	}


3859
	pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
3860 3861

	add_bio_to_retry(raid_bi, conf);
3862 3863
}

3864 3865
static int bio_fits_rdev(struct bio *bi)
{
3866
	struct request_queue *q = bdev_get_queue(bi->bi_bdev);
3867

3868
	if ((bi->bi_size>>9) > queue_max_sectors(q))
3869 3870
		return 0;
	blk_recount_segments(q, bi);
3871
	if (bi->bi_phys_segments > queue_max_segments(q))
3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883
		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;
}


3884
static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
3885
{
3886
	struct r5conf *conf = mddev->private;
N
NeilBrown 已提交
3887
	int dd_idx;
3888
	struct bio* align_bi;
3889
	struct md_rdev *rdev;
3890
	sector_t end_sector;
3891 3892

	if (!in_chunk_boundary(mddev, raid_bio)) {
3893
		pr_debug("chunk_aligned_read : non aligned\n");
3894 3895 3896
		return 0;
	}
	/*
3897
	 * use bio_clone_mddev to make a copy of the bio
3898
	 */
3899
	align_bi = bio_clone_mddev(raid_bio, GFP_NOIO, mddev);
3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910
	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
	 */
3911 3912
	align_bi->bi_sector =  raid5_compute_sector(conf, raid_bio->bi_sector,
						    0,
3913
						    &dd_idx, NULL);
3914

3915
	end_sector = align_bi->bi_sector + (align_bi->bi_size >> 9);
3916
	rcu_read_lock();
3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927
	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) {
3928 3929 3930
		sector_t first_bad;
		int bad_sectors;

3931 3932
		atomic_inc(&rdev->nr_pending);
		rcu_read_unlock();
3933 3934 3935 3936
		raid_bio->bi_next = (void*)rdev;
		align_bi->bi_bdev =  rdev->bdev;
		align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);

3937 3938 3939 3940
		if (!bio_fits_rdev(align_bi) ||
		    is_badblock(rdev, align_bi->bi_sector, align_bi->bi_size>>9,
				&first_bad, &bad_sectors)) {
			/* too big in some way, or has a known bad block */
3941 3942 3943 3944 3945
			bio_put(align_bi);
			rdev_dec_pending(rdev, mddev);
			return 0;
		}

3946 3947 3948
		/* No reshape active, so we can trust rdev->data_offset */
		align_bi->bi_sector += rdev->data_offset;

3949 3950 3951 3952 3953 3954 3955
		spin_lock_irq(&conf->device_lock);
		wait_event_lock_irq(conf->wait_for_stripe,
				    conf->quiesce == 0,
				    conf->device_lock, /* nothing */);
		atomic_inc(&conf->active_aligned_reads);
		spin_unlock_irq(&conf->device_lock);

3956 3957 3958 3959
		generic_make_request(align_bi);
		return 1;
	} else {
		rcu_read_unlock();
3960
		bio_put(align_bi);
3961 3962 3963 3964
		return 0;
	}
}

3965 3966 3967 3968 3969 3970 3971 3972 3973 3974
/* __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.
 */
3975
static struct stripe_head *__get_priority_stripe(struct r5conf *conf)
3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007 4008 4009 4010 4011 4012 4013 4014 4015 4016
{
	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;
}
4017

4018 4019 4020 4021 4022 4023 4024 4025 4026 4027 4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048 4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073
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;

	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);
		}
		spin_unlock_irq(&conf->device_lock);
	}
	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);
}

4074
static void make_request(struct mddev *mddev, struct bio * bi)
L
Linus Torvalds 已提交
4075
{
4076
	struct r5conf *conf = mddev->private;
4077
	int dd_idx;
L
Linus Torvalds 已提交
4078 4079 4080
	sector_t new_sector;
	sector_t logical_sector, last_sector;
	struct stripe_head *sh;
4081
	const int rw = bio_data_dir(bi);
4082
	int remaining;
L
Linus Torvalds 已提交
4083

T
Tejun Heo 已提交
4084 4085
	if (unlikely(bi->bi_rw & REQ_FLUSH)) {
		md_flush_request(mddev, bi);
4086
		return;
4087 4088
	}

4089
	md_write_start(mddev, bi);
4090

4091
	if (rw == READ &&
4092
	     mddev->reshape_position == MaxSector &&
4093
	     chunk_aligned_read(mddev,bi))
4094
		return;
4095

L
Linus Torvalds 已提交
4096 4097 4098 4099
	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 */
4100

L
Linus Torvalds 已提交
4101 4102
	for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
		DEFINE_WAIT(w);
4103
		int previous;
4104

4105
	retry:
4106
		previous = 0;
4107
		prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
4108
		if (unlikely(conf->reshape_progress != MaxSector)) {
4109
			/* spinlock is needed as reshape_progress may be
4110 4111
			 * 64bit on a 32bit platform, and so it might be
			 * possible to see a half-updated value
4112
			 * Of course reshape_progress could change after
4113 4114 4115 4116
			 * the lock is dropped, so once we get a reference
			 * to the stripe that we think it is, we will have
			 * to check again.
			 */
4117
			spin_lock_irq(&conf->device_lock);
4118
			if (mddev->reshape_backwards
4119 4120
			    ? logical_sector < conf->reshape_progress
			    : logical_sector >= conf->reshape_progress) {
4121 4122
				previous = 1;
			} else {
4123
				if (mddev->reshape_backwards
4124 4125
				    ? logical_sector < conf->reshape_safe
				    : logical_sector >= conf->reshape_safe) {
4126 4127 4128 4129 4130
					spin_unlock_irq(&conf->device_lock);
					schedule();
					goto retry;
				}
			}
4131 4132
			spin_unlock_irq(&conf->device_lock);
		}
4133

4134 4135
		new_sector = raid5_compute_sector(conf, logical_sector,
						  previous,
4136
						  &dd_idx, NULL);
4137
		pr_debug("raid456: make_request, sector %llu logical %llu\n",
L
Linus Torvalds 已提交
4138 4139 4140
			(unsigned long long)new_sector, 
			(unsigned long long)logical_sector);

4141
		sh = get_active_stripe(conf, new_sector, previous,
4142
				       (bi->bi_rw&RWA_MASK), 0);
L
Linus Torvalds 已提交
4143
		if (sh) {
4144
			if (unlikely(previous)) {
4145
				/* expansion might have moved on while waiting for a
4146 4147 4148 4149 4150 4151
				 * 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.
4152 4153 4154
				 */
				int must_retry = 0;
				spin_lock_irq(&conf->device_lock);
4155
				if (mddev->reshape_backwards
4156 4157
				    ? logical_sector >= conf->reshape_progress
				    : logical_sector < conf->reshape_progress)
4158 4159 4160 4161 4162
					/* mismatch, need to try again */
					must_retry = 1;
				spin_unlock_irq(&conf->device_lock);
				if (must_retry) {
					release_stripe(sh);
4163
					schedule();
4164 4165 4166
					goto retry;
				}
			}
4167

4168
			if (rw == WRITE &&
4169
			    logical_sector >= mddev->suspend_lo &&
4170 4171
			    logical_sector < mddev->suspend_hi) {
				release_stripe(sh);
4172 4173 4174 4175 4176 4177 4178 4179 4180 4181
				/* 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();
4182 4183
				goto retry;
			}
4184 4185

			if (test_bit(STRIPE_EXPANDING, &sh->state) ||
4186
			    !add_stripe_bio(sh, bi, dd_idx, rw)) {
4187 4188
				/* Stripe is busy expanding or
				 * add failed due to overlap.  Flush everything
L
Linus Torvalds 已提交
4189 4190
				 * and wait a while
				 */
N
NeilBrown 已提交
4191
				md_wakeup_thread(mddev->thread);
L
Linus Torvalds 已提交
4192 4193 4194 4195 4196
				release_stripe(sh);
				schedule();
				goto retry;
			}
			finish_wait(&conf->wait_for_overlap, &w);
4197 4198
			set_bit(STRIPE_HANDLE, &sh->state);
			clear_bit(STRIPE_DELAYED, &sh->state);
4199
			if ((bi->bi_rw & REQ_SYNC) &&
4200 4201
			    !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
				atomic_inc(&conf->preread_active_stripes);
4202
			release_stripe_plug(mddev, sh);
L
Linus Torvalds 已提交
4203 4204 4205 4206 4207 4208 4209
		} 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;
		}
	}
4210

4211
	remaining = raid5_dec_bi_active_stripes(bi);
4212
	if (remaining == 0) {
L
Linus Torvalds 已提交
4213

