raid1.c 59.9 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


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-- ; ) {
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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 new_disk = -1;
	int start_disk;
	int i;
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	sector_t new_distance, current_distance;
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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:
	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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	}

	/* make sure the disk is operational */
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	for (i = 0 ; i < conf->raid_disks ; i++) {
		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
		    || !test_bit(In_sync, &rdev->flags))
			continue;

		new_disk = disk;
		if (!test_bit(WriteMostly, &rdev->flags))
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			break;
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	}
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	if (new_disk < 0 || choose_first)
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		goto rb_out;

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	/*
	 * 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;

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	current_distance = abs(this_sector 
			       - conf->mirrors[new_disk].head_position);
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	/* look for a better disk - i.e. head is closer */
	start_disk = new_disk;
	for (i = 1; i < conf->raid_disks; i++) {
		int disk = start_disk + 1;
		if (disk >= conf->raid_disks)
			disk -= conf->raid_disks;
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		rdev = rcu_dereference(conf->mirrors[disk].rdev);
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		if (r1_bio->bios[disk] == IO_BLOCKED
		    || rdev == NULL
		    || !test_bit(In_sync, &rdev->flags)
		    || 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;
		}
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	}
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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)) {
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			struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
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			atomic_inc(&rdev->nr_pending);
			rcu_read_unlock();

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

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static void raid1_unplug(struct request_queue *q)
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{
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	mddev_t *mddev = q->queuedata;

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

554 555 556
static int raid1_congested(void *data, int bits)
{
	mddev_t *mddev = data;
557
	conf_t *conf = mddev->private;
558 559
	int i, ret = 0;

560 561 562
	if (mddev_congested(mddev, bits))
		return 1;

563 564 565 566
	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)) {
567
			struct request_queue *q = bdev_get_queue(rdev->bdev);
568 569 570 571

			/* Note the '|| 1' - when read_balance prefers
			 * non-congested targets, it can be removed
			 */
572
			if ((bits & (1<<BDI_async_congested)) || 1)
573 574 575 576 577 578 579 580 581 582
				ret |= bdi_congested(&q->backing_dev_info, bits);
			else
				ret &= bdi_congested(&q->backing_dev_info, bits);
		}
	}
	rcu_read_unlock();
	return ret;
}


583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613
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;
}

614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633
/* 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

637
static void raise_barrier(conf_t *conf)
L
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638 639
{
	spin_lock_irq(&conf->resync_lock);
640 641 642 643 644 645 646 647 648

	/* 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++;

N
NeilBrown 已提交
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	/* Now wait for all pending IO to complete */
650 651 652 653 654 655 656 657 658 659 660
	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;
661
	BUG_ON(conf->barrier <= 0);
662 663 664 665 666 667 668 669 670 671 672 673 674 675 676
	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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	}
678
	conf->nr_pending++;
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	spin_unlock_irq(&conf->resync_lock);
}

682 683 684 685 686 687 688 689 690
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);
}

691 692 693 694 695
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
696 697 698 699 700 701 702 703
	 * 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.
704 705 706 707 708
	 */
	spin_lock_irq(&conf->resync_lock);
	conf->barrier++;
	conf->nr_waiting++;
	wait_event_lock_irq(conf->wait_barrier,
709
			    conf->nr_pending == conf->nr_queued+1,
710
			    conf->resync_lock,
711 712
			    ({ flush_pending_writes(conf);
			       raid1_unplug(conf->mddev->queue); }));
713 714 715 716 717 718 719 720 721 722 723 724
	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);
}

725

726 727 728 729 730
/* 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)
731 732 733
{
	int i;
	struct bio_vec *bvec;
734
	struct bio_vec *pages = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
735 736 737 738 739
					GFP_NOIO);
	if (unlikely(!pages))
		goto do_sync_io;

	bio_for_each_segment(bvec, bio, i) {
740 741
		pages[i].bv_page = alloc_page(GFP_NOIO);
		if (unlikely(!pages[i].bv_page))
742
			goto do_sync_io;
743
		memcpy(kmap(pages[i].bv_page) + bvec->bv_offset,
744
			kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
745
		kunmap(pages[i].bv_page);
746 747 748 749 750 751 752
		kunmap(bvec->bv_page);
	}

	return pages;

do_sync_io:
	if (pages)
753 754
		for (i = 0; i < bio->bi_vcnt && pages[i].bv_page; i++)
			put_page(pages[i].bv_page);
755 756 757 758 759
	kfree(pages);
	PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
	return NULL;
}

760
static int make_request(mddev_t *mddev, struct bio * bio)
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761
{
762
	conf_t *conf = mddev->private;
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763 764 765
	mirror_info_t *mirror;
	r1bio_t *r1_bio;
	struct bio *read_bio;
766
	int i, targets = 0, disks;
767
	struct bitmap *bitmap;
768
	unsigned long flags;
769
	struct bio_vec *behind_pages = NULL;
770
	const int rw = bio_data_dir(bio);
771
	const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
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772
	const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
773
	mdk_rdev_t *blocked_rdev;
774

L
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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.
	 */
780

781 782
	md_write_start(mddev, bio); /* wait on superblock update early */

783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801
	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);
	}
802

803
	wait_barrier(conf);
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805 806
	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;
816
	r1_bio->state = 0;
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	r1_bio->mddev = mddev;
	r1_bio->sector = bio->bi_sector;

820
	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;

833 834 835 836 837 838 839 840 841
		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;

844
		read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
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		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;
851
		read_bio->bi_rw = READ | do_sync;
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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;
866 867
 retry_write:
	blocked_rdev = NULL;
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868 869
	rcu_read_lock();
	for (i = 0;  i < disks; i++) {
870 871 872 873 874 875 876
		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);
878
			if (test_bit(Faulty, &rdev->flags)) {
879
				rdev_dec_pending(rdev, mddev);
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880
				r1_bio->bios[i] = NULL;
881
			} else {
L
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				r1_bio->bios[i] = bio;
883 884
				targets++;
			}
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		} else
			r1_bio->bios[i] = NULL;
	}
	rcu_read_unlock();

890 891 892 893 894 895 896 897 898 899 900 901 902 903
	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;
	}

904 905
	BUG_ON(targets == 0); /* we never fail the last device */

906 907 908 909 910 911
	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);
	}

912 913 914 915
	/* 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 */
916
	if (bitmap &&
917 918
	    (atomic_read(&bitmap->behind_writes)
	     < mddev->bitmap_info.max_write_behind) &&
919
	    !waitqueue_active(&bitmap->behind_wait) &&
920 921 922
	    (behind_pages = alloc_behind_pages(bio)) != NULL)
		set_bit(R1BIO_BehindIO, &r1_bio->state);

923
	atomic_set(&r1_bio->remaining, 1);
924
	atomic_set(&r1_bio->behind_remaining, 0);
925

926 927
	bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
				test_bit(R1BIO_BehindIO, &r1_bio->state));
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928 929 930 931 932
	for (i = 0; i < disks; i++) {
		struct bio *mbio;
		if (!r1_bio->bios[i])
			continue;

933
		mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
L
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934 935 936 937 938
		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
939
		mbio->bi_rw = WRITE | do_flush_fua | do_sync;
L
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940 941
		mbio->bi_private = r1_bio;

942 943 944 945 946 947 948 949
		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
950
			 * know the original bi_idx, so we just free
951 952 953
			 * them all
			 */
			__bio_for_each_segment(bvec, mbio, j, 0)
954
				bvec->bv_page = behind_pages[j].bv_page;
955 956 957 958
			if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
				atomic_inc(&r1_bio->behind_remaining);
		}

L
Linus Torvalds 已提交
959
		atomic_inc(&r1_bio->remaining);
960 961 962 963
		spin_lock_irqsave(&conf->device_lock, flags);
		bio_list_add(&conf->pending_bio_list, mbio);
		blk_plug_device(mddev->queue);
		spin_unlock_irqrestore(&conf->device_lock, flags);
L
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964
	}
965
	r1_bio_write_done(r1_bio, bio->bi_vcnt, behind_pages, behind_pages != NULL);
966
	kfree(behind_pages); /* the behind pages are attached to the bios now */
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967

968
	/* In case raid1d snuck in to freeze_array */
969 970
	wake_up(&conf->wait_barrier);

971 972
	if (do_sync)
		md_wakeup_thread(mddev->thread);
973

L
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974 975 976 977 978
	return 0;
}

static void status(struct seq_file *seq, mddev_t *mddev)
{
979
	conf_t *conf = mddev->private;
L
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980 981 982
	int i;

	seq_printf(seq, " [%d/%d] [", conf->raid_disks,
983
		   conf->raid_disks - mddev->degraded);
984 985 986
	rcu_read_lock();
	for (i = 0; i < conf->raid_disks; i++) {
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
L
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987
		seq_printf(seq, "%s",
988 989 990
			   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];
998
	conf_t *conf = mddev->private;
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999 1000 1001 1002 1003 1004 1005

	/*
	 * 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
	 */
1006
	if (test_bit(In_sync, &rdev->flags)
1007
	    && (conf->raid_disks - mddev->degraded) == 1) {
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		/*
		 * Don't fail the drive, act as though we were just a
1010 1011 1012
		 * normal single drive.
		 * However don't try a recovery from this drive as
		 * it is very likely to fail.
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1013
		 */
1014
		mddev->recovery_disabled = 1;
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1015
		return;
1016
	}
1017 1018 1019
	if (test_and_clear_bit(In_sync, &rdev->flags)) {
		unsigned long flags;
		spin_lock_irqsave(&conf->device_lock, flags);
L
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		mddev->degraded++;
1021
		set_bit(Faulty, &rdev->flags);
1022
		spin_unlock_irqrestore(&conf->device_lock, flags);
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		/*
		 * if recovery is running, make sure it aborts.
		 */
1026
		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1027 1028
	} else
		set_bit(Faulty, &rdev->flags);
1029
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
N
NeilBrown 已提交
1030 1031 1032 1033
	printk(KERN_ALERT "md/raid1:%s: Disk failure on %s, disabling device.\n"
	       KERN_ALERT "md/raid1:%s: Operation continuing on %d devices.\n",
	       mdname(mddev), bdevname(rdev->bdev, b),
	       mdname(mddev), conf->raid_disks - mddev->degraded);
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1034 1035 1036 1037 1038 1039
}

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

N
NeilBrown 已提交
1040
	printk(KERN_DEBUG "RAID1 conf printout:\n");
L
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1041
	if (!conf) {
N
NeilBrown 已提交
1042
		printk(KERN_DEBUG "(!conf)\n");
L
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1043 1044
		return;
	}
N
NeilBrown 已提交
1045
	printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
L
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1046 1047
		conf->raid_disks);

