raid1.c 64.3 KB
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/*
 * raid1.c : Multiple Devices driver for Linux
 *
 * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
 *
 * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
 *
 * RAID-1 management functions.
 *
 * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
 *
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 * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
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 * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
 *
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 * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
 * bitmapped intelligence in resync:
 *
 *      - bitmap marked during normal i/o
 *      - bitmap used to skip nondirty blocks during sync
 *
 * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
 * - persistent bitmap code
 *
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 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * You should have received a copy of the GNU General Public License
 * (for example /usr/src/linux/COPYING); if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

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#include <linux/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 <linux/ratelimit.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
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#define PRINTK(x...) do { if (DEBUG) printk(x); } while (0)
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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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	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.
 */
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static void call_bio_endio(r1bio_t *r1_bio)
{
	struct bio *bio = r1_bio->master_bio;
	int done;
	conf_t *conf = r1_bio->mddev->private;

	if (bio->bi_phys_segments) {
		unsigned long flags;
		spin_lock_irqsave(&conf->device_lock, flags);
		bio->bi_phys_segments--;
		done = (bio->bi_phys_segments == 0);
		spin_unlock_irqrestore(&conf->device_lock, flags);
	} else
		done = 1;

	if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
		clear_bit(BIO_UPTODATE, &bio->bi_flags);
	if (done) {
		bio_endio(bio, 0);
		/*
		 * Wake up any possible resync thread that waits for the device
		 * to go idle.
		 */
		allow_barrier(conf);
	}
}

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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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		call_bio_endio(r1_bio);
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	}
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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];
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		printk_ratelimited(
			KERN_ERR "md/raid1:%s: %s: "
			"rescheduling sector %llu\n",
			mdname(conf->mddev),
			bdevname(conf->mirrors[mirror].rdev->bdev,
				 b),
			(unsigned long long)r1_bio->sector);
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		set_bit(R1BIO_ReadError, &r1_bio->state);
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		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)
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{
	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 */
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			int i = r1_bio->behind_page_count;
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			while (i--)
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				safe_put_page(r1_bio->behind_pages[i]);
			kfree(r1_bio->behind_pages);
			r1_bio->behind_pages = NULL;
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		}
		/* 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),
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				test_bit(R1BIO_BehindIO, &r1_bio->state));
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		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);
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				call_bio_endio(r1_bio);
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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);
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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.
 */
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static int read_balance(conf_t *conf, r1bio_t *r1_bio, int *max_sectors)
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{
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	const sector_t this_sector = r1_bio->sector;
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	int sectors;
	int best_good_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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	sectors = r1_bio->sectors;
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	best_disk = -1;
	best_dist = MaxSector;
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	best_good_sectors = 0;

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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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		sector_t first_bad;
		int bad_sectors;

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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.
		 */
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		if (is_badblock(rdev, this_sector, sectors,
				&first_bad, &bad_sectors)) {
			if (best_dist < MaxSector)
				/* already have a better device */
				continue;
			if (first_bad <= this_sector) {
				/* cannot read here. If this is the 'primary'
				 * device, then we must not read beyond
				 * bad_sectors from another device..
				 */
				bad_sectors -= (this_sector - first_bad);
				if (choose_first && sectors > bad_sectors)
					sectors = bad_sectors;
				if (best_good_sectors > sectors)
					best_good_sectors = sectors;

			} else {
				sector_t good_sectors = first_bad - this_sector;
				if (good_sectors > best_good_sectors) {
					best_good_sectors = good_sectors;
					best_disk = disk;
				}
				if (choose_first)
					break;
			}
			continue;
		} else
			best_good_sectors = sectors;

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		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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		sectors = best_good_sectors;
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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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	*max_sectors = sectors;
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	return best_disk;
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}

559
int md_raid1_congested(mddev_t *mddev, int bits)
560
{
561
	conf_t *conf = mddev->private;
562 563 564 565 566 567
	int i, ret = 0;

	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)) {
568
			struct request_queue *q = bdev_get_queue(rdev->bdev);
569

570 571
			BUG_ON(!q);

572 573 574
			/* Note the '|| 1' - when read_balance prefers
			 * non-congested targets, it can be removed
			 */
575
			if ((bits & (1<<BDI_async_congested)) || 1)
576 577 578 579 580 581 582 583
				ret |= bdi_congested(&q->backing_dev_info, bits);
			else
				ret &= bdi_congested(&q->backing_dev_info, bits);
		}
	}
	rcu_read_unlock();
	return ret;
}
584
EXPORT_SYMBOL_GPL(md_raid1_congested);
585

586 587 588 589 590 591 592
static int raid1_congested(void *data, int bits)
{
	mddev_t *mddev = data;

	return mddev_congested(mddev, bits) ||
		md_raid1_congested(mddev, bits);
}
593

594
static void flush_pending_writes(conf_t *conf)
595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616
{
	/* 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);
617 618
}

619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638
/* 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

642
static void raise_barrier(conf_t *conf)
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{
	spin_lock_irq(&conf->resync_lock);
645 646 647

	/* Wait until no block IO is waiting */
	wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
648
			    conf->resync_lock, );
649 650 651 652

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

653
	/* Now wait for all pending IO to complete */
654 655
	wait_event_lock_irq(conf->wait_barrier,
			    !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
656
			    conf->resync_lock, );
657 658 659 660 661 662 663

	spin_unlock_irq(&conf->resync_lock);
}

static void lower_barrier(conf_t *conf)
{
	unsigned long flags;
664
	BUG_ON(conf->barrier <= 0);
665 666 667 668 669 670 671 672 673 674 675 676 677
	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,
678
				    );
679
		conf->nr_waiting--;
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	}
681
	conf->nr_pending++;
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	spin_unlock_irq(&conf->resync_lock);
}

685 686 687 688 689 690 691 692 693
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);
}

694 695 696 697 698
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
699 700 701 702 703 704 705 706
	 * 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.
707 708 709 710 711
	 */
	spin_lock_irq(&conf->resync_lock);
	conf->barrier++;
	conf->nr_waiting++;
	wait_event_lock_irq(conf->wait_barrier,
712
			    conf->nr_pending == conf->nr_queued+1,
713
			    conf->resync_lock,
714
			    flush_pending_writes(conf));
715 716 717 718 719 720 721 722 723 724 725 726
	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);
}