4214
		if ( rw == WRITE )
L
Linus Torvalds 已提交
4215
			md_write_end(mddev);
4216

4217
		bio_endio(bi, 0);
L
Linus Torvalds 已提交
4218 4219 4220
	}
}

4221
static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
D
Dan Williams 已提交
4222

4223
static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
L
Linus Torvalds 已提交
4224
{
4225 4226 4227 4228 4229 4230 4231 4232 4233
	/* 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.
	 */
4234
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4235
	struct stripe_head *sh;
4236
	sector_t first_sector, last_sector;
4237 4238 4239
	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;
4240 4241
	int i;
	int dd_idx;
4242
	sector_t writepos, readpos, safepos;
4243
	sector_t stripe_addr;
4244
	int reshape_sectors;
4245
	struct list_head stripes;
4246

4247 4248
	if (sector_nr == 0) {
		/* If restarting in the middle, skip the initial sectors */
4249
		if (mddev->reshape_backwards &&
4250 4251 4252
		    conf->reshape_progress < raid5_size(mddev, 0, 0)) {
			sector_nr = raid5_size(mddev, 0, 0)
				- conf->reshape_progress;
4253
		} else if (!mddev->reshape_backwards &&
4254 4255
			   conf->reshape_progress > 0)
			sector_nr = conf->reshape_progress;
4256
		sector_div(sector_nr, new_data_disks);
4257
		if (sector_nr) {
4258 4259
			mddev->curr_resync_completed = sector_nr;
			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4260 4261 4262
			*skipped = 1;
			return sector_nr;
		}
4263 4264
	}

4265 4266 4267 4268
	/* 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
	 */
4269 4270
	if (mddev->new_chunk_sectors > mddev->chunk_sectors)
		reshape_sectors = mddev->new_chunk_sectors;
4271
	else
4272
		reshape_sectors = mddev->chunk_sectors;
4273

4274 4275 4276 4277 4278
	/* 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
4279
	 */
4280
	writepos = conf->reshape_progress;
4281
	sector_div(writepos, new_data_disks);
4282 4283
	readpos = conf->reshape_progress;
	sector_div(readpos, data_disks);
4284
	safepos = conf->reshape_safe;
4285
	sector_div(safepos, data_disks);
4286
	if (mddev->reshape_backwards) {
4287
		writepos -= min_t(sector_t, reshape_sectors, writepos);
4288
		readpos += reshape_sectors;
4289
		safepos += reshape_sectors;
4290
	} else {
4291
		writepos += reshape_sectors;
4292 4293
		readpos -= min_t(sector_t, reshape_sectors, readpos);
		safepos -= min_t(sector_t, reshape_sectors, safepos);
4294
	}
4295

4296 4297 4298 4299 4300 4301 4302 4303 4304 4305 4306 4307 4308 4309 4310
	/* 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;
	}

4311 4312 4313 4314
	/* '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.
4315 4316 4317 4318
	 * 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
4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330
	 * 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???
	 */
4331 4332 4333 4334 4335 4336
	if (conf->min_offset_diff < 0) {
		safepos += -conf->min_offset_diff;
		readpos += -conf->min_offset_diff;
	} else
		writepos += conf->min_offset_diff;

4337
	if ((mddev->reshape_backwards
4338 4339 4340
	     ? (safepos > writepos && readpos < writepos)
	     : (safepos < writepos && readpos > writepos)) ||
	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4341 4342 4343
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes)==0);
4344
		mddev->reshape_position = conf->reshape_progress;
4345
		mddev->curr_resync_completed = sector_nr;
4346
		conf->reshape_checkpoint = jiffies;
4347
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
4348
		md_wakeup_thread(mddev->thread);
4349
		wait_event(mddev->sb_wait, mddev->flags == 0 ||
4350 4351
			   kthread_should_stop());
		spin_lock_irq(&conf->device_lock);
4352
		conf->reshape_safe = mddev->reshape_position;
4353 4354
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4355
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4356 4357
	}

4358
	INIT_LIST_HEAD(&stripes);
4359
	for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
4360
		int j;
4361
		int skipped_disk = 0;
4362
		sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
4363 4364 4365 4366 4367 4368 4369 4370 4371
		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;
4372
			if (conf->level == 6 &&
4373
			    j == sh->qd_idx)
4374
				continue;
4375
			s = compute_blocknr(sh, j, 0);
D
Dan Williams 已提交
4376
			if (s < raid5_size(mddev, 0, 0)) {
4377
				skipped_disk = 1;
4378 4379 4380 4381 4382 4383
				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);
		}
4384
		if (!skipped_disk) {
4385 4386 4387
			set_bit(STRIPE_EXPAND_READY, &sh->state);
			set_bit(STRIPE_HANDLE, &sh->state);
		}
4388
		list_add(&sh->lru, &stripes);
4389 4390
	}
	spin_lock_irq(&conf->device_lock);
4391
	if (mddev->reshape_backwards)
4392
		conf->reshape_progress -= reshape_sectors * new_data_disks;
4393
	else
4394
		conf->reshape_progress += reshape_sectors * new_data_disks;
4395 4396 4397 4398 4399 4400 4401
	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 =
4402
		raid5_compute_sector(conf, stripe_addr*(new_data_disks),
4403
				     1, &dd_idx, NULL);
4404
	last_sector =
4405
		raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
4406
					    * new_data_disks - 1),
4407
				     1, &dd_idx, NULL);
A
Andre Noll 已提交
4408 4409
	if (last_sector >= mddev->dev_sectors)
		last_sector = mddev->dev_sectors - 1;
4410
	while (first_sector <= last_sector) {
4411
		sh = get_active_stripe(conf, first_sector, 1, 0, 1);
4412 4413 4414 4415 4416
		set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
		set_bit(STRIPE_HANDLE, &sh->state);
		release_stripe(sh);
		first_sector += STRIPE_SECTORS;
	}
4417 4418 4419 4420 4421 4422 4423 4424
	/* 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);
	}
4425 4426 4427
	/* If this takes us to the resync_max point where we have to pause,
	 * then we need to write out the superblock.
	 */
4428
	sector_nr += reshape_sectors;
4429 4430
	if ((sector_nr - mddev->curr_resync_completed) * 2
	    >= mddev->resync_max - mddev->curr_resync_completed) {
4431 4432 4433
		/* Cannot proceed until we've updated the superblock... */
		wait_event(conf->wait_for_overlap,
			   atomic_read(&conf->reshape_stripes) == 0);
4434
		mddev->reshape_position = conf->reshape_progress;
4435
		mddev->curr_resync_completed = sector_nr;
4436
		conf->reshape_checkpoint = jiffies;
4437 4438 4439 4440 4441 4442
		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);
4443
		conf->reshape_safe = mddev->reshape_position;
4444 4445
		spin_unlock_irq(&conf->device_lock);
		wake_up(&conf->wait_for_overlap);
4446
		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4447
	}
4448
	return reshape_sectors;
4449 4450 4451
}

/* FIXME go_faster isn't used */
4452
static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
4453
{
4454
	struct r5conf *conf = mddev->private;
4455
	struct stripe_head *sh;
A
Andre Noll 已提交
4456
	sector_t max_sector = mddev->dev_sectors;
N
NeilBrown 已提交
4457
	sector_t sync_blocks;
4458 4459
	int still_degraded = 0;
	int i;
L
Linus Torvalds 已提交
4460

4461
	if (sector_nr >= max_sector) {
L
Linus Torvalds 已提交
4462
		/* just being told to finish up .. nothing much to do */
4463

4464 4465 4466 4467
		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
			end_reshape(conf);
			return 0;
		}
4468 4469 4470 4471

		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
					&sync_blocks, 1);
4472
		else /* completed sync */
4473 4474 4475
			conf->fullsync = 0;
		bitmap_close_sync(mddev->bitmap);

L
Linus Torvalds 已提交
4476 4477
		return 0;
	}
4478

4479 4480 4481
	/* Allow raid5_quiesce to complete */
	wait_event(conf->wait_for_overlap, conf->quiesce != 2);

4482 4483
	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
		return reshape_request(mddev, sector_nr, skipped);
4484

4485 4486 4487 4488 4489 4490
	/* 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
	 */

4491
	/* if there is too many failed drives and we are trying
L
Linus Torvalds 已提交
4492 4493 4494
	 * to resync, then assert that we are finished, because there is
	 * nothing we can do.
	 */
4495
	if (mddev->degraded >= conf->max_degraded &&
4496
	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
A
Andre Noll 已提交
4497
		sector_t rv = mddev->dev_sectors - sector_nr;
4498
		*skipped = 1;
L
Linus Torvalds 已提交
4499 4500
		return rv;
	}
4501
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
4502
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
4503 4504 4505 4506 4507 4508
	    !conf->fullsync && sync_blocks >= STRIPE_SECTORS) {
		/* we can skip this block, and probably more */
		sync_blocks /= STRIPE_SECTORS;
		*skipped = 1;
		return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
	}
L
Linus Torvalds 已提交
4509