1048
	rcu_read_lock();
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1049 1050
	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
1051 1052
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev)
N
NeilBrown 已提交
1053
			printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1054 1055 1056
			       i, !test_bit(In_sync, &rdev->flags),
			       !test_bit(Faulty, &rdev->flags),
			       bdevname(rdev->bdev,b));
L
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1057
	}
1058
	rcu_read_unlock();
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1059 1060 1061 1062
}

static void close_sync(conf_t *conf)
{
1063 1064
	wait_barrier(conf);
	allow_barrier(conf);
L
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1065 1066 1067 1068 1069 1070 1071 1072 1073

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

static int raid1_spare_active(mddev_t *mddev)
{
	int i;
	conf_t *conf = mddev->private;
1074 1075
	int count = 0;
	unsigned long flags;
L
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	/*
	 * Find all failed disks within the RAID1 configuration 
1079 1080
	 * and mark them readable.
	 * Called under mddev lock, so rcu protection not needed.
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1081 1082
	 */
	for (i = 0; i < conf->raid_disks; i++) {
1083 1084 1085
		mdk_rdev_t *rdev = conf->mirrors[i].rdev;
		if (rdev
		    && !test_bit(Faulty, &rdev->flags)
1086
		    && !test_and_set_bit(In_sync, &rdev->flags)) {
1087
			count++;
1088
			sysfs_notify_dirent(rdev->sysfs_state);
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1089 1090
		}
	}
1091 1092 1093
	spin_lock_irqsave(&conf->device_lock, flags);
	mddev->degraded -= count;
	spin_unlock_irqrestore(&conf->device_lock, flags);
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1094 1095

	print_conf(conf);
1096
	return count;
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}


static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
{
	conf_t *conf = mddev->private;
1103
	int err = -EEXIST;
1104
	int mirror = 0;
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1105
	mirror_info_t *p;
1106 1107
	int first = 0;
	int last = mddev->raid_disks - 1;
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1109 1110 1111 1112
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;

	for (mirror = first; mirror <= last; mirror++)
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1113 1114
		if ( !(p=conf->mirrors+mirror)->rdev) {

1115 1116
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
1117 1118 1119 1120 1121
			/* 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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1122
			 */
1123 1124 1125 1126 1127
			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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1128 1129 1130

			p->head_position = 0;
			rdev->raid_disk = mirror;
1131
			err = 0;
1132 1133 1134 1135
			/* 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)
1136
				conf->fullsync = 1;
1137
			rcu_assign_pointer(p->rdev, rdev);
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1138 1139
			break;
		}
1140
	md_integrity_add_rdev(rdev, mddev);
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1141
	print_conf(conf);
1142
	return err;
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1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154
}

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) {
1155
		if (test_bit(In_sync, &rdev->flags) ||
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1156 1157 1158 1159
		    atomic_read(&rdev->nr_pending)) {
			err = -EBUSY;
			goto abort;
		}
N
NeilBrown 已提交
1160
		/* Only remove non-faulty devices if recovery
1161 1162 1163
		 * is not possible.
		 */
		if (!test_bit(Faulty, &rdev->flags) &&
1164
		    !mddev->recovery_disabled &&
1165 1166 1167 1168
		    mddev->degraded < conf->raid_disks) {
			err = -EBUSY;
			goto abort;
		}
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1169
		p->rdev = NULL;
1170
		synchronize_rcu();
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1171 1172 1173 1174
		if (atomic_read(&rdev->nr_pending)) {
			/* lost the race, try later */
			err = -EBUSY;
			p->rdev = rdev;
1175
			goto abort;
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1176
		}
1177
		md_integrity_register(mddev);
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	}
abort:

	print_conf(conf);
	return err;
}


1186
static void end_sync_read(struct bio *bio, int error)
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1187
{
1188
	r1bio_t *r1_bio = bio->bi_private;
1189
	int i;
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1190

1191 1192 1193 1194 1195
	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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1196 1197 1198 1199 1200
	/*
	 * 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
	 */
1201
	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
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		set_bit(R1BIO_Uptodate, &r1_bio->state);
1203 1204 1205

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

1208
static void end_sync_write(struct bio *bio, int error)
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1209 1210
{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1211
	r1bio_t *r1_bio = bio->bi_private;
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1212
	mddev_t *mddev = r1_bio->mddev;
1213
	conf_t *conf = mddev->private;
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1214 1215 1216 1217 1218 1219 1220 1221
	int i;
	int mirror=0;

	for (i = 0; i < conf->raid_disks; i++)
		if (r1_bio->bios[i] == bio) {
			mirror = i;
			break;
		}
1222
	if (!uptodate) {
N
NeilBrown 已提交
1223
		sector_t sync_blocks = 0;
1224 1225 1226 1227
		sector_t s = r1_bio->sector;
		long sectors_to_go = r1_bio->sectors;
		/* make sure these bits doesn't get cleared. */
		do {
1228
			bitmap_end_sync(mddev->bitmap, s,
1229 1230 1231 1232
					&sync_blocks, 1);
			s += sync_blocks;
			sectors_to_go -= sync_blocks;
		} while (sectors_to_go > 0);
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1233
		md_error(mddev, conf->mirrors[mirror].rdev);
1234
	}
1235