727

728 729
/* duplicate the data pages for behind I/O 
 */
730
static void alloc_behind_pages(struct bio *bio, r1bio_t *r1_bio)
731 732 733
{
	int i;
	struct bio_vec *bvec;
734
	struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page*),
735 736
					GFP_NOIO);
	if (unlikely(!pages))
737
		return;
738 739

	bio_for_each_segment(bvec, bio, i) {
740 741
		pages[i] = alloc_page(GFP_NOIO);
		if (unlikely(!pages[i]))
742
			goto do_sync_io;
743
		memcpy(kmap(pages[i]) + bvec->bv_offset,
744
			kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
745
		kunmap(pages[i]);
746 747
		kunmap(bvec->bv_page);
	}
748 749 750 751
	r1_bio->behind_pages = pages;
	r1_bio->behind_page_count = bio->bi_vcnt;
	set_bit(R1BIO_BehindIO, &r1_bio->state);
	return;
752 753

do_sync_io:
754 755 756
	for (i = 0; i < bio->bi_vcnt; i++)
		if (pages[i])
			put_page(pages[i]);
757 758 759 760
	kfree(pages);
	PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
}

761
static int make_request(mddev_t *mddev, struct bio * bio)
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{
763
	conf_t *conf = mddev->private;
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	mirror_info_t *mirror;
	r1bio_t *r1_bio;
	struct bio *read_bio;
767
	int i, targets = 0, disks;
768
	struct bitmap *bitmap;
769
	unsigned long flags;
770
	const int rw = bio_data_dir(bio);
771
	const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
772
	const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
773
	mdk_rdev_t *blocked_rdev;
774
	int plugged;
775

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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.
	 */
781

782 783
	md_write_start(mddev, bio); /* wait on superblock update early */

784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802
	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);
	}
803

804
	wait_barrier(conf);
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806 807
	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;
817
	r1_bio->state = 0;
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	r1_bio->mddev = mddev;
	r1_bio->sector = bio->bi_sector;

821 822 823 824 825 826 827 828 829 830
	/* We might need to issue multiple reads to different
	 * devices if there are bad blocks around, so we keep
	 * track of the number of reads in bio->bi_phys_segments.
	 * If this is 0, there is only one r1_bio and no locking
	 * will be needed when requests complete.  If it is
	 * non-zero, then it is the number of not-completed requests.
	 */
	bio->bi_phys_segments = 0;
	clear_bit(BIO_SEG_VALID, &bio->bi_flags);

831
	if (rw == READ) {
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		/*
		 * read balancing logic:
		 */
835 836 837 838 839
		int max_sectors;
		int rdisk;

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

848 849 850 851 852 853 854 855 856
		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;

859
		read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
860 861
		md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
			    max_sectors);
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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;
868
		read_bio->bi_rw = READ | do_sync;
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		read_bio->bi_private = r1_bio;

871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902
		if (max_sectors < r1_bio->sectors) {
			/* could not read all from this device, so we will
			 * need another r1_bio.
			 */
			int sectors_handled;

			sectors_handled = (r1_bio->sector + max_sectors
					   - bio->bi_sector);
			r1_bio->sectors = max_sectors;
			spin_lock_irq(&conf->device_lock);
			if (bio->bi_phys_segments == 0)
				bio->bi_phys_segments = 2;
			else
				bio->bi_phys_segments++;
			spin_unlock_irq(&conf->device_lock);
			/* Cannot call generic_make_request directly
			 * as that will be queued in __make_request
			 * and subsequent mempool_alloc might block waiting
			 * for it.  So hand bio over to raid1d.
			 */
			reschedule_retry(r1_bio);

			r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);

			r1_bio->master_bio = bio;
			r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
			r1_bio->state = 0;
			r1_bio->mddev = mddev;
			r1_bio->sector = bio->bi_sector + sectors_handled;
			goto read_again;
		} else
			generic_make_request(read_bio);
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		return 0;
	}

	/*
	 * WRITE:
	 */
	/* first select target devices under spinlock and
	 * inc refcount on their rdev.  Record them by setting
	 * bios[x] to bio
	 */
913 914
	plugged = mddev_check_plugged(mddev);

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	disks = conf->raid_disks;
916 917
 retry_write:
	blocked_rdev = NULL;
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	rcu_read_lock();
	for (i = 0;  i < disks; i++) {
920 921 922 923 924 925 926
		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);
928
			if (test_bit(Faulty, &rdev->flags)) {
929
				rdev_dec_pending(rdev, mddev);
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				r1_bio->bios[i] = NULL;
931
			} else {
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				r1_bio->bios[i] = bio;
933 934
				targets++;
			}
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		} else
			r1_bio->bios[i] = NULL;
	}
	rcu_read_unlock();

940 941 942 943 944 945 946 947 948 949 950 951 952 953
	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;
	}

954 955 956 957 958 959
	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);
	}

960 961 962 963
	/* 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 */
964
	if (bitmap &&
965 966
	    (atomic_read(&bitmap->behind_writes)
	     < mddev->bitmap_info.max_write_behind) &&
967 968
	    !waitqueue_active(&bitmap->behind_wait))
		alloc_behind_pages(bio, r1_bio);
969

970
	atomic_set(&r1_bio->remaining, 1);
971
	atomic_set(&r1_bio->behind_remaining, 0);
972

973 974
	bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
				test_bit(R1BIO_BehindIO, &r1_bio->state));
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	for (i = 0; i < disks; i++) {
		struct bio *mbio;
		if (!r1_bio->bios[i])
			continue;

980
		mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
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		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;
986
		mbio->bi_rw = WRITE | do_flush_fua | do_sync;
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		mbio->bi_private = r1_bio;

989
		if (r1_bio->behind_pages) {
990 991 992 993 994 995 996
			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
997
			 * know the original bi_idx, so we just free
998 999 1000
			 * them all
			 */
			__bio_for_each_segment(bvec, mbio, j, 0)
1001
				bvec->bv_page = r1_bio->behind_pages[j];
1002 1003 1004 1005
			if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
				atomic_inc(&r1_bio->behind_remaining);
		}

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		atomic_inc(&r1_bio->remaining);
1007 1008 1009
		spin_lock_irqsave(&conf->device_lock, flags);
		bio_list_add(&conf->pending_bio_list, mbio);
		spin_unlock_irqrestore(&conf->device_lock, flags);
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	}
1011
	r1_bio_write_done(r1_bio);
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1013
	/* In case raid1d snuck in to freeze_array */
1014 1015
	wake_up(&conf->wait_barrier);

1016
	if (do_sync || !bitmap || !plugged)
1017
		md_wakeup_thread(mddev->thread);
1018

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	return 0;
}

static void status(struct seq_file *seq, mddev_t *mddev)
{
1024
	conf_t *conf = mddev->private;
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	int i;

	seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1028
		   conf->raid_disks - mddev->degraded);
1029 1030 1031
	rcu_read_lock();
	for (i = 0; i < conf->raid_disks; i++) {
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
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		seq_printf(seq, "%s",
1033 1034 1035
			   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];
1043
	conf_t *conf = mddev->private;
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	/*
	 * If it is not operational, then we have already marked it as dead
	 * else if it is the last working disks, ignore the error, let the
	 * next level up know.
	 * else mark the drive as failed
	 */
1051
	if (test_bit(In_sync, &rdev->flags)
1052
	    && (conf->raid_disks - mddev->degraded) == 1) {
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		/*
		 * Don't fail the drive, act as though we were just a
1055 1056 1057
		 * normal single drive.
		 * However don't try a recovery from this drive as
		 * it is very likely to fail.
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		 */
1059
		conf->recovery_disabled = mddev->recovery_disabled;
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		return;
1061
	}
1062
	set_bit(Blocked, &rdev->flags);
1063 1064 1065
	if (test_and_clear_bit(In_sync, &rdev->flags)) {
		unsigned long flags;
		spin_lock_irqsave(&conf->device_lock, flags);
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		mddev->degraded++;
1067
		set_bit(Faulty, &rdev->flags);
1068
		spin_unlock_irqrestore(&conf->device_lock, flags);
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		/*
		 * if recovery is running, make sure it aborts.
		 */
1072
		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1073 1074
	} else
		set_bit(Faulty, &rdev->flags);
1075
	set_bit(MD_CHANGE_DEVS, &mddev->flags);
1076 1077 1078
	printk(KERN_ALERT
	       "md/raid1:%s: Disk failure on %s, disabling device.\n"
	       "md/raid1:%s: Operation continuing on %d devices.\n",
1079 1080
	       mdname(mddev), bdevname(rdev->bdev, b),
	       mdname(mddev), conf->raid_disks - mddev->degraded);
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}

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

1087
	printk(KERN_DEBUG "RAID1 conf printout:\n");
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	if (!conf) {
1089
		printk(KERN_DEBUG "(!conf)\n");
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		return;
	}
1092
	printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
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1093 1094
		conf->raid_disks);

1095
	rcu_read_lock();
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	for (i = 0; i < conf->raid_disks; i++) {
		char b[BDEVNAME_SIZE];
1098 1099
		mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev)
1100
			printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1101 1102 1103
			       i, !test_bit(In_sync, &rdev->flags),
			       !test_bit(Faulty, &rdev->flags),
			       bdevname(rdev->bdev,b));
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1104
	}
1105
	rcu_read_unlock();
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}

static void close_sync(conf_t *conf)
{
1110 1111
	wait_barrier(conf);
	allow_barrier(conf);
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	mempool_destroy(conf->r1buf_pool);
	conf->r1buf_pool = NULL;
}

static int raid1_spare_active(mddev_t *mddev)
{
	int i;
	conf_t *conf = mddev->private;
1121 1122
	int count = 0;
	unsigned long flags;
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	/*
	 * Find all failed disks within the RAID1 configuration 
1126 1127
	 * and mark them readable.
	 * Called under mddev lock, so rcu protection not needed.
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	 */
	for (i = 0; i < conf->raid_disks; i++) {
1130 1131 1132
		mdk_rdev_t *rdev = conf->mirrors[i].rdev;
		if (rdev
		    && !test_bit(Faulty, &rdev->flags)
1133
		    && !test_and_set_bit(In_sync, &rdev->flags)) {
1134
			count++;
1135
			sysfs_notify_dirent_safe(rdev->sysfs_state);
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1136 1137
		}
	}
1138 1139 1140
	spin_lock_irqsave(&conf->device_lock, flags);
	mddev->degraded -= count;
	spin_unlock_irqrestore(&conf->device_lock, flags);
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	print_conf(conf);
1143
	return count;
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}


static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
{
	conf_t *conf = mddev->private;
1150
	int err = -EEXIST;
1151
	int mirror = 0;
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	mirror_info_t *p;
1153 1154
	int first = 0;
	int last = mddev->raid_disks - 1;
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1156 1157 1158
	if (mddev->recovery_disabled == conf->recovery_disabled)
		return -EBUSY;

1159 1160 1161 1162
	if (rdev->raid_disk >= 0)
		first = last = rdev->raid_disk;

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

1165 1166
			disk_stack_limits(mddev->gendisk, rdev->bdev,
					  rdev->data_offset << 9);
1167 1168 1169 1170 1171
			/* 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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			 */
1173 1174 1175 1176 1177
			if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
				blk_queue_max_segments(mddev->queue, 1);
				blk_queue_segment_boundary(mddev->queue,
							   PAGE_CACHE_SIZE - 1);
			}
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			p->head_position = 0;
			rdev->raid_disk = mirror;
1181
			err = 0;
1182 1183 1184 1185
			/* 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)
1186
				conf->fullsync = 1;
1187
			rcu_assign_pointer(p->rdev, rdev);
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			break;
		}
1190
	md_integrity_add_rdev(rdev, mddev);
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	print_conf(conf);
1192
	return err;
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}

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

	print_conf(conf);
	rdev = p->rdev;
	if (rdev) {
1205
		if (test_bit(In_sync, &rdev->flags) ||
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		    atomic_read(&rdev->nr_pending)) {
			err = -EBUSY;
			goto abort;
		}
1210
		/* Only remove non-faulty devices if recovery
1211 1212 1213
		 * is not possible.
		 */
		if (!test_bit(Faulty, &rdev->flags) &&
1214
		    mddev->recovery_disabled != conf->recovery_disabled &&
1215 1216 1217 1218
		    mddev->degraded < conf->raid_disks) {
			err = -EBUSY;
			goto abort;
		}
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		p->rdev = NULL;
1220
		synchronize_rcu();
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		if (atomic_read(&rdev->nr_pending)) {
			/* lost the race, try later */
			err = -EBUSY;
			p->rdev = rdev;
1225
			goto abort;
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1226
		}
1227
		err = md_integrity_register(mddev);
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	}
abort:

	print_conf(conf);
	return err;
}


1236
static void end_sync_read(struct bio *bio, int error)
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1237
{
1238
	r1bio_t *r1_bio = bio->bi_private;
1239
	int i;
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1241 1242 1243 1244 1245
	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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1246 1247 1248 1249 1250
	/*
	 * 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
	 */
1251
	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
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		set_bit(R1BIO_Uptodate, &r1_bio->state);
1253 1254 1255