N
NeilBrown 已提交
4510 4511
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);

4512
	sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
L
Linus Torvalds 已提交
4513
	if (sh == NULL) {
4514
		sh = get_active_stripe(conf, sector_nr, 0, 0, 0);
L
Linus Torvalds 已提交
4515
		/* make sure we don't swamp the stripe cache if someone else
4516
		 * is trying to get access
L
Linus Torvalds 已提交
4517
		 */
4518
		schedule_timeout_uninterruptible(1);
L
Linus Torvalds 已提交
4519
	}
4520 4521 4522 4523
	/* 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.
	 */
4524
	for (i = 0; i < conf->raid_disks; i++)
4525 4526 4527 4528 4529
		if (conf->disks[i].rdev == NULL)
			still_degraded = 1;

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

4530
	set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
L
Linus Torvalds 已提交
4531

4532
	handle_stripe(sh);
L
Linus Torvalds 已提交
4533 4534 4535 4536 4537
	release_stripe(sh);

	return STRIPE_SECTORS;
}

4538
static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
4539 4540 4541 4542 4543 4544 4545 4546 4547 4548 4549 4550
{
	/* 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;
4551
	int dd_idx;
4552 4553 4554 4555 4556 4557
	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);
4558
	sector = raid5_compute_sector(conf, logical_sector,
4559
				      0, &dd_idx, NULL);
4560 4561 4562
	last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);

	for (; logical_sector < last_sector;
4563 4564 4565
	     logical_sector += STRIPE_SECTORS,
		     sector += STRIPE_SECTORS,
		     scnt++) {
4566

4567
		if (scnt < raid5_bi_processed_stripes(raid_bio))
4568 4569 4570
			/* already done this stripe */
			continue;

4571
		sh = get_active_stripe(conf, sector, 0, 1, 0);
4572 4573 4574

		if (!sh) {
			/* failed to get a stripe - must wait */
4575
			raid5_set_bi_processed_stripes(raid_bio, scnt);
4576 4577 4578 4579
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4580 4581
		if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
			release_stripe(sh);
4582
			raid5_set_bi_processed_stripes(raid_bio, scnt);
4583 4584 4585 4586
			conf->retry_read_aligned = raid_bio;
			return handled;
		}

4587
		set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
4588
		handle_stripe(sh);
4589 4590 4591
		release_stripe(sh);
		handled++;
	}
4592
	remaining = raid5_dec_bi_active_stripes(raid_bio);
4593 4594
	if (remaining == 0)
		bio_endio(raid_bio, 0);
4595 4596 4597 4598 4599
	if (atomic_dec_and_test(&conf->active_aligned_reads))
		wake_up(&conf->wait_for_stripe);
	return handled;
}

4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620 4621 4622 4623
#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;
}
4624

L
Linus Torvalds 已提交
4625 4626 4627 4628 4629 4630 4631
/*
 * 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.
 */
4632
static void raid5d(struct mddev *mddev)
L
Linus Torvalds 已提交
4633
{
4634
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
4635
	int handled;
4636
	struct blk_plug plug;
L
Linus Torvalds 已提交
4637

4638
	pr_debug("+++ raid5d active\n");
L
Linus Torvalds 已提交
4639 4640 4641

	md_check_recovery(mddev);

4642
	blk_start_plug(&plug);
L
Linus Torvalds 已提交
4643 4644 4645
	handled = 0;
	spin_lock_irq(&conf->device_lock);
	while (1) {
4646
		struct bio *bio;
4647
		int batch_size;
L
Linus Torvalds 已提交
4648

4649
		if (
4650 4651 4652
		    !list_empty(&conf->bitmap_list)) {
			/* Now is a good time to flush some bitmap updates */
			conf->seq_flush++;
4653
			spin_unlock_irq(&conf->device_lock);
4654
			bitmap_unplug(mddev->bitmap);
4655
			spin_lock_irq(&conf->device_lock);
4656
			conf->seq_write = conf->seq_flush;
4657 4658
			activate_bit_delay(conf);
		}
4659
		raid5_activate_delayed(conf);
4660

4661 4662 4663 4664 4665 4666 4667 4668 4669 4670
		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++;
		}

4671 4672
		batch_size = handle_active_stripes(conf);
		if (!batch_size)
L
Linus Torvalds 已提交
4673
			break;
4674
		handled += batch_size;
L
Linus Torvalds 已提交
4675

4676 4677
		if (mddev->flags & ~(1<<MD_CHANGE_PENDING)) {
			spin_unlock_irq(&conf->device_lock);
4678
			md_check_recovery(mddev);
4679 4680
			spin_lock_irq(&conf->device_lock);
		}
L
Linus Torvalds 已提交
4681
	}
4682
	pr_debug("%d stripes handled\n", handled);
L
Linus Torvalds 已提交
4683 4684 4685

	spin_unlock_irq(&conf->device_lock);

4686
	async_tx_issue_pending_all();
4687
	blk_finish_plug(&plug);
L
Linus Torvalds 已提交
4688

4689
	pr_debug("--- raid5d inactive\n");
L
Linus Torvalds 已提交
4690 4691
}

4692
static ssize_t
4693
raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
4694
{
4695
	struct r5conf *conf = mddev->private;
4696 4697 4698 4699
	if (conf)
		return sprintf(page, "%d\n", conf->max_nr_stripes);
	else
		return 0;
4700 4701
}

4702
int
4703
raid5_set_cache_size(struct mddev *mddev, int size)
4704
{
4705
	struct r5conf *conf = mddev->private;
4706 4707
	int err;

4708
	if (size <= 16 || size > 32768)
4709
		return -EINVAL;
4710
	while (size < conf->max_nr_stripes) {
4711 4712 4713 4714 4715
		if (drop_one_stripe(conf))
			conf->max_nr_stripes--;
		else
			break;
	}
4716 4717 4718
	err = md_allow_write(mddev);
	if (err)
		return err;
4719
	while (size > conf->max_nr_stripes) {
4720 4721 4722 4723
		if (grow_one_stripe(conf))
			conf->max_nr_stripes++;
		else break;
	}
4724 4725 4726 4727 4728
	return 0;
}
EXPORT_SYMBOL(raid5_set_cache_size);

static ssize_t
4729
raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
4730
{
4731
	struct r5conf *conf = mddev->private;
4732 4733 4734 4735 4736 4737 4738 4739 4740 4741 4742 4743 4744
	unsigned long new;
	int err;

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

	if (strict_strtoul(page, 10, &new))
		return -EINVAL;
	err = raid5_set_cache_size(mddev, new);
	if (err)
		return err;
4745 4746
	return len;
}
4747

4748 4749 4750 4751
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);
4752

4753
static ssize_t
4754
raid5_show_preread_threshold(struct mddev *mddev, char *page)
4755
{
4756
	struct r5conf *conf = mddev->private;
4757 4758 4759 4760 4761 4762 4763
	if (conf)
		return sprintf(page, "%d\n", conf->bypass_threshold);
	else
		return 0;
}

static ssize_t
4764
raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
4765
{
4766
	struct r5conf *conf = mddev->private;
4767
	unsigned long new;
4768 4769 4770 4771 4772
	if (len >= PAGE_SIZE)
		return -EINVAL;
	if (!conf)
		return -ENODEV;

4773
	if (strict_strtoul(page, 10, &new))
4774
		return -EINVAL;
4775
	if (new > conf->max_nr_stripes)
4776 4777 4778 4779 4780 4781 4782 4783 4784 4785 4786
		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);

4787
static ssize_t
4788
stripe_cache_active_show(struct mddev *mddev, char *page)
4789
{
4790
	struct r5conf *conf = mddev->private;
4791 4792 4793 4794
	if (conf)
		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
	else
		return 0;
4795 4796
}

4797 4798
static struct md_sysfs_entry
raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
4799

4800
static struct attribute *raid5_attrs[] =  {
4801 4802
	&raid5_stripecache_size.attr,
	&raid5_stripecache_active.attr,
4803
	&raid5_preread_bypass_threshold.attr,
4804 4805
	NULL,
};
4806 4807 4808
static struct attribute_group raid5_attrs_group = {
	.name = NULL,
	.attrs = raid5_attrs,
4809 4810
};