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1236 1237 1238
	update_head_pos(mirror, r1_bio);

	if (atomic_dec_and_test(&r1_bio->remaining)) {
1239
		sector_t s = r1_bio->sectors;
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1240
		put_buf(r1_bio);
1241
		md_done_sync(mddev, s, uptodate);
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1242 1243 1244 1245 1246
	}
}

static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
{
1247
	conf_t *conf = mddev->private;
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1248 1249 1250 1251 1252 1253
	int i;
	int disks = conf->raid_disks;
	struct bio *bio, *wbio;

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

1254

1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276
	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;
1277
				rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1278 1279 1280 1281
				break;
			}
		r1_bio->read_disk = primary;
		for (i=0; i<mddev->raid_disks; i++)
1282
			if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1283 1284 1285 1286
				int j;
				int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
				struct bio *pbio = r1_bio->bios[primary];
				struct bio *sbio = r1_bio->bios[i];
1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299

				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;
1300 1301
				if (j >= 0)
					mddev->resync_mismatches += r1_bio->sectors;
1302 1303
				if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
					      && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1304
					sbio->bi_end_io = NULL;
1305 1306
					rdev_dec_pending(conf->mirrors[i].rdev, mddev);
				} else {
1307
					/* fixup the bio for reuse */
1308
					int size;
1309 1310 1311 1312 1313 1314 1315 1316 1317 1318
					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;
1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329
					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),
1330 1331
						       page_address(pbio->bi_io_vec[j].bv_page),
						       PAGE_SIZE);
1332
					}
1333

1334 1335 1336
				}
			}
	}
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Linus Torvalds 已提交
1337
	if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1338 1339 1340
		/* 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
1341
		 * read into the pages we already have so we don't
1342 1343 1344 1345
		 * 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.
L
Linus Torvalds 已提交
1346
		 */
1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360
		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) {
1361 1362 1363 1364
					/* No rcu protection needed here devices
					 * can only be removed when no resync is
					 * active, and resync is currently active
					 */
1365
					rdev = conf->mirrors[d].rdev;
1366
					if (sync_page_io(rdev,
1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380
							 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) {
1381
				int start = d;
1382 1383 1384 1385 1386 1387 1388 1389 1390
				/* 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;
1391
					atomic_add(s, &rdev->corrected_errors);
1392
					if (sync_page_io(rdev,
1393 1394 1395
							 sect + rdev->data_offset,
							 s<<9,
							 bio->bi_io_vec[idx].bv_page,
1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406
							 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;
1407
					if (sync_page_io(rdev,
1408 1409 1410
							 sect + rdev->data_offset,
							 s<<9,
							 bio->bi_io_vec[idx].bv_page,
1411
							 READ) == 0)
1412 1413 1414 1415 1416 1417
						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);
N
NeilBrown 已提交
1418
				printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1419
				       " for block %llu\n",
N
NeilBrown 已提交
1420 1421
				       mdname(mddev),
				       bdevname(bio->bi_bdev, b),
1422 1423 1424 1425 1426 1427 1428 1429 1430
				       (unsigned long long)r1_bio->sector);
				md_done_sync(mddev, r1_bio->sectors, 0);
				put_buf(r1_bio);
				return;
			}
			sectors -= s;
			sect += s;
			idx ++;
		}
L
Linus Torvalds 已提交
1431
	}
1432 1433 1434 1435

	/*
	 * schedule writes
	 */
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1436 1437 1438
	atomic_set(&r1_bio->remaining, 1);
	for (i = 0; i < disks ; i++) {
		wbio = r1_bio->bios[i];
1439 1440 1441 1442
		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
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1443 1444
			continue;

1445 1446
		wbio->bi_rw = WRITE;
		wbio->bi_end_io = end_sync_write;
L
Linus Torvalds 已提交
1447 1448
		atomic_inc(&r1_bio->remaining);
		md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1449

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1450 1451 1452 1453
		generic_make_request(wbio);
	}

	if (atomic_dec_and_test(&r1_bio->remaining)) {
1454
		/* if we're here, all write(s) have completed, so clean up */
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1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467
		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.
 */

1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490
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) &&
1491
			    sync_page_io(rdev,
1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516
					 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)) {
1517
				if (sync_page_io(rdev,
1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533
						 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)) {
1534
				if (sync_page_io(rdev,
1535 1536 1537 1538 1539 1540 1541 1542
						 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
N
NeilBrown 已提交
1543
					       "md/raid1:%s: read error corrected "
1544 1545
					       "(%d sectors at %llu on %s)\n",
					       mdname(mddev), s,
1546 1547
					       (unsigned long long)(sect +
					           rdev->data_offset),
1548 1549 1550 1551 1552 1553 1554 1555 1556
					       bdevname(rdev->bdev, b));
				}
			}
		}
		sectors -= s;
		sect += s;
	}
}