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

1258
static void end_sync_write(struct bio *bio, int error)
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1259 1260
{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1261
	r1bio_t *r1_bio = bio->bi_private;
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	mddev_t *mddev = r1_bio->mddev;
1263
	conf_t *conf = mddev->private;
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	int i;
	int mirror=0;

	for (i = 0; i < conf->raid_disks; i++)
		if (r1_bio->bios[i] == bio) {
			mirror = i;
			break;
		}
1272
	if (!uptodate) {
1273
		sector_t sync_blocks = 0;
1274 1275 1276 1277
		sector_t s = r1_bio->sector;
		long sectors_to_go = r1_bio->sectors;
		/* make sure these bits doesn't get cleared. */
		do {
1278
			bitmap_end_sync(mddev->bitmap, s,
1279 1280 1281 1282
					&sync_blocks, 1);
			s += sync_blocks;
			sectors_to_go -= sync_blocks;
		} while (sectors_to_go > 0);
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		md_error(mddev, conf->mirrors[mirror].rdev);
1284
	}
1285

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	update_head_pos(mirror, r1_bio);

	if (atomic_dec_and_test(&r1_bio->remaining)) {
1289
		sector_t s = r1_bio->sectors;
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1290
		put_buf(r1_bio);
1291
		md_done_sync(mddev, s, uptodate);
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1292 1293 1294
	}
}

1295
static int fix_sync_read_error(r1bio_t *r1_bio)
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{
1297 1298 1299 1300 1301 1302 1303
	/* 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.
1304 1305 1306
	 * We don't need to check is_badblock() again as we
	 * made sure that anything with a bad block in range
	 * will have bi_end_io clear.
1307 1308
	 */
	mddev_t *mddev = r1_bio->mddev;
1309
	conf_t *conf = mddev->private;
1310 1311 1312 1313 1314 1315 1316 1317 1318 1319
	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;
1320
		int start;
1321 1322 1323 1324 1325 1326 1327 1328 1329 1330

		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;
1331
				if (sync_page_io(rdev, sect, s<<9,
1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342
						 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);

1343
		if (!success) {
1344 1345 1346 1347 1348 1349 1350 1351 1352
			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);
1353
			put_buf(r1_bio);
1354
			return 0;
1355
		}
1356 1357 1358 1359 1360 1361 1362 1363 1364 1365

		start = d;
		/* write it back and re-read */
		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;
1366
			if (sync_page_io(rdev, sect, s<<9,
1367 1368 1369 1370 1371
					 bio->bi_io_vec[idx].bv_page,
					 WRITE, false) == 0) {
				r1_bio->bios[d]->bi_end_io = NULL;
				rdev_dec_pending(rdev, mddev);
				md_error(mddev, rdev);
1372
			}
1373 1374 1375 1376 1377 1378 1379 1380 1381
		}
		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;
1382
			if (sync_page_io(rdev, sect, s<<9,
1383 1384 1385
					 bio->bi_io_vec[idx].bv_page,
					 READ, false) == 0)
				md_error(mddev, rdev);
1386 1387
			else
				atomic_add(s, &rdev->corrected_errors);
1388
		}
1389 1390 1391 1392
		sectors -= s;
		sect += s;
		idx ++;
	}
1393
	set_bit(R1BIO_Uptodate, &r1_bio->state);
1394
	set_bit(BIO_UPTODATE, &bio->bi_flags);
1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411
	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;

1412
	for (primary = 0; primary < conf->raid_disks; primary++)
1413 1414 1415 1416 1417 1418 1419
		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;
1420 1421 1422 1423 1424 1425
	for (i = 0; i < conf->raid_disks; i++) {
		int j;
		int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
		struct bio *pbio = r1_bio->bios[primary];
		struct bio *sbio = r1_bio->bios[i];
		int size;
1426

1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438
		if (r1_bio->bios[i]->bi_end_io != end_sync_read)
			continue;

		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;
1439
			}
1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474
		} 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))) {
			/* No need to write to this device. */
			sbio->bi_end_io = NULL;
			rdev_dec_pending(conf->mirrors[i].rdev, mddev);
			continue;
		}
		/* fixup the bio for reuse */
		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);
1475
		}
1476
	}
1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492
	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];

	if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
		/* ouch - failed to read all of that. */
		if (!fix_sync_read_error(r1_bio))
			return;
1493 1494 1495 1496

	if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
		if (process_checks(r1_bio) < 0)
			return;
1497 1498 1499
	/*
	 * schedule writes
	 */
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	atomic_set(&r1_bio->remaining, 1);
	for (i = 0; i < disks ; i++) {
		wbio = r1_bio->bios[i];
1503 1504 1505 1506
		if (wbio->bi_end_io == NULL ||
		    (wbio->bi_end_io == end_sync_read &&
		     (i == r1_bio->read_disk ||
		      !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
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			continue;

1509 1510
		wbio->bi_rw = WRITE;
		wbio->bi_end_io = end_sync_write;
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1511 1512
		atomic_inc(&r1_bio->remaining);
		md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1513

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		generic_make_request(wbio);
	}

	if (atomic_dec_and_test(&r1_bio->remaining)) {
1518
		/* if we're here, all write(s) have completed, so clean up */
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1519 1520 1521 1522 1523 1524 1525 1526 1527 1528
		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.
1529
 *	3.	Performs writes following reads for array synchronising.
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1530 1531
 */

1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551
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....
			 */
1552 1553 1554
			sector_t first_bad;
			int bad_sectors;

1555 1556 1557
			rdev = conf->mirrors[d].rdev;
			if (rdev &&
			    test_bit(In_sync, &rdev->flags) &&
1558 1559
			    is_badblock(rdev, sect, s,
					&first_bad, &bad_sectors) == 0 &&
1560 1561
			    sync_page_io(rdev, sect, s<<9,
					 conf->tmppage, READ, false))
1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583
				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)) {
1584 1585
				if (sync_page_io(rdev, sect, s<<9,
						 conf->tmppage, WRITE, false)
1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599
				    == 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)) {
1600 1601
				if (sync_page_io(rdev, sect, s<<9,
						 conf->tmppage, READ, false)
1602 1603 1604 1605 1606 1607
				    == 0)
					/* Well, this device is dead */
					md_error(mddev, rdev);
				else {
					atomic_add(s, &rdev->corrected_errors);
					printk(KERN_INFO
1608
					       "md/raid1:%s: read error corrected "
1609 1610
					       "(%d sectors at %llu on %s)\n",
					       mdname(mddev), s,
1611 1612
					       (unsigned long long)(sect +
					           rdev->data_offset),
1613 1614 1615 1616 1617 1618 1619 1620 1621
					       bdevname(rdev->bdev, b));
				}
			}
		}
		sectors -= s;
		sect += s;
	}
}

