raid1.c 58.5 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/slab.h>
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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


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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;
	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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	return kzalloc(size, gfp_flags);
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}

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);
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	if (!r1_bio)
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		return NULL;

	/*
	 * Allocate bios : 1 for reading, n-1 for writing
	 */
	for (j = pi->raid_disks ; j-- ; ) {
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		bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
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		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())
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			printk(KERN_ERR "md/raid1:%s: %s: rescheduling sector %llu\n",
			       mdname(conf->mddev),
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			       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 r1_bio_write_done(r1bio_t *r1_bio, int vcnt, struct bio_vec *bv,
			      int behind)
{
	if (atomic_dec_and_test(&r1_bio->remaining))
	{
		/* 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 = vcnt;
			while (i--)
				safe_put_page(bv[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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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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	/*
	 * 'one mirror IO has finished' event handler:
	 */
	r1_bio->bios[mirror] = NULL;
	to_put = bio;
	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
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		/*
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		 * 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.
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		 */
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		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);
				bio_endio(mbio, 0);
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			}
		}
	}
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	rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);

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	/*
	 * Let's see if all mirrored write operations have finished
	 * already.
	 */
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	r1_bio_write_done(r1_bio, bio->bi_vcnt, bio->bi_io_vec, behind);
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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)
{
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	const sector_t this_sector = r1_bio->sector;
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	const int sectors = r1_bio->sectors;
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	int start_disk;
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	int best_disk;
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	int i;
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	sector_t best_dist;
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	mdk_rdev_t *rdev;
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	int choose_first;
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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:
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	best_disk = -1;
	best_dist = MaxSector;
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	if (conf->mddev->recovery_cp < MaxSector &&
	    (this_sector + sectors >= conf->next_resync)) {
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		choose_first = 1;
		start_disk = 0;
	} else {
		choose_first = 0;
		start_disk = conf->last_used;
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	}

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	for (i = 0 ; i < conf->raid_disks ; i++) {
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		sector_t dist;
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		int disk = start_disk + i;
		if (disk >= conf->raid_disks)
			disk -= conf->raid_disks;

		rdev = rcu_dereference(conf->mirrors[disk].rdev);
		if (r1_bio->bios[disk] == IO_BLOCKED
		    || rdev == NULL
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		    || test_bit(Faulty, &rdev->flags))
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			continue;
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		if (!test_bit(In_sync, &rdev->flags) &&
		    rdev->recovery_offset < this_sector + sectors)
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			continue;
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		if (test_bit(WriteMostly, &rdev->flags)) {
			/* Don't balance among write-mostly, just
			 * use the first as a last resort */
			if (best_disk < 0)
				best_disk = disk;
			continue;
		}
		/* This is a reasonable device to use.  It might
		 * even be best.
		 */
		dist = abs(this_sector - conf->mirrors[disk].head_position);
		if (choose_first
		    /* Don't change to another disk for sequential reads */
		    || conf->next_seq_sect == this_sector
		    || dist == 0
		    /* If device is idle, use it */
		    || atomic_read(&rdev->nr_pending) == 0) {
			best_disk = disk;
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			break;
		}
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		if (dist < best_dist) {
			best_dist = dist;
			best_disk = disk;
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		}
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	}
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	if (best_disk >= 0) {
		rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
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		if (!rdev)
			goto retry;
		atomic_inc(&rdev->nr_pending);
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		if (test_bit(Faulty, &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;
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		conf->last_used = best_disk;
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	}
	rcu_read_unlock();

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	return best_disk;
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}

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static int raid1_congested(void *data, int bits)
{
	mddev_t *mddev = data;
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	conf_t *conf = mddev->private;
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	int i, ret = 0;

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	if (mddev_congested(mddev, bits))
		return 1;

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	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)) {
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			struct request_queue *q = bdev_get_queue(rdev->bdev);
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			/* Note the '|| 1' - when read_balance prefers
			 * non-congested targets, it can be removed
			 */
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			if ((bits & (1<<BDI_async_congested)) || 1)
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				ret |= bdi_congested(&q->backing_dev_info, bits);
			else
				ret &= bdi_congested(&q->backing_dev_info, bits);
		}
	}
	rcu_read_unlock();
	return ret;
}


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static void flush_pending_writes(conf_t *conf)
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{
	/* Any writes that have been queued but are awaiting
	 * bitmap updates get flushed here.
	 */
	spin_lock_irq(&conf->device_lock);

	if (conf->pending_bio_list.head) {
		struct bio *bio;
		bio = bio_list_get(&conf->pending_bio_list);
		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;
		}
	} else
		spin_unlock_irq(&conf->device_lock);
J
Jens Axboe 已提交
551 552
}

553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572
/* 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.
L
Linus Torvalds 已提交
573 574 575
 */
#define RESYNC_DEPTH 32

576
static void raise_barrier(conf_t *conf)
L
Linus Torvalds 已提交
577 578
{
	spin_lock_irq(&conf->resync_lock);
579 580 581

	/* Wait until no block IO is waiting */
	wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
N
NeilBrown 已提交
582
			    conf->resync_lock, );
583 584 585 586

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

N
NeilBrown 已提交
587
	/* Now wait for all pending IO to complete */
588 589
	wait_event_lock_irq(conf->wait_barrier,
			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
N
NeilBrown 已提交
590
			    conf->resync_lock, );
591 592 593 594 595 596 597

	spin_unlock_irq(&conf->resync_lock);
}

static void lower_barrier(conf_t *conf)
{
	unsigned long flags;
598
	BUG_ON(conf->barrier <= 0);
599 600 601 602 603 604 605 606 607 608 609 610 611
	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,
N
NeilBrown 已提交
612
				    );
613
		conf->nr_waiting--;
L
Linus Torvalds 已提交
614
	}
615
	conf->nr_pending++;
L
Linus Torvalds 已提交
616 617 618
	spin_unlock_irq(&conf->resync_lock);
}

619 620 621 622 623 624 625 626 627
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);
}

628 629 630 631 632
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
633 634 635 636 637 638 639 640
	 * 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.
641 642 643 644 645
	 */
	spin_lock_irq(&conf->resync_lock);
	conf->barrier++;
	conf->nr_waiting++;
	wait_event_lock_irq(conf->wait_barrier,
646
			    conf->nr_pending == conf->nr_queued+1,
647
			    conf->resync_lock,
N
NeilBrown 已提交
648
			    flush_pending_writes(conf));
649 650 651 652 653 654 655 656 657 658 659 660
	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);
}

661

662 663 664 665 666
/* duplicate the data pages for behind I/O 
 * We return a list of bio_vec rather than just page pointers
 * as it makes freeing easier
 */
static struct bio_vec *alloc_behind_pages(struct bio *bio)
667 668 669
{
	int i;
	struct bio_vec *bvec;
670
	struct bio_vec *pages = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
671 672 673 674 675
					GFP_NOIO);
	if (unlikely(!pages))
		goto do_sync_io;

	bio_for_each_segment(bvec, bio, i) {
676 677
		pages[i].bv_page = alloc_page(GFP_NOIO);
		if (unlikely(!pages[i].bv_page))
678
			goto do_sync_io;
679
		memcpy(kmap(pages[i].bv_page) + bvec->bv_offset,
680
			kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
681
		kunmap(pages[i].bv_page);
682 683 684 685 686 687 688
		kunmap(bvec->bv_page);
	}

	return pages;

do_sync_io:
	if (pages)
689 690
		for (i = 0; i < bio->bi_vcnt && pages[i].bv_page; i++)
			put_page(pages[i].bv_page);
691 692 693 694 695
	kfree(pages);
	PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
	return NULL;
}

696
static int make_request(mddev_t *mddev, struct bio * bio)
L
Linus Torvalds 已提交
697
{
698
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
699 700 701
	mirror_info_t *mirror;
	r1bio_t *r1_bio;
	struct bio *read_bio;
702
	int i, targets = 0, disks;
703
	struct bitmap *bitmap;
704
	unsigned long flags;
705
	struct bio_vec *behind_pages = NULL;
706
	const int rw = bio_data_dir(bio);
707
	const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
T
Tejun Heo 已提交
708
	const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
709
	mdk_rdev_t *blocked_rdev;
N
NeilBrown 已提交
710
	int plugged;
711

L
Linus Torvalds 已提交
712 713 714 715 716
	/*
	 * 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.
	 */
717

718 719
	md_write_start(mddev, bio); /* wait on superblock update early */

720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738
	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);
	}
739

740
	wait_barrier(conf);
L
Linus Torvalds 已提交
741

742 743
	bitmap = mddev->bitmap;

L
Linus Torvalds 已提交
744 745 746 747 748 749 750 751 752
	/*
	 * 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;
753
	r1_bio->state = 0;
L
Linus Torvalds 已提交
754 755 756
	r1_bio->mddev = mddev;
	r1_bio->sector = bio->bi_sector;

757
	if (rw == READ) {
L
Linus Torvalds 已提交
758 759 760 761 762 763 764 765 766 767 768 769
		/*
		 * 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;

770 771 772 773 774 775 776 777 778
		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);
		}
L
Linus Torvalds 已提交
779 780
		r1_bio->read_disk = rdisk;

781
		read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
L
Linus Torvalds 已提交
782 783 784 785 786 787

		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;
788
		read_bio->bi_rw = READ | do_sync;
L
Linus Torvalds 已提交
789 790 791 792 793 794 795 796 797 798 799 800 801
		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
	 */
N
NeilBrown 已提交
802 803
	plugged = mddev_check_plugged(mddev);

L
Linus Torvalds 已提交
804
	disks = conf->raid_disks;
805 806
 retry_write:
	blocked_rdev = NULL;
L
Linus Torvalds 已提交
807 808
	rcu_read_lock();
	for (i = 0;  i < disks; i++) {
809 810 811 812 813 814 815
		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)) {
L
Linus Torvalds 已提交
816
			atomic_inc(&rdev->nr_pending);
817
			if (test_bit(Faulty, &rdev->flags)) {
818
				rdev_dec_pending(rdev, mddev);
L
Linus Torvalds 已提交
819
				r1_bio->bios[i] = NULL;
820
			} else {
L
Linus Torvalds 已提交
821
				r1_bio->bios[i] = bio;
822 823
				targets++;
			}
L
Linus Torvalds 已提交
824 825 826 827 828
		} else
			r1_bio->bios[i] = NULL;
	}
	rcu_read_unlock();

829 830 831 832 833 834 835 836 837 838 839 840 841 842
	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;
	}

843 844
	BUG_ON(targets == 0); /* we never fail the last device */

845 846 847 848 849 850
	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);
	}

851 852 853 854
	/* 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 */
855
	if (bitmap &&
856 857
	    (atomic_read(&bitmap->behind_writes)
	     < mddev->bitmap_info.max_write_behind) &&
858
	    !waitqueue_active(&bitmap->behind_wait) &&
859 860 861
	    (behind_pages = alloc_behind_pages(bio)) != NULL)
		set_bit(R1BIO_BehindIO, &r1_bio->state);

862
	atomic_set(&r1_bio->remaining, 1);
863
	atomic_set(&r1_bio->behind_remaining, 0);
864

865 866
	bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
				test_bit(R1BIO_BehindIO, &r1_bio->state));
L
Linus Torvalds 已提交
867 868 869 870 871
	for (i = 0; i < disks; i++) {
		struct bio *mbio;
		if (!r1_bio->bios[i])
			continue;

872
		mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
L
Linus Torvalds 已提交
873 874 875 876 877
		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;
T
Tejun Heo 已提交
878
		mbio->bi_rw = WRITE | do_flush_fua | do_sync;
L
Linus Torvalds 已提交
879 880
		mbio->bi_private = r1_bio;

881 882 883 884 885 886 887 888
		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
N
NeilBrown 已提交
889
			 * know the original bi_idx, so we just free
890 891 892
			 * them all
			 */
			__bio_for_each_segment(bvec, mbio, j, 0)
893
				bvec->bv_page = behind_pages[j].bv_page;
894 895 896 897
			if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
				atomic_inc(&r1_bio->behind_remaining);
		}

L
Linus Torvalds 已提交
898
		atomic_inc(&r1_bio->remaining);
899 900 901
		spin_lock_irqsave(&conf->device_lock, flags);
		bio_list_add(&conf->pending_bio_list, mbio);
		spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
902
	}
903
	r1_bio_write_done(r1_bio, bio->bi_vcnt, behind_pages, behind_pages != NULL);
904
	kfree(behind_pages); /* the behind pages are attached to the bios now */
L
Linus Torvalds 已提交
905

906
	/* In case raid1d snuck in to freeze_array */
907 908
	wake_up(&conf->wait_barrier);

N
NeilBrown 已提交
909
	if (do_sync || !bitmap || !plugged)
910
		md_wakeup_thread(mddev->thread);
911

L
Linus Torvalds 已提交
912 913 914 915 916
	return 0;
}

static void status(struct seq_file *seq, mddev_t *mddev)
{
917
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
918 919 920
	int i;

	seq_printf(seq, " [%d/%d] [", conf->raid_disks,
921
		   conf->raid_disks - mddev->degraded);
922 923 924
	rcu_read_lock();
	for (i = 0; i < conf->raid_disks; i++) {
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
L
Linus Torvalds 已提交
925
		seq_printf(seq, "%s",
926 927 928
			   rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
	}
	rcu_read_unlock();
L
Linus Torvalds 已提交
929 930 931 932 933 934 935
	seq_printf(seq, "]");
}


static void error(mddev_t *mddev, mdk_rdev_t *rdev)
{
	char b[BDEVNAME_SIZE];
936
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
937 938 939 940 941 942 943

	/*
	 * 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
	 */
944
	if (test_bit(In_sync, &rdev->flags)
945
	    && (conf->raid_disks - mddev->degraded) == 1) {
L
Linus Torvalds 已提交
946 947
		/*
		 * Don't fail the drive, act as though we were just a
948 949 950
		 * normal single drive.
		 * However don't try a recovery from this drive as
		 * it is very likely to fail.
L
Linus Torvalds 已提交
951
		 */
952
		mddev->recovery_disabled = 1;
L
Linus Torvalds 已提交
953
		return;
954
	}
955 956 957
	if (test_and_clear_bit(In_sync, &rdev->flags)) {
		unsigned long flags;
		spin_lock_irqsave(&conf->device_lock, flags);
L
Linus Torvalds 已提交
958
		mddev->degraded++;
959
		set_bit(Faulty, &rdev->flags);
960
		spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
961 962 963
		/*
		 * if recovery is running, make sure it aborts.
		 */
964
		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
965 966
	} else
		set_bit(Faulty, &rdev->flags);
967
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
968 969 970
	printk(KERN_ALERT
	       "md/raid1:%s: Disk failure on %s, disabling device.\n"
	       "md/raid1:%s: Operation continuing on %d devices.\n",
N
NeilBrown 已提交
971 972
	       mdname(mddev), bdevname(rdev->bdev, b),
	       mdname(mddev), conf->raid_disks - mddev->degraded);
L
Linus Torvalds 已提交
973 974 975 976 977 978
}

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

N
NeilBrown 已提交
979
	printk(KERN_DEBUG "RAID1 conf printout:\n");
L
Linus Torvalds 已提交
980
	if (!conf) {
N
NeilBrown 已提交
981
		printk(KERN_DEBUG "(!conf)\n");
L
Linus Torvalds 已提交
982 983
		return;
	}
N
NeilBrown 已提交
984
	printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
L
Linus Torvalds 已提交
985 986
		conf->raid_disks);

987
	rcu_read_lock();
L
Linus Torvalds 已提交
988 989
	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
990 991
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev)
N
NeilBrown 已提交
992
			printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
993 994 995
			       i, !test_bit(In_sync, &rdev->flags),
			       !test_bit(Faulty, &rdev->flags),
			       bdevname(rdev->bdev,b));
L
Linus Torvalds 已提交
996
	}
997
	rcu_read_unlock();
L
Linus Torvalds 已提交
998 999 1000 1001
}

static void close_sync(conf_t *conf)
{
1002 1003
	wait_barrier(conf);
	allow_barrier(conf);
L
Linus Torvalds 已提交
1004 1005 1006 1007 1008 1009 1010 1011 1012

	mempool_destroy(conf->r1buf_pool);
	conf->r1buf_pool = NULL;
}

static int raid1_spare_active(mddev_t *mddev)
{
	int i;
	conf_t *conf = mddev->private;
1013 1014
	int count = 0;
	unsigned long flags;
L
Linus Torvalds 已提交
1015 1016 1017

	/*
	 * Find all failed disks within the RAID1 configuration 
1018 1019
	 * and mark them readable.
	 * Called under mddev lock, so rcu protection not needed.
L
Linus Torvalds 已提交
1020 1021
	 */
	for (i = 0; i < conf->raid_disks; i++) {
1022 1023 1024
		mdk_rdev_t *rdev = conf->mirrors[i].rdev;
		if (rdev
		    && !test_bit(Faulty, &rdev->flags)
1025
		    && !test_and_set_bit(In_sync, &rdev->flags)) {
1026
			count++;
1027
			sysfs_notify_dirent(rdev->sysfs_state);
L
Linus Torvalds 已提交
1028 1029
		}
	}
1030 1031 1032
	spin_lock_irqsave(&conf->device_lock, flags);
	mddev->degraded -= count;
	spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
1033 1034

	print_conf(conf);
1035
	return count;
L
Linus Torvalds 已提交
1036 1037 1038 1039 1040 1041
}


static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
{
	conf_t *conf = mddev->private;
1042
	int err = -EEXIST;
1043
	int mirror = 0;
L
Linus Torvalds 已提交
1044
	mirror_info_t *p;
1045 1046
	int first = 0;
	int last = mddev->raid_disks - 1;
L
Linus Torvalds 已提交
1047

1048 1049 1050 1051
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;

	for (mirror = first; mirror <= last; mirror++)
L
Linus Torvalds 已提交
1052 1053
		if ( !(p=conf->mirrors+mirror)->rdev) {

1054 1055
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
1056 1057 1058 1059 1060
			/* 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.
L
Linus Torvalds 已提交
1061
			 */
1062 1063 1064 1065 1066
			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
1067 1068 1069

			p->head_position = 0;
			rdev->raid_disk = mirror;
1070
			err = 0;
1071 1072 1073 1074
			/* 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)
1075
				conf->fullsync = 1;
1076
			rcu_assign_pointer(p->rdev, rdev);
L
Linus Torvalds 已提交
1077 1078
			break;
		}
1079
	md_integrity_add_rdev(rdev, mddev);
L
Linus Torvalds 已提交
1080
	print_conf(conf);
1081
	return err;
L
Linus Torvalds 已提交
1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093
}

