raid1.c 62.3 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);
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	if (!r1_bio && pi->mddev)
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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);
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	r1bio_t *r1_bio = bio->bi_private;
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	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);
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	r1bio_t *r1_bio = 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);
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		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

	/* 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;
680
	BUG_ON(conf->barrier <= 0);
681 682 683 684 685 686 687 688 689 690 691 692 693 694 695
	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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	}
697
	conf->nr_pending++;
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	spin_unlock_irq(&conf->resync_lock);
}

701 702 703 704 705 706 707 708 709
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);
}

710 711 712 713 714
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
715 716 717 718 719 720 721 722
	 * 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.
723 724 725 726 727
	 */
	spin_lock_irq(&conf->resync_lock);
	conf->barrier++;
	conf->nr_waiting++;
	wait_event_lock_irq(conf->wait_barrier,
728
			    conf->nr_pending == conf->nr_queued+1,
729
			    conf->resync_lock,
730 731
			    ({ flush_pending_writes(conf);
			       raid1_unplug(conf->mddev->queue); }));
732 733 734 735 736 737 738 739 740 741 742 743
	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);
}

744

745 746 747 748 749
/* duplicate the data pages for behind I/O */
static struct page **alloc_behind_pages(struct bio *bio)
{
	int i;
	struct bio_vec *bvec;
750
	struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769
					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++)
770
			put_page(pages[i]);
771 772 773 774 775
	kfree(pages);
	PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
	return NULL;
}

776
static int make_request(mddev_t *mddev, struct bio * bio)
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{
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
	const bool do_sync = bio_rw_flagged(bio, BIO_RW_SYNCIO);
	bool do_barriers;
790
	mdk_rdev_t *blocked_rdev;
791

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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.
796 797 798
	 * 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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	 */
800

801 802
	md_write_start(mddev, bio); /* wait on superblock update early */

803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821
	if (bio_data_dir(bio) == WRITE &&
	    bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
	    bio->bi_sector < mddev->suspend_hi) {
		/* As the suspend_* range is controlled by
		 * userspace, we want an interruptible
		 * wait.
		 */
		DEFINE_WAIT(w);
		for (;;) {
			flush_signals(current);
			prepare_to_wait(&conf->wait_barrier,
					&w, TASK_INTERRUPTIBLE);
			if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
			    bio->bi_sector >= mddev->suspend_hi)
				break;
			schedule();
		}
		finish_wait(&conf->wait_barrier, &w);
	}
822 823
	if (unlikely(!mddev->barriers_work &&
		     bio_rw_flagged(bio, BIO_RW_BARRIER))) {
824 825
		if (rw == WRITE)
			md_write_end(mddev);
826
		bio_endio(bio, -EOPNOTSUPP);
827 828 829
		return 0;
	}

830
	wait_barrier(conf);
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832 833
	bitmap = mddev->bitmap;

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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;
843
	r1_bio->state = 0;
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	r1_bio->mddev = mddev;
	r1_bio->sector = bio->bi_sector;

847
	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;

860 861 862 863 864 865 866 867 868
		if (test_bit(WriteMostly, &mirror->rdev->flags) &&
		    bitmap) {
			/* Reading from a write-mostly device must
			 * take care not to over-take any writes
			 * that are 'behind'
			 */
			wait_event(bitmap->behind_wait,
				   atomic_read(&bitmap->behind_writes) == 0);
		}
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		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;
878
		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;
893 894 895 896 897 898 899
#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
900 901
 retry_write:
	blocked_rdev = NULL;
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	rcu_read_lock();
	for (i = 0;  i < disks; i++) {
904 905 906 907 908 909 910
		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);
912
			if (test_bit(Faulty, &rdev->flags)) {
913
				rdev_dec_pending(rdev, mddev);
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				r1_bio->bios[i] = NULL;
915
			} else {
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				r1_bio->bios[i] = bio;
917 918
				targets++;
			}
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		} else
			r1_bio->bios[i] = NULL;
	}
	rcu_read_unlock();

924 925 926 927 928 929 930 931 932 933 934 935 936 937
	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;
	}

938 939
	BUG_ON(targets == 0); /* we never fail the last device */

940 941 942 943 944 945
	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);
	}

946 947 948 949
	/* do behind I/O ?
	 * Not if there are too many, or cannot allocate memory,
	 * or a reader on WriteMostly is waiting for behind writes 
	 * to flush */
950
	if (bitmap &&
951 952
	    (atomic_read(&bitmap->behind_writes)
	     < mddev->bitmap_info.max_write_behind) &&
953
	    !waitqueue_active(&bitmap->behind_wait) &&
954 955 956
	    (behind_pages = alloc_behind_pages(bio)) != NULL)
		set_bit(R1BIO_BehindIO, &r1_bio->state);