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1622 1623 1624 1625 1626
static void raid1d(mddev_t *mddev)
{
	r1bio_t *r1_bio;
	struct bio *bio;
	unsigned long flags;
1627
	conf_t *conf = mddev->private;
L
Linus Torvalds 已提交
1628 1629
	struct list_head *head = &conf->retry_list;
	mdk_rdev_t *rdev;
1630
	struct blk_plug plug;
L
Linus Torvalds 已提交
1631 1632

	md_check_recovery(mddev);
1633 1634

	blk_start_plug(&plug);
L
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1635 1636
	for (;;) {
		char b[BDEVNAME_SIZE];
1637

1638 1639
		if (atomic_read(&mddev->plug_cnt) == 0)
			flush_pending_writes(conf);
1640

1641 1642 1643
		spin_lock_irqsave(&conf->device_lock, flags);
		if (list_empty(head)) {
			spin_unlock_irqrestore(&conf->device_lock, flags);
L
Linus Torvalds 已提交
1644
			break;
1645
		}
L
Linus Torvalds 已提交
1646 1647
		r1_bio = list_entry(head->prev, r1bio_t, retry_list);
		list_del(head->prev);
1648
		conf->nr_queued--;
L
Linus Torvalds 已提交
1649 1650 1651
		spin_unlock_irqrestore(&conf->device_lock, flags);

		mddev = r1_bio->mddev;
1652
		conf = mddev->private;
1653
		if (test_bit(R1BIO_IsSync, &r1_bio->state))
L
Linus Torvalds 已提交
1654
			sync_request_write(mddev, r1_bio);
1655
		else if (test_bit(R1BIO_ReadError, &r1_bio->state)) {
L
Linus Torvalds 已提交
1656
			int disk;
1657
			int max_sectors;
1658

1659
			clear_bit(R1BIO_ReadError, &r1_bio->state);
1660 1661 1662 1663 1664 1665 1666 1667
			/* 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
			 */
1668 1669 1670 1671 1672 1673
			if (mddev->ro == 0) {
				freeze_array(conf);
				fix_read_error(conf, r1_bio->read_disk,
					       r1_bio->sector,
					       r1_bio->sectors);
				unfreeze_array(conf);
1674 1675 1676
			} else
				md_error(mddev,
					 conf->mirrors[r1_bio->read_disk].rdev);
1677

L
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			bio = r1_bio->bios[r1_bio->read_disk];
1679 1680 1681 1682
			bdevname(bio->bi_bdev, b);
read_more:
			disk = read_balance(conf, r1_bio, &max_sectors);
			if (disk == -1) {
1683
				printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
L
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1684
				       " read error for block %llu\n",
1685
				       mdname(mddev), b,
L
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1686 1687 1688
				       (unsigned long long)r1_bio->sector);
				raid_end_bio_io(r1_bio);
			} else {
1689
				const unsigned long do_sync = r1_bio->master_bio->bi_rw & REQ_SYNC;
1690 1691 1692 1693 1694
				if (bio) {
					r1_bio->bios[r1_bio->read_disk] =
						mddev->ro ? IO_BLOCKED : NULL;
					bio_put(bio);
				}
L
Linus Torvalds 已提交
1695
				r1_bio->read_disk = disk;
1696 1697
				bio = bio_clone_mddev(r1_bio->master_bio,
						      GFP_NOIO, mddev);
1698 1699 1700
				md_trim_bio(bio,
					    r1_bio->sector - bio->bi_sector,
					    max_sectors);
L
Linus Torvalds 已提交
1701 1702
				r1_bio->bios[r1_bio->read_disk] = bio;
				rdev = conf->mirrors[disk].rdev;
1703 1704 1705 1706 1707 1708 1709
				printk_ratelimited(
					KERN_ERR
					"md/raid1:%s: redirecting sector %llu"
					" to other mirror: %s\n",
					mdname(mddev),
					(unsigned long long)r1_bio->sector,
					bdevname(rdev->bdev, b));
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				bio->bi_sector = r1_bio->sector + rdev->data_offset;
				bio->bi_bdev = rdev->bdev;
				bio->bi_end_io = raid1_end_read_request;
1713
				bio->bi_rw = READ | do_sync;
L
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1714
				bio->bi_private = r1_bio;
1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746
				if (max_sectors < r1_bio->sectors) {
					/* Drat - have to split this up more */
					struct bio *mbio = r1_bio->master_bio;
					int sectors_handled =
						r1_bio->sector + max_sectors
						- mbio->bi_sector;
					r1_bio->sectors = max_sectors;
					spin_lock_irq(&conf->device_lock);
					if (mbio->bi_phys_segments == 0)
						mbio->bi_phys_segments = 2;
					else
						mbio->bi_phys_segments++;
					spin_unlock_irq(&conf->device_lock);
					generic_make_request(bio);
					bio = NULL;

					r1_bio = mempool_alloc(conf->r1bio_pool,
							       GFP_NOIO);

					r1_bio->master_bio = mbio;
					r1_bio->sectors = (mbio->bi_size >> 9)
						- sectors_handled;
					r1_bio->state = 0;
					set_bit(R1BIO_ReadError,
						&r1_bio->state);
					r1_bio->mddev = mddev;
					r1_bio->sector = mbio->bi_sector
						+ sectors_handled;

					goto read_more;
				} else
					generic_make_request(bio);
L
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1747
			}
1748 1749 1750 1751 1752
		} else {
			/* just a partial read to be scheduled from separate
			 * context
			 */
			generic_make_request(r1_bio->bios[r1_bio->read_disk]);
L
Linus Torvalds 已提交
1753
		}
1754
		cond_resched();
1755 1756
		if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
			md_check_recovery(mddev);
L
Linus Torvalds 已提交
1757
	}
1758
	blk_finish_plug(&plug);
L
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1759 1760 1761 1762 1763 1764 1765 1766
}


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

	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1767
	BUG_ON(conf->r1buf_pool);
L
Linus Torvalds 已提交
1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785
	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.
 */

1786
static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
L
Linus Torvalds 已提交
1787
{
1788
	conf_t *conf = mddev->private;
L
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1789 1790 1791
	r1bio_t *r1_bio;
	struct bio *bio;
	sector_t max_sector, nr_sectors;
1792
	int disk = -1;
L
Linus Torvalds 已提交
1793
	int i;
1794 1795
	int wonly = -1;
	int write_targets = 0, read_targets = 0;
1796
	sector_t sync_blocks;
1797
	int still_degraded = 0;
1798 1799
	int good_sectors = RESYNC_SECTORS;
	int min_bad = 0; /* number of sectors that are bad in all devices */
L
Linus Torvalds 已提交
1800 1801 1802

	if (!conf->r1buf_pool)
		if (init_resync(conf))
1803
			return 0;
L
Linus Torvalds 已提交
1804