4811
static sector_t
4812
raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
4813
{
4814
	struct r5conf *conf = mddev->private;
4815 4816 4817

	if (!sectors)
		sectors = mddev->dev_sectors;
4818
	if (!raid_disks)
4819
		/* size is defined by the smallest of previous and new size */
4820
		raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
4821

4822
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
4823
	sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
4824 4825 4826
	return sectors * (raid_disks - conf->max_degraded);
}

4827
static void raid5_free_percpu(struct r5conf *conf)
4828 4829 4830 4831 4832 4833 4834 4835 4836 4837 4838
{
	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);
4839
		kfree(percpu->scribble);
4840 4841 4842 4843 4844 4845 4846 4847 4848
	}
#ifdef CONFIG_HOTPLUG_CPU
	unregister_cpu_notifier(&conf->cpu_notify);
#endif
	put_online_cpus();

	free_percpu(conf->percpu);
}

4849
static void free_conf(struct r5conf *conf)
4850 4851
{
	shrink_stripes(conf);
4852
	raid5_free_percpu(conf);
4853 4854 4855 4856 4857
	kfree(conf->disks);
	kfree(conf->stripe_hashtbl);
	kfree(conf);
}

4858 4859 4860 4861
#ifdef CONFIG_HOTPLUG_CPU
static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action,
			      void *hcpu)
{
4862
	struct r5conf *conf = container_of(nfb, struct r5conf, cpu_notify);
4863 4864 4865 4866 4867 4868
	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:
4869
		if (conf->level == 6 && !percpu->spare_page)
4870
			percpu->spare_page = alloc_page(GFP_KERNEL);
4871 4872 4873 4874 4875 4876 4877
		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);
4878 4879
			pr_err("%s: failed memory allocation for cpu%ld\n",
			       __func__, cpu);
4880
			return notifier_from_errno(-ENOMEM);
4881 4882 4883 4884 4885
		}
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		safe_put_page(percpu->spare_page);
4886
		kfree(percpu->scribble);
4887
		percpu->spare_page = NULL;
4888
		percpu->scribble = NULL;
4889 4890 4891 4892 4893 4894 4895 4896
		break;
	default:
		break;
	}
	return NOTIFY_OK;
}
#endif

4897
static int raid5_alloc_percpu(struct r5conf *conf)
4898 4899 4900
{
	unsigned long cpu;
	struct page *spare_page;
4901
	struct raid5_percpu __percpu *allcpus;
4902
	void *scribble;
4903 4904 4905 4906 4907 4908 4909 4910 4911 4912
	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) {
4913 4914 4915 4916 4917 4918 4919 4920
		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;
		}
4921
		scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
4922
		if (!scribble) {
4923 4924 4925
			err = -ENOMEM;
			break;
		}
4926
		per_cpu_ptr(conf->percpu, cpu)->scribble = scribble;
4927 4928 4929 4930 4931 4932 4933 4934 4935 4936 4937 4938
	}
#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;
}

4939
static struct r5conf *setup_conf(struct mddev *mddev)
L
Linus Torvalds 已提交
4940
{
4941
	struct r5conf *conf;
4942
	int raid_disk, memory, max_disks;
4943
	struct md_rdev *rdev;
L
Linus Torvalds 已提交
4944
	struct disk_info *disk;
4945
	char pers_name[6];
L
Linus Torvalds 已提交
4946

N
NeilBrown 已提交
4947 4948 4949
	if (mddev->new_level != 5
	    && mddev->new_level != 4
	    && mddev->new_level != 6) {
4950
		printk(KERN_ERR "md/raid:%s: raid level not set to 4/5/6 (%d)\n",
N
NeilBrown 已提交
4951 4952
		       mdname(mddev), mddev->new_level);
		return ERR_PTR(-EIO);
L
Linus Torvalds 已提交
4953
	}
N
NeilBrown 已提交
4954 4955 4956 4957
	if ((mddev->new_level == 5
	     && !algorithm_valid_raid5(mddev->new_layout)) ||
	    (mddev->new_level == 6
	     && !algorithm_valid_raid6(mddev->new_layout))) {
4958
		printk(KERN_ERR "md/raid:%s: layout %d not supported\n",
N
NeilBrown 已提交
4959 4960
		       mdname(mddev), mddev->new_layout);
		return ERR_PTR(-EIO);
4961
	}
N
NeilBrown 已提交
4962
	if (mddev->new_level == 6 && mddev->raid_disks < 4) {
4963
		printk(KERN_ERR "md/raid:%s: not enough configured devices (%d, minimum 4)\n",
N
NeilBrown 已提交
4964 4965
		       mdname(mddev), mddev->raid_disks);
		return ERR_PTR(-EINVAL);
4966 4967
	}

4968 4969 4970
	if (!mddev->new_chunk_sectors ||
	    (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
	    !is_power_of_2(mddev->new_chunk_sectors)) {
4971 4972
		printk(KERN_ERR "md/raid:%s: invalid chunk size %d\n",
		       mdname(mddev), mddev->new_chunk_sectors << 9);
N
NeilBrown 已提交
4973
		return ERR_PTR(-EINVAL);
4974 4975
	}

4976
	conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
N
NeilBrown 已提交
4977
	if (conf == NULL)
L
Linus Torvalds 已提交
4978
		goto abort;
4979 4980 4981 4982 4983 4984 4985 4986 4987 4988 4989 4990
	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;
4991
	conf->recovery_disabled = mddev->recovery_disabled - 1;
N
NeilBrown 已提交
4992 4993 4994 4995 4996

	conf->raid_disks = mddev->raid_disks;
	if (mddev->reshape_position == MaxSector)
		conf->previous_raid_disks = mddev->raid_disks;
	else
4997
		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
4998 4999
	max_disks = max(conf->raid_disks, conf->previous_raid_disks);
	conf->scribble_len = scribble_len(max_disks);
5000

5001
	conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
5002 5003 5004
			      GFP_KERNEL);
	if (!conf->disks)
		goto abort;
5005

L
Linus Torvalds 已提交
5006 5007
	conf->mddev = mddev;

5008
	if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
L
Linus Torvalds 已提交
5009 5010
		goto abort;

5011 5012 5013 5014
	conf->level = mddev->new_level;
	if (raid5_alloc_percpu(conf) != 0)
		goto abort;

5015
	pr_debug("raid456: run(%s) called.\n", mdname(mddev));
L
Linus Torvalds 已提交
5016

N
NeilBrown 已提交
5017
	rdev_for_each(rdev, mddev) {
L
Linus Torvalds 已提交
5018
		raid_disk = rdev->raid_disk;
5019
		if (raid_disk >= max_disks
L
Linus Torvalds 已提交
5020 5021 5022 5023
		    || raid_disk < 0)
			continue;
		disk = conf->disks + raid_disk;

5024 5025 5026 5027 5028 5029 5030 5031 5032
		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
5033

5034
		if (test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
5035
			char b[BDEVNAME_SIZE];
5036 5037 5038
			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
5039
		} else if (rdev->saved_raid_disk != raid_disk)
5040 5041
			/* Cannot rely on bitmap to complete recovery */
			conf->fullsync = 1;
L
Linus Torvalds 已提交
5042 5043
	}

5044
	conf->chunk_sectors = mddev->new_chunk_sectors;
N
NeilBrown 已提交
5045
	conf->level = mddev->new_level;
5046 5047 5048 5049
	if (conf->level == 6)
		conf->max_degraded = 2;
	else
		conf->max_degraded = 1;
N
NeilBrown 已提交
5050
	conf->algorithm = mddev->new_layout;
L
Linus Torvalds 已提交
5051
	conf->max_nr_stripes = NR_STRIPES;
5052
	conf->reshape_progress = mddev->reshape_position;
5053
	if (conf->reshape_progress != MaxSector) {
5054
		conf->prev_chunk_sectors = mddev->chunk_sectors;
5055 5056
		conf->prev_algo = mddev->layout;
	}
L
Linus Torvalds 已提交
5057

N
NeilBrown 已提交
5058
	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
5059
		 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
N
NeilBrown 已提交
5060 5061
	if (grow_stripes(conf, conf->max_nr_stripes)) {
		printk(KERN_ERR
5062 5063
		       "md/raid:%s: couldn't allocate %dkB for buffers\n",
		       mdname(mddev), memory);
N
NeilBrown 已提交
5064 5065
		goto abort;
	} else
5066 5067
		printk(KERN_INFO "md/raid:%s: allocated %dkB\n",
		       mdname(mddev), memory);
L
Linus Torvalds 已提交
5068