957
	atomic_set(&r1_bio->remaining, 0);
958
	atomic_set(&r1_bio->behind_remaining, 0);
959

960
	do_barriers = bio_rw_flagged(bio, BIO_RW_BARRIER);
961 962 963
	if (do_barriers)
		set_bit(R1BIO_Barrier, &r1_bio->state);

964
	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;
976 977
		mbio->bi_rw = WRITE | (do_barriers << BIO_RW_BARRIER) |
			(do_sync << BIO_RW_SYNCIO);
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		mbio->bi_private = r1_bio;

980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996
		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);

999
		bio_list_add(&bl, mbio);
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	}
1001
	kfree(behind_pages); /* the behind pages are attached to the bios now */
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1003 1004
	bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
				test_bit(R1BIO_BehindIO, &r1_bio->state));
1005 1006 1007 1008 1009 1010 1011
	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);

1012 1013 1014
	/* In case raid1d snuck into freeze_array */
	wake_up(&conf->wait_barrier);

1015 1016
	if (do_sync)
		md_wakeup_thread(mddev->thread);
1017 1018 1019 1020 1021
#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)
{
1027
	conf_t *conf = mddev->private;
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	int i;

	seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1031
		   conf->raid_disks - mddev->degraded);
1032 1033 1034
	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",
1036 1037 1038
			   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];
1046
	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
	 */
1054
	if (test_bit(In_sync, &rdev->flags)
1055
	    && (conf->raid_disks - mddev->degraded) == 1) {
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		/*
		 * Don't fail the drive, act as though we were just a
1058 1059 1060
		 * normal single drive.
		 * However don't try a recovery from this drive as
		 * it is very likely to fail.
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		 */
1062
		mddev->recovery_disabled = 1;
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		return;
1064
	}
1065 1066 1067
	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++;
1069
		set_bit(Faulty, &rdev->flags);
1070
		spin_unlock_irqrestore(&conf->device_lock, flags);
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		/*
		 * if recovery is running, make sure it aborts.
		 */
1074
		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1075 1076
	} else
		set_bit(Faulty, &rdev->flags);
1077
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
1078 1079
	printk(KERN_ALERT "raid1: Disk failure on %s, disabling device.\n"
		"raid1: Operation continuing on %d devices.\n",
1080
		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;
	}
1092
	printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
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		conf->raid_disks);

1095
	rcu_read_lock();
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	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
1098 1099
		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",
1101 1102 1103
			       i, !test_bit(In_sync, &rdev->flags),
			       !test_bit(Faulty, &rdev->flags),
			       bdevname(rdev->bdev,b));
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	}
1105
	rcu_read_unlock();
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}

static void close_sync(conf_t *conf)
{
1110 1111
	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 
1124 1125
	 * 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++) {
1128 1129 1130
		mdk_rdev_t *rdev = conf->mirrors[i].rdev;
		if (rdev
		    && !test_bit(Faulty, &rdev->flags)
1131 1132 1133
		    && !test_and_set_bit(In_sync, &rdev->flags)) {
			unsigned long flags;
			spin_lock_irqsave(&conf->device_lock, flags);
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			mddev->degraded--;
1135
			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;
1147
	int err = -EEXIST;
1148
	int mirror = 0;
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	mirror_info_t *p;
1150 1151
	int first = 0;
	int last = mddev->raid_disks - 1;
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1153 1154 1155 1156
	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) {

1159 1160
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
1161 1162 1163 1164 1165
			/* as we don't honour merge_bvec_fn, we must
			 * never risk violating it, so limit
			 * ->max_segments to one lying with a single
			 * page, as a one page request is never in
			 * violation.
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			 */
1167 1168 1169 1170 1171
			if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
				blk_queue_max_segments(mddev->queue, 1);
				blk_queue_segment_boundary(mddev->queue,
							   PAGE_CACHE_SIZE - 1);
			}
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			p->head_position = 0;
			rdev->raid_disk = mirror;
1175
			err = 0;
1176 1177 1178 1179
			/* 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)
1180
				conf->fullsync = 1;
1181
			rcu_assign_pointer(p->rdev, rdev);
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			break;
		}
1184
	md_integrity_add_rdev(rdev, mddev);
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	print_conf(conf);
1186
	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) {
1199
		if (test_bit(In_sync, &rdev->flags) ||
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		    atomic_read(&rdev->nr_pending)) {
			err = -EBUSY;
			goto abort;
		}
1204 1205 1206 1207 1208 1209 1210 1211
		/* 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;
1213
		synchronize_rcu();
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		if (atomic_read(&rdev->nr_pending)) {
			/* lost the race, try later */
			err = -EBUSY;
			p->rdev = rdev;
1218
			goto abort;
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		}
1220
		md_integrity_register(mddev);
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	}
abort:

	print_conf(conf);
	return err;
}


1229
static void end_sync_read(struct bio *bio, int error)
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{
1231
	r1bio_t *r1_bio = bio->bi_private;
1232
	int i;
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1234 1235 1236 1237 1238
	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
	 */
1244
	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
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		set_bit(R1BIO_Uptodate, &r1_bio->state);
1246 1247 1248

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

1251
static void end_sync_write(struct bio *bio, int error)
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{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1254
	r1bio_t *r1_bio = bio->bi_private;
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	mddev_t *mddev = r1_bio->mddev;
1256
	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;
		}
1265 1266 1267 1268 1269 1270
	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 {
1271
			bitmap_end_sync(mddev->bitmap, s,
1272 1273 1274 1275
					&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);
1277
	}
1278

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	update_head_pos(mirror, r1_bio);

	if (atomic_dec_and_test(&r1_bio->remaining)) {
1282
		sector_t s = r1_bio->sectors;
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		put_buf(r1_bio);
1284
		md_done_sync(mddev, s, uptodate);
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	}
}

static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
{
1290
	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];

1297

1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319
	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;
1320
				rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1321 1322 1323 1324
				break;
			}
		r1_bio->read_disk = primary;
		for (i=0; i<mddev->raid_disks; i++)
1325
			if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1326 1327 1328 1329
				int j;
				int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
				struct bio *pbio = r1_bio->bios[primary];
				struct bio *sbio = r1_bio->bios[i];
1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342

				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;
1343 1344
				if (j >= 0)
					mddev->resync_mismatches += r1_bio->sectors;
1345 1346
				if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
					      && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1347
					sbio->bi_end_io = NULL;
1348 1349
					rdev_dec_pending(conf->mirrors[i].rdev, mddev);
				} else {
1350
					/* fixup the bio for reuse */
1351
					int size;
1352 1353 1354 1355 1356 1357 1358 1359 1360 1361
					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;
1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372
					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),
1373 1374
						       page_address(pbio->bi_io_vec[j].bv_page),
						       PAGE_SIZE);
1375
					}
1376

1377 1378 1379
				}
			}
	}
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	if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1381 1382 1383
		/* 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
1384
		 * read into the pages we already have so we don't
1385 1386 1387 1388
		 * 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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		 */
1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403
		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) {
1404 1405 1406 1407
					/* No rcu protection needed here devices
					 * can only be removed when no resync is
					 * active, and resync is currently active
					 */
1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423
					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) {
1424
				int start = d;
1425 1426 1427 1428 1429 1430 1431 1432 1433
				/* 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;
1434
					atomic_add(s, &rdev->corrected_errors);
1435 1436 1437 1438
					if (sync_page_io(rdev->bdev,
							 sect + rdev->data_offset,
							 s<<9,
							 bio->bi_io_vec[idx].bv_page,
1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450
							 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,
1451 1452 1453
							 sect + rdev->data_offset,
							 s<<9,
							 bio->bi_io_vec[idx].bv_page,
1454
							 READ) == 0)
1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472
						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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	}
1474 1475 1476 1477

	/*
	 * schedule writes
	 */
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	atomic_set(&r1_bio->remaining, 1);
	for (i = 0; i < disks ; i++) {
		wbio = r1_bio->bios[i];
1481 1482 1483 1484
		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;

1487 1488
		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)) {
1496
		/* 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.
 */

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 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587
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,
1588 1589
					       (unsigned long long)(sect +
					           rdev->data_offset),
1590 1591 1592 1593 1594 1595 1596 1597 1598
					       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;
1604
	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];
1613

1614
		unplug += flush_pending_writes(conf);
1615

1616 1617 1618
		spin_lock_irqsave(&conf->device_lock, flags);
		if (list_empty(head)) {
			spin_unlock_irqrestore(&conf->device_lock, flags);
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			break;
1620
		}
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		r1_bio = list_entry(head->prev, r1bio_t, retry_list);
		list_del(head->prev);
1623
		conf->nr_queued--;
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		spin_unlock_irqrestore(&conf->device_lock, flags);

		mddev = r1_bio->mddev;
1627
		conf = mddev->private;
L
Linus Torvalds 已提交
1628 1629 1630
		if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
			sync_request_write(mddev, r1_bio);
			unplug = 1;
1631 1632
		} else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
			/* some requests in the r1bio were BIO_RW_BARRIER
1633
			 * requests which failed with -EOPNOTSUPP.  Hohumm..
1634 1635 1636
			 * Better resubmit without the barrier.
			 * We know which devices to resubmit for, because
			 * all others have had their bios[] entry cleared.
1637
			 * We already have a nr_pending reference on these rdevs.
1638 1639
			 */
			int i;
1640
			const bool do_sync = bio_rw_flagged(r1_bio->master_bio, BIO_RW_SYNCIO);
1641 1642
			clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
			clear_bit(R1BIO_Barrier, &r1_bio->state);
1643 1644 1645
			for (i=0; i < conf->raid_disks; i++)
				if (r1_bio->bios[i])
					atomic_inc(&r1_bio->remaining);
1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660
			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;
1661 1662
					bio->bi_rw = WRITE |
						(do_sync << BIO_RW_SYNCIO);
1663 1664 1665 1666
					bio->bi_private = r1_bio;
					r1_bio->bios[i] = bio;
					generic_make_request(bio);
				}
L
Linus Torvalds 已提交
1667 1668
		} else {
			int disk;
1669 1670 1671 1672 1673 1674 1675 1676 1677

			/* 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
			 */
1678 1679 1680 1681 1682 1683
			if (mddev->ro == 0) {
				freeze_array(conf);
				fix_read_error(conf, r1_bio->read_disk,
					       r1_bio->sector,
					       r1_bio->sectors);
				unfreeze_array(conf);
1684 1685 1686
			} else
				md_error(mddev,
					 conf->mirrors[r1_bio->read_disk].rdev);
1687

L
Linus Torvalds 已提交
1688
			bio = r1_bio->bios[r1_bio->read_disk];
1689
			if ((disk=read_balance(conf, r1_bio)) == -1) {
L
Linus Torvalds 已提交
1690 1691 1692 1693 1694 1695
				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 {
1696
				const bool do_sync = bio_rw_flagged(r1_bio->master_bio, BIO_RW_SYNCIO);
1697 1698
				r1_bio->bios[r1_bio->read_disk] =
					mddev->ro ? IO_BLOCKED : NULL;
L
Linus Torvalds 已提交
1699 1700 1701 1702 1703 1704
				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())
1705 1706 1707 1708
					printk(KERN_ERR "raid1: redirecting sector %llu to"
					       " other mirror: %s\n",
					       (unsigned long long)r1_bio->sector,
					       bdevname(rdev->bdev,b));
L
Linus Torvalds 已提交
1709 1710 1711
				bio->bi_sector = r1_bio->sector + rdev->data_offset;
				bio->bi_bdev = rdev->bdev;
				bio->bi_end_io = raid1_end_read_request;
1712
				bio->bi_rw = READ | (do_sync << BIO_RW_SYNCIO);
L
Linus Torvalds 已提交
1713 1714 1715 1716 1717
				bio->bi_private = r1_bio;
				unplug = 1;
				generic_make_request(bio);
			}
		}
N
NeilBrown 已提交
1718
		cond_resched();
L
Linus Torvalds 已提交
1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729
	}
	if (unplug)
		unplug_slaves(mddev);
}


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

	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1730
	BUG_ON(conf->r1buf_pool);
L
Linus Torvalds 已提交
1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748
	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.
 */

1749
static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
L
Linus Torvalds 已提交
1750
{
1751
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
1752 1753 1754
	r1bio_t *r1_bio;
	struct bio *bio;
	sector_t max_sector, nr_sectors;
1755
	int disk = -1;
L
Linus Torvalds 已提交
1756
	int i;
1757 1758
	int wonly = -1;
	int write_targets = 0, read_targets = 0;
1759
	int sync_blocks;
1760
	int still_degraded = 0;
L
Linus Torvalds 已提交
1761 1762

	if (!conf->r1buf_pool)
1763 1764 1765 1766
	{
/*
		printk("sync start - bitmap %p\n", mddev->bitmap);
*/
L
Linus Torvalds 已提交
1767
		if (init_resync(conf))
1768
			return 0;
1769
	}
L
Linus Torvalds 已提交
1770

A
Andre Noll 已提交
1771
	max_sector = mddev->dev_sectors;
L
Linus Torvalds 已提交
1772
	if (sector_nr >= max_sector) {
1773 1774 1775 1776 1777
		/* 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
		 */
1778 1779
		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1780
						&sync_blocks, 1);
1781
		else /* completed sync */
1782
			conf->fullsync = 0;
1783 1784

		bitmap_close_sync(mddev->bitmap);
L
Linus Torvalds 已提交
1785 1786 1787 1788
		close_sync(conf);
		return 0;
	}

1789 1790
	if (mddev->bitmap == NULL &&
	    mddev->recovery_cp == MaxSector &&
1791
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1792 1793 1794 1795
	    conf->fullsync == 0) {
		*skipped = 1;
		return max_sector - sector_nr;
	}
1796 1797 1798
	/* before building a request, check if we can skip these blocks..
	 * This call the bitmap_start_sync doesn't actually record anything
	 */
1799
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1800
	    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1801 1802 1803 1804
		/* We can skip this block, and probably several more */
		*skipped = 1;
		return sync_blocks;
	}
L
Linus Torvalds 已提交
1805
	/*
1806 1807 1808
	 * 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
1809
	 */
1810
	if (!go_faster && conf->nr_waiting)
L
Linus Torvalds 已提交
1811
		msleep_interruptible(1000);
1812

N
NeilBrown 已提交
1813
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1814 1815 1816
	raise_barrier(conf);

	conf->next_resync = sector_nr;
L
Linus Torvalds 已提交
1817

1818 1819
	r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
	rcu_read_lock();
L
Linus Torvalds 已提交
1820
	/*
1821 1822 1823 1824 1825 1826
	 * 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
1827 1828 1829 1830
	 */

	r1_bio->mddev = mddev;
	r1_bio->sector = sector_nr;
1831
	r1_bio->state = 0;
L
Linus Torvalds 已提交
1832 1833 1834
	set_bit(R1BIO_IsSync, &r1_bio->state);

	for (i=0; i < conf->raid_disks; i++) {
1835
		mdk_rdev_t *rdev;
L
Linus Torvalds 已提交
1836 1837 1838 1839 1840
		bio = r1_bio->bios[i];

		/* take from bio_init */
		bio->bi_next = NULL;
		bio->bi_flags |= 1 << BIO_UPTODATE;
1841
		bio->bi_rw = READ;
L
Linus Torvalds 已提交
1842 1843 1844 1845 1846 1847 1848
		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;

1849 1850 1851
		rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev == NULL ||
			   test_bit(Faulty, &rdev->flags)) {
1852 1853
			still_degraded = 1;
			continue;
1854
		} else if (!test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
1855 1856 1857
			bio->bi_rw = WRITE;
			bio->bi_end_io = end_sync_write;
			write_targets ++;
1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873
		} 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
1874 1875
		bio->bi_private = r1_bio;
	}
1876 1877 1878 1879
	rcu_read_unlock();
	if (disk < 0)
		disk = wonly;
	r1_bio->read_disk = disk;
1880

1881 1882 1883 1884 1885
	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
1886 1887 1888
		/* There is nowhere to write, so all non-sync
		 * drives must be failed - so we are finished
		 */
1889 1890
		sector_t rv = max_sector - sector_nr;
		*skipped = 1;
L
Linus Torvalds 已提交
1891 1892 1893 1894
		put_buf(r1_bio);
		return rv;
	}

1895 1896
	if (max_sector > mddev->resync_max)
		max_sector = mddev->resync_max; /* Don't do IO beyond here */
L
Linus Torvalds 已提交
1897
	nr_sectors = 0;
1898
	sync_blocks = 0;
L
Linus Torvalds 已提交
1899 1900 1901 1902 1903 1904 1905
	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;
1906 1907
		if (sync_blocks == 0) {
			if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1908 1909 1910
					       &sync_blocks, still_degraded) &&
			    !conf->fullsync &&
			    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1911
				break;
1912
			BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1913 1914
			if (len > (sync_blocks<<9))
				len = sync_blocks<<9;
1915
		}
1916

L
Linus Torvalds 已提交
1917 1918 1919
		for (i=0 ; i < conf->raid_disks; i++) {
			bio = r1_bio->bios[i];
			if (bio->bi_end_io) {
1920
				page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
L
Linus Torvalds 已提交
1921 1922
				if (bio_add_page(bio, page, len, 0) == 0) {
					/* stop here */
1923
					bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
L
Linus Torvalds 已提交
1924 1925 1926
					while (i > 0) {
						i--;
						bio = r1_bio->bios[i];
1927 1928
						if (bio->bi_end_io==NULL)
							continue;
L
Linus Torvalds 已提交
1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939
						/* 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;
1940
		sync_blocks -= (len>>9);
L
Linus Torvalds 已提交
1941 1942 1943 1944
	} while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
 bio_full:
	r1_bio->sectors = nr_sectors;

1945 1946 1947 1948 1949 1950 1951 1952
	/* 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) {
1953
				md_sync_acct(bio->bi_bdev, nr_sectors);
1954 1955 1956 1957 1958 1959
				generic_make_request(bio);
			}
		}
	} else {
		atomic_set(&r1_bio->remaining, 1);
		bio = r1_bio->bios[r1_bio->read_disk];
1960
		md_sync_acct(bio->bi_bdev, nr_sectors);
1961
		generic_make_request(bio);
L
Linus Torvalds 已提交
1962

1963
	}
L
Linus Torvalds 已提交
1964 1965 1966
	return nr_sectors;
}

1967 1968 1969 1970 1971 1972 1973 1974
static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
{
	if (sectors)
		return sectors;

	return mddev->dev_sectors;
}

1975
static conf_t *setup_conf(mddev_t *mddev)
L
Linus Torvalds 已提交
1976 1977
{
	conf_t *conf;
1978
	int i;
L
Linus Torvalds 已提交
1979 1980
	mirror_info_t *disk;
	mdk_rdev_t *rdev;
1981
	int err = -ENOMEM;
L
Linus Torvalds 已提交
1982

1983
	conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
L
Linus Torvalds 已提交
1984
	if (!conf)
1985
		goto abort;
L
Linus Torvalds 已提交
1986

1987
	conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
L
Linus Torvalds 已提交
1988 1989
				 GFP_KERNEL);
	if (!conf->mirrors)
1990
		goto abort;
L
Linus Torvalds 已提交
1991

1992 1993
	conf->tmppage = alloc_page(GFP_KERNEL);
	if (!conf->tmppage)
1994
		goto abort;
1995

1996
	conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
L
Linus Torvalds 已提交
1997
	if (!conf->poolinfo)
1998
		goto abort;
L
Linus Torvalds 已提交
1999 2000 2001 2002 2003
	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)
2004 2005
		goto abort;

2006
	conf->poolinfo->mddev = mddev;
L
Linus Torvalds 已提交
2007

2008
	spin_lock_init(&conf->device_lock);
2009
	list_for_each_entry(rdev, &mddev->disks, same_set) {
2010
		int disk_idx = rdev->raid_disk;
L
Linus Torvalds 已提交
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024
		if (disk_idx >= mddev->raid_disks
		    || disk_idx < 0)
			continue;
		disk = conf->mirrors + disk_idx;

		disk->rdev = rdev;

		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);
2025
	init_waitqueue_head(&conf->wait_barrier);
L
Linus Torvalds 已提交
2026

2027 2028 2029
	bio_list_init(&conf->pending_bio_list);
	bio_list_init(&conf->flushing_bio_list);

2030
	conf->last_used = -1;
L
Linus Torvalds 已提交
2031 2032 2033 2034
	for (i = 0; i < conf->raid_disks; i++) {

		disk = conf->mirrors + i;

2035 2036
		if (!disk->rdev ||
		    !test_bit(In_sync, &disk->rdev->flags)) {
L
Linus Torvalds 已提交
2037
			disk->head_position = 0;
2038 2039
			if (disk->rdev)
				conf->fullsync = 1;
2040 2041 2042 2043 2044 2045
		} else if (conf->last_used < 0)
			/*
			 * The first working device is used as a
			 * starting point to read balancing.
			 */
			conf->last_used = i;
L
Linus Torvalds 已提交
2046
	}
2047 2048 2049

	err = -EIO;
	if (conf->last_used < 0) {
2050
		printk(KERN_ERR "raid1: no operational mirrors for %s\n",
2051 2052 2053 2054 2055 2056 2057 2058 2059 2060
		       mdname(mddev));
		goto abort;
	}
	err = -ENOMEM;
	conf->thread = md_register_thread(raid1d, mddev, NULL);
	if (!conf->thread) {
		printk(KERN_ERR
		       "raid1: couldn't allocate thread for %s\n",
		       mdname(mddev));
		goto abort;
2061
	}
L
Linus Torvalds 已提交
2062

2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092
	return conf;

 abort:
	if (conf) {
		if (conf->r1bio_pool)
			mempool_destroy(conf->r1bio_pool);
		kfree(conf->mirrors);
		safe_put_page(conf->tmppage);
		kfree(conf->poolinfo);
		kfree(conf);
	}
	return ERR_PTR(err);
}

static int run(mddev_t *mddev)
{
	conf_t *conf;
	int i;
	mdk_rdev_t *rdev;

	if (mddev->level != 1) {
		printk("raid1: %s: raid level not set to mirroring (%d)\n",
		       mdname(mddev), mddev->level);
		return -EIO;
	}
	if (mddev->reshape_position != MaxSector) {
		printk("raid1: %s: reshape_position set but not supported\n",
		       mdname(mddev));
		return -EIO;
	}
L
Linus Torvalds 已提交
2093
	/*
2094 2095 2096
	 * copy the already verified devices into our private RAID1
	 * bookkeeping area. [whatever we allocate in run(),
	 * should be freed in stop()]
L
Linus Torvalds 已提交
2097
	 */
2098 2099 2100 2101
	if (mddev->private == NULL)
		conf = setup_conf(mddev);
	else
		conf = mddev->private;
L
Linus Torvalds 已提交
2102

2103 2104
	if (IS_ERR(conf))
		return PTR_ERR(conf);
L
Linus Torvalds 已提交
2105

2106 2107 2108 2109 2110
	mddev->queue->queue_lock = &conf->device_lock;
	list_for_each_entry(rdev, &mddev->disks, same_set) {
		disk_stack_limits(mddev->gendisk, rdev->bdev,
				  rdev->data_offset << 9);
		/* as we don't honour merge_bvec_fn, we must never risk
2111 2112
		 * violating it, so limit ->max_segments to 1 lying within
		 * a single page, as a one page request is never in violation.
2113
		 */
2114 2115 2116 2117 2118
		if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
			blk_queue_max_segments(mddev->queue, 1);
			blk_queue_segment_boundary(mddev->queue,
						   PAGE_CACHE_SIZE - 1);
		}
L
Linus Torvalds 已提交
2119
	}
2120

2121 2122 2123 2124 2125 2126 2127 2128 2129 2130
	mddev->degraded = 0;
	for (i=0; i < conf->raid_disks; i++)
		if (conf->mirrors[i].rdev == NULL ||
		    !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
		    test_bit(Faulty, &conf->mirrors[i].rdev->flags))
			mddev->degraded++;

	if (conf->raid_disks - mddev->degraded == 1)
		mddev->recovery_cp = MaxSector;

2131 2132 2133 2134
	if (mddev->recovery_cp != MaxSector)
		printk(KERN_NOTICE "raid1: %s is not clean"
		       " -- starting background reconstruction\n",
		       mdname(mddev));
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2135 2136 2137 2138
	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);
2139

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2140 2141 2142
	/*
	 * Ok, everything is just fine now
	 */
2143 2144 2145 2146
	mddev->thread = conf->thread;
	conf->thread = NULL;
	mddev->private = conf;

2147
	md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
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2148

2149
	mddev->queue->unplug_fn = raid1_unplug;
2150 2151
	mddev->queue->backing_dev_info.congested_fn = raid1_congested;
	mddev->queue->backing_dev_info.congested_data = mddev;
2152
	md_integrity_register(mddev);
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2153 2154 2155 2156 2157
	return 0;
}

static int stop(mddev_t *mddev)
{
2158
	conf_t *conf = mddev->private;
2159 2160 2161
	struct bitmap *bitmap = mddev->bitmap;

	/* wait for behind writes to complete */
2162 2163
	if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
		printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop.\n", mdname(mddev));
2164
		/* need to kick something here to make sure I/O goes? */
2165 2166
		wait_event(bitmap->behind_wait,
			   atomic_read(&bitmap->behind_writes) == 0);
2167
	}
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2168

2169 2170 2171
	raise_barrier(conf);
	lower_barrier(conf);

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2172 2173 2174 2175 2176
	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);
2177 2178
	kfree(conf->mirrors);
	kfree(conf->poolinfo);
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2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192
	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.
	 */
2193
	md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
D
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2194 2195
	if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
		return -EINVAL;
2196
	set_capacity(mddev->gendisk, mddev->array_sectors);
2197
	revalidate_disk(mddev->gendisk);
D
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2198
	if (sectors > mddev->dev_sectors &&
2199
	    mddev->recovery_cp == MaxSector) {
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Andre Noll 已提交
2200
		mddev->recovery_cp = mddev->dev_sectors;
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2201 2202
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
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2203
	mddev->dev_sectors = sectors;
2204
	mddev->resync_max_sectors = sectors;
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2205 2206 2207
	return 0;
}

2208
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.
2217 2218 2219
	 *
	 * 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;
2224
	conf_t *conf = mddev->private;
2225
	int cnt, raid_disks;
2226
	unsigned long flags;
2227
	int d, d2, err;
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2228

2229
	/* Cannot change chunk_size, layout, or level */
2230
	if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2231 2232
	    mddev->layout != mddev->new_layout ||
	    mddev->level != mddev->new_level) {
2233
		mddev->new_chunk_sectors = mddev->chunk_sectors;
2234 2235 2236 2237 2238
		mddev->new_layout = mddev->layout;
		mddev->new_level = mddev->level;
		return -EINVAL;
	}

2239 2240 2241
	err = md_allow_write(mddev);
	if (err)
		return err;
2242

2243 2244
	raid_disks = mddev->raid_disks + mddev->delta_disks;

2245 2246 2247 2248 2249 2250
	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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2251
			return -EBUSY;
2252
	}
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2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265

	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;
	}
2266
	newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
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	if (!newmirrors) {
		kfree(newpoolinfo);
		mempool_destroy(newpool);
		return -ENOMEM;
	}

2273
	raise_barrier(conf);
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2274 2275 2276 2277

	/* ok, everything is stopped */
	oldpool = conf->r1bio_pool;
	conf->r1bio_pool = newpool;
2278

2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293
	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));
2294
		}
2295 2296 2297
		if (rdev)
			newmirrors[d2++].rdev = rdev;
	}
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2298 2299 2300 2301 2302
	kfree(conf->mirrors);
	conf->mirrors = newmirrors;
	kfree(conf->poolinfo);
	conf->poolinfo = newpoolinfo;

2303
	spin_lock_irqsave(&conf->device_lock, flags);
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2304
	mddev->degraded += (raid_disks - conf->raid_disks);
2305
	spin_unlock_irqrestore(&conf->device_lock, flags);
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2306
	conf->raid_disks = mddev->raid_disks = raid_disks;
2307
	mddev->delta_disks = 0;
L
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2308

2309
	conf->last_used = 0; /* just make sure it is in-range */
2310
	lower_barrier(conf);
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2311 2312 2313 2314 2315 2316 2317 2318

	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	md_wakeup_thread(mddev->thread);

	mempool_destroy(oldpool);
	return 0;
}

2319
static void raid1_quiesce(mddev_t *mddev, int state)
2320
{
2321
	conf_t *conf = mddev->private;
2322 2323

	switch(state) {
2324 2325 2326
	case 2: /* wake for suspend */
		wake_up(&conf->wait_barrier);
		break;
2327
	case 1:
2328
		raise_barrier(conf);
2329
		break;
2330
	case 0:
2331
		lower_barrier(conf);
2332 2333 2334 2335
		break;
	}
}

2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352
static void *raid1_takeover(mddev_t *mddev)
{
	/* raid1 can take over:
	 *  raid5 with 2 devices, any layout or chunk size
	 */
	if (mddev->level == 5 && mddev->raid_disks == 2) {
		conf_t *conf;
		mddev->new_level = 1;
		mddev->new_layout = 0;
		mddev->new_chunk_sectors = 0;
		conf = setup_conf(mddev);
		if (!IS_ERR(conf))
			conf->barrier = 1;
		return conf;
	}
	return ERR_PTR(-EINVAL);
}
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2353

2354
static struct mdk_personality raid1_personality =
L
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2355 2356
{
	.name		= "raid1",
2357
	.level		= 1,
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2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368
	.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,
2369
	.size		= raid1_size,
2370
	.check_reshape	= raid1_reshape,
2371
	.quiesce	= raid1_quiesce,
2372
	.takeover	= raid1_takeover,
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2373 2374 2375 2376
};

static int __init raid_init(void)
{
2377
	return register_md_personality(&raid1_personality);
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2378 2379 2380 2381
}

static void raid_exit(void)
{
2382
	unregister_md_personality(&raid1_personality);
L
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2383 2384 2385 2386 2387
}

module_init(raid_init);
module_exit(raid_exit);
MODULE_LICENSE("GPL");
2388
MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
L
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2389
MODULE_ALIAS("md-personality-3"); /* RAID1 */
2390
MODULE_ALIAS("md-raid1");
2391
MODULE_ALIAS("md-level-1");