L
Linus Torvalds 已提交
1557 1558 1559 1560 1561
static void raid1d(mddev_t *mddev)
{
	r1bio_t *r1_bio;
	struct bio *bio;
	unsigned long flags;
1562
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
1563 1564 1565 1566 1567 1568 1569 1570
	struct list_head *head = &conf->retry_list;
	int unplug=0;
	mdk_rdev_t *rdev;

	md_check_recovery(mddev);
	
	for (;;) {
		char b[BDEVNAME_SIZE];
1571

1572
		unplug += flush_pending_writes(conf);
1573

1574 1575 1576
		spin_lock_irqsave(&conf->device_lock, flags);
		if (list_empty(head)) {
			spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
1577
			break;
1578
		}
L
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1579 1580
		r1_bio = list_entry(head->prev, r1bio_t, retry_list);
		list_del(head->prev);
1581
		conf->nr_queued--;
L
Linus Torvalds 已提交
1582 1583 1584
		spin_unlock_irqrestore(&conf->device_lock, flags);

		mddev = r1_bio->mddev;
1585
		conf = mddev->private;
L
Linus Torvalds 已提交
1586 1587 1588 1589 1590
		if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
			sync_request_write(mddev, r1_bio);
			unplug = 1;
		} else {
			int disk;
1591 1592 1593 1594 1595 1596 1597 1598 1599

			/* 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
			 */
1600 1601 1602 1603 1604 1605
			if (mddev->ro == 0) {
				freeze_array(conf);
				fix_read_error(conf, r1_bio->read_disk,
					       r1_bio->sector,
					       r1_bio->sectors);
				unfreeze_array(conf);
1606 1607 1608
			} else
				md_error(mddev,
					 conf->mirrors[r1_bio->read_disk].rdev);
1609

L
Linus Torvalds 已提交
1610
			bio = r1_bio->bios[r1_bio->read_disk];
1611
			if ((disk=read_balance(conf, r1_bio)) == -1) {
N
NeilBrown 已提交
1612
				printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
L
Linus Torvalds 已提交
1613
				       " read error for block %llu\n",
N
NeilBrown 已提交
1614
				       mdname(mddev),
L
Linus Torvalds 已提交
1615 1616 1617 1618
				       bdevname(bio->bi_bdev,b),
				       (unsigned long long)r1_bio->sector);
				raid_end_bio_io(r1_bio);
			} else {
1619
				const unsigned long do_sync = r1_bio->master_bio->bi_rw & REQ_SYNC;
1620 1621
				r1_bio->bios[r1_bio->read_disk] =
					mddev->ro ? IO_BLOCKED : NULL;
L
Linus Torvalds 已提交
1622 1623
				r1_bio->read_disk = disk;
				bio_put(bio);
1624 1625
				bio = bio_clone_mddev(r1_bio->master_bio,
						      GFP_NOIO, mddev);
L
Linus Torvalds 已提交
1626 1627 1628
				r1_bio->bios[r1_bio->read_disk] = bio;
				rdev = conf->mirrors[disk].rdev;
				if (printk_ratelimit())
N
NeilBrown 已提交
1629
					printk(KERN_ERR "md/raid1:%s: redirecting sector %llu to"
1630
					       " other mirror: %s\n",
N
NeilBrown 已提交
1631
					       mdname(mddev),
1632 1633
					       (unsigned long long)r1_bio->sector,
					       bdevname(rdev->bdev,b));
L
Linus Torvalds 已提交
1634 1635 1636
				bio->bi_sector = r1_bio->sector + rdev->data_offset;
				bio->bi_bdev = rdev->bdev;
				bio->bi_end_io = raid1_end_read_request;
1637
				bio->bi_rw = READ | do_sync;
L
Linus Torvalds 已提交
1638 1639 1640 1641 1642
				bio->bi_private = r1_bio;
				unplug = 1;
				generic_make_request(bio);
			}
		}
N
NeilBrown 已提交
1643
		cond_resched();
L
Linus Torvalds 已提交
1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654
	}
	if (unplug)
		unplug_slaves(mddev);
}


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

	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1655
	BUG_ON(conf->r1buf_pool);
L
Linus Torvalds 已提交
1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673
	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.
 */

1674
static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
L
Linus Torvalds 已提交
1675
{
1676
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
1677 1678 1679
	r1bio_t *r1_bio;
	struct bio *bio;
	sector_t max_sector, nr_sectors;
1680
	int disk = -1;
L
Linus Torvalds 已提交
1681
	int i;
1682 1683
	int wonly = -1;
	int write_targets = 0, read_targets = 0;
N
NeilBrown 已提交
1684
	sector_t sync_blocks;
1685
	int still_degraded = 0;
L
Linus Torvalds 已提交
1686 1687 1688

	if (!conf->r1buf_pool)
		if (init_resync(conf))
1689
			return 0;
L
Linus Torvalds 已提交
1690

A
Andre Noll 已提交
1691
	max_sector = mddev->dev_sectors;
L
Linus Torvalds 已提交
1692
	if (sector_nr >= max_sector) {
1693 1694 1695 1696 1697
		/* 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
		 */
1698 1699
		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1700
						&sync_blocks, 1);
1701
		else /* completed sync */
1702
			conf->fullsync = 0;
1703 1704

		bitmap_close_sync(mddev->bitmap);
L
Linus Torvalds 已提交
1705 1706 1707 1708
		close_sync(conf);
		return 0;
	}

1709 1710
	if (mddev->bitmap == NULL &&
	    mddev->recovery_cp == MaxSector &&
1711
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1712 1713 1714 1715
	    conf->fullsync == 0) {
		*skipped = 1;
		return max_sector - sector_nr;
	}
1716 1717 1718
	/* before building a request, check if we can skip these blocks..
	 * This call the bitmap_start_sync doesn't actually record anything
	 */
1719
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1720
	    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1721 1722 1723 1724
		/* We can skip this block, and probably several more */
		*skipped = 1;
		return sync_blocks;
	}
L
Linus Torvalds 已提交
1725
	/*
1726 1727 1728
	 * 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
1729
	 */
1730
	if (!go_faster && conf->nr_waiting)
L
Linus Torvalds 已提交
1731
		msleep_interruptible(1000);
1732

N
NeilBrown 已提交
1733
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1734
	r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1735 1736 1737
	raise_barrier(conf);

	conf->next_resync = sector_nr;
L
Linus Torvalds 已提交
1738

1739
	rcu_read_lock();
L
Linus Torvalds 已提交
1740
	/*
1741 1742 1743 1744 1745 1746
	 * 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
1747 1748 1749 1750
	 */

	r1_bio->mddev = mddev;
	r1_bio->sector = sector_nr;
1751
	r1_bio->state = 0;
L
Linus Torvalds 已提交
1752 1753 1754
	set_bit(R1BIO_IsSync, &r1_bio->state);

	for (i=0; i < conf->raid_disks; i++) {
1755
		mdk_rdev_t *rdev;
L
Linus Torvalds 已提交
1756 1757 1758 1759
		bio = r1_bio->bios[i];

		/* take from bio_init */
		bio->bi_next = NULL;
1760
		bio->bi_flags &= ~(BIO_POOL_MASK-1);
L
Linus Torvalds 已提交
1761
		bio->bi_flags |= 1 << BIO_UPTODATE;
1762
		bio->bi_comp_cpu = -1;
1763
		bio->bi_rw = READ;
L
Linus Torvalds 已提交
1764 1765 1766 1767 1768 1769 1770
		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;

1771 1772 1773
		rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev == NULL ||
			   test_bit(Faulty, &rdev->flags)) {
1774 1775
			still_degraded = 1;
			continue;
1776
		} else if (!test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
1777 1778 1779
			bio->bi_rw = WRITE;
			bio->bi_end_io = end_sync_write;
			write_targets ++;
1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795
		} 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
1796 1797
		bio->bi_private = r1_bio;
	}
1798 1799 1800 1801
	rcu_read_unlock();
	if (disk < 0)
		disk = wonly;
	r1_bio->read_disk = disk;
1802

1803 1804 1805 1806 1807
	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
1808 1809 1810
		/* There is nowhere to write, so all non-sync
		 * drives must be failed - so we are finished
		 */
1811 1812
		sector_t rv = max_sector - sector_nr;
		*skipped = 1;
L
Linus Torvalds 已提交
1813 1814 1815 1816
		put_buf(r1_bio);
		return rv;
	}

1817 1818
	if (max_sector > mddev->resync_max)
		max_sector = mddev->resync_max; /* Don't do IO beyond here */
L
Linus Torvalds 已提交
1819
	nr_sectors = 0;
1820
	sync_blocks = 0;
L
Linus Torvalds 已提交
1821 1822 1823 1824 1825 1826 1827
	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;
1828 1829
		if (sync_blocks == 0) {
			if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1830 1831 1832
					       &sync_blocks, still_degraded) &&
			    !conf->fullsync &&
			    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1833
				break;
1834
			BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1835
			if ((len >> 9) > sync_blocks)
1836
				len = sync_blocks<<9;
1837
		}
1838

L
Linus Torvalds 已提交
1839 1840 1841
		for (i=0 ; i < conf->raid_disks; i++) {
			bio = r1_bio->bios[i];
			if (bio->bi_end_io) {
1842
				page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
L
Linus Torvalds 已提交
1843 1844
				if (bio_add_page(bio, page, len, 0) == 0) {
					/* stop here */
1845
					bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
L
Linus Torvalds 已提交
1846 1847 1848
					while (i > 0) {
						i--;
						bio = r1_bio->bios[i];
1849 1850
						if (bio->bi_end_io==NULL)
							continue;
L
Linus Torvalds 已提交
1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861
						/* 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;
1862
		sync_blocks -= (len>>9);
L
Linus Torvalds 已提交
1863 1864 1865 1866
	} while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
 bio_full:
	r1_bio->sectors = nr_sectors;

1867 1868 1869 1870 1871 1872 1873 1874
	/* 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) {
1875
				md_sync_acct(bio->bi_bdev, nr_sectors);
1876 1877 1878 1879 1880 1881
				generic_make_request(bio);
			}
		}
	} else {
		atomic_set(&r1_bio->remaining, 1);
		bio = r1_bio->bios[r1_bio->read_disk];
1882
		md_sync_acct(bio->bi_bdev, nr_sectors);
1883
		generic_make_request(bio);
L
Linus Torvalds 已提交
1884

1885
	}
L
Linus Torvalds 已提交
1886 1887 1888
	return nr_sectors;
}

1889 1890 1891 1892 1893 1894 1895 1896
static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
{
	if (sectors)
		return sectors;

	return mddev->dev_sectors;
}

1897
static conf_t *setup_conf(mddev_t *mddev)
L
Linus Torvalds 已提交
1898 1899
{
	conf_t *conf;
1900
	int i;
L
Linus Torvalds 已提交
1901 1902
	mirror_info_t *disk;
	mdk_rdev_t *rdev;
1903
	int err = -ENOMEM;
L
Linus Torvalds 已提交
1904

1905
	conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
L
Linus Torvalds 已提交
1906
	if (!conf)
1907
		goto abort;
L
Linus Torvalds 已提交
1908

1909
	conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
L
Linus Torvalds 已提交
1910 1911
				 GFP_KERNEL);
	if (!conf->mirrors)
1912
		goto abort;
L
Linus Torvalds 已提交
1913

1914 1915
	conf->tmppage = alloc_page(GFP_KERNEL);
	if (!conf->tmppage)
1916
		goto abort;
1917

1918
	conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
L
Linus Torvalds 已提交
1919
	if (!conf->poolinfo)
1920
		goto abort;
L
Linus Torvalds 已提交
1921 1922 1923 1924 1925
	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)
1926 1927
		goto abort;

1928
	conf->poolinfo->mddev = mddev;
L
Linus Torvalds 已提交
1929

1930
	spin_lock_init(&conf->device_lock);
1931
	list_for_each_entry(rdev, &mddev->disks, same_set) {
1932
		int disk_idx = rdev->raid_disk;
L
Linus Torvalds 已提交
1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946
		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);
1947
	init_waitqueue_head(&conf->wait_barrier);
L
Linus Torvalds 已提交
1948

1949 1950
	bio_list_init(&conf->pending_bio_list);

1951
	conf->last_used = -1;
L
Linus Torvalds 已提交
1952 1953 1954 1955
	for (i = 0; i < conf->raid_disks; i++) {

		disk = conf->mirrors + i;

1956 1957
		if (!disk->rdev ||
		    !test_bit(In_sync, &disk->rdev->flags)) {
L
Linus Torvalds 已提交
1958
			disk->head_position = 0;
1959 1960
			if (disk->rdev)
				conf->fullsync = 1;
1961 1962 1963 1964 1965 1966
		} 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
1967
	}
1968 1969 1970

	err = -EIO;
	if (conf->last_used < 0) {
N
NeilBrown 已提交
1971
		printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
1972 1973 1974 1975 1976 1977 1978
		       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
1979
		       "md/raid1:%s: couldn't allocate thread\n",
1980 1981
		       mdname(mddev));
		goto abort;
1982
	}
L
Linus Torvalds 已提交
1983

1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
	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
2005
		printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2006 2007 2008 2009
		       mdname(mddev), mddev->level);
		return -EIO;
	}
	if (mddev->reshape_position != MaxSector) {
N
NeilBrown 已提交
2010
		printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2011 2012 2013
		       mdname(mddev));
		return -EIO;
	}
L
Linus Torvalds 已提交
2014
	/*
2015 2016 2017
	 * 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
2018
	 */
2019 2020 2021 2022
	if (mddev->private == NULL)
		conf = setup_conf(mddev);
	else
		conf = mddev->private;
L
Linus Torvalds 已提交
2023

2024 2025
	if (IS_ERR(conf))
		return PTR_ERR(conf);
L
Linus Torvalds 已提交
2026

2027 2028 2029 2030 2031
	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
2032 2033
		 * violating it, so limit ->max_segments to 1 lying within
		 * a single page, as a one page request is never in violation.
2034
		 */
2035 2036 2037 2038 2039
		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
2040
	}
2041

2042 2043 2044 2045 2046 2047 2048 2049 2050 2051
	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;

2052
	if (mddev->recovery_cp != MaxSector)
N
NeilBrown 已提交
2053
		printk(KERN_NOTICE "md/raid1:%s: not clean"
2054 2055
		       " -- starting background reconstruction\n",
		       mdname(mddev));
L
Linus Torvalds 已提交
2056
	printk(KERN_INFO 
N
NeilBrown 已提交
2057
		"md/raid1:%s: active with %d out of %d mirrors\n",
L
Linus Torvalds 已提交
2058 2059
		mdname(mddev), mddev->raid_disks - mddev->degraded, 
		mddev->raid_disks);
2060

L
Linus Torvalds 已提交
2061 2062 2063
	/*
	 * Ok, everything is just fine now
	 */
2064 2065 2066 2067
	mddev->thread = conf->thread;
	conf->thread = NULL;
	mddev->private = conf;

2068
	md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
L
Linus Torvalds 已提交
2069

2070
	mddev->queue->unplug_fn = raid1_unplug;
2071 2072
	mddev->queue->backing_dev_info.congested_fn = raid1_congested;
	mddev->queue->backing_dev_info.congested_data = mddev;
2073
	md_integrity_register(mddev);
L
Linus Torvalds 已提交
2074 2075 2076 2077 2078
	return 0;
}

static int stop(mddev_t *mddev)
{
2079
	conf_t *conf = mddev->private;
2080 2081 2082
	struct bitmap *bitmap = mddev->bitmap;

	/* wait for behind writes to complete */
2083
	if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
N
NeilBrown 已提交
2084 2085
		printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
		       mdname(mddev));
2086
		/* need to kick something here to make sure I/O goes? */
2087 2088
		wait_event(bitmap->behind_wait,
			   atomic_read(&bitmap->behind_writes) == 0);
2089
	}
L
Linus Torvalds 已提交
2090

2091 2092 2093
	raise_barrier(conf);
	lower_barrier(conf);

L
Linus Torvalds 已提交
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	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);
2099 2100
	kfree(conf->mirrors);
	kfree(conf->poolinfo);
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	kfree(conf);
	mddev->private = NULL;
	return 0;
}

static int raid1_resize(mddev_t *mddev, sector_t sectors)
{
	/* no resync is happening, and there is enough space
	 * on all devices, so we can resize.
	 * We need to make sure resync covers any new space.
	 * If the array is shrinking we should possibly wait until
	 * any io in the removed space completes, but it hardly seems
	 * worth it.
	 */
2115
	md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
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2116 2117
	if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
		return -EINVAL;
2118
	set_capacity(mddev->gendisk, mddev->array_sectors);
2119
	revalidate_disk(mddev->gendisk);
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2120
	if (sectors > mddev->dev_sectors &&
2121
	    mddev->recovery_cp == MaxSector) {
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2122
		mddev->recovery_cp = mddev->dev_sectors;
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2123 2124
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
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2125
	mddev->dev_sectors = sectors;
2126
	mddev->resync_max_sectors = sectors;
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	return 0;
}

2130
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.
2139 2140 2141
	 *
	 * 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;
2146
	conf_t *conf = mddev->private;
2147
	int cnt, raid_disks;
2148
	unsigned long flags;
2149
	int d, d2, err;
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2151
	/* Cannot change chunk_size, layout, or level */
2152
	if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2153 2154
	    mddev->layout != mddev->new_layout ||
	    mddev->level != mddev->new_level) {
2155
		mddev->new_chunk_sectors = mddev->chunk_sectors;
2156 2157 2158 2159 2160
		mddev->new_layout = mddev->layout;
		mddev->new_level = mddev->level;
		return -EINVAL;
	}

2161 2162 2163
	err = md_allow_write(mddev);
	if (err)
		return err;
2164

2165 2166
	raid_disks = mddev->raid_disks + mddev->delta_disks;

2167 2168 2169 2170 2171 2172
	if (raid_disks < conf->raid_disks) {
		cnt=0;
		for (d= 0; d < conf->raid_disks; d++)
			if (conf->mirrors[d].rdev)
				cnt++;
		if (cnt > raid_disks)
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			return -EBUSY;
2174
	}
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	newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
	if (!newpoolinfo)
		return -ENOMEM;
	newpoolinfo->mddev = mddev;
	newpoolinfo->raid_disks = raid_disks;

	newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
				 r1bio_pool_free, newpoolinfo);
	if (!newpool) {
		kfree(newpoolinfo);
		return -ENOMEM;
	}
2188
	newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
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	if (!newmirrors) {
		kfree(newpoolinfo);
		mempool_destroy(newpool);
		return -ENOMEM;
	}

2195
	raise_barrier(conf);
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	/* ok, everything is stopped */
	oldpool = conf->r1bio_pool;
	conf->r1bio_pool = newpool;
2200

2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212
	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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				       "md/raid1:%s: cannot register "
				       "%s\n",
				       mdname(mddev), nm);
2216
		}
2217 2218 2219
		if (rdev)
			newmirrors[d2++].rdev = rdev;
	}
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	kfree(conf->mirrors);
	conf->mirrors = newmirrors;
	kfree(conf->poolinfo);
	conf->poolinfo = newpoolinfo;

2225
	spin_lock_irqsave(&conf->device_lock, flags);
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2226
	mddev->degraded += (raid_disks - conf->raid_disks);
2227
	spin_unlock_irqrestore(&conf->device_lock, flags);
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2228
	conf->raid_disks = mddev->raid_disks = raid_disks;
2229
	mddev->delta_disks = 0;
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2230

2231
	conf->last_used = 0; /* just make sure it is in-range */
2232
	lower_barrier(conf);
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	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	md_wakeup_thread(mddev->thread);

	mempool_destroy(oldpool);
	return 0;
}

2241
static void raid1_quiesce(mddev_t *mddev, int state)
2242
{
2243
	conf_t *conf = mddev->private;
2244 2245

	switch(state) {
2246 2247 2248
	case 2: /* wake for suspend */
		wake_up(&conf->wait_barrier);
		break;
2249
	case 1:
2250
		raise_barrier(conf);
2251
		break;
2252
	case 0:
2253
		lower_barrier(conf);
2254 2255 2256 2257
		break;
	}
}

2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274
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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2276
static struct mdk_personality raid1_personality =
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{
	.name		= "raid1",
2279
	.level		= 1,
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	.owner		= THIS_MODULE,
	.make_request	= make_request,
	.run		= run,
	.stop		= stop,
	.status		= status,
	.error_handler	= error,
	.hot_add_disk	= raid1_add_disk,
	.hot_remove_disk= raid1_remove_disk,
	.spare_active	= raid1_spare_active,
	.sync_request	= sync_request,
	.resize		= raid1_resize,
2291
	.size		= raid1_size,
2292
	.check_reshape	= raid1_reshape,
2293
	.quiesce	= raid1_quiesce,
2294
	.takeover	= raid1_takeover,
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};

static int __init raid_init(void)
{
2299
	return register_md_personality(&raid1_personality);
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}

static void raid_exit(void)
{
2304
	unregister_md_personality(&raid1_personality);
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}

module_init(raid_init);
module_exit(raid_exit);
MODULE_LICENSE("GPL");
2310
MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
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MODULE_ALIAS("md-personality-3"); /* RAID1 */
2312
MODULE_ALIAS("md-raid1");
2313
MODULE_ALIAS("md-level-1");