5069 5070
	sprintf(pers_name, "raid%d", mddev->new_level);
	conf->thread = md_register_thread(raid5d, mddev, pers_name);
N
NeilBrown 已提交
5071 5072
	if (!conf->thread) {
		printk(KERN_ERR
5073
		       "md/raid:%s: couldn't allocate thread.\n",
N
NeilBrown 已提交
5074
		       mdname(mddev));
5075 5076
		goto abort;
	}
N
NeilBrown 已提交
5077 5078 5079 5080 5081

	return conf;

 abort:
	if (conf) {
5082
		free_conf(conf);
N
NeilBrown 已提交
5083 5084 5085 5086 5087
		return ERR_PTR(-EIO);
	} else
		return ERR_PTR(-ENOMEM);
}

5088 5089 5090 5091 5092 5093 5094 5095 5096 5097 5098 5099 5100 5101 5102 5103 5104 5105 5106 5107 5108 5109 5110 5111 5112 5113 5114

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;
}

5115
static int run(struct mddev *mddev)
N
NeilBrown 已提交
5116
{
5117
	struct r5conf *conf;
5118
	int working_disks = 0;
5119
	int dirty_parity_disks = 0;
5120
	struct md_rdev *rdev;
5121
	sector_t reshape_offset = 0;
5122
	int i;
5123 5124
	long long min_offset_diff = 0;
	int first = 1;
N
NeilBrown 已提交
5125

5126
	if (mddev->recovery_cp != MaxSector)
5127
		printk(KERN_NOTICE "md/raid:%s: not clean"
5128 5129
		       " -- starting background reconstruction\n",
		       mdname(mddev));
5130 5131 5132 5133 5134 5135 5136 5137 5138 5139 5140 5141 5142 5143 5144 5145 5146

	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
5147 5148
	if (mddev->reshape_position != MaxSector) {
		/* Check that we can continue the reshape.
5149 5150 5151 5152 5153 5154 5155 5156 5157 5158
		 * 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
5159 5160 5161
		 */
		sector_t here_new, here_old;
		int old_disks;
5162
		int max_degraded = (mddev->level == 6 ? 2 : 1);
N
NeilBrown 已提交
5163

5164
		if (mddev->new_level != mddev->level) {
5165
			printk(KERN_ERR "md/raid:%s: unsupported reshape "
N
NeilBrown 已提交
5166 5167 5168 5169 5170 5171 5172 5173 5174 5175
			       "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;
5176
		if (sector_div(here_new, mddev->new_chunk_sectors *
N
NeilBrown 已提交
5177
			       (mddev->raid_disks - max_degraded))) {
5178 5179
			printk(KERN_ERR "md/raid:%s: reshape_position not "
			       "on a stripe boundary\n", mdname(mddev));
N
NeilBrown 已提交
5180 5181
			return -EINVAL;
		}
5182
		reshape_offset = here_new * mddev->new_chunk_sectors;
N
NeilBrown 已提交
5183 5184
		/* here_new is the stripe we will write to */
		here_old = mddev->reshape_position;
5185
		sector_div(here_old, mddev->chunk_sectors *
N
NeilBrown 已提交
5186 5187 5188
			   (old_disks-max_degraded));
		/* here_old is the first stripe that we might need to read
		 * from */
5189
		if (mddev->delta_disks == 0) {
5190 5191 5192 5193 5194 5195
			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;
			}
5196
			/* We cannot be sure it is safe to start an in-place
5197
			 * reshape.  It is only safe if user-space is monitoring
5198 5199 5200 5201 5202
			 * 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.
			 */
5203 5204 5205 5206 5207 5208 5209
			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",
5210
				       mdname(mddev));
5211 5212
				return -EINVAL;
			}
5213
		} else if (mddev->reshape_backwards
5214
		    ? (here_new * mddev->new_chunk_sectors + min_offset_diff <=
5215 5216
		       here_old * mddev->chunk_sectors)
		    : (here_new * mddev->new_chunk_sectors >=
5217
		       here_old * mddev->chunk_sectors + (-min_offset_diff))) {
N
NeilBrown 已提交
5218
			/* Reading from the same stripe as writing to - bad */
5219 5220 5221
			printk(KERN_ERR "md/raid:%s: reshape_position too early for "
			       "auto-recovery - aborting.\n",
			       mdname(mddev));
N
NeilBrown 已提交
5222 5223
			return -EINVAL;
		}
5224 5225
		printk(KERN_INFO "md/raid:%s: reshape will continue\n",
		       mdname(mddev));
N
NeilBrown 已提交
5226 5227 5228 5229
		/* OK, we should be able to continue; */
	} else {
		BUG_ON(mddev->level != mddev->new_level);
		BUG_ON(mddev->layout != mddev->new_layout);
5230
		BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
N
NeilBrown 已提交
5231
		BUG_ON(mddev->delta_disks != 0);
L
Linus Torvalds 已提交
5232
	}
N
NeilBrown 已提交
5233

5234 5235 5236 5237 5238
	if (mddev->private == NULL)
		conf = setup_conf(mddev);
	else
		conf = mddev->private;

N
NeilBrown 已提交
5239 5240 5241
	if (IS_ERR(conf))
		return PTR_ERR(conf);

5242
	conf->min_offset_diff = min_offset_diff;
N
NeilBrown 已提交
5243 5244 5245 5246
	mddev->thread = conf->thread;
	conf->thread = NULL;
	mddev->private = conf;

5247 5248 5249 5250 5251 5252 5253 5254 5255 5256 5257
	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)
5258
			continue;
5259 5260 5261 5262 5263 5264 5265
		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;
		}
5266
		if (test_bit(In_sync, &rdev->flags)) {
N
NeilBrown 已提交
5267
			working_disks++;
5268 5269
			continue;
		}
5270 5271 5272 5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286 5287 5288 5289 5290 5291 5292 5293 5294 5295 5296 5297
		/* This disc is not fully in-sync.  However if it
		 * just stored parity (beyond the recovery_offset),
		 * when we don't need to be concerned about the
		 * array being dirty.
		 * When reshape goes 'backwards', we never have
		 * partially completed devices, so we only need
		 * to worry about reshape going forwards.
		 */
		/* Hack because v0.91 doesn't store recovery_offset properly. */
		if (mddev->major_version == 0 &&
		    mddev->minor_version > 90)
			rdev->recovery_offset = reshape_offset;
			
		if (rdev->recovery_offset < reshape_offset) {
			/* We need to check old and new layout */
			if (!only_parity(rdev->raid_disk,
					 conf->algorithm,
					 conf->raid_disks,
					 conf->max_degraded))
				continue;
		}
		if (!only_parity(rdev->raid_disk,
				 conf->prev_algo,
				 conf->previous_raid_disks,
				 conf->max_degraded))
			continue;
		dirty_parity_disks++;
	}
N
NeilBrown 已提交
5298

5299 5300 5301
	/*
	 * 0 for a fully functional array, 1 or 2 for a degraded array.
	 */
5302
	mddev->degraded = calc_degraded(conf);
N
NeilBrown 已提交
5303

5304
	if (has_failed(conf)) {
5305
		printk(KERN_ERR "md/raid:%s: not enough operational devices"
L
Linus Torvalds 已提交
5306
			" (%d/%d failed)\n",
5307
			mdname(mddev), mddev->degraded, conf->raid_disks);
L
Linus Torvalds 已提交
5308 5309 5310
		goto abort;
	}

N
NeilBrown 已提交
5311
	/* device size must be a multiple of chunk size */
5312
	mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
N
NeilBrown 已提交
5313 5314
	mddev->resync_max_sectors = mddev->dev_sectors;

5315
	if (mddev->degraded > dirty_parity_disks &&
L
Linus Torvalds 已提交
5316
	    mddev->recovery_cp != MaxSector) {
5317 5318
		if (mddev->ok_start_degraded)
			printk(KERN_WARNING
5319 5320
			       "md/raid:%s: starting dirty degraded array"
			       " - data corruption possible.\n",
5321 5322 5323
			       mdname(mddev));
		else {
			printk(KERN_ERR
5324
			       "md/raid:%s: cannot start dirty degraded array.\n",
5325 5326 5327
			       mdname(mddev));
			goto abort;
		}
L
Linus Torvalds 已提交
5328 5329 5330
	}

	if (mddev->degraded == 0)
5331 5332
		printk(KERN_INFO "md/raid:%s: raid level %d active with %d out of %d"
		       " devices, algorithm %d\n", mdname(mddev), conf->level,
5333 5334
		       mddev->raid_disks-mddev->degraded, mddev->raid_disks,
		       mddev->new_layout);
L
Linus Torvalds 已提交
5335
	else
5336 5337 5338 5339 5340
		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
5341 5342 5343

	print_raid5_conf(conf);

5344 5345
	if (conf->reshape_progress != MaxSector) {
		conf->reshape_safe = conf->reshape_progress;
5346 5347 5348 5349 5350 5351
		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,
5352
							"reshape");
5353 5354
	}

L
Linus Torvalds 已提交
5355 5356

	/* Ok, everything is just fine now */
5357 5358
	if (mddev->to_remove == &raid5_attrs_group)
		mddev->to_remove = NULL;
N
NeilBrown 已提交
5359 5360
	else if (mddev->kobj.sd &&
	    sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
5361
		printk(KERN_WARNING
5362
		       "raid5: failed to create sysfs attributes for %s\n",
5363
		       mdname(mddev));
5364
	md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
5365

5366
	if (mddev->queue) {
5367
		int chunk_size;
5368 5369 5370 5371 5372 5373 5374 5375 5376
		/* 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
5377

5378
		blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
5379

N
NeilBrown 已提交
5380 5381
		mddev->queue->backing_dev_info.congested_data = mddev;
		mddev->queue->backing_dev_info.congested_fn = raid5_congested;
5382

5383 5384 5385 5386
		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));
5387

5388
		rdev_for_each(rdev, mddev) {
5389 5390
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
5391 5392 5393
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->new_data_offset << 9);
		}
5394
	}
5395

L
Linus Torvalds 已提交
5396 5397
	return 0;
abort:
5398
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
5399 5400
	print_raid5_conf(conf);
	free_conf(conf);
L
Linus Torvalds 已提交
5401
	mddev->private = NULL;
5402
	printk(KERN_ALERT "md/raid:%s: failed to run raid set.\n", mdname(mddev));
L
Linus Torvalds 已提交
5403 5404 5405
	return -EIO;
}

5406
static int stop(struct mddev *mddev)
L
Linus Torvalds 已提交
5407
{
5408
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5409

5410
	md_unregister_thread(&mddev->thread);
N
NeilBrown 已提交
5411 5412
	if (mddev->queue)
		mddev->queue->backing_dev_info.congested_fn = NULL;
5413
	free_conf(conf);
5414 5415
	mddev->private = NULL;
	mddev->to_remove = &raid5_attrs_group;
L
Linus Torvalds 已提交
5416 5417 5418
	return 0;
}

5419
static void status(struct seq_file *seq, struct mddev *mddev)
L
Linus Torvalds 已提交
5420
{
5421
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5422 5423
	int i;

5424 5425
	seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
		mddev->chunk_sectors / 2, mddev->layout);
5426
	seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
L
Linus Torvalds 已提交
5427 5428 5429
	for (i = 0; i < conf->raid_disks; i++)
		seq_printf (seq, "%s",
			       conf->disks[i].rdev &&
5430
			       test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
L
Linus Torvalds 已提交
5431 5432 5433
	seq_printf (seq, "]");
}

5434
static void print_raid5_conf (struct r5conf *conf)
L
Linus Torvalds 已提交
5435 5436 5437 5438
{
	int i;
	struct disk_info *tmp;

5439
	printk(KERN_DEBUG "RAID conf printout:\n");
L
Linus Torvalds 已提交
5440 5441 5442 5443
	if (!conf) {
		printk("(conf==NULL)\n");
		return;
	}
5444 5445 5446
	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
5447 5448 5449 5450 5451

	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
		tmp = conf->disks + i;
		if (tmp->rdev)
5452 5453 5454
			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
5455 5456 5457
	}
}

5458
static int raid5_spare_active(struct mddev *mddev)
L
Linus Torvalds 已提交
5459 5460
{
	int i;
5461
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5462
	struct disk_info *tmp;
5463 5464
	int count = 0;
	unsigned long flags;
L
Linus Torvalds 已提交
5465 5466 5467

	for (i = 0; i < conf->raid_disks; i++) {
		tmp = conf->disks + i;
5468 5469 5470 5471 5472 5473 5474 5475 5476 5477 5478 5479 5480 5481 5482 5483 5484 5485 5486
		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
5487
		    && tmp->rdev->recovery_offset == MaxSector
5488
		    && !test_bit(Faulty, &tmp->rdev->flags)
5489
		    && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
5490
			count++;
5491
			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
L
Linus Torvalds 已提交
5492 5493
		}
	}
5494
	spin_lock_irqsave(&conf->device_lock, flags);
5495
	mddev->degraded = calc_degraded(conf);
5496
	spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
5497
	print_raid5_conf(conf);
5498
	return count;
L
Linus Torvalds 已提交
5499 5500
}

5501
static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5502
{
5503
	struct r5conf *conf = mddev->private;
L
Linus Torvalds 已提交
5504
	int err = 0;
5505
	int number = rdev->raid_disk;
5506
	struct md_rdev **rdevp;
L
Linus Torvalds 已提交
5507 5508 5509
	struct disk_info *p = conf->disks + number;

	print_raid5_conf(conf);
5510 5511 5512 5513 5514 5515 5516 5517 5518 5519 5520 5521 5522 5523 5524 5525 5526 5527 5528 5529 5530 5531
	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) &&
5532
	    (!p->replacement || p->replacement == rdev) &&
5533 5534 5535 5536 5537 5538 5539 5540 5541 5542
	    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;
5543 5544 5545 5546 5547 5548 5549 5550 5551 5552 5553 5554 5555 5556
	} 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
5557 5558 5559 5560 5561 5562
abort:

	print_raid5_conf(conf);
	return err;
}

5563
static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
L
Linus Torvalds 已提交
5564
{
5565
	struct r5conf *conf = mddev->private;
5566
	int err = -EEXIST;
L
Linus Torvalds 已提交
5567 5568
	int disk;
	struct disk_info *p;
5569 5570
	int first = 0;
	int last = conf->raid_disks - 1;
L
Linus Torvalds 已提交
5571

5572 5573 5574
	if (mddev->recovery_disabled == conf->recovery_disabled)
		return -EBUSY;

N
NeilBrown 已提交
5575
	if (rdev->saved_raid_disk < 0 && has_failed(conf))
L
Linus Torvalds 已提交
5576
		/* no point adding a device */
5577
		return -EINVAL;
L
Linus Torvalds 已提交
5578

5579 5580
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;
L
Linus Torvalds 已提交
5581 5582

	/*
5583 5584
	 * find the disk ... but prefer rdev->saved_raid_disk
	 * if possible.
L
Linus Torvalds 已提交
5585
	 */
5586
	if (rdev->saved_raid_disk >= 0 &&
5587
	    rdev->saved_raid_disk >= first &&
5588
	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
5589 5590 5591
		first = rdev->saved_raid_disk;

	for (disk = first; disk <= last; disk++) {
5592 5593
		p = conf->disks + disk;
		if (p->rdev == NULL) {
5594
			clear_bit(In_sync, &rdev->flags);
L
Linus Torvalds 已提交
5595
			rdev->raid_disk = disk;
5596
			err = 0;
5597 5598
			if (rdev->saved_raid_disk != disk)
				conf->fullsync = 1;
5599
			rcu_assign_pointer(p->rdev, rdev);
5600
			goto out;
L
Linus Torvalds 已提交
5601
		}
5602 5603 5604
	}
	for (disk = first; disk <= last; disk++) {
		p = conf->disks + disk;
5605 5606 5607 5608 5609 5610 5611 5612 5613 5614 5615
		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;
		}
	}
5616
out:
L
Linus Torvalds 已提交
5617
	print_raid5_conf(conf);
5618
	return err;
L
Linus Torvalds 已提交
5619 5620
}

5621
static int raid5_resize(struct mddev *mddev, sector_t sectors)
L
Linus Torvalds 已提交
5622 5623 5624 5625 5626 5627 5628 5629
{
	/* 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.
	 */
5630
	sector_t newsize;
5631
	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
5632 5633 5634
	newsize = raid5_size(mddev, sectors, mddev->raid_disks);
	if (mddev->external_size &&
	    mddev->array_sectors > newsize)
D
Dan Williams 已提交
5635
		return -EINVAL;
5636 5637 5638 5639 5640 5641
	if (mddev->bitmap) {
		int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
		if (ret)
			return ret;
	}
	md_set_array_sectors(mddev, newsize);
5642
	set_capacity(mddev->gendisk, mddev->array_sectors);
5643
	revalidate_disk(mddev->gendisk);
5644 5645
	if (sectors > mddev->dev_sectors &&
	    mddev->recovery_cp > mddev->dev_sectors) {
A
Andre Noll 已提交
5646
		mddev->recovery_cp = mddev->dev_sectors;
L
Linus Torvalds 已提交
5647 5648
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
A
Andre Noll 已提交
5649
	mddev->dev_sectors = sectors;
5650
	mddev->resync_max_sectors = sectors;
L
Linus Torvalds 已提交
5651 5652 5653
	return 0;
}