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) {
1094
		if (test_bit(In_sync, &rdev->flags) ||
L
Linus Torvalds 已提交
1095 1096 1097 1098
		    atomic_read(&rdev->nr_pending)) {
			err = -EBUSY;
			goto abort;
		}
N
NeilBrown 已提交
1099
		/* Only remove non-faulty devices if recovery
1100 1101 1102
		 * is not possible.
		 */
		if (!test_bit(Faulty, &rdev->flags) &&
1103
		    !mddev->recovery_disabled &&
1104 1105 1106 1107
		    mddev->degraded < conf->raid_disks) {
			err = -EBUSY;
			goto abort;
		}
L
Linus Torvalds 已提交
1108
		p->rdev = NULL;
1109
		synchronize_rcu();
L
Linus Torvalds 已提交
1110 1111 1112 1113
		if (atomic_read(&rdev->nr_pending)) {
			/* lost the race, try later */
			err = -EBUSY;
			p->rdev = rdev;
1114
			goto abort;
L
Linus Torvalds 已提交
1115
		}
1116
		err = md_integrity_register(mddev);
L
Linus Torvalds 已提交
1117 1118 1119 1120 1121 1122 1123 1124
	}
abort:

	print_conf(conf);
	return err;
}


1125
static void end_sync_read(struct bio *bio, int error)
L
Linus Torvalds 已提交
1126
{
1127
	r1bio_t *r1_bio = bio->bi_private;
1128
	int i;
L
Linus Torvalds 已提交
1129

1130 1131 1132 1133 1134
	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);
L
Linus Torvalds 已提交
1135 1136 1137 1138 1139
	/*
	 * 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
	 */
1140
	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
L
Linus Torvalds 已提交
1141
		set_bit(R1BIO_Uptodate, &r1_bio->state);
1142 1143 1144

	if (atomic_dec_and_test(&r1_bio->remaining))
		reschedule_retry(r1_bio);
L
Linus Torvalds 已提交
1145 1146
}

1147
static void end_sync_write(struct bio *bio, int error)
L
Linus Torvalds 已提交
1148 1149
{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1150
	r1bio_t *r1_bio = bio->bi_private;
L
Linus Torvalds 已提交
1151
	mddev_t *mddev = r1_bio->mddev;
1152
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
1153 1154 1155 1156 1157 1158 1159 1160
	int i;
	int mirror=0;

	for (i = 0; i < conf->raid_disks; i++)
		if (r1_bio->bios[i] == bio) {
			mirror = i;
			break;
		}
1161
	if (!uptodate) {
N
NeilBrown 已提交
1162
		sector_t sync_blocks = 0;
1163 1164 1165 1166
		sector_t s = r1_bio->sector;
		long sectors_to_go = r1_bio->sectors;
		/* make sure these bits doesn't get cleared. */
		do {
1167
			bitmap_end_sync(mddev->bitmap, s,
1168 1169 1170 1171
					&sync_blocks, 1);
			s += sync_blocks;
			sectors_to_go -= sync_blocks;
		} while (sectors_to_go > 0);
L
Linus Torvalds 已提交
1172
		md_error(mddev, conf->mirrors[mirror].rdev);
1173
	}
1174

L
Linus Torvalds 已提交
1175 1176 1177
	update_head_pos(mirror, r1_bio);

	if (atomic_dec_and_test(&r1_bio->remaining)) {
1178
		sector_t s = r1_bio->sectors;
L
Linus Torvalds 已提交
1179
		put_buf(r1_bio);
1180
		md_done_sync(mddev, s, uptodate);
L
Linus Torvalds 已提交
1181 1182 1183
	}
}

1184
static int fix_sync_read_error(r1bio_t *r1_bio)
L
Linus Torvalds 已提交
1185
{
1186 1187 1188 1189 1190 1191 1192 1193 1194
	/* Try some synchronous reads of other devices to get
	 * good data, much like with normal read errors.  Only
	 * read into the pages we already have so we don't
	 * 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.
	 */
	mddev_t *mddev = r1_bio->mddev;
1195
	conf_t *conf = mddev->private;
1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273
	struct bio *bio = r1_bio->bios[r1_bio->read_disk];
	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) {
				/* No rcu protection needed here devices
				 * can only be removed when no resync is
				 * active, and resync is currently active
				 */
				rdev = conf->mirrors[d].rdev;
				if (sync_page_io(rdev,
						 sect,
						 s<<9,
						 bio->bi_io_vec[idx].bv_page,
						 READ, false)) {
					success = 1;
					break;
				}
			}
			d++;
			if (d == conf->raid_disks)
				d = 0;
		} while (!success && d != r1_bio->read_disk);

		if (success) {
			int start = d;
			/* 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;
				atomic_add(s, &rdev->corrected_errors);
				if (sync_page_io(rdev,
						 sect,
						 s<<9,
						 bio->bi_io_vec[idx].bv_page,
						 WRITE, false) == 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,
						 sect,
						 s<<9,
						 bio->bi_io_vec[idx].bv_page,
						 READ, false) == 0)
					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 "md/raid1:%s: %s: unrecoverable I/O read error"
			       " for block %llu\n",
			       mdname(mddev),
			       bdevname(bio->bi_bdev, b),
			       (unsigned long long)r1_bio->sector);
			md_done_sync(mddev, r1_bio->sectors, 0);
1274
			put_buf(r1_bio);
1275
			return 0;
1276
		}
1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298
		sectors -= s;
		sect += s;
		idx ++;
	}
	return 1;
}

static int process_checks(r1bio_t *r1_bio)
{
	/* 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
	 */
	mddev_t *mddev = r1_bio->mddev;
	conf_t *conf = mddev->private;
	int primary;
	int i;

	if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1299
		for (i=0; i<mddev->raid_disks; i++)
1300 1301
			if (r1_bio->bios[i]->bi_end_io == end_sync_read)
				md_error(mddev, conf->mirrors[i].rdev);
1302

1303 1304 1305
		md_done_sync(mddev, r1_bio->sectors, 1);
		put_buf(r1_bio);
		return -1;
1306
	}
1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329
	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;
			rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
			break;
		}
	r1_bio->read_disk = primary;
	for (i=0; i<mddev->raid_disks; i++)
		if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
			int j;
			int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
			struct bio *pbio = r1_bio->bios[primary];
			struct bio *sbio = r1_bio->bios[i];

			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))
1330 1331
						break;
				}
1332 1333 1334 1335 1336 1337 1338 1339
			} else
				j = 0;
			if (j >= 0)
				mddev->resync_mismatches += r1_bio->sectors;
			if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
				      && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
				sbio->bi_end_io = NULL;
				rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1340
			} else {
1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367
				/* fixup the bio for reuse */
				int size;
				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;
				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),
					       page_address(pbio->bi_io_vec[j].bv_page),
					       PAGE_SIZE);
				}

1368 1369
			}
		}
1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381
	return 0;
}

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

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

1382

1383 1384 1385 1386 1387 1388 1389 1390
	if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
		if (process_checks(r1_bio) < 0)
			return;

	if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
		/* ouch - failed to read all of that. */
		if (!fix_sync_read_error(r1_bio))
			return;
1391 1392 1393
	/*
	 * schedule writes
	 */
L
Linus Torvalds 已提交
1394 1395 1396
	atomic_set(&r1_bio->remaining, 1);
	for (i = 0; i < disks ; i++) {
		wbio = r1_bio->bios[i];
1397 1398 1399 1400
		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))))
L
Linus Torvalds 已提交
1401 1402
			continue;

1403 1404
		wbio->bi_rw = WRITE;
		wbio->bi_end_io = end_sync_write;
L
Linus Torvalds 已提交
1405 1406
		atomic_inc(&r1_bio->remaining);
		md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1407

L
Linus Torvalds 已提交
1408 1409 1410 1411
		generic_make_request(wbio);
	}

	if (atomic_dec_and_test(&r1_bio->remaining)) {
1412
		/* if we're here, all write(s) have completed, so clean up */
L
Linus Torvalds 已提交
1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425
		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.
 */

1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448
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) &&
J
Jonathan Brassow 已提交
1449 1450
			    sync_page_io(rdev, sect, s<<9,
					 conf->tmppage, READ, false))
1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472
				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)) {
J
Jonathan Brassow 已提交
1473 1474
				if (sync_page_io(rdev, sect, s<<9,
						 conf->tmppage, WRITE, false)
1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488
				    == 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)) {
J
Jonathan Brassow 已提交
1489 1490
				if (sync_page_io(rdev, sect, s<<9,
						 conf->tmppage, READ, false)
1491 1492 1493 1494 1495 1496
				    == 0)
					/* Well, this device is dead */
					md_error(mddev, rdev);
				else {
					atomic_add(s, &rdev->corrected_errors);
					printk(KERN_INFO
N
NeilBrown 已提交
1497
					       "md/raid1:%s: read error corrected "
1498 1499
					       "(%d sectors at %llu on %s)\n",
					       mdname(mddev), s,
1500 1501
					       (unsigned long long)(sect +
					           rdev->data_offset),
1502 1503 1504 1505 1506 1507 1508 1509 1510
					       bdevname(rdev->bdev, b));
				}
			}
		}
		sectors -= s;
		sect += s;
	}
}

L
Linus Torvalds 已提交
1511 1512 1513 1514 1515
static void raid1d(mddev_t *mddev)
{
	r1bio_t *r1_bio;
	struct bio *bio;
	unsigned long flags;
1516
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
1517 1518
	struct list_head *head = &conf->retry_list;
	mdk_rdev_t *rdev;
1519
	struct blk_plug plug;
L
Linus Torvalds 已提交
1520 1521

	md_check_recovery(mddev);
1522 1523

	blk_start_plug(&plug);
L
Linus Torvalds 已提交
1524 1525
	for (;;) {
		char b[BDEVNAME_SIZE];
1526

N
NeilBrown 已提交
1527 1528
		if (atomic_read(&mddev->plug_cnt) == 0)
			flush_pending_writes(conf);
1529

1530 1531 1532
		spin_lock_irqsave(&conf->device_lock, flags);
		if (list_empty(head)) {
			spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
1533
			break;
1534
		}
L
Linus Torvalds 已提交
1535 1536
		r1_bio = list_entry(head->prev, r1bio_t, retry_list);
		list_del(head->prev);
1537
		conf->nr_queued--;
L
Linus Torvalds 已提交
1538 1539 1540
		spin_unlock_irqrestore(&conf->device_lock, flags);

		mddev = r1_bio->mddev;
1541
		conf = mddev->private;
J
Jens Axboe 已提交
1542
		if (test_bit(R1BIO_IsSync, &r1_bio->state))
L
Linus Torvalds 已提交
1543
			sync_request_write(mddev, r1_bio);
J
Jens Axboe 已提交
1544
		else {
L
Linus Torvalds 已提交
1545
			int disk;
1546 1547 1548 1549 1550 1551 1552 1553 1554

			/* 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
			 */
1555 1556 1557 1558 1559 1560
			if (mddev->ro == 0) {
				freeze_array(conf);
				fix_read_error(conf, r1_bio->read_disk,
					       r1_bio->sector,
					       r1_bio->sectors);
				unfreeze_array(conf);
1561 1562 1563
			} else
				md_error(mddev,
					 conf->mirrors[r1_bio->read_disk].rdev);
1564

L
Linus Torvalds 已提交
1565
			bio = r1_bio->bios[r1_bio->read_disk];
1566
			if ((disk=read_balance(conf, r1_bio)) == -1) {
N
NeilBrown 已提交
1567
				printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
L
Linus Torvalds 已提交
1568
				       " read error for block %llu\n",
N
NeilBrown 已提交
1569
				       mdname(mddev),
L
Linus Torvalds 已提交
1570 1571 1572 1573
				       bdevname(bio->bi_bdev,b),
				       (unsigned long long)r1_bio->sector);
				raid_end_bio_io(r1_bio);
			} else {
1574
				const unsigned long do_sync = r1_bio->master_bio->bi_rw & REQ_SYNC;
1575 1576
				r1_bio->bios[r1_bio->read_disk] =
					mddev->ro ? IO_BLOCKED : NULL;
L
Linus Torvalds 已提交
1577 1578
				r1_bio->read_disk = disk;
				bio_put(bio);
1579 1580
				bio = bio_clone_mddev(r1_bio->master_bio,
						      GFP_NOIO, mddev);
L
Linus Torvalds 已提交
1581 1582 1583
				r1_bio->bios[r1_bio->read_disk] = bio;
				rdev = conf->mirrors[disk].rdev;
				if (printk_ratelimit())
N
NeilBrown 已提交
1584
					printk(KERN_ERR "md/raid1:%s: redirecting sector %llu to"
1585
					       " other mirror: %s\n",
N
NeilBrown 已提交
1586
					       mdname(mddev),
1587 1588
					       (unsigned long long)r1_bio->sector,
					       bdevname(rdev->bdev,b));
L
Linus Torvalds 已提交
1589 1590 1591
				bio->bi_sector = r1_bio->sector + rdev->data_offset;
				bio->bi_bdev = rdev->bdev;
				bio->bi_end_io = raid1_end_read_request;
1592
				bio->bi_rw = READ | do_sync;
L
Linus Torvalds 已提交
1593 1594 1595 1596
				bio->bi_private = r1_bio;
				generic_make_request(bio);
			}
		}
N
NeilBrown 已提交
1597
		cond_resched();
L
Linus Torvalds 已提交
1598
	}
1599
	blk_finish_plug(&plug);
L
Linus Torvalds 已提交
1600 1601 1602 1603 1604 1605 1606 1607
}


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

	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1608
	BUG_ON(conf->r1buf_pool);
L
Linus Torvalds 已提交
1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626
	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.
 */

1627
static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
L
Linus Torvalds 已提交
1628
{
1629
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
1630 1631 1632
	r1bio_t *r1_bio;
	struct bio *bio;
	sector_t max_sector, nr_sectors;
1633
	int disk = -1;
L
Linus Torvalds 已提交
1634
	int i;
1635 1636
	int wonly = -1;
	int write_targets = 0, read_targets = 0;
N
NeilBrown 已提交
1637
	sector_t sync_blocks;
1638
	int still_degraded = 0;
L
Linus Torvalds 已提交
1639 1640 1641

	if (!conf->r1buf_pool)
		if (init_resync(conf))
1642
			return 0;
L
Linus Torvalds 已提交
1643

A
Andre Noll 已提交
1644
	max_sector = mddev->dev_sectors;
L
Linus Torvalds 已提交
1645
	if (sector_nr >= max_sector) {
1646 1647 1648 1649 1650
		/* 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
		 */
1651 1652
		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1653
						&sync_blocks, 1);
1654
		else /* completed sync */
1655
			conf->fullsync = 0;
1656 1657

		bitmap_close_sync(mddev->bitmap);
L
Linus Torvalds 已提交
1658 1659 1660 1661
		close_sync(conf);
		return 0;
	}

1662 1663
	if (mddev->bitmap == NULL &&
	    mddev->recovery_cp == MaxSector &&
1664
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1665 1666 1667 1668
	    conf->fullsync == 0) {
		*skipped = 1;
		return max_sector - sector_nr;
	}
1669 1670 1671
	/* before building a request, check if we can skip these blocks..
	 * This call the bitmap_start_sync doesn't actually record anything
	 */
1672
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1673
	    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1674 1675 1676 1677
		/* We can skip this block, and probably several more */
		*skipped = 1;
		return sync_blocks;
	}
L
Linus Torvalds 已提交
1678
	/*
1679 1680 1681
	 * 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
1682
	 */
1683
	if (!go_faster && conf->nr_waiting)
L
Linus Torvalds 已提交
1684
		msleep_interruptible(1000);
1685

N
NeilBrown 已提交
1686
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1687
	r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1688 1689 1690
	raise_barrier(conf);

	conf->next_resync = sector_nr;
L
Linus Torvalds 已提交
1691

1692
	rcu_read_lock();
L
Linus Torvalds 已提交
1693
	/*
1694 1695 1696 1697 1698 1699
	 * 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
1700 1701 1702 1703
	 */

	r1_bio->mddev = mddev;
	r1_bio->sector = sector_nr;
1704
	r1_bio->state = 0;
L
Linus Torvalds 已提交
1705 1706 1707
	set_bit(R1BIO_IsSync, &r1_bio->state);

	for (i=0; i < conf->raid_disks; i++) {
1708
		mdk_rdev_t *rdev;
L
Linus Torvalds 已提交
1709 1710 1711 1712
		bio = r1_bio->bios[i];

		/* take from bio_init */
		bio->bi_next = NULL;
1713
		bio->bi_flags &= ~(BIO_POOL_MASK-1);
L
Linus Torvalds 已提交
1714
		bio->bi_flags |= 1 << BIO_UPTODATE;
1715
		bio->bi_comp_cpu = -1;
1716
		bio->bi_rw = READ;
L
Linus Torvalds 已提交
1717 1718 1719 1720 1721 1722 1723
		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;

1724 1725 1726
		rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev == NULL ||
			   test_bit(Faulty, &rdev->flags)) {
1727 1728
			still_degraded = 1;
			continue;
1729
		} else if (!test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
1730 1731 1732
			bio->bi_rw = WRITE;
			bio->bi_end_io = end_sync_write;
			write_targets ++;
1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748
		} 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
1749 1750
		bio->bi_private = r1_bio;
	}
1751 1752 1753 1754
	rcu_read_unlock();
	if (disk < 0)
		disk = wonly;
	r1_bio->read_disk = disk;
1755

1756 1757 1758 1759 1760
	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
1761 1762 1763
		/* There is nowhere to write, so all non-sync
		 * drives must be failed - so we are finished
		 */
1764 1765
		sector_t rv = max_sector - sector_nr;
		*skipped = 1;
L
Linus Torvalds 已提交
1766 1767 1768 1769
		put_buf(r1_bio);
		return rv;
	}

1770 1771
	if (max_sector > mddev->resync_max)
		max_sector = mddev->resync_max; /* Don't do IO beyond here */
L
Linus Torvalds 已提交
1772
	nr_sectors = 0;
1773
	sync_blocks = 0;
L
Linus Torvalds 已提交
1774 1775 1776 1777 1778 1779 1780
	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;
1781 1782
		if (sync_blocks == 0) {
			if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1783 1784 1785
					       &sync_blocks, still_degraded) &&
			    !conf->fullsync &&
			    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1786
				break;
1787
			BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1788
			if ((len >> 9) > sync_blocks)
1789
				len = sync_blocks<<9;
1790
		}
1791

L
Linus Torvalds 已提交
1792 1793 1794
		for (i=0 ; i < conf->raid_disks; i++) {
			bio = r1_bio->bios[i];
			if (bio->bi_end_io) {
1795
				page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
L
Linus Torvalds 已提交
1796 1797
				if (bio_add_page(bio, page, len, 0) == 0) {
					/* stop here */
1798
					bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
L
Linus Torvalds 已提交
1799 1800 1801
					while (i > 0) {
						i--;
						bio = r1_bio->bios[i];
1802 1803
						if (bio->bi_end_io==NULL)
							continue;
L
Linus Torvalds 已提交
1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814
						/* 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;
1815
		sync_blocks -= (len>>9);
L
Linus Torvalds 已提交
1816 1817 1818 1819
	} while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
 bio_full:
	r1_bio->sectors = nr_sectors;

1820 1821 1822 1823 1824 1825 1826 1827
	/* 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) {
1828
				md_sync_acct(bio->bi_bdev, nr_sectors);
1829 1830 1831 1832 1833 1834
				generic_make_request(bio);
			}
		}
	} else {
		atomic_set(&r1_bio->remaining, 1);
		bio = r1_bio->bios[r1_bio->read_disk];
1835
		md_sync_acct(bio->bi_bdev, nr_sectors);
1836
		generic_make_request(bio);
L
Linus Torvalds 已提交
1837

1838
	}
L
Linus Torvalds 已提交
1839 1840 1841
	return nr_sectors;
}

1842 1843 1844 1845 1846 1847 1848 1849
static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
{
	if (sectors)
		return sectors;

	return mddev->dev_sectors;
}

1850
static conf_t *setup_conf(mddev_t *mddev)
L
Linus Torvalds 已提交
1851 1852
{
	conf_t *conf;
1853
	int i;
L
Linus Torvalds 已提交
1854 1855
	mirror_info_t *disk;
	mdk_rdev_t *rdev;
1856
	int err = -ENOMEM;
L
Linus Torvalds 已提交
1857

1858
	conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
L
Linus Torvalds 已提交
1859
	if (!conf)
1860
		goto abort;
L
Linus Torvalds 已提交
1861

1862
	conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
L
Linus Torvalds 已提交
1863 1864
				 GFP_KERNEL);
	if (!conf->mirrors)
1865
		goto abort;
L
Linus Torvalds 已提交
1866

1867 1868
	conf->tmppage = alloc_page(GFP_KERNEL);
	if (!conf->tmppage)
1869
		goto abort;
1870

1871
	conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
L
Linus Torvalds 已提交
1872
	if (!conf->poolinfo)
1873
		goto abort;
L
Linus Torvalds 已提交
1874 1875 1876 1877 1878
	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)
1879 1880
		goto abort;

1881
	conf->poolinfo->mddev = mddev;
L
Linus Torvalds 已提交
1882

1883
	spin_lock_init(&conf->device_lock);
1884
	list_for_each_entry(rdev, &mddev->disks, same_set) {
1885
		int disk_idx = rdev->raid_disk;
L
Linus Torvalds 已提交
1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899
		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);
1900
	init_waitqueue_head(&conf->wait_barrier);
L
Linus Torvalds 已提交
1901

1902 1903
	bio_list_init(&conf->pending_bio_list);

1904
	conf->last_used = -1;
L
Linus Torvalds 已提交
1905 1906 1907 1908
	for (i = 0; i < conf->raid_disks; i++) {

		disk = conf->mirrors + i;

1909 1910
		if (!disk->rdev ||
		    !test_bit(In_sync, &disk->rdev->flags)) {
L
Linus Torvalds 已提交
1911
			disk->head_position = 0;
1912 1913
			if (disk->rdev)
				conf->fullsync = 1;
1914 1915 1916 1917 1918 1919
		} 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
1920
	}
1921 1922 1923

	err = -EIO;
	if (conf->last_used < 0) {
N
NeilBrown 已提交
1924
		printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
1925 1926 1927 1928 1929 1930 1931
		       mdname(mddev));
		goto abort;
	}
	err = -ENOMEM;
	conf->thread = md_register_thread(raid1d, mddev, NULL);
	if (!conf->thread) {
		printk(KERN_ERR
N
NeilBrown 已提交
1932
		       "md/raid1:%s: couldn't allocate thread\n",
1933 1934
		       mdname(mddev));
		goto abort;
1935
	}
L
Linus Torvalds 已提交
1936

1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957
	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) {
N
NeilBrown 已提交
1958
		printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
1959 1960 1961 1962
		       mdname(mddev), mddev->level);
		return -EIO;
	}
	if (mddev->reshape_position != MaxSector) {
N
NeilBrown 已提交
1963
		printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
1964 1965 1966
		       mdname(mddev));
		return -EIO;
	}
L
Linus Torvalds 已提交
1967
	/*
1968 1969 1970
	 * 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
1971
	 */
1972 1973 1974 1975
	if (mddev->private == NULL)
		conf = setup_conf(mddev);
	else
		conf = mddev->private;
L
Linus Torvalds 已提交
1976

1977 1978
	if (IS_ERR(conf))
		return PTR_ERR(conf);
L
Linus Torvalds 已提交
1979

1980 1981 1982 1983
	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
1984 1985
		 * violating it, so limit ->max_segments to 1 lying within
		 * a single page, as a one page request is never in violation.
1986
		 */
1987 1988 1989 1990 1991
		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
1992
	}
1993

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
	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;

2004
	if (mddev->recovery_cp != MaxSector)
N
NeilBrown 已提交
2005
		printk(KERN_NOTICE "md/raid1:%s: not clean"
2006 2007
		       " -- starting background reconstruction\n",
		       mdname(mddev));
L
Linus Torvalds 已提交
2008
	printk(KERN_INFO 
N
NeilBrown 已提交
2009
		"md/raid1:%s: active with %d out of %d mirrors\n",
L
Linus Torvalds 已提交
2010 2011
		mdname(mddev), mddev->raid_disks - mddev->degraded, 
		mddev->raid_disks);
2012

L
Linus Torvalds 已提交
2013 2014 2015
	/*
	 * Ok, everything is just fine now
	 */
2016 2017 2018 2019
	mddev->thread = conf->thread;
	conf->thread = NULL;
	mddev->private = conf;

2020
	md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
L
Linus Torvalds 已提交
2021

2022 2023
	mddev->queue->backing_dev_info.congested_fn = raid1_congested;
	mddev->queue->backing_dev_info.congested_data = mddev;
2024
	return md_integrity_register(mddev);
L
Linus Torvalds 已提交
2025 2026 2027 2028
}

static int stop(mddev_t *mddev)
{
2029
	conf_t *conf = mddev->private;
2030 2031 2032
	struct bitmap *bitmap = mddev->bitmap;

	/* wait for behind writes to complete */
2033
	if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
N
NeilBrown 已提交
2034 2035
		printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
		       mdname(mddev));
2036
		/* need to kick something here to make sure I/O goes? */
2037 2038
		wait_event(bitmap->behind_wait,
			   atomic_read(&bitmap->behind_writes) == 0);
2039
	}
L
Linus Torvalds 已提交
2040

2041 2042 2043
	raise_barrier(conf);
	lower_barrier(conf);

L
Linus Torvalds 已提交
2044 2045 2046 2047
	md_unregister_thread(mddev->thread);
	mddev->thread = NULL;
	if (conf->r1bio_pool)
		mempool_destroy(conf->r1bio_pool);
2048 2049
	kfree(conf->mirrors);
	kfree(conf->poolinfo);
L
Linus Torvalds 已提交
2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063
	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.
	 */
2064
	md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
D
Dan Williams 已提交
2065 2066
	if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
		return -EINVAL;
2067
	set_capacity(mddev->gendisk, mddev->array_sectors);
2068
	revalidate_disk(mddev->gendisk);
D
Dan Williams 已提交
2069
	if (sectors > mddev->dev_sectors &&
2070
	    mddev->recovery_cp == MaxSector) {
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2071
		mddev->recovery_cp = mddev->dev_sectors;
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2072 2073
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
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2074
	mddev->dev_sectors = sectors;
2075
	mddev->resync_max_sectors = sectors;
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2076 2077 2078
	return 0;
}

2079
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.
2088 2089 2090
	 *
	 * 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;
2095
	conf_t *conf = mddev->private;
2096
	int cnt, raid_disks;
2097
	unsigned long flags;
2098
	int d, d2, err;
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2099

2100
	/* Cannot change chunk_size, layout, or level */
2101
	if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2102 2103
	    mddev->layout != mddev->new_layout ||
	    mddev->level != mddev->new_level) {
2104
		mddev->new_chunk_sectors = mddev->chunk_sectors;
2105 2106 2107 2108 2109
		mddev->new_layout = mddev->layout;
		mddev->new_level = mddev->level;
		return -EINVAL;
	}

2110 2111 2112
	err = md_allow_write(mddev);
	if (err)
		return err;
2113

2114 2115
	raid_disks = mddev->raid_disks + mddev->delta_disks;

2116 2117 2118 2119 2120 2121
	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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2122
			return -EBUSY;
2123
	}
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2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136

	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;
	}
2137
	newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
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2138 2139 2140 2141 2142 2143
	if (!newmirrors) {
		kfree(newpoolinfo);
		mempool_destroy(newpool);
		return -ENOMEM;
	}

2144
	raise_barrier(conf);
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2145 2146 2147 2148

	/* ok, everything is stopped */
	oldpool = conf->r1bio_pool;
	conf->r1bio_pool = newpool;
2149

2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161
	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
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2162 2163 2164
				       "md/raid1:%s: cannot register "
				       "%s\n",
				       mdname(mddev), nm);
2165
		}
2166 2167 2168
		if (rdev)
			newmirrors[d2++].rdev = rdev;
	}
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2169 2170 2171 2172 2173
	kfree(conf->mirrors);
	conf->mirrors = newmirrors;
	kfree(conf->poolinfo);
	conf->poolinfo = newpoolinfo;

2174
	spin_lock_irqsave(&conf->device_lock, flags);
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2175
	mddev->degraded += (raid_disks - conf->raid_disks);
2176
	spin_unlock_irqrestore(&conf->device_lock, flags);
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2177
	conf->raid_disks = mddev->raid_disks = raid_disks;
2178
	mddev->delta_disks = 0;
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2179

2180
	conf->last_used = 0; /* just make sure it is in-range */
2181
	lower_barrier(conf);
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2182 2183 2184 2185 2186 2187 2188 2189

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

	mempool_destroy(oldpool);
	return 0;
}

2190
static void raid1_quiesce(mddev_t *mddev, int state)
2191
{
2192
	conf_t *conf = mddev->private;
2193 2194

	switch(state) {
2195 2196 2197
	case 2: /* wake for suspend */
		wake_up(&conf->wait_barrier);
		break;
2198
	case 1:
2199
		raise_barrier(conf);
2200
		break;
2201
	case 0:
2202
		lower_barrier(conf);
2203 2204 2205 2206
		break;
	}
}

2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223
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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2224

2225
static struct mdk_personality raid1_personality =
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2226 2227
{
	.name		= "raid1",
2228
	.level		= 1,
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2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239
	.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,
2240
	.size		= raid1_size,
2241
	.check_reshape	= raid1_reshape,
2242
	.quiesce	= raid1_quiesce,
2243
	.takeover	= raid1_takeover,
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2244 2245 2246 2247
};

static int __init raid_init(void)
{
2248
	return register_md_personality(&raid1_personality);
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2249 2250 2251 2252
}

static void raid_exit(void)
{
2253
	unregister_md_personality(&raid1_personality);
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2254 2255 2256 2257 2258
}

module_init(raid_init);
module_exit(raid_exit);
MODULE_LICENSE("GPL");
2259
MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
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2260
MODULE_ALIAS("md-personality-3"); /* RAID1 */
2261
MODULE_ALIAS("md-raid1");
2262
MODULE_ALIAS("md-level-1");