/*
* 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
*
* Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
* Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
*
* 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
*
* 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.
*/
#include "dm-bio-list.h"
#include <linux/raid/raid1.h>
#include <linux/raid/bitmