raid1.c 60.7 KB
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/*
 * raid1.c : Multiple Devices driver for Linux
 *
 * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
 *
 * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
 *
 * RAID-1 management functions.
 *
 * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
 *
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 * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
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 * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
 *
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 * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
 * bitmapped intelligence in resync:
 *
 *      - bitmap marked during normal i/o
 *      - bitmap used to skip nondirty blocks during sync
 *
 * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
 * - persistent bitmap code
 *
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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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#include <linux/delay.h>
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#include <linux/blkdev.h>
#include <linux/seq_file.h>
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#include "md.h"
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#include "raid1.h"
#include "bitmap.h"
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#define DEBUG 0
#if DEBUG
#define PRINTK(x...) printk(x)
#else
#define PRINTK(x...)
#endif
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/*
 * Number of guaranteed r1bios in case of extreme VM load:
 */
#define	NR_RAID1_BIOS 256


static void unplug_slaves(mddev_t *mddev);

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static void allow_barrier(conf_t *conf);
static void lower_barrier(conf_t *conf);
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static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
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{
	struct pool_info *pi = data;
	r1bio_t *r1_bio;
	int size = offsetof(r1bio_t, bios[pi->raid_disks]);

	/* allocate a r1bio with room for raid_disks entries in the bios array */
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	r1_bio = kzalloc(size, gfp_flags);
	if (!r1_bio)
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		unplug_slaves(pi->mddev);

	return r1_bio;
}

static void r1bio_pool_free(void *r1_bio, void *data)
{
	kfree(r1_bio);
}

#define RESYNC_BLOCK_SIZE (64*1024)
//#define RESYNC_BLOCK_SIZE PAGE_SIZE
#define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
#define RESYNC_WINDOW (2048*1024)

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static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
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{
	struct pool_info *pi = data;
	struct page *page;
	r1bio_t *r1_bio;
	struct bio *bio;
	int i, j;

	r1_bio = r1bio_pool_alloc(gfp_flags, pi);
	if (!r1_bio) {
		unplug_slaves(pi->mddev);
		return NULL;
	}

	/*
	 * Allocate bios : 1 for reading, n-1 for writing
	 */
	for (j = pi->raid_disks ; j-- ; ) {
		bio = bio_alloc(gfp_flags, RESYNC_PAGES);
		if (!bio)
			goto out_free_bio;
		r1_bio->bios[j] = bio;
	}
	/*
	 * Allocate RESYNC_PAGES data pages and attach them to
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	 * the first bio.
	 * If this is a user-requested check/repair, allocate
	 * RESYNC_PAGES for each bio.
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	 */
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	if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
		j = pi->raid_disks;
	else
		j = 1;
	while(j--) {
		bio = r1_bio->bios[j];
		for (i = 0; i < RESYNC_PAGES; i++) {
			page = alloc_page(gfp_flags);
			if (unlikely(!page))
				goto out_free_pages;

			bio->bi_io_vec[i].bv_page = page;
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			bio->bi_vcnt = i+1;
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		}
	}
	/* If not user-requests, copy the page pointers to all bios */
	if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
		for (i=0; i<RESYNC_PAGES ; i++)
			for (j=1; j<pi->raid_disks; j++)
				r1_bio->bios[j]->bi_io_vec[i].bv_page =
					r1_bio->bios[0]->bi_io_vec[i].bv_page;
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	}

	r1_bio->master_bio = NULL;

	return r1_bio;

out_free_pages:
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	for (j=0 ; j < pi->raid_disks; j++)
		for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
			put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
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	j = -1;
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out_free_bio:
	while ( ++j < pi->raid_disks )
		bio_put(r1_bio->bios[j]);
	r1bio_pool_free(r1_bio, data);
	return NULL;
}

static void r1buf_pool_free(void *__r1_bio, void *data)
{
	struct pool_info *pi = data;
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	int i,j;
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	r1bio_t *r1bio = __r1_bio;

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	for (i = 0; i < RESYNC_PAGES; i++)
		for (j = pi->raid_disks; j-- ;) {
			if (j == 0 ||
			    r1bio->bios[j]->bi_io_vec[i].bv_page !=
			    r1bio->bios[0]->bi_io_vec[i].bv_page)
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				safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
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		}
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	for (i=0 ; i < pi->raid_disks; i++)
		bio_put(r1bio->bios[i]);

	r1bio_pool_free(r1bio, data);
}

static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
{
	int i;

	for (i = 0; i < conf->raid_disks; i++) {
		struct bio **bio = r1_bio->bios + i;
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		if (*bio && *bio != IO_BLOCKED)
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			bio_put(*bio);
		*bio = NULL;
	}
}

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static void free_r1bio(r1bio_t *r1_bio)
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{
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	conf_t *conf = r1_bio->mddev->private;
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	/*
	 * Wake up any possible resync thread that waits for the device
	 * to go idle.
	 */
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	allow_barrier(conf);
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	put_all_bios(conf, r1_bio);
	mempool_free(r1_bio, conf->r1bio_pool);
}

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static void put_buf(r1bio_t *r1_bio)
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{
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	conf_t *conf = r1_bio->mddev->private;
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	int i;

	for (i=0; i<conf->raid_disks; i++) {
		struct bio *bio = r1_bio->bios[i];
		if (bio->bi_end_io)
			rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
	}
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	mempool_free(r1_bio, conf->r1buf_pool);

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	lower_barrier(conf);
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}

static void reschedule_retry(r1bio_t *r1_bio)
{
	unsigned long flags;
	mddev_t *mddev = r1_bio->mddev;
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	conf_t *conf = mddev->private;
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	spin_lock_irqsave(&conf->device_lock, flags);
	list_add(&r1_bio->retry_list, &conf->retry_list);
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	conf->nr_queued ++;
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	spin_unlock_irqrestore(&conf->device_lock, flags);

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	wake_up(&conf->wait_barrier);
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	md_wakeup_thread(mddev->thread);
}

/*
 * raid_end_bio_io() is called when we have finished servicing a mirrored
 * operation and are ready to return a success/failure code to the buffer
 * cache layer.
 */
static void raid_end_bio_io(r1bio_t *r1_bio)
{
	struct bio *bio = r1_bio->master_bio;

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	/* if nobody has done the final endio yet, do it now */
	if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
		PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
			(bio_data_dir(bio) == WRITE) ? "write" : "read",
			(unsigned long long) bio->bi_sector,
			(unsigned long long) bio->bi_sector +
				(bio->bi_size >> 9) - 1);

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		bio_endio(bio,
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			test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
	}
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	free_r1bio(r1_bio);
}

/*
 * Update disk head position estimator based on IRQ completion info.
 */
static inline void update_head_pos(int disk, r1bio_t *r1_bio)
{
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	conf_t *conf = r1_bio->mddev->private;
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	conf->mirrors[disk].head_position =
		r1_bio->sector + (r1_bio->sectors);
}

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static void raid1_end_read_request(struct bio *bio, int error)
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{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
	int mirror;
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	conf_t *conf = r1_bio->mddev->private;
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	mirror = r1_bio->read_disk;
	/*
	 * this branch is our 'one mirror IO has finished' event handler:
	 */
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	update_head_pos(mirror, r1_bio);

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	if (uptodate)
		set_bit(R1BIO_Uptodate, &r1_bio->state);
	else {
		/* If all other devices have failed, we want to return
		 * the error upwards rather than fail the last device.
		 * Here we redefine "uptodate" to mean "Don't want to retry"
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		 */
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		unsigned long flags;
		spin_lock_irqsave(&conf->device_lock, flags);
		if (r1_bio->mddev->degraded == conf->raid_disks ||
		    (r1_bio->mddev->degraded == conf->raid_disks-1 &&
		     !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
			uptodate = 1;
		spin_unlock_irqrestore(&conf->device_lock, flags);
	}
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	if (uptodate)
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		raid_end_bio_io(r1_bio);
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	else {
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		/*
		 * oops, read error:
		 */
		char b[BDEVNAME_SIZE];
		if (printk_ratelimit())
			printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
			       bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
		reschedule_retry(r1_bio);
	}

	rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
}

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static void raid1_end_write_request(struct bio *bio, int error)
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{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
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	int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
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	conf_t *conf = r1_bio->mddev->private;
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	struct bio *to_put = NULL;
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	for (mirror = 0; mirror < conf->raid_disks; mirror++)
		if (r1_bio->bios[mirror] == bio)
			break;

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	if (error == -EOPNOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
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		set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
		set_bit(R1BIO_BarrierRetry, &r1_bio->state);
		r1_bio->mddev->barriers_work = 0;
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		/* Don't rdev_dec_pending in this branch - keep it for the retry */
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	} else {
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		/*
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		 * this branch is our 'one mirror IO has finished' event handler:
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		 */
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		r1_bio->bios[mirror] = NULL;
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		to_put = bio;
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		if (!uptodate) {
			md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
			/* an I/O failed, we can't clear the bitmap */
			set_bit(R1BIO_Degraded, &r1_bio->state);
		} else
			/*
			 * Set R1BIO_Uptodate in our master bio, so that
			 * we will return a good error code for to the higher
			 * levels even if IO on some other mirrored buffer fails.
			 *
			 * The 'master' represents the composite IO operation to
			 * user-side. So if something waits for IO, then it will
			 * wait for the 'master' bio.
			 */
			set_bit(R1BIO_Uptodate, &r1_bio->state);

		update_head_pos(mirror, r1_bio);

		if (behind) {
			if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
				atomic_dec(&r1_bio->behind_remaining);

			/* In behind mode, we ACK the master bio once the I/O has safely
			 * reached all non-writemostly disks. Setting the Returned bit
			 * ensures that this gets done only once -- we don't ever want to
			 * return -EIO here, instead we'll wait */

			if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
			    test_bit(R1BIO_Uptodate, &r1_bio->state)) {
				/* Maybe we can return now */
				if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
					struct bio *mbio = r1_bio->master_bio;
					PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
					       (unsigned long long) mbio->bi_sector,
					       (unsigned long long) mbio->bi_sector +
					       (mbio->bi_size >> 9) - 1);
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					bio_endio(mbio, 0);
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				}
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			}
		}
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		rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
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	}
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	/*
	 *
	 * Let's see if all mirrored write operations have finished
	 * already.
	 */
	if (atomic_dec_and_test(&r1_bio->remaining)) {
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		if (test_bit(R1BIO_BarrierRetry, &r1_bio->state))
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			reschedule_retry(r1_bio);
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		else {
			/* it really is the end of this request */
			if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
				/* free extra copy of the data pages */
				int i = bio->bi_vcnt;
				while (i--)
					safe_put_page(bio->bi_io_vec[i].bv_page);
			}
			/* clear the bitmap if all writes complete successfully */
			bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
					r1_bio->sectors,
					!test_bit(R1BIO_Degraded, &r1_bio->state),
					behind);
			md_write_end(r1_bio->mddev);
			raid_end_bio_io(r1_bio);
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		}
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	}
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	if (to_put)
		bio_put(to_put);
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}


/*
 * This routine returns the disk from which the requested read should
 * be done. There is a per-array 'next expected sequential IO' sector
 * number - if this matches on the next IO then we use the last disk.
 * There is also a per-disk 'last know head position' sector that is
 * maintained from IRQ contexts, both the normal and the resync IO
 * completion handlers update this position correctly. If there is no
 * perfect sequential match then we pick the disk whose head is closest.
 *
 * If there are 2 mirrors in the same 2 devices, performance degrades
 * because position is mirror, not device based.
 *
 * The rdev for the device selected will have nr_pending incremented.
 */
static int read_balance(conf_t *conf, r1bio_t *r1_bio)
{
	const unsigned long this_sector = r1_bio->sector;
	int new_disk = conf->last_used, disk = new_disk;
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	int wonly_disk = -1;
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	const int sectors = r1_bio->sectors;
	sector_t new_distance, current_distance;
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	mdk_rdev_t *rdev;
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	rcu_read_lock();
	/*
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	 * Check if we can balance. We can balance on the whole
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	 * device if no resync is going on, or below the resync window.
	 * We take the first readable disk when above the resync window.
	 */
 retry:
	if (conf->mddev->recovery_cp < MaxSector &&
	    (this_sector + sectors >= conf->next_resync)) {
		/* Choose the first operation device, for consistancy */
		new_disk = 0;

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		for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
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		     r1_bio->bios[new_disk] == IO_BLOCKED ||
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		     !rdev || !test_bit(In_sync, &rdev->flags)
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			     || test_bit(WriteMostly, &rdev->flags);
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		     rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
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			if (rdev && test_bit(In_sync, &rdev->flags) &&
				r1_bio->bios[new_disk] != IO_BLOCKED)
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				wonly_disk = new_disk;

			if (new_disk == conf->raid_disks - 1) {
				new_disk = wonly_disk;
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				break;
			}
		}
		goto rb_out;
	}


	/* make sure the disk is operational */
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	for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
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	     r1_bio->bios[new_disk] == IO_BLOCKED ||
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	     !rdev || !test_bit(In_sync, &rdev->flags) ||
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		     test_bit(WriteMostly, &rdev->flags);
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	     rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
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		if (rdev && test_bit(In_sync, &rdev->flags) &&
		    r1_bio->bios[new_disk] != IO_BLOCKED)
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			wonly_disk = new_disk;

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		if (new_disk <= 0)
			new_disk = conf->raid_disks;
		new_disk--;
		if (new_disk == disk) {
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			new_disk = wonly_disk;
			break;
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		}
	}
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	if (new_disk < 0)
		goto rb_out;

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	disk = new_disk;
	/* now disk == new_disk == starting point for search */

	/*
	 * Don't change to another disk for sequential reads:
	 */
	if (conf->next_seq_sect == this_sector)
		goto rb_out;
	if (this_sector == conf->mirrors[new_disk].head_position)
		goto rb_out;

	current_distance = abs(this_sector - conf->mirrors[disk].head_position);

	/* Find the disk whose head is closest */

	do {
		if (disk <= 0)
			disk = conf->raid_disks;
		disk--;

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		rdev = rcu_dereference(conf->mirrors[disk].rdev);
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		if (!rdev || r1_bio->bios[disk] == IO_BLOCKED ||
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		    !test_bit(In_sync, &rdev->flags) ||
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		    test_bit(WriteMostly, &rdev->flags))
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			continue;

		if (!atomic_read(&rdev->nr_pending)) {
			new_disk = disk;
			break;
		}
		new_distance = abs(this_sector - conf->mirrors[disk].head_position);
		if (new_distance < current_distance) {
			current_distance = new_distance;
			new_disk = disk;
		}
	} while (disk != conf->last_used);

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 rb_out:
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	if (new_disk >= 0) {
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		rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
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		if (!rdev)
			goto retry;
		atomic_inc(&rdev->nr_pending);
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		if (!test_bit(In_sync, &rdev->flags)) {
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			/* cannot risk returning a device that failed
			 * before we inc'ed nr_pending
			 */
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			rdev_dec_pending(rdev, conf->mddev);
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			goto retry;
		}
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		conf->next_seq_sect = this_sector + sectors;
		conf->last_used = new_disk;
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	}
	rcu_read_unlock();

	return new_disk;
}

static void unplug_slaves(mddev_t *mddev)
{
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	conf_t *conf = mddev->private;
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	int i;

	rcu_read_lock();
	for (i=0; i<mddev->raid_disks; i++) {
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		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
550
		if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
551
			struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
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			atomic_inc(&rdev->nr_pending);
			rcu_read_unlock();

556
			blk_unplug(r_queue);
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			rdev_dec_pending(rdev, mddev);
			rcu_read_lock();
		}
	}
	rcu_read_unlock();
}

565
static void raid1_unplug(struct request_queue *q)
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{
567 568 569 570
	mddev_t *mddev = q->queuedata;

	unplug_slaves(mddev);
	md_wakeup_thread(mddev->thread);
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}

573 574 575
static int raid1_congested(void *data, int bits)
{
	mddev_t *mddev = data;
576
	conf_t *conf = mddev->private;
577 578
	int i, ret = 0;

579 580 581
	if (mddev_congested(mddev, bits))
		return 1;

582 583 584 585
	rcu_read_lock();
	for (i = 0; i < mddev->raid_disks; i++) {
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev && !test_bit(Faulty, &rdev->flags)) {
586
			struct request_queue *q = bdev_get_queue(rdev->bdev);
587 588 589 590

			/* Note the '|| 1' - when read_balance prefers
			 * non-congested targets, it can be removed
			 */
591
			if ((bits & (1<<BDI_async_congested)) || 1)
592 593 594 595 596 597 598 599 600 601
				ret |= bdi_congested(&q->backing_dev_info, bits);
			else
				ret &= bdi_congested(&q->backing_dev_info, bits);
		}
	}
	rcu_read_unlock();
	return ret;
}


602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632
static int flush_pending_writes(conf_t *conf)
{
	/* Any writes that have been queued but are awaiting
	 * bitmap updates get flushed here.
	 * We return 1 if any requests were actually submitted.
	 */
	int rv = 0;

	spin_lock_irq(&conf->device_lock);

	if (conf->pending_bio_list.head) {
		struct bio *bio;
		bio = bio_list_get(&conf->pending_bio_list);
		blk_remove_plug(conf->mddev->queue);
		spin_unlock_irq(&conf->device_lock);
		/* flush any pending bitmap writes to
		 * disk before proceeding w/ I/O */
		bitmap_unplug(conf->mddev->bitmap);

		while (bio) { /* submit pending writes */
			struct bio *next = bio->bi_next;
			bio->bi_next = NULL;
			generic_make_request(bio);
			bio = next;
		}
		rv = 1;
	} else
		spin_unlock_irq(&conf->device_lock);
	return rv;
}

633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652
/* Barriers....
 * Sometimes we need to suspend IO while we do something else,
 * either some resync/recovery, or reconfigure the array.
 * To do this we raise a 'barrier'.
 * The 'barrier' is a counter that can be raised multiple times
 * to count how many activities are happening which preclude
 * normal IO.
 * We can only raise the barrier if there is no pending IO.
 * i.e. if nr_pending == 0.
 * We choose only to raise the barrier if no-one is waiting for the
 * barrier to go down.  This means that as soon as an IO request
 * is ready, no other operations which require a barrier will start
 * until the IO request has had a chance.
 *
 * So: regular IO calls 'wait_barrier'.  When that returns there
 *    is no backgroup IO happening,  It must arrange to call
 *    allow_barrier when it has finished its IO.
 * backgroup IO calls must call raise_barrier.  Once that returns
 *    there is no normal IO happeing.  It must arrange to call
 *    lower_barrier when the particular background IO completes.
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 */
#define RESYNC_DEPTH 32

656
static void raise_barrier(conf_t *conf)
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{
	spin_lock_irq(&conf->resync_lock);
659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694

	/* Wait until no block IO is waiting */
	wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
			    conf->resync_lock,
			    raid1_unplug(conf->mddev->queue));

	/* block any new IO from starting */
	conf->barrier++;

	/* No wait for all pending IO to complete */
	wait_event_lock_irq(conf->wait_barrier,
			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
			    conf->resync_lock,
			    raid1_unplug(conf->mddev->queue));

	spin_unlock_irq(&conf->resync_lock);
}

static void lower_barrier(conf_t *conf)
{
	unsigned long flags;
	spin_lock_irqsave(&conf->resync_lock, flags);
	conf->barrier--;
	spin_unlock_irqrestore(&conf->resync_lock, flags);
	wake_up(&conf->wait_barrier);
}

static void wait_barrier(conf_t *conf)
{
	spin_lock_irq(&conf->resync_lock);
	if (conf->barrier) {
		conf->nr_waiting++;
		wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
				    conf->resync_lock,
				    raid1_unplug(conf->mddev->queue));
		conf->nr_waiting--;
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	}
696
	conf->nr_pending++;
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	spin_unlock_irq(&conf->resync_lock);
}

700 701 702 703 704 705 706 707 708
static void allow_barrier(conf_t *conf)
{
	unsigned long flags;
	spin_lock_irqsave(&conf->resync_lock, flags);
	conf->nr_pending--;
	spin_unlock_irqrestore(&conf->resync_lock, flags);
	wake_up(&conf->wait_barrier);
}

709 710 711 712 713
static void freeze_array(conf_t *conf)
{
	/* stop syncio and normal IO and wait for everything to
	 * go quite.
	 * We increment barrier and nr_waiting, and then
714 715 716 717 718 719 720 721
	 * wait until nr_pending match nr_queued+1
	 * This is called in the context of one normal IO request
	 * that has failed. Thus any sync request that might be pending
	 * will be blocked by nr_pending, and we need to wait for
	 * pending IO requests to complete or be queued for re-try.
	 * Thus the number queued (nr_queued) plus this request (1)
	 * must match the number of pending IOs (nr_pending) before
	 * we continue.
722 723 724 725 726
	 */
	spin_lock_irq(&conf->resync_lock);
	conf->barrier++;
	conf->nr_waiting++;
	wait_event_lock_irq(conf->wait_barrier,
727
			    conf->nr_pending == conf->nr_queued+1,
728
			    conf->resync_lock,
729 730
			    ({ flush_pending_writes(conf);
			       raid1_unplug(conf->mddev->queue); }));
731 732 733 734 735 736 737 738 739 740 741 742
	spin_unlock_irq(&conf->resync_lock);
}
static void unfreeze_array(conf_t *conf)
{
	/* reverse the effect of the freeze */
	spin_lock_irq(&conf->resync_lock);
	conf->barrier--;
	conf->nr_waiting--;
	wake_up(&conf->wait_barrier);
	spin_unlock_irq(&conf->resync_lock);
}

743

744 745 746 747 748
/* duplicate the data pages for behind I/O */
static struct page **alloc_behind_pages(struct bio *bio)
{
	int i;
	struct bio_vec *bvec;
749
	struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768
					GFP_NOIO);
	if (unlikely(!pages))
		goto do_sync_io;

	bio_for_each_segment(bvec, bio, i) {
		pages[i] = alloc_page(GFP_NOIO);
		if (unlikely(!pages[i]))
			goto do_sync_io;
		memcpy(kmap(pages[i]) + bvec->bv_offset,
			kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
		kunmap(pages[i]);
		kunmap(bvec->bv_page);
	}

	return pages;

do_sync_io:
	if (pages)
		for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
769
			put_page(pages[i]);
770 771 772 773 774
	kfree(pages);
	PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
	return NULL;
}

775
static int make_request(struct request_queue *q, struct bio * bio)
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{
	mddev_t *mddev = q->queuedata;
778
	conf_t *conf = mddev->private;
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	mirror_info_t *mirror;
	r1bio_t *r1_bio;
	struct bio *read_bio;
782
	int i, targets = 0, disks;
783
	struct bitmap *bitmap;
784 785
	unsigned long flags;
	struct bio_list bl;
786
	struct page **behind_pages = NULL;
787
	const int rw = bio_data_dir(bio);
788 789 790
	const bool do_sync = bio_rw_flagged(bio, BIO_RW_SYNCIO);
	int cpu;
	bool do_barriers;
791
	mdk_rdev_t *blocked_rdev;
792

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	/*
	 * Register the new request and wait if the reconstruction
	 * thread has put up a bar for new requests.
	 * Continue immediately if no resync is active currently.
797 798 799
	 * We test barriers_work *after* md_write_start as md_write_start
	 * may cause the first superblock write, and that will check out
	 * if barriers work.
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	 */
801

802 803
	md_write_start(mddev, bio); /* wait on superblock update early */

804 805
	if (unlikely(!mddev->barriers_work &&
		     bio_rw_flagged(bio, BIO_RW_BARRIER))) {
806 807
		if (rw == WRITE)
			md_write_end(mddev);
808
		bio_endio(bio, -EOPNOTSUPP);
809 810 811
		return 0;
	}

812
	wait_barrier(conf);
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814 815
	bitmap = mddev->bitmap;

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	cpu = part_stat_lock();
	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
		      bio_sectors(bio));
	part_stat_unlock();
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	/*
	 * make_request() can abort the operation when READA is being
	 * used and no empty request is available.
	 *
	 */
	r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);

	r1_bio->master_bio = bio;
	r1_bio->sectors = bio->bi_size >> 9;
831
	r1_bio->state = 0;
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	r1_bio->mddev = mddev;
	r1_bio->sector = bio->bi_sector;

835
	if (rw == READ) {
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		/*
		 * read balancing logic:
		 */
		int rdisk = read_balance(conf, r1_bio);

		if (rdisk < 0) {
			/* couldn't find anywhere to read from */
			raid_end_bio_io(r1_bio);
			return 0;
		}
		mirror = conf->mirrors + rdisk;

		r1_bio->read_disk = rdisk;

		read_bio = bio_clone(bio, GFP_NOIO);

		r1_bio->bios[rdisk] = read_bio;

		read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
		read_bio->bi_bdev = mirror->rdev->bdev;
		read_bio->bi_end_io = raid1_end_read_request;
857
		read_bio->bi_rw = READ | (do_sync << BIO_RW_SYNCIO);
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		read_bio->bi_private = r1_bio;

		generic_make_request(read_bio);
		return 0;
	}

	/*
	 * WRITE:
	 */
	/* first select target devices under spinlock and
	 * inc refcount on their rdev.  Record them by setting
	 * bios[x] to bio
	 */
	disks = conf->raid_disks;
872 873 874 875 876 877 878
#if 0
	{ static int first=1;
	if (first) printk("First Write sector %llu disks %d\n",
			  (unsigned long long)r1_bio->sector, disks);
	first = 0;
	}
#endif
879 880
 retry_write:
	blocked_rdev = NULL;
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	rcu_read_lock();
	for (i = 0;  i < disks; i++) {
883 884 885 886 887 888 889
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
			atomic_inc(&rdev->nr_pending);
			blocked_rdev = rdev;
			break;
		}
		if (rdev && !test_bit(Faulty, &rdev->flags)) {
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			atomic_inc(&rdev->nr_pending);
891
			if (test_bit(Faulty, &rdev->flags)) {
892
				rdev_dec_pending(rdev, mddev);
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				r1_bio->bios[i] = NULL;
			} else
				r1_bio->bios[i] = bio;
896
			targets++;
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		} else
			r1_bio->bios[i] = NULL;
	}
	rcu_read_unlock();

902 903 904 905 906 907 908 909 910 911 912 913 914 915
	if (unlikely(blocked_rdev)) {
		/* Wait for this device to become unblocked */
		int j;

		for (j = 0; j < i; j++)
			if (r1_bio->bios[j])
				rdev_dec_pending(conf->mirrors[j].rdev, mddev);

		allow_barrier(conf);
		md_wait_for_blocked_rdev(blocked_rdev, mddev);
		wait_barrier(conf);
		goto retry_write;
	}

916 917
	BUG_ON(targets == 0); /* we never fail the last device */

918 919 920 921 922 923
	if (targets < conf->raid_disks) {
		/* array is degraded, we will not clear the bitmap
		 * on I/O completion (see raid1_end_write_request) */
		set_bit(R1BIO_Degraded, &r1_bio->state);
	}

924 925 926 927 928 929
	/* do behind I/O ? */
	if (bitmap &&
	    atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind &&
	    (behind_pages = alloc_behind_pages(bio)) != NULL)
		set_bit(R1BIO_BehindIO, &r1_bio->state);

930
	atomic_set(&r1_bio->remaining, 0);
931
	atomic_set(&r1_bio->behind_remaining, 0);
932

933
	do_barriers = bio_rw_flagged(bio, BIO_RW_BARRIER);
934 935 936
	if (do_barriers)
		set_bit(R1BIO_Barrier, &r1_bio->state);

937
	bio_list_init(&bl);
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	for (i = 0; i < disks; i++) {
		struct bio *mbio;
		if (!r1_bio->bios[i])
			continue;

		mbio = bio_clone(bio, GFP_NOIO);
		r1_bio->bios[i] = mbio;

		mbio->bi_sector	= r1_bio->sector + conf->mirrors[i].rdev->data_offset;
		mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
		mbio->bi_end_io	= raid1_end_write_request;
949 950
		mbio->bi_rw = WRITE | (do_barriers << BIO_RW_BARRIER) |
			(do_sync << BIO_RW_SYNCIO);
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		mbio->bi_private = r1_bio;

953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969
		if (behind_pages) {
			struct bio_vec *bvec;
			int j;

			/* Yes, I really want the '__' version so that
			 * we clear any unused pointer in the io_vec, rather
			 * than leave them unchanged.  This is important
			 * because when we come to free the pages, we won't
			 * know the originial bi_idx, so we just free
			 * them all
			 */
			__bio_for_each_segment(bvec, mbio, j, 0)
				bvec->bv_page = behind_pages[j];
			if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
				atomic_inc(&r1_bio->behind_remaining);
		}

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		atomic_inc(&r1_bio->remaining);

972
		bio_list_add(&bl, mbio);
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	}
974
	kfree(behind_pages); /* the behind pages are attached to the bios now */
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976 977
	bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
				test_bit(R1BIO_BehindIO, &r1_bio->state));
978 979 980 981 982 983 984
	spin_lock_irqsave(&conf->device_lock, flags);
	bio_list_merge(&conf->pending_bio_list, &bl);
	bio_list_init(&bl);

	blk_plug_device(mddev->queue);
	spin_unlock_irqrestore(&conf->device_lock, flags);

985 986 987
	/* In case raid1d snuck into freeze_array */
	wake_up(&conf->wait_barrier);

988 989
	if (do_sync)
		md_wakeup_thread(mddev->thread);
990 991 992 993 994
#if 0
	while ((bio = bio_list_pop(&bl)) != NULL)
		generic_make_request(bio);
#endif

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	return 0;
}

static void status(struct seq_file *seq, mddev_t *mddev)
{
1000
	conf_t *conf = mddev->private;
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	int i;

	seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1004
		   conf->raid_disks - mddev->degraded);
1005 1006 1007
	rcu_read_lock();
	for (i = 0; i < conf->raid_disks; i++) {
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
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		seq_printf(seq, "%s",
1009 1010 1011
			   rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
	}
	rcu_read_unlock();
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	seq_printf(seq, "]");
}


static void error(mddev_t *mddev, mdk_rdev_t *rdev)
{
	char b[BDEVNAME_SIZE];
1019
	conf_t *conf = mddev->private;
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	/*
	 * If it is not operational, then we have already marked it as dead
	 * else if it is the last working disks, ignore the error, let the
	 * next level up know.
	 * else mark the drive as failed
	 */
1027
	if (test_bit(In_sync, &rdev->flags)
1028
	    && (conf->raid_disks - mddev->degraded) == 1) {
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		/*
		 * Don't fail the drive, act as though we were just a
1031 1032 1033
		 * normal single drive.
		 * However don't try a recovery from this drive as
		 * it is very likely to fail.
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		 */
1035
		mddev->recovery_disabled = 1;
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		return;
1037
	}
1038 1039 1040
	if (test_and_clear_bit(In_sync, &rdev->flags)) {
		unsigned long flags;
		spin_lock_irqsave(&conf->device_lock, flags);
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		mddev->degraded++;
1042
		set_bit(Faulty, &rdev->flags);
1043
		spin_unlock_irqrestore(&conf->device_lock, flags);
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		/*
		 * if recovery is running, make sure it aborts.
		 */
1047
		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1048 1049
	} else
		set_bit(Faulty, &rdev->flags);
1050
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
1051 1052
	printk(KERN_ALERT "raid1: Disk failure on %s, disabling device.\n"
		"raid1: Operation continuing on %d devices.\n",
1053
		bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
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}

static void print_conf(conf_t *conf)
{
	int i;

	printk("RAID1 conf printout:\n");
	if (!conf) {
		printk("(!conf)\n");
		return;
	}
1065
	printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
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		conf->raid_disks);

1068
	rcu_read_lock();
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	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
1071 1072
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev)
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			printk(" disk %d, wo:%d, o:%d, dev:%s\n",
1074 1075 1076
			       i, !test_bit(In_sync, &rdev->flags),
			       !test_bit(Faulty, &rdev->flags),
			       bdevname(rdev->bdev,b));
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	}
1078
	rcu_read_unlock();
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}

static void close_sync(conf_t *conf)
{
1083 1084
	wait_barrier(conf);
	allow_barrier(conf);
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	mempool_destroy(conf->r1buf_pool);
	conf->r1buf_pool = NULL;
}

static int raid1_spare_active(mddev_t *mddev)
{
	int i;
	conf_t *conf = mddev->private;

	/*
	 * Find all failed disks within the RAID1 configuration 
1097 1098
	 * and mark them readable.
	 * Called under mddev lock, so rcu protection not needed.
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	 */
	for (i = 0; i < conf->raid_disks; i++) {
1101 1102 1103
		mdk_rdev_t *rdev = conf->mirrors[i].rdev;
		if (rdev
		    && !test_bit(Faulty, &rdev->flags)
1104 1105 1106
		    && !test_and_set_bit(In_sync, &rdev->flags)) {
			unsigned long flags;
			spin_lock_irqsave(&conf->device_lock, flags);
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			mddev->degraded--;
1108
			spin_unlock_irqrestore(&conf->device_lock, flags);
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		}
	}

	print_conf(conf);
	return 0;
}


static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
{
	conf_t *conf = mddev->private;
1120
	int err = -EEXIST;
1121
	int mirror = 0;
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	mirror_info_t *p;
1123 1124
	int first = 0;
	int last = mddev->raid_disks - 1;
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1126 1127 1128 1129
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;

	for (mirror = first; mirror <= last; mirror++)
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		if ( !(p=conf->mirrors+mirror)->rdev) {

1132 1133
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
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			/* as we don't honour merge_bvec_fn, we must never risk
			 * violating it, so limit ->max_sector to one PAGE, as
			 * a one page request is never in violation.
			 */
			if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1139
			    queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
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				blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);

			p->head_position = 0;
			rdev->raid_disk = mirror;
1144
			err = 0;
1145 1146 1147 1148
			/* As all devices are equivalent, we don't need a full recovery
			 * if this was recently any drive of the array
			 */
			if (rdev->saved_raid_disk < 0)
1149
				conf->fullsync = 1;
1150
			rcu_assign_pointer(p->rdev, rdev);
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			break;
		}
1153
	md_integrity_add_rdev(rdev, mddev);
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	print_conf(conf);
1155
	return err;
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}

static int raid1_remove_disk(mddev_t *mddev, int number)
{
	conf_t *conf = mddev->private;
	int err = 0;
	mdk_rdev_t *rdev;
	mirror_info_t *p = conf->mirrors+ number;

	print_conf(conf);
	rdev = p->rdev;
	if (rdev) {
1168
		if (test_bit(In_sync, &rdev->flags) ||
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		    atomic_read(&rdev->nr_pending)) {
			err = -EBUSY;
			goto abort;
		}
1173 1174 1175 1176 1177 1178 1179 1180
		/* Only remove non-faulty devices is recovery
		 * is not possible.
		 */
		if (!test_bit(Faulty, &rdev->flags) &&
		    mddev->degraded < conf->raid_disks) {
			err = -EBUSY;
			goto abort;
		}
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		p->rdev = NULL;
1182
		synchronize_rcu();
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		if (atomic_read(&rdev->nr_pending)) {
			/* lost the race, try later */
			err = -EBUSY;
			p->rdev = rdev;
1187
			goto abort;
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		}
1189
		md_integrity_register(mddev);
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	}
abort:

	print_conf(conf);
	return err;
}


1198
static void end_sync_read(struct bio *bio, int error)
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{
	r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1201
	int i;
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1203 1204 1205 1206 1207
	for (i=r1_bio->mddev->raid_disks; i--; )
		if (r1_bio->bios[i] == bio)
			break;
	BUG_ON(i < 0);
	update_head_pos(i, r1_bio);
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	/*
	 * we have read a block, now it needs to be re-written,
	 * or re-read if the read failed.
	 * We don't do much here, just schedule handling by raid1d
	 */
1213
	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
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		set_bit(R1BIO_Uptodate, &r1_bio->state);
1215 1216 1217

	if (atomic_dec_and_test(&r1_bio->remaining))
		reschedule_retry(r1_bio);
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}

1220
static void end_sync_write(struct bio *bio, int error)
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{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
	mddev_t *mddev = r1_bio->mddev;
1225
	conf_t *conf = mddev->private;
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	int i;
	int mirror=0;

	for (i = 0; i < conf->raid_disks; i++)
		if (r1_bio->bios[i] == bio) {
			mirror = i;
			break;
		}
1234 1235 1236 1237 1238 1239
	if (!uptodate) {
		int sync_blocks = 0;
		sector_t s = r1_bio->sector;
		long sectors_to_go = r1_bio->sectors;
		/* make sure these bits doesn't get cleared. */
		do {
1240
			bitmap_end_sync(mddev->bitmap, s,
1241 1242 1243 1244
					&sync_blocks, 1);
			s += sync_blocks;
			sectors_to_go -= sync_blocks;
		} while (sectors_to_go > 0);
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		md_error(mddev, conf->mirrors[mirror].rdev);
1246
	}
1247

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	update_head_pos(mirror, r1_bio);

	if (atomic_dec_and_test(&r1_bio->remaining)) {
1251
		sector_t s = r1_bio->sectors;
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		put_buf(r1_bio);
1253
		md_done_sync(mddev, s, uptodate);
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	}
}

static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
{
1259
	conf_t *conf = mddev->private;
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	int i;
	int disks = conf->raid_disks;
	struct bio *bio, *wbio;

	bio = r1_bio->bios[r1_bio->read_disk];

1266

1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288
	if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
		/* We have read all readable devices.  If we haven't
		 * got the block, then there is no hope left.
		 * If we have, then we want to do a comparison
		 * and skip the write if everything is the same.
		 * If any blocks failed to read, then we need to
		 * attempt an over-write
		 */
		int primary;
		if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
			for (i=0; i<mddev->raid_disks; i++)
				if (r1_bio->bios[i]->bi_end_io == end_sync_read)
					md_error(mddev, conf->mirrors[i].rdev);

			md_done_sync(mddev, r1_bio->sectors, 1);
			put_buf(r1_bio);
			return;
		}
		for (primary=0; primary<mddev->raid_disks; primary++)
			if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
			    test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
				r1_bio->bios[primary]->bi_end_io = NULL;
1289
				rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1290 1291 1292 1293
				break;
			}
		r1_bio->read_disk = primary;
		for (i=0; i<mddev->raid_disks; i++)
1294
			if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1295 1296 1297 1298
				int j;
				int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
				struct bio *pbio = r1_bio->bios[primary];
				struct bio *sbio = r1_bio->bios[i];
1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311

				if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
					for (j = vcnt; j-- ; ) {
						struct page *p, *s;
						p = pbio->bi_io_vec[j].bv_page;
						s = sbio->bi_io_vec[j].bv_page;
						if (memcmp(page_address(p),
							   page_address(s),
							   PAGE_SIZE))
							break;
					}
				} else
					j = 0;
1312 1313
				if (j >= 0)
					mddev->resync_mismatches += r1_bio->sectors;
1314 1315
				if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
					      && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1316
					sbio->bi_end_io = NULL;
1317 1318
					rdev_dec_pending(conf->mirrors[i].rdev, mddev);
				} else {
1319
					/* fixup the bio for reuse */
1320
					int size;
1321 1322 1323 1324 1325 1326 1327 1328 1329 1330
					sbio->bi_vcnt = vcnt;
					sbio->bi_size = r1_bio->sectors << 9;
					sbio->bi_idx = 0;
					sbio->bi_phys_segments = 0;
					sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
					sbio->bi_flags |= 1 << BIO_UPTODATE;
					sbio->bi_next = NULL;
					sbio->bi_sector = r1_bio->sector +
						conf->mirrors[i].rdev->data_offset;
					sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341
					size = sbio->bi_size;
					for (j = 0; j < vcnt ; j++) {
						struct bio_vec *bi;
						bi = &sbio->bi_io_vec[j];
						bi->bv_offset = 0;
						if (size > PAGE_SIZE)
							bi->bv_len = PAGE_SIZE;
						else
							bi->bv_len = size;
						size -= PAGE_SIZE;
						memcpy(page_address(bi->bv_page),
1342 1343
						       page_address(pbio->bi_io_vec[j].bv_page),
						       PAGE_SIZE);
1344
					}
1345

1346 1347 1348
				}
			}
	}
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	if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1350 1351 1352
		/* ouch - failed to read all of that.
		 * Try some synchronous reads of other devices to get
		 * good data, much like with normal read errors.  Only
1353
		 * read into the pages we already have so we don't
1354 1355 1356 1357
		 * need to re-issue the read request.
		 * We don't need to freeze the array, because being in an
		 * active sync request, there is no normal IO, and
		 * no overlapping syncs.
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		 */
1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372
		sector_t sect = r1_bio->sector;
		int sectors = r1_bio->sectors;
		int idx = 0;

		while(sectors) {
			int s = sectors;
			int d = r1_bio->read_disk;
			int success = 0;
			mdk_rdev_t *rdev;

			if (s > (PAGE_SIZE>>9))
				s = PAGE_SIZE >> 9;
			do {
				if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1373 1374 1375 1376
					/* No rcu protection needed here devices
					 * can only be removed when no resync is
					 * active, and resync is currently active
					 */
1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392
					rdev = conf->mirrors[d].rdev;
					if (sync_page_io(rdev->bdev,
							 sect + rdev->data_offset,
							 s<<9,
							 bio->bi_io_vec[idx].bv_page,
							 READ)) {
						success = 1;
						break;
					}
				}
				d++;
				if (d == conf->raid_disks)
					d = 0;
			} while (!success && d != r1_bio->read_disk);

			if (success) {
1393
				int start = d;
1394 1395 1396 1397 1398 1399 1400 1401 1402
				/* write it back and re-read */
				set_bit(R1BIO_Uptodate, &r1_bio->state);
				while (d != r1_bio->read_disk) {
					if (d == 0)
						d = conf->raid_disks;
					d--;
					if (r1_bio->bios[d]->bi_end_io != end_sync_read)
						continue;
					rdev = conf->mirrors[d].rdev;
1403
					atomic_add(s, &rdev->corrected_errors);
1404 1405 1406 1407
					if (sync_page_io(rdev->bdev,
							 sect + rdev->data_offset,
							 s<<9,
							 bio->bi_io_vec[idx].bv_page,
1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419
							 WRITE) == 0)
						md_error(mddev, rdev);
				}
				d = start;
				while (d != r1_bio->read_disk) {
					if (d == 0)
						d = conf->raid_disks;
					d--;
					if (r1_bio->bios[d]->bi_end_io != end_sync_read)
						continue;
					rdev = conf->mirrors[d].rdev;
					if (sync_page_io(rdev->bdev,
1420 1421 1422
							 sect + rdev->data_offset,
							 s<<9,
							 bio->bi_io_vec[idx].bv_page,
1423
							 READ) == 0)
1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441
						md_error(mddev, rdev);
				}
			} else {
				char b[BDEVNAME_SIZE];
				/* Cannot read from anywhere, array is toast */
				md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
				printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
				       " for block %llu\n",
				       bdevname(bio->bi_bdev,b),
				       (unsigned long long)r1_bio->sector);
				md_done_sync(mddev, r1_bio->sectors, 0);
				put_buf(r1_bio);
				return;
			}
			sectors -= s;
			sect += s;
			idx ++;
		}
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	}
1443 1444 1445 1446

	/*
	 * schedule writes
	 */
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	atomic_set(&r1_bio->remaining, 1);
	for (i = 0; i < disks ; i++) {
		wbio = r1_bio->bios[i];
1450 1451 1452 1453
		if (wbio->bi_end_io == NULL ||
		    (wbio->bi_end_io == end_sync_read &&
		     (i == r1_bio->read_disk ||
		      !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
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			continue;

1456 1457
		wbio->bi_rw = WRITE;
		wbio->bi_end_io = end_sync_write;
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		atomic_inc(&r1_bio->remaining);
		md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
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		generic_make_request(wbio);
	}

	if (atomic_dec_and_test(&r1_bio->remaining)) {
1465
		/* if we're here, all write(s) have completed, so clean up */
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		md_done_sync(mddev, r1_bio->sectors, 1);
		put_buf(r1_bio);
	}
}

/*
 * This is a kernel thread which:
 *
 *	1.	Retries failed read operations on working mirrors.
 *	2.	Updates the raid superblock when problems encounter.
 *	3.	Performs writes following reads for array syncronising.
 */

1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556
static void fix_read_error(conf_t *conf, int read_disk,
			   sector_t sect, int sectors)
{
	mddev_t *mddev = conf->mddev;
	while(sectors) {
		int s = sectors;
		int d = read_disk;
		int success = 0;
		int start;
		mdk_rdev_t *rdev;

		if (s > (PAGE_SIZE>>9))
			s = PAGE_SIZE >> 9;

		do {
			/* Note: no rcu protection needed here
			 * as this is synchronous in the raid1d thread
			 * which is the thread that might remove
			 * a device.  If raid1d ever becomes multi-threaded....
			 */
			rdev = conf->mirrors[d].rdev;
			if (rdev &&
			    test_bit(In_sync, &rdev->flags) &&
			    sync_page_io(rdev->bdev,
					 sect + rdev->data_offset,
					 s<<9,
					 conf->tmppage, READ))
				success = 1;
			else {
				d++;
				if (d == conf->raid_disks)
					d = 0;
			}
		} while (!success && d != read_disk);

		if (!success) {
			/* Cannot read from anywhere -- bye bye array */
			md_error(mddev, conf->mirrors[read_disk].rdev);
			break;
		}
		/* write it back and re-read */
		start = d;
		while (d != read_disk) {
			if (d==0)
				d = conf->raid_disks;
			d--;
			rdev = conf->mirrors[d].rdev;
			if (rdev &&
			    test_bit(In_sync, &rdev->flags)) {
				if (sync_page_io(rdev->bdev,
						 sect + rdev->data_offset,
						 s<<9, conf->tmppage, WRITE)
				    == 0)
					/* Well, this device is dead */
					md_error(mddev, rdev);
			}
		}
		d = start;
		while (d != read_disk) {
			char b[BDEVNAME_SIZE];
			if (d==0)
				d = conf->raid_disks;
			d--;
			rdev = conf->mirrors[d].rdev;
			if (rdev &&
			    test_bit(In_sync, &rdev->flags)) {
				if (sync_page_io(rdev->bdev,
						 sect + rdev->data_offset,
						 s<<9, conf->tmppage, READ)
				    == 0)
					/* Well, this device is dead */
					md_error(mddev, rdev);
				else {
					atomic_add(s, &rdev->corrected_errors);
					printk(KERN_INFO
					       "raid1:%s: read error corrected "
					       "(%d sectors at %llu on %s)\n",
					       mdname(mddev), s,
1557 1558
					       (unsigned long long)(sect +
					           rdev->data_offset),
1559 1560 1561 1562 1563 1564 1565 1566 1567
					       bdevname(rdev->bdev, b));
				}
			}
		}
		sectors -= s;
		sect += s;
	}
}

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static void raid1d(mddev_t *mddev)
{
	r1bio_t *r1_bio;
	struct bio *bio;
	unsigned long flags;
1573
	conf_t *conf = mddev->private;
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	struct list_head *head = &conf->retry_list;
	int unplug=0;
	mdk_rdev_t *rdev;

	md_check_recovery(mddev);
	
	for (;;) {
		char b[BDEVNAME_SIZE];
1582

1583
		unplug += flush_pending_writes(conf);
1584

1585 1586 1587
		spin_lock_irqsave(&conf->device_lock, flags);
		if (list_empty(head)) {
			spin_unlock_irqrestore(&conf->device_lock, flags);
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			break;
1589
		}
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		r1_bio = list_entry(head->prev, r1bio_t, retry_list);
		list_del(head->prev);
1592
		conf->nr_queued--;
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		spin_unlock_irqrestore(&conf->device_lock, flags);

		mddev = r1_bio->mddev;
1596
		conf = mddev->private;
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		if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
			sync_request_write(mddev, r1_bio);
			unplug = 1;
1600 1601
		} else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
			/* some requests in the r1bio were BIO_RW_BARRIER
1602
			 * requests which failed with -EOPNOTSUPP.  Hohumm..
1603 1604 1605
			 * Better resubmit without the barrier.
			 * We know which devices to resubmit for, because
			 * all others have had their bios[] entry cleared.
1606
			 * We already have a nr_pending reference on these rdevs.
1607 1608
			 */
			int i;
1609
			const bool do_sync = bio_rw_flagged(r1_bio->master_bio, BIO_RW_SYNCIO);
1610 1611
			clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
			clear_bit(R1BIO_Barrier, &r1_bio->state);
1612 1613 1614
			for (i=0; i < conf->raid_disks; i++)
				if (r1_bio->bios[i])
					atomic_inc(&r1_bio->remaining);
1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629
			for (i=0; i < conf->raid_disks; i++)
				if (r1_bio->bios[i]) {
					struct bio_vec *bvec;
					int j;

					bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
					/* copy pages from the failed bio, as
					 * this might be a write-behind device */
					__bio_for_each_segment(bvec, bio, j, 0)
						bvec->bv_page = bio_iovec_idx(r1_bio->bios[i], j)->bv_page;
					bio_put(r1_bio->bios[i]);
					bio->bi_sector = r1_bio->sector +
						conf->mirrors[i].rdev->data_offset;
					bio->bi_bdev = conf->mirrors[i].rdev->bdev;
					bio->bi_end_io = raid1_end_write_request;
1630 1631
					bio->bi_rw = WRITE |
						(do_sync << BIO_RW_SYNCIO);
1632 1633 1634 1635
					bio->bi_private = r1_bio;
					r1_bio->bios[i] = bio;
					generic_make_request(bio);
				}
L
Linus Torvalds 已提交
1636 1637
		} else {
			int disk;
1638 1639 1640 1641 1642 1643 1644 1645 1646

			/* we got a read error. Maybe the drive is bad.  Maybe just
			 * the block and we can fix it.
			 * We freeze all other IO, and try reading the block from
			 * other devices.  When we find one, we re-write
			 * and check it that fixes the read error.
			 * This is all done synchronously while the array is
			 * frozen
			 */
1647 1648 1649 1650 1651 1652
			if (mddev->ro == 0) {
				freeze_array(conf);
				fix_read_error(conf, r1_bio->read_disk,
					       r1_bio->sector,
					       r1_bio->sectors);
				unfreeze_array(conf);
1653 1654
			}

L
Linus Torvalds 已提交
1655
			bio = r1_bio->bios[r1_bio->read_disk];
1656 1657
			if ((disk=read_balance(conf, r1_bio)) == -1 ||
			    disk == r1_bio->read_disk) {
L
Linus Torvalds 已提交
1658 1659 1660 1661 1662 1663
				printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
				       " read error for block %llu\n",
				       bdevname(bio->bi_bdev,b),
				       (unsigned long long)r1_bio->sector);
				raid_end_bio_io(r1_bio);
			} else {
1664
				const bool do_sync = bio_rw_flagged(r1_bio->master_bio, BIO_RW_SYNCIO);
1665 1666
				r1_bio->bios[r1_bio->read_disk] =
					mddev->ro ? IO_BLOCKED : NULL;
L
Linus Torvalds 已提交
1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679
				r1_bio->read_disk = disk;
				bio_put(bio);
				bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
				r1_bio->bios[r1_bio->read_disk] = bio;
				rdev = conf->mirrors[disk].rdev;
				if (printk_ratelimit())
					printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
					       " another mirror\n",
					       bdevname(rdev->bdev,b),
					       (unsigned long long)r1_bio->sector);
				bio->bi_sector = r1_bio->sector + rdev->data_offset;
				bio->bi_bdev = rdev->bdev;
				bio->bi_end_io = raid1_end_read_request;
1680
				bio->bi_rw = READ | (do_sync << BIO_RW_SYNCIO);
L
Linus Torvalds 已提交
1681 1682 1683 1684 1685
				bio->bi_private = r1_bio;
				unplug = 1;
				generic_make_request(bio);
			}
		}
N
NeilBrown 已提交
1686
		cond_resched();
L
Linus Torvalds 已提交
1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697
	}
	if (unplug)
		unplug_slaves(mddev);
}


static int init_resync(conf_t *conf)
{
	int buffs;

	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1698
	BUG_ON(conf->r1buf_pool);
L
Linus Torvalds 已提交
1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716
	conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
					  conf->poolinfo);
	if (!conf->r1buf_pool)
		return -ENOMEM;
	conf->next_resync = 0;
	return 0;
}

/*
 * perform a "sync" on one "block"
 *
 * We need to make sure that no normal I/O request - particularly write
 * requests - conflict with active sync requests.
 *
 * This is achieved by tracking pending requests and a 'barrier' concept
 * that can be installed to exclude normal IO requests.
 */

1717
static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
L
Linus Torvalds 已提交
1718
{
1719
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
1720 1721 1722
	r1bio_t *r1_bio;
	struct bio *bio;
	sector_t max_sector, nr_sectors;
1723
	int disk = -1;
L
Linus Torvalds 已提交
1724
	int i;
1725 1726
	int wonly = -1;
	int write_targets = 0, read_targets = 0;
1727
	int sync_blocks;
1728
	int still_degraded = 0;
L
Linus Torvalds 已提交
1729 1730

	if (!conf->r1buf_pool)
1731 1732 1733 1734
	{
/*
		printk("sync start - bitmap %p\n", mddev->bitmap);
*/
L
Linus Torvalds 已提交
1735
		if (init_resync(conf))
1736
			return 0;
1737
	}
L
Linus Torvalds 已提交
1738

A
Andre Noll 已提交
1739
	max_sector = mddev->dev_sectors;
L
Linus Torvalds 已提交
1740
	if (sector_nr >= max_sector) {
1741 1742 1743 1744 1745
		/* If we aborted, we need to abort the
		 * sync on the 'current' bitmap chunk (there will
		 * only be one in raid1 resync.
		 * We can find the current addess in mddev->curr_resync
		 */
1746 1747
		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1748
						&sync_blocks, 1);
1749
		else /* completed sync */
1750
			conf->fullsync = 0;
1751 1752

		bitmap_close_sync(mddev->bitmap);
L
Linus Torvalds 已提交
1753 1754 1755 1756
		close_sync(conf);
		return 0;
	}

1757 1758
	if (mddev->bitmap == NULL &&
	    mddev->recovery_cp == MaxSector &&
1759
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1760 1761 1762 1763
	    conf->fullsync == 0) {
		*skipped = 1;
		return max_sector - sector_nr;
	}
1764 1765 1766
	/* before building a request, check if we can skip these blocks..
	 * This call the bitmap_start_sync doesn't actually record anything
	 */
1767
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1768
	    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1769 1770 1771 1772
		/* We can skip this block, and probably several more */
		*skipped = 1;
		return sync_blocks;
	}
L
Linus Torvalds 已提交
1773
	/*
1774 1775 1776
	 * If there is non-resync activity waiting for a turn,
	 * and resync is going fast enough,
	 * then let it though before starting on this new sync request.
L
Linus Torvalds 已提交
1777
	 */
1778
	if (!go_faster && conf->nr_waiting)
L
Linus Torvalds 已提交
1779
		msleep_interruptible(1000);
1780

N
NeilBrown 已提交
1781
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1782 1783 1784
	raise_barrier(conf);

	conf->next_resync = sector_nr;
L
Linus Torvalds 已提交
1785

1786 1787
	r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
	rcu_read_lock();
L
Linus Torvalds 已提交
1788
	/*
1789 1790 1791 1792 1793 1794
	 * If we get a correctably read error during resync or recovery,
	 * we might want to read from a different device.  So we
	 * flag all drives that could conceivably be read from for READ,
	 * and any others (which will be non-In_sync devices) for WRITE.
	 * If a read fails, we try reading from something else for which READ
	 * is OK.
L
Linus Torvalds 已提交
1795 1796 1797 1798
	 */

	r1_bio->mddev = mddev;
	r1_bio->sector = sector_nr;
1799
	r1_bio->state = 0;
L
Linus Torvalds 已提交
1800 1801 1802
	set_bit(R1BIO_IsSync, &r1_bio->state);

	for (i=0; i < conf->raid_disks; i++) {
1803
		mdk_rdev_t *rdev;
L
Linus Torvalds 已提交
1804 1805 1806 1807 1808
		bio = r1_bio->bios[i];

		/* take from bio_init */
		bio->bi_next = NULL;
		bio->bi_flags |= 1 << BIO_UPTODATE;
1809
		bio->bi_rw = READ;
L
Linus Torvalds 已提交
1810 1811 1812 1813 1814 1815 1816
		bio->bi_vcnt = 0;
		bio->bi_idx = 0;
		bio->bi_phys_segments = 0;
		bio->bi_size = 0;
		bio->bi_end_io = NULL;
		bio->bi_private = NULL;

1817 1818 1819
		rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev == NULL ||
			   test_bit(Faulty, &rdev->flags)) {
1820 1821
			still_degraded = 1;
			continue;
1822
		} else if (!test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
1823 1824 1825
			bio->bi_rw = WRITE;
			bio->bi_end_io = end_sync_write;
			write_targets ++;
1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841
		} else {
			/* may need to read from here */
			bio->bi_rw = READ;
			bio->bi_end_io = end_sync_read;
			if (test_bit(WriteMostly, &rdev->flags)) {
				if (wonly < 0)
					wonly = i;
			} else {
				if (disk < 0)
					disk = i;
			}
			read_targets++;
		}
		atomic_inc(&rdev->nr_pending);
		bio->bi_sector = sector_nr + rdev->data_offset;
		bio->bi_bdev = rdev->bdev;
L
Linus Torvalds 已提交
1842 1843
		bio->bi_private = r1_bio;
	}
1844 1845 1846 1847
	rcu_read_unlock();
	if (disk < 0)
		disk = wonly;
	r1_bio->read_disk = disk;
1848

1849 1850 1851 1852 1853
	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
		/* extra read targets are also write targets */
		write_targets += read_targets-1;

	if (write_targets == 0 || read_targets == 0) {
L
Linus Torvalds 已提交
1854 1855 1856
		/* There is nowhere to write, so all non-sync
		 * drives must be failed - so we are finished
		 */
1857 1858
		sector_t rv = max_sector - sector_nr;
		*skipped = 1;
L
Linus Torvalds 已提交
1859 1860 1861 1862
		put_buf(r1_bio);
		return rv;
	}

1863 1864
	if (max_sector > mddev->resync_max)
		max_sector = mddev->resync_max; /* Don't do IO beyond here */
L
Linus Torvalds 已提交
1865
	nr_sectors = 0;
1866
	sync_blocks = 0;
L
Linus Torvalds 已提交
1867 1868 1869 1870 1871 1872 1873
	do {
		struct page *page;
		int len = PAGE_SIZE;
		if (sector_nr + (len>>9) > max_sector)
			len = (max_sector - sector_nr) << 9;
		if (len == 0)
			break;
1874 1875
		if (sync_blocks == 0) {
			if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1876 1877 1878
					       &sync_blocks, still_degraded) &&
			    !conf->fullsync &&
			    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1879
				break;
1880
			BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1881 1882
			if (len > (sync_blocks<<9))
				len = sync_blocks<<9;
1883
		}
1884

L
Linus Torvalds 已提交
1885 1886 1887
		for (i=0 ; i < conf->raid_disks; i++) {
			bio = r1_bio->bios[i];
			if (bio->bi_end_io) {
1888
				page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
L
Linus Torvalds 已提交
1889 1890
				if (bio_add_page(bio, page, len, 0) == 0) {
					/* stop here */
1891
					bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
L
Linus Torvalds 已提交
1892 1893 1894
					while (i > 0) {
						i--;
						bio = r1_bio->bios[i];
1895 1896
						if (bio->bi_end_io==NULL)
							continue;
L
Linus Torvalds 已提交
1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907
						/* remove last page from this bio */
						bio->bi_vcnt--;
						bio->bi_size -= len;
						bio->bi_flags &= ~(1<< BIO_SEG_VALID);
					}
					goto bio_full;
				}
			}
		}
		nr_sectors += len>>9;
		sector_nr += len>>9;
1908
		sync_blocks -= (len>>9);
L
Linus Torvalds 已提交
1909 1910 1911 1912
	} while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
 bio_full:
	r1_bio->sectors = nr_sectors;

1913 1914 1915 1916 1917 1918 1919 1920
	/* For a user-requested sync, we read all readable devices and do a
	 * compare
	 */
	if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
		atomic_set(&r1_bio->remaining, read_targets);
		for (i=0; i<conf->raid_disks; i++) {
			bio = r1_bio->bios[i];
			if (bio->bi_end_io == end_sync_read) {
1921
				md_sync_acct(bio->bi_bdev, nr_sectors);
1922 1923 1924 1925 1926 1927
				generic_make_request(bio);
			}
		}
	} else {
		atomic_set(&r1_bio->remaining, 1);
		bio = r1_bio->bios[r1_bio->read_disk];
1928
		md_sync_acct(bio->bi_bdev, nr_sectors);
1929
		generic_make_request(bio);
L
Linus Torvalds 已提交
1930

1931
	}
L
Linus Torvalds 已提交
1932 1933 1934
	return nr_sectors;
}

1935 1936 1937 1938 1939 1940 1941 1942
static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
{
	if (sectors)
		return sectors;

	return mddev->dev_sectors;
}

L
Linus Torvalds 已提交
1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954
static int run(mddev_t *mddev)
{
	conf_t *conf;
	int i, j, disk_idx;
	mirror_info_t *disk;
	mdk_rdev_t *rdev;

	if (mddev->level != 1) {
		printk("raid1: %s: raid level not set to mirroring (%d)\n",
		       mdname(mddev), mddev->level);
		goto out;
	}
1955 1956 1957 1958 1959
	if (mddev->reshape_position != MaxSector) {
		printk("raid1: %s: reshape_position set but not supported\n",
		       mdname(mddev));
		goto out;
	}
L
Linus Torvalds 已提交
1960 1961 1962 1963 1964
	/*
	 * copy the already verified devices into our private RAID1
	 * bookkeeping area. [whatever we allocate in run(),
	 * should be freed in stop()]
	 */
1965
	conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
L
Linus Torvalds 已提交
1966 1967 1968 1969
	mddev->private = conf;
	if (!conf)
		goto out_no_mem;

1970
	conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
L
Linus Torvalds 已提交
1971 1972 1973 1974
				 GFP_KERNEL);
	if (!conf->mirrors)
		goto out_no_mem;

1975 1976 1977 1978
	conf->tmppage = alloc_page(GFP_KERNEL);
	if (!conf->tmppage)
		goto out_no_mem;

L
Linus Torvalds 已提交
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989
	conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
	if (!conf->poolinfo)
		goto out_no_mem;
	conf->poolinfo->mddev = mddev;
	conf->poolinfo->raid_disks = mddev->raid_disks;
	conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
					  r1bio_pool_free,
					  conf->poolinfo);
	if (!conf->r1bio_pool)
		goto out_no_mem;

1990 1991 1992
	spin_lock_init(&conf->device_lock);
	mddev->queue->queue_lock = &conf->device_lock;

1993
	list_for_each_entry(rdev, &mddev->disks, same_set) {
L
Linus Torvalds 已提交
1994 1995 1996 1997 1998 1999 2000
		disk_idx = rdev->raid_disk;
		if (disk_idx >= mddev->raid_disks
		    || disk_idx < 0)
			continue;
		disk = conf->mirrors + disk_idx;

		disk->rdev = rdev;
2001 2002
		disk_stack_limits(mddev->gendisk, rdev->bdev,
				  rdev->data_offset << 9);
L
Linus Torvalds 已提交
2003 2004 2005 2006 2007
		/* as we don't honour merge_bvec_fn, we must never risk
		 * violating it, so limit ->max_sector to one PAGE, as
		 * a one page request is never in violation.
		 */
		if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
2008
		    queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
L
Linus Torvalds 已提交
2009 2010 2011 2012 2013 2014 2015 2016 2017
			blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);

		disk->head_position = 0;
	}
	conf->raid_disks = mddev->raid_disks;
	conf->mddev = mddev;
	INIT_LIST_HEAD(&conf->retry_list);

	spin_lock_init(&conf->resync_lock);
2018
	init_waitqueue_head(&conf->wait_barrier);
L
Linus Torvalds 已提交
2019

2020 2021 2022
	bio_list_init(&conf->pending_bio_list);
	bio_list_init(&conf->flushing_bio_list);

L
Linus Torvalds 已提交
2023 2024 2025 2026 2027 2028

	mddev->degraded = 0;
	for (i = 0; i < conf->raid_disks; i++) {

		disk = conf->mirrors + i;

2029 2030
		if (!disk->rdev ||
		    !test_bit(In_sync, &disk->rdev->flags)) {
L
Linus Torvalds 已提交
2031 2032
			disk->head_position = 0;
			mddev->degraded++;
2033 2034
			if (disk->rdev)
				conf->fullsync = 1;
L
Linus Torvalds 已提交
2035 2036
		}
	}
2037 2038 2039 2040 2041 2042 2043
	if (mddev->degraded == conf->raid_disks) {
		printk(KERN_ERR "raid1: no operational mirrors for %s\n",
			mdname(mddev));
		goto out_free_conf;
	}
	if (conf->raid_disks - mddev->degraded == 1)
		mddev->recovery_cp = MaxSector;
L
Linus Torvalds 已提交
2044 2045 2046 2047 2048 2049 2050

	/*
	 * find the first working one and use it as a starting point
	 * to read balancing.
	 */
	for (j = 0; j < conf->raid_disks &&
		     (!conf->mirrors[j].rdev ||
2051
		      !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++)
L
Linus Torvalds 已提交
2052 2053 2054 2055
		/* nothing */;
	conf->last_used = j;


2056
	mddev->thread = md_register_thread(raid1d, mddev, NULL);
2057 2058 2059 2060 2061
	if (!mddev->thread) {
		printk(KERN_ERR
		       "raid1: couldn't allocate thread for %s\n",
		       mdname(mddev));
		goto out_free_conf;
L
Linus Torvalds 已提交
2062
	}
2063

2064 2065 2066 2067
	if (mddev->recovery_cp != MaxSector)
		printk(KERN_NOTICE "raid1: %s is not clean"
		       " -- starting background reconstruction\n",
		       mdname(mddev));
L
Linus Torvalds 已提交
2068 2069 2070 2071 2072 2073 2074
	printk(KERN_INFO 
		"raid1: raid set %s active with %d out of %d mirrors\n",
		mdname(mddev), mddev->raid_disks - mddev->degraded, 
		mddev->raid_disks);
	/*
	 * Ok, everything is just fine now
	 */
2075
	md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
L
Linus Torvalds 已提交
2076

2077
	mddev->queue->unplug_fn = raid1_unplug;
2078 2079
	mddev->queue->backing_dev_info.congested_fn = raid1_congested;
	mddev->queue->backing_dev_info.congested_data = mddev;
2080
	md_integrity_register(mddev);
L
Linus Torvalds 已提交
2081 2082 2083 2084 2085 2086 2087 2088 2089 2090
	return 0;

out_no_mem:
	printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
	       mdname(mddev));

out_free_conf:
	if (conf) {
		if (conf->r1bio_pool)
			mempool_destroy(conf->r1bio_pool);
2091
		kfree(conf->mirrors);
2092
		safe_put_page(conf->tmppage);
2093
		kfree(conf->poolinfo);
L
Linus Torvalds 已提交
2094 2095 2096 2097 2098 2099 2100 2101 2102
		kfree(conf);
		mddev->private = NULL;
	}
out:
	return -EIO;
}

static int stop(mddev_t *mddev)
{
2103
	conf_t *conf = mddev->private;
2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114
	struct bitmap *bitmap = mddev->bitmap;
	int behind_wait = 0;

	/* wait for behind writes to complete */
	while (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
		behind_wait++;
		printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), behind_wait);
		set_current_state(TASK_UNINTERRUPTIBLE);
		schedule_timeout(HZ); /* wait a second */
		/* need to kick something here to make sure I/O goes? */
	}
L
Linus Torvalds 已提交
2115

2116 2117 2118
	raise_barrier(conf);
	lower_barrier(conf);

L
Linus Torvalds 已提交
2119 2120 2121 2122 2123
	md_unregister_thread(mddev->thread);
	mddev->thread = NULL;
	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
	if (conf->r1bio_pool)
		mempool_destroy(conf->r1bio_pool);
2124 2125
	kfree(conf->mirrors);
	kfree(conf->poolinfo);
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	kfree(conf);
	mddev->private = NULL;
	return 0;
}

static int raid1_resize(mddev_t *mddev, sector_t sectors)
{
	/* 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.
	 */
2140
	md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
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	if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
		return -EINVAL;
2143
	set_capacity(mddev->gendisk, mddev->array_sectors);
2144
	mddev->changed = 1;
2145
	revalidate_disk(mddev->gendisk);
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2146
	if (sectors > mddev->dev_sectors &&
2147
	    mddev->recovery_cp == MaxSector) {
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2148
		mddev->recovery_cp = mddev->dev_sectors;
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		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
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	mddev->dev_sectors = sectors;
2152
	mddev->resync_max_sectors = sectors;
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	return 0;
}

2156
static int raid1_reshape(mddev_t *mddev)
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{
	/* We need to:
	 * 1/ resize the r1bio_pool
	 * 2/ resize conf->mirrors
	 *
	 * We allocate a new r1bio_pool if we can.
	 * Then raise a device barrier and wait until all IO stops.
	 * Then resize conf->mirrors and swap in the new r1bio pool.
2165 2166 2167
	 *
	 * At the same time, we "pack" the devices so that all the missing
	 * devices have the higher raid_disk numbers.
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	 */
	mempool_t *newpool, *oldpool;
	struct pool_info *newpoolinfo;
	mirror_info_t *newmirrors;
2172
	conf_t *conf = mddev->private;
2173
	int cnt, raid_disks;
2174
	unsigned long flags;
2175
	int d, d2, err;
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2177
	/* Cannot change chunk_size, layout, or level */
2178
	if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2179 2180
	    mddev->layout != mddev->new_layout ||
	    mddev->level != mddev->new_level) {
2181
		mddev->new_chunk_sectors = mddev->chunk_sectors;
2182 2183 2184 2185 2186
		mddev->new_layout = mddev->layout;
		mddev->new_level = mddev->level;
		return -EINVAL;
	}

2187 2188 2189
	err = md_allow_write(mddev);
	if (err)
		return err;
2190

2191 2192
	raid_disks = mddev->raid_disks + mddev->delta_disks;

2193 2194 2195 2196 2197 2198
	if (raid_disks < conf->raid_disks) {
		cnt=0;
		for (d= 0; d < conf->raid_disks; d++)
			if (conf->mirrors[d].rdev)
				cnt++;
		if (cnt > raid_disks)
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			return -EBUSY;
2200
	}
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	newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
	if (!newpoolinfo)
		return -ENOMEM;
	newpoolinfo->mddev = mddev;
	newpoolinfo->raid_disks = raid_disks;

	newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
				 r1bio_pool_free, newpoolinfo);
	if (!newpool) {
		kfree(newpoolinfo);
		return -ENOMEM;
	}
2214
	newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
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	if (!newmirrors) {
		kfree(newpoolinfo);
		mempool_destroy(newpool);
		return -ENOMEM;
	}

2221
	raise_barrier(conf);
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	/* ok, everything is stopped */
	oldpool = conf->r1bio_pool;
	conf->r1bio_pool = newpool;
2226

2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241
	for (d = d2 = 0; d < conf->raid_disks; d++) {
		mdk_rdev_t *rdev = conf->mirrors[d].rdev;
		if (rdev && rdev->raid_disk != d2) {
			char nm[20];
			sprintf(nm, "rd%d", rdev->raid_disk);
			sysfs_remove_link(&mddev->kobj, nm);
			rdev->raid_disk = d2;
			sprintf(nm, "rd%d", rdev->raid_disk);
			sysfs_remove_link(&mddev->kobj, nm);
			if (sysfs_create_link(&mddev->kobj,
					      &rdev->kobj, nm))
				printk(KERN_WARNING
				       "md/raid1: cannot register "
				       "%s for %s\n",
				       nm, mdname(mddev));
2242
		}
2243 2244 2245
		if (rdev)
			newmirrors[d2++].rdev = rdev;
	}
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	kfree(conf->mirrors);
	conf->mirrors = newmirrors;
	kfree(conf->poolinfo);
	conf->poolinfo = newpoolinfo;

2251
	spin_lock_irqsave(&conf->device_lock, flags);
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2252
	mddev->degraded += (raid_disks - conf->raid_disks);
2253
	spin_unlock_irqrestore(&conf->device_lock, flags);
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2254
	conf->raid_disks = mddev->raid_disks = raid_disks;
2255
	mddev->delta_disks = 0;
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2256

2257
	conf->last_used = 0; /* just make sure it is in-range */
2258
	lower_barrier(conf);
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	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	md_wakeup_thread(mddev->thread);

	mempool_destroy(oldpool);
	return 0;
}

2267
static void raid1_quiesce(mddev_t *mddev, int state)
2268
{
2269
	conf_t *conf = mddev->private;
2270 2271

	switch(state) {
2272
	case 1:
2273
		raise_barrier(conf);
2274
		break;
2275
	case 0:
2276
		lower_barrier(conf);
2277 2278 2279 2280
		break;
	}
}

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2282
static struct mdk_personality raid1_personality =
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{
	.name		= "raid1",
2285
	.level		= 1,
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	.owner		= THIS_MODULE,
	.make_request	= make_request,
	.run		= run,
	.stop		= stop,
	.status		= status,
	.error_handler	= error,
	.hot_add_disk	= raid1_add_disk,
	.hot_remove_disk= raid1_remove_disk,
	.spare_active	= raid1_spare_active,
	.sync_request	= sync_request,
	.resize		= raid1_resize,
2297
	.size		= raid1_size,
2298
	.check_reshape	= raid1_reshape,
2299
	.quiesce	= raid1_quiesce,
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};

static int __init raid_init(void)
{
2304
	return register_md_personality(&raid1_personality);
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}

static void raid_exit(void)
{
2309
	unregister_md_personality(&raid1_personality);
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}

module_init(raid_init);
module_exit(raid_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS("md-personality-3"); /* RAID1 */
2316
MODULE_ALIAS("md-raid1");
2317
MODULE_ALIAS("md-level-1");