1805
	max_sector = mddev->dev_sectors;
L
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1806
	if (sector_nr >= max_sector) {
1807 1808 1809 1810 1811
		/* 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
		 */
1812 1813
		if (mddev->curr_resync < max_sector) /* aborted */
			bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1814
						&sync_blocks, 1);
1815
		else /* completed sync */
1816
			conf->fullsync = 0;
1817 1818

		bitmap_close_sync(mddev->bitmap);
L
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1819 1820 1821 1822
		close_sync(conf);
		return 0;
	}

1823 1824
	if (mddev->bitmap == NULL &&
	    mddev->recovery_cp == MaxSector &&
1825
	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1826 1827 1828 1829
	    conf->fullsync == 0) {
		*skipped = 1;
		return max_sector - sector_nr;
	}
1830 1831 1832
	/* before building a request, check if we can skip these blocks..
	 * This call the bitmap_start_sync doesn't actually record anything
	 */
1833
	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1834
	    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1835 1836 1837 1838
		/* We can skip this block, and probably several more */
		*skipped = 1;
		return sync_blocks;
	}
L
Linus Torvalds 已提交
1839
	/*
1840 1841 1842
	 * 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
1843
	 */
1844
	if (!go_faster && conf->nr_waiting)
L
Linus Torvalds 已提交
1845
		msleep_interruptible(1000);
1846

1847
	bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1848
	r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1849 1850 1851
	raise_barrier(conf);

	conf->next_resync = sector_nr;
L
Linus Torvalds 已提交
1852

1853
	rcu_read_lock();
L
Linus Torvalds 已提交
1854
	/*
1855 1856 1857 1858 1859 1860
	 * 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
1861 1862 1863 1864
	 */

	r1_bio->mddev = mddev;
	r1_bio->sector = sector_nr;
1865
	r1_bio->state = 0;
L
Linus Torvalds 已提交
1866 1867 1868
	set_bit(R1BIO_IsSync, &r1_bio->state);

	for (i=0; i < conf->raid_disks; i++) {
1869
		mdk_rdev_t *rdev;
L
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1870 1871 1872 1873
		bio = r1_bio->bios[i];

		/* take from bio_init */
		bio->bi_next = NULL;
1874
		bio->bi_flags &= ~(BIO_POOL_MASK-1);
L
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1875
		bio->bi_flags |= 1 << BIO_UPTODATE;
1876
		bio->bi_comp_cpu = -1;
1877
		bio->bi_rw = READ;
L
Linus Torvalds 已提交
1878 1879 1880 1881 1882 1883 1884
		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;

1885 1886
		rdev = rcu_dereference(conf->mirrors[i].rdev);
		if (rdev == NULL ||
1887
		    test_bit(Faulty, &rdev->flags)) {
1888
			still_degraded = 1;
1889
		} else if (!test_bit(In_sync, &rdev->flags)) {
L
Linus Torvalds 已提交
1890 1891 1892
			bio->bi_rw = WRITE;
			bio->bi_end_io = end_sync_write;
			write_targets ++;
1893 1894
		} else {
			/* may need to read from here */
1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919
			sector_t first_bad = MaxSector;
			int bad_sectors;

			if (is_badblock(rdev, sector_nr, good_sectors,
					&first_bad, &bad_sectors)) {
				if (first_bad > sector_nr)
					good_sectors = first_bad - sector_nr;
				else {
					bad_sectors -= (sector_nr - first_bad);
					if (min_bad == 0 ||
					    min_bad > bad_sectors)
						min_bad = bad_sectors;
				}
			}
			if (sector_nr < first_bad) {
				if (test_bit(WriteMostly, &rdev->flags)) {
					if (wonly < 0)
						wonly = i;
				} else {
					if (disk < 0)
						disk = i;
				}
				bio->bi_rw = READ;
				bio->bi_end_io = end_sync_read;
				read_targets++;
1920 1921
			}
		}
1922 1923 1924 1925 1926 1927
		if (bio->bi_end_io) {
			atomic_inc(&rdev->nr_pending);
			bio->bi_sector = sector_nr + rdev->data_offset;
			bio->bi_bdev = rdev->bdev;
			bio->bi_private = r1_bio;
		}
L
Linus Torvalds 已提交
1928
	}
1929 1930 1931 1932
	rcu_read_unlock();
	if (disk < 0)
		disk = wonly;
	r1_bio->read_disk = disk;
1933

1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
	if (read_targets == 0 && min_bad > 0) {
		/* These sectors are bad on all InSync devices, so we
		 * need to mark them bad on all write targets
		 */
		int ok = 1;
		for (i = 0 ; i < conf->raid_disks ; i++)
			if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
				mdk_rdev_t *rdev =
					rcu_dereference(conf->mirrors[i].rdev);
				ok = rdev_set_badblocks(rdev, sector_nr,
							min_bad, 0
					) && ok;
			}
		set_bit(MD_CHANGE_DEVS, &mddev->flags);
		*skipped = 1;
		put_buf(r1_bio);

		if (!ok) {
			/* Cannot record the badblocks, so need to
			 * abort the resync.
			 * If there are multiple read targets, could just
			 * fail the really bad ones ???
			 */
			conf->recovery_disabled = mddev->recovery_disabled;
			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
			return 0;
		} else
			return min_bad;

	}
	if (min_bad > 0 && min_bad < good_sectors) {
		/* only resync enough to reach the next bad->good
		 * transition */
		good_sectors = min_bad;
	}

1970 1971 1972 1973 1974
	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
1975 1976 1977
		/* There is nowhere to write, so all non-sync
		 * drives must be failed - so we are finished
		 */
1978 1979
		sector_t rv = max_sector - sector_nr;
		*skipped = 1;
L
Linus Torvalds 已提交
1980 1981 1982 1983
		put_buf(r1_bio);
		return rv;
	}

1984 1985
	if (max_sector > mddev->resync_max)
		max_sector = mddev->resync_max; /* Don't do IO beyond here */
1986 1987
	if (max_sector > sector_nr + good_sectors)
		max_sector = sector_nr + good_sectors;
L
Linus Torvalds 已提交
1988
	nr_sectors = 0;
1989
	sync_blocks = 0;
L
Linus Torvalds 已提交
1990 1991 1992 1993 1994 1995 1996
	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;
1997 1998
		if (sync_blocks == 0) {
			if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1999 2000 2001
					       &sync_blocks, still_degraded) &&
			    !conf->fullsync &&
			    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2002
				break;
2003
			BUG_ON(sync_blocks < (PAGE_SIZE>>9));
2004
			if ((len >> 9) > sync_blocks)
2005
				len = sync_blocks<<9;
2006
		}
2007

L
Linus Torvalds 已提交
2008 2009 2010
		for (i=0 ; i < conf->raid_disks; i++) {
			bio = r1_bio->bios[i];
			if (bio->bi_end_io) {
2011
				page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
L
Linus Torvalds 已提交
2012 2013
				if (bio_add_page(bio, page, len, 0) == 0) {
					/* stop here */
2014
					bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
L
Linus Torvalds 已提交
2015 2016 2017
					while (i > 0) {
						i--;
						bio = r1_bio->bios[i];
2018 2019
						if (bio->bi_end_io==NULL)
							continue;
L
Linus Torvalds 已提交
2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030
						/* 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;
2031
		sync_blocks -= (len>>9);
L
Linus Torvalds 已提交
2032 2033 2034 2035
	} while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
 bio_full:
	r1_bio->sectors = nr_sectors;

2036 2037 2038 2039 2040 2041 2042 2043
	/* 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) {
2044
				md_sync_acct(bio->bi_bdev, nr_sectors);
2045 2046 2047 2048 2049 2050
				generic_make_request(bio);
			}
		}
	} else {
		atomic_set(&r1_bio->remaining, 1);
		bio = r1_bio->bios[r1_bio->read_disk];
2051
		md_sync_acct(bio->bi_bdev, nr_sectors);
2052
		generic_make_request(bio);
L
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2053

2054
	}
L
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2055 2056 2057
	return nr_sectors;
}

2058 2059 2060 2061 2062 2063 2064 2065
static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
{
	if (sectors)
		return sectors;

	return mddev->dev_sectors;
}

2066
static conf_t *setup_conf(mddev_t *mddev)
L
Linus Torvalds 已提交
2067 2068
{
	conf_t *conf;
2069
	int i;
L
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2070 2071
	mirror_info_t *disk;
	mdk_rdev_t *rdev;
2072
	int err = -ENOMEM;
L
Linus Torvalds 已提交
2073

2074
	conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
L
Linus Torvalds 已提交
2075
	if (!conf)
2076
		goto abort;
L
Linus Torvalds 已提交
2077

2078
	conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
L
Linus Torvalds 已提交
2079 2080
				 GFP_KERNEL);
	if (!conf->mirrors)
2081
		goto abort;
L
Linus Torvalds 已提交
2082

2083 2084
	conf->tmppage = alloc_page(GFP_KERNEL);
	if (!conf->tmppage)
2085
		goto abort;
2086

2087
	conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
L
Linus Torvalds 已提交
2088
	if (!conf->poolinfo)
2089
		goto abort;
L
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2090 2091 2092 2093 2094
	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)
2095 2096
		goto abort;

2097
	conf->poolinfo->mddev = mddev;
L
Linus Torvalds 已提交
2098

2099
	spin_lock_init(&conf->device_lock);
2100
	list_for_each_entry(rdev, &mddev->disks, same_set) {
2101
		int disk_idx = rdev->raid_disk;
L
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2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115
		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);
2116
	init_waitqueue_head(&conf->wait_barrier);
L
Linus Torvalds 已提交
2117

2118 2119
	bio_list_init(&conf->pending_bio_list);

2120
	conf->last_used = -1;
L
Linus Torvalds 已提交
2121 2122 2123 2124
	for (i = 0; i < conf->raid_disks; i++) {

		disk = conf->mirrors + i;

2125 2126
		if (!disk->rdev ||
		    !test_bit(In_sync, &disk->rdev->flags)) {
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2127
			disk->head_position = 0;
2128 2129
			if (disk->rdev)
				conf->fullsync = 1;
2130 2131 2132 2133 2134 2135
		} else if (conf->last_used < 0)
			/*
			 * The first working device is used as a
			 * starting point to read balancing.
			 */
			conf->last_used = i;
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2136
	}
2137 2138 2139

	err = -EIO;
	if (conf->last_used < 0) {
2140
		printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
2141 2142 2143 2144 2145 2146 2147
		       mdname(mddev));
		goto abort;
	}
	err = -ENOMEM;
	conf->thread = md_register_thread(raid1d, mddev, NULL);
	if (!conf->thread) {
		printk(KERN_ERR
2148
		       "md/raid1:%s: couldn't allocate thread\n",
2149 2150
		       mdname(mddev));
		goto abort;
2151
	}
L
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2152

2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173
	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) {
2174
		printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2175 2176 2177 2178
		       mdname(mddev), mddev->level);
		return -EIO;
	}
	if (mddev->reshape_position != MaxSector) {
2179
		printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2180 2181 2182
		       mdname(mddev));
		return -EIO;
	}
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2183
	/*
2184 2185 2186
	 * copy the already verified devices into our private RAID1
	 * bookkeeping area. [whatever we allocate in run(),
	 * should be freed in stop()]
L
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2187
	 */
2188 2189 2190 2191
	if (mddev->private == NULL)
		conf = setup_conf(mddev);
	else
		conf = mddev->private;
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2192

2193 2194
	if (IS_ERR(conf))
		return PTR_ERR(conf);
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2195

2196
	list_for_each_entry(rdev, &mddev->disks, same_set) {
2197 2198
		if (!mddev->gendisk)
			continue;
2199 2200 2201
		disk_stack_limits(mddev->gendisk, rdev->bdev,
				  rdev->data_offset << 9);
		/* as we don't honour merge_bvec_fn, we must never risk
2202 2203
		 * violating it, so limit ->max_segments to 1 lying within
		 * a single page, as a one page request is never in violation.
2204
		 */
2205 2206 2207 2208 2209
		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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2210
	}
2211

2212 2213 2214 2215 2216 2217 2218 2219 2220 2221
	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;

2222
	if (mddev->recovery_cp != MaxSector)
2223
		printk(KERN_NOTICE "md/raid1:%s: not clean"
2224 2225
		       " -- starting background reconstruction\n",
		       mdname(mddev));
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2226
	printk(KERN_INFO 
2227
		"md/raid1:%s: active with %d out of %d mirrors\n",
L
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2228 2229
		mdname(mddev), mddev->raid_disks - mddev->degraded, 
		mddev->raid_disks);
2230

L
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2231 2232 2233
	/*
	 * Ok, everything is just fine now
	 */
2234 2235 2236 2237
	mddev->thread = conf->thread;
	conf->thread = NULL;
	mddev->private = conf;

2238
	md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
L
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2239

2240 2241 2242 2243
	if (mddev->queue) {
		mddev->queue->backing_dev_info.congested_fn = raid1_congested;
		mddev->queue->backing_dev_info.congested_data = mddev;
	}
2244
	return md_integrity_register(mddev);
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2245 2246 2247 2248
}

static int stop(mddev_t *mddev)
{
2249
	conf_t *conf = mddev->private;
2250 2251 2252
	struct bitmap *bitmap = mddev->bitmap;

	/* wait for behind writes to complete */
2253
	if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2254 2255
		printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
		       mdname(mddev));
2256
		/* need to kick something here to make sure I/O goes? */
2257 2258
		wait_event(bitmap->behind_wait,
			   atomic_read(&bitmap->behind_writes) == 0);
2259
	}
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2260

2261 2262 2263
	raise_barrier(conf);
	lower_barrier(conf);

L
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2264 2265 2266 2267
	md_unregister_thread(mddev->thread);
	mddev->thread = NULL;
	if (conf->r1bio_pool)
		mempool_destroy(conf->r1bio_pool);
2268 2269
	kfree(conf->mirrors);
	kfree(conf->poolinfo);
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2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283
	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.
	 */
2284
	md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
2285 2286
	if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
		return -EINVAL;
2287
	set_capacity(mddev->gendisk, mddev->array_sectors);
2288
	revalidate_disk(mddev->gendisk);
2289
	if (sectors > mddev->dev_sectors &&
2290
	    mddev->recovery_cp > mddev->dev_sectors) {
2291
		mddev->recovery_cp = mddev->dev_sectors;
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2292 2293
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
	}
2294
	mddev->dev_sectors = sectors;
2295
	mddev->resync_max_sectors = sectors;
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2296 2297 2298
	return 0;
}

2299
static int raid1_reshape(mddev_t *mddev)
L
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2300 2301 2302 2303 2304 2305 2306 2307
{
	/* 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.
2308 2309 2310
	 *
	 * At the same time, we "pack" the devices so that all the missing
	 * devices have the higher raid_disk numbers.
L
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2311 2312 2313 2314
	 */
	mempool_t *newpool, *oldpool;
	struct pool_info *newpoolinfo;
	mirror_info_t *newmirrors;
2315
	conf_t *conf = mddev->private;
2316
	int cnt, raid_disks;
2317
	unsigned long flags;
2318
	int d, d2, err;
L
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2319

2320
	/* Cannot change chunk_size, layout, or level */
2321
	if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2322 2323
	    mddev->layout != mddev->new_layout ||
	    mddev->level != mddev->new_level) {
2324
		mddev->new_chunk_sectors = mddev->chunk_sectors;
2325 2326 2327 2328 2329
		mddev->new_layout = mddev->layout;
		mddev->new_level = mddev->level;
		return -EINVAL;
	}

2330 2331 2332
	err = md_allow_write(mddev);
	if (err)
		return err;
2333

2334 2335
	raid_disks = mddev->raid_disks + mddev->delta_disks;

2336 2337 2338 2339 2340 2341
	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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2342
			return -EBUSY;
2343
	}
L
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2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356

	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;
	}
2357
	newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
L
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2358 2359 2360 2361 2362 2363
	if (!newmirrors) {
		kfree(newpoolinfo);
		mempool_destroy(newpool);
		return -ENOMEM;
	}

2364
	raise_barrier(conf);
L
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2365 2366 2367 2368

	/* ok, everything is stopped */
	oldpool = conf->r1bio_pool;
	conf->r1bio_pool = newpool;
2369

2370 2371 2372
	for (d = d2 = 0; d < conf->raid_disks; d++) {
		mdk_rdev_t *rdev = conf->mirrors[d].rdev;
		if (rdev && rdev->raid_disk != d2) {
2373
			sysfs_unlink_rdev(mddev, rdev);
2374
			rdev->raid_disk = d2;
2375 2376
			sysfs_unlink_rdev(mddev, rdev);
			if (sysfs_link_rdev(mddev, rdev))
2377
				printk(KERN_WARNING
2378 2379
				       "md/raid1:%s: cannot register rd%d\n",
				       mdname(mddev), rdev->raid_disk);
2380
		}
2381 2382 2383
		if (rdev)
			newmirrors[d2++].rdev = rdev;
	}
L
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2384 2385 2386 2387 2388
	kfree(conf->mirrors);
	conf->mirrors = newmirrors;
	kfree(conf->poolinfo);
	conf->poolinfo = newpoolinfo;

2389
	spin_lock_irqsave(&conf->device_lock, flags);
L
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2390
	mddev->degraded += (raid_disks - conf->raid_disks);
2391
	spin_unlock_irqrestore(&conf->device_lock, flags);
L
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2392
	conf->raid_disks = mddev->raid_disks = raid_disks;
2393
	mddev->delta_disks = 0;
L
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2394

2395
	conf->last_used = 0; /* just make sure it is in-range */
2396
	lower_barrier(conf);
L
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2397 2398 2399 2400 2401 2402 2403 2404

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

	mempool_destroy(oldpool);
	return 0;
}

2405
static void raid1_quiesce(mddev_t *mddev, int state)
2406
{
2407
	conf_t *conf = mddev->private;
2408 2409

	switch(state) {
2410 2411 2412
	case 2: /* wake for suspend */
		wake_up(&conf->wait_barrier);
		break;
2413
	case 1:
2414
		raise_barrier(conf);
2415
		break;
2416
	case 0:
2417
		lower_barrier(conf);
2418 2419 2420 2421
		break;
	}
}

2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438
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);
}
L
Linus Torvalds 已提交
2439

2440
static struct mdk_personality raid1_personality =
L
Linus Torvalds 已提交
2441 2442
{
	.name		= "raid1",
2443
	.level		= 1,
L
Linus Torvalds 已提交
2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454
	.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,
2455
	.size		= raid1_size,
2456
	.check_reshape	= raid1_reshape,
2457
	.quiesce	= raid1_quiesce,
2458
	.takeover	= raid1_takeover,
L
Linus Torvalds 已提交
2459 2460 2461 2462
};

static int __init raid_init(void)
{
2463
	return register_md_personality(&raid1_personality);
L
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2464 2465 2466 2467
}

static void raid_exit(void)
{
2468
	unregister_md_personality(&raid1_personality);
L
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2469 2470 2471 2472 2473
}

module_init(raid_init);
module_exit(raid_exit);
MODULE_LICENSE("GPL");
2474
MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
L
Linus Torvalds 已提交
2475
MODULE_ALIAS("md-personality-3"); /* RAID1 */
2476
MODULE_ALIAS("md-raid1");
2477
MODULE_ALIAS("md-level-1");
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