5654
static int check_stripe_cache(struct mddev *mddev)
5655 5656 5657 5658 5659 5660 5661 5662 5663
{
	/* 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.
	 */
5664
	struct r5conf *conf = mddev->private;
5665 5666 5667 5668
	if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes ||
	    ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
	    > conf->max_nr_stripes) {
5669 5670
		printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
		       mdname(mddev),
5671 5672 5673 5674 5675 5676 5677
		       ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
			/ STRIPE_SIZE)*4);
		return 0;
	}
	return 1;
}

5678
static int check_reshape(struct mddev *mddev)
5679
{
5680
	struct r5conf *conf = mddev->private;
5681

5682 5683
	if (mddev->delta_disks == 0 &&
	    mddev->new_layout == mddev->layout &&
5684
	    mddev->new_chunk_sectors == mddev->chunk_sectors)
5685
		return 0; /* nothing to do */
5686
	if (has_failed(conf))
5687 5688 5689 5690 5691 5692 5693 5694 5695 5696 5697 5698 5699
		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;
	}
5700

5701
	if (!check_stripe_cache(mddev))
5702 5703
		return -ENOSPC;

5704
	return resize_stripes(conf, conf->raid_disks + mddev->delta_disks);
5705 5706
}

5707
static int raid5_start_reshape(struct mddev *mddev)
5708
{
5709
	struct r5conf *conf = mddev->private;
5710
	struct md_rdev *rdev;
5711
	int spares = 0;
5712
	unsigned long flags;
5713

5714
	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
5715 5716
		return -EBUSY;

5717 5718 5719
	if (!check_stripe_cache(mddev))
		return -ENOSPC;

5720 5721 5722
	if (has_failed(conf))
		return -EINVAL;

5723
	rdev_for_each(rdev, mddev) {
5724 5725
		if (!test_bit(In_sync, &rdev->flags)
		    && !test_bit(Faulty, &rdev->flags))
5726
			spares++;
5727
	}
5728

5729
	if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
5730 5731 5732 5733 5734
		/* Not enough devices even to make a degraded array
		 * of that size
		 */
		return -EINVAL;

5735 5736 5737 5738 5739 5740
	/* 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) {
5741
		printk(KERN_ERR "md/raid:%s: array size must be reduced "
5742 5743 5744 5745
		       "before number of disks\n", mdname(mddev));
		return -EINVAL;
	}

5746
	atomic_set(&conf->reshape_stripes, 0);
5747 5748
	spin_lock_irq(&conf->device_lock);
	conf->previous_raid_disks = conf->raid_disks;
5749
	conf->raid_disks += mddev->delta_disks;
5750 5751
	conf->prev_chunk_sectors = conf->chunk_sectors;
	conf->chunk_sectors = mddev->new_chunk_sectors;
5752 5753
	conf->prev_algo = conf->algorithm;
	conf->algorithm = mddev->new_layout;
5754 5755 5756 5757 5758
	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();
5759
	if (mddev->reshape_backwards)
5760 5761 5762 5763
		conf->reshape_progress = raid5_size(mddev, 0, 0);
	else
		conf->reshape_progress = 0;
	conf->reshape_safe = conf->reshape_progress;
5764 5765 5766 5767
	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.
5768 5769 5770 5771
	 * 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.
5772
	 */
5773
	if (mddev->delta_disks >= 0) {
N
NeilBrown 已提交
5774
		rdev_for_each(rdev, mddev)
5775 5776 5777 5778
			if (rdev->raid_disk < 0 &&
			    !test_bit(Faulty, &rdev->flags)) {
				if (raid5_add_disk(mddev, rdev) == 0) {
					if (rdev->raid_disk
5779
					    >= conf->previous_raid_disks)
5780
						set_bit(In_sync, &rdev->flags);
5781
					else
5782
						rdev->recovery_offset = 0;
5783 5784

					if (sysfs_link_rdev(mddev, rdev))
5785
						/* Failure here is OK */;
5786
				}
5787 5788 5789 5790 5791
			} 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);
			}
5792

5793 5794 5795 5796
		/* When a reshape changes the number of devices,
		 * ->degraded is measured against the larger of the
		 * pre and post number of devices.
		 */
5797
		spin_lock_irqsave(&conf->device_lock, flags);
5798
		mddev->degraded = calc_degraded(conf);
5799 5800
		spin_unlock_irqrestore(&conf->device_lock, flags);
	}
5801
	mddev->raid_disks = conf->raid_disks;
5802
	mddev->reshape_position = conf->reshape_progress;
5803
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
5804

5805 5806 5807 5808 5809
	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,
5810
						"reshape");
5811 5812 5813 5814
	if (!mddev->sync_thread) {
		mddev->recovery = 0;
		spin_lock_irq(&conf->device_lock);
		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
5815 5816 5817
		rdev_for_each(rdev, mddev)
			rdev->new_data_offset = rdev->data_offset;
		smp_wmb();
5818
		conf->reshape_progress = MaxSector;
5819
		mddev->reshape_position = MaxSector;
5820 5821 5822
		spin_unlock_irq(&conf->device_lock);
		return -EAGAIN;
	}
5823
	conf->reshape_checkpoint = jiffies;
5824 5825 5826 5827 5828
	md_wakeup_thread(mddev->sync_thread);
	md_new_event(mddev);
	return 0;
}

5829 5830 5831
/* This is called from the reshape thread and should make any
 * changes needed in 'conf'
 */
5832
static void end_reshape(struct r5conf *conf)
5833 5834
{

5835
	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
5836
		struct md_rdev *rdev;
5837 5838

		spin_lock_irq(&conf->device_lock);
5839
		conf->previous_raid_disks = conf->raid_disks;
5840 5841 5842
		rdev_for_each(rdev, conf->mddev)
			rdev->data_offset = rdev->new_data_offset;
		smp_wmb();
5843
		conf->reshape_progress = MaxSector;
5844
		spin_unlock_irq(&conf->device_lock);
5845
		wake_up(&conf->wait_for_overlap);
5846 5847 5848 5849

		/* read-ahead size must cover two whole stripes, which is
		 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
		 */
5850
		if (conf->mddev->queue) {
5851
			int data_disks = conf->raid_disks - conf->max_degraded;
5852
			int stripe = data_disks * ((conf->chunk_sectors << 9)
5853
						   / PAGE_SIZE);
5854 5855 5856
			if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
				conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
		}
5857 5858 5859
	}
}

5860 5861 5862
/* This is called from the raid5d thread with mddev_lock held.
 * It makes config changes to the device.
 */
5863
static void raid5_finish_reshape(struct mddev *mddev)
5864
{
5865
	struct r5conf *conf = mddev->private;
5866 5867 5868

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

5869 5870 5871
		if (mddev->delta_disks > 0) {
			md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
			set_capacity(mddev->gendisk, mddev->array_sectors);
5872
			revalidate_disk(mddev->gendisk);
5873 5874
		} else {
			int d;
5875 5876 5877
			spin_lock_irq(&conf->device_lock);
			mddev->degraded = calc_degraded(conf);
			spin_unlock_irq(&conf->device_lock);
5878 5879
			for (d = conf->raid_disks ;
			     d < conf->raid_disks - mddev->delta_disks;
5880
			     d++) {
5881
				struct md_rdev *rdev = conf->disks[d].rdev;
5882 5883 5884 5885 5886
				if (rdev)
					clear_bit(In_sync, &rdev->flags);
				rdev = conf->disks[d].replacement;
				if (rdev)
					clear_bit(In_sync, &rdev->flags);
5887
			}
5888
		}
5889
		mddev->layout = conf->algorithm;
5890
		mddev->chunk_sectors = conf->chunk_sectors;
5891 5892
		mddev->reshape_position = MaxSector;
		mddev->delta_disks = 0;
5893
		mddev->reshape_backwards = 0;
5894 5895 5896
	}
}

5897
static void raid5_quiesce(struct mddev *mddev, int state)
5898
{
5899
	struct r5conf *conf = mddev->private;
5900 5901

	switch(state) {
5902 5903 5904 5905
	case 2: /* resume for a suspend */
		wake_up(&conf->wait_for_overlap);
		break;

5906 5907
	case 1: /* stop all writes */
		spin_lock_irq(&conf->device_lock);
5908 5909 5910 5911
		/* '2' tells resync/reshape to pause so that all
		 * active stripes can drain
		 */
		conf->quiesce = 2;
5912
		wait_event_lock_irq(conf->wait_for_stripe,
5913 5914
				    atomic_read(&conf->active_stripes) == 0 &&
				    atomic_read(&conf->active_aligned_reads) == 0,
5915
				    conf->device_lock, /* nothing */);
5916
		conf->quiesce = 1;
5917
		spin_unlock_irq(&conf->device_lock);
5918 5919
		/* allow reshape to continue */
		wake_up(&conf->wait_for_overlap);
5920 5921 5922 5923 5924 5925
		break;

	case 0: /* re-enable writes */
		spin_lock_irq(&conf->device_lock);
		conf->quiesce = 0;
		wake_up(&conf->wait_for_stripe);
5926
		wake_up(&conf->wait_for_overlap);
5927 5928 5929 5930
		spin_unlock_irq(&conf->device_lock);
		break;
	}
}
5931

5932

5933
static void *raid45_takeover_raid0(struct mddev *mddev, int level)
5934
{
5935
	struct r0conf *raid0_conf = mddev->private;
5936
	sector_t sectors;
5937

D
Dan Williams 已提交
5938
	/* for raid0 takeover only one zone is supported */
5939
	if (raid0_conf->nr_strip_zones > 1) {
5940 5941
		printk(KERN_ERR "md/raid:%s: cannot takeover raid0 with more than one zone.\n",
		       mdname(mddev));
D
Dan Williams 已提交
5942 5943 5944
		return ERR_PTR(-EINVAL);
	}

5945 5946
	sectors = raid0_conf->strip_zone[0].zone_end;
	sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
5947
	mddev->dev_sectors = sectors;
D
Dan Williams 已提交
5948
	mddev->new_level = level;
5949 5950 5951 5952 5953 5954 5955 5956 5957 5958 5959
	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);
}


5960
static void *raid5_takeover_raid1(struct mddev *mddev)
5961 5962 5963 5964 5965 5966 5967 5968 5969 5970 5971 5972 5973 5974 5975 5976 5977 5978 5979 5980 5981
{
	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;
5982
	mddev->new_chunk_sectors = chunksect;
5983 5984 5985 5986

	return setup_conf(mddev);
}

5987
static void *raid5_takeover_raid6(struct mddev *mddev)
5988 5989 5990 5991 5992 5993 5994 5995 5996 5997 5998 5999 6000 6001 6002 6003 6004 6005 6006 6007 6008 6009 6010 6011 6012 6013 6014 6015 6016 6017 6018 6019
{
	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);
}

6020

6021
static int raid5_check_reshape(struct mddev *mddev)
6022
{
6023 6024 6025 6026
	/* 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.
6027
	 */
6028
	struct r5conf *conf = mddev->private;
6029
	int new_chunk = mddev->new_chunk_sectors;
6030

6031
	if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
6032 6033
		return -EINVAL;
	if (new_chunk > 0) {
6034
		if (!is_power_of_2(new_chunk))
6035
			return -EINVAL;
6036
		if (new_chunk < (PAGE_SIZE>>9))
6037
			return -EINVAL;
6038
		if (mddev->array_sectors & (new_chunk-1))
6039 6040 6041 6042 6043 6044
			/* not factor of array size */
			return -EINVAL;
	}

	/* They look valid */

6045
	if (mddev->raid_disks == 2) {
6046 6047 6048 6049
		/* can make the change immediately */
		if (mddev->new_layout >= 0) {
			conf->algorithm = mddev->new_layout;
			mddev->layout = mddev->new_layout;
6050 6051
		}
		if (new_chunk > 0) {
6052 6053
			conf->chunk_sectors = new_chunk ;
			mddev->chunk_sectors = new_chunk;
6054 6055 6056
		}
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		md_wakeup_thread(mddev->thread);
6057
	}
6058
	return check_reshape(mddev);
6059 6060
}

6061
static int raid6_check_reshape(struct mddev *mddev)
6062
{
6063
	int new_chunk = mddev->new_chunk_sectors;
6064

6065
	if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
6066
		return -EINVAL;
6067
	if (new_chunk > 0) {
6068
		if (!is_power_of_2(new_chunk))
6069
			return -EINVAL;
6070
		if (new_chunk < (PAGE_SIZE >> 9))
6071
			return -EINVAL;
6072
		if (mddev->array_sectors & (new_chunk-1))
6073 6074
			/* not factor of array size */
			return -EINVAL;
6075
	}
6076 6077

	/* They look valid */
6078
	return check_reshape(mddev);
6079 6080
}

6081
static void *raid5_takeover(struct mddev *mddev)
6082 6083
{
	/* raid5 can take over:
D
Dan Williams 已提交
6084
	 *  raid0 - if there is only one strip zone - make it a raid4 layout
6085 6086 6087 6088
	 *  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
6089 6090
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 5);
6091 6092
	if (mddev->level == 1)
		return raid5_takeover_raid1(mddev);
6093 6094 6095 6096 6097
	if (mddev->level == 4) {
		mddev->new_layout = ALGORITHM_PARITY_N;
		mddev->new_level = 5;
		return setup_conf(mddev);
	}
6098 6099
	if (mddev->level == 6)
		return raid5_takeover_raid6(mddev);
6100 6101 6102 6103

	return ERR_PTR(-EINVAL);
}

6104
static void *raid4_takeover(struct mddev *mddev)
6105
{
D
Dan Williams 已提交
6106 6107 6108
	/* raid4 can take over:
	 *  raid0 - if there is only one strip zone
	 *  raid5 - if layout is right
6109
	 */
D
Dan Williams 已提交
6110 6111
	if (mddev->level == 0)
		return raid45_takeover_raid0(mddev, 4);
6112 6113 6114 6115 6116 6117 6118 6119
	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);
}
6120

6121
static struct md_personality raid5_personality;
6122

6123
static void *raid6_takeover(struct mddev *mddev)
6124 6125 6126 6127 6128 6129 6130 6131 6132 6133 6134 6135 6136 6137 6138 6139 6140 6141 6142 6143 6144 6145 6146 6147 6148 6149 6150 6151 6152 6153 6154 6155 6156 6157 6158 6159 6160 6161 6162 6163 6164 6165 6166 6167 6168 6169
{
	/* 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);
}


6170
static struct md_personality raid6_personality =
6171 6172 6173 6174 6175 6176 6177 6178 6179 6180 6181 6182 6183 6184
{
	.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,
6185
	.size		= raid5_size,
6186
	.check_reshape	= raid6_check_reshape,
6187
	.start_reshape  = raid5_start_reshape,
6188
	.finish_reshape = raid5_finish_reshape,
6189
	.quiesce	= raid5_quiesce,
6190
	.takeover	= raid6_takeover,
6191
};
6192
static struct md_personality raid5_personality =
L
Linus Torvalds 已提交
6193 6194
{
	.name		= "raid5",
6195
	.level		= 5,
L
Linus Torvalds 已提交
6196 6197 6198 6199 6200 6201 6202 6203 6204 6205 6206
	.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,
6207
	.size		= raid5_size,
6208 6209
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
6210
	.finish_reshape = raid5_finish_reshape,
6211
	.quiesce	= raid5_quiesce,
6212
	.takeover	= raid5_takeover,
L
Linus Torvalds 已提交
6213 6214
};

6215
static struct md_personality raid4_personality =
L
Linus Torvalds 已提交
6216
{
6217 6218 6219 6220 6221 6222 6223 6224 6225 6226 6227 6228 6229
	.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,
6230
	.size		= raid5_size,
6231 6232
	.check_reshape	= raid5_check_reshape,
	.start_reshape  = raid5_start_reshape,
6233
	.finish_reshape = raid5_finish_reshape,
6234
	.quiesce	= raid5_quiesce,
6235
	.takeover	= raid4_takeover,
6236 6237 6238 6239
};

static int __init raid5_init(void)
{
6240
	register_md_personality(&raid6_personality);
6241 6242 6243
	register_md_personality(&raid5_personality);
	register_md_personality(&raid4_personality);
	return 0;
L
Linus Torvalds 已提交
6244 6245
}

6246
static void raid5_exit(void)
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{
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	unregister_md_personality(&raid6_personality);
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	unregister_md_personality(&raid5_personality);
	unregister_md_personality(&raid4_personality);
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}

module_init(raid5_init);
module_exit(raid5_exit);
MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
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MODULE_ALIAS("md-personality-4"); /* RAID5 */
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MODULE_ALIAS("md-raid5");
MODULE_ALIAS("md-raid4");
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MODULE_ALIAS("md-level-5");
MODULE_ALIAS("md-level-4");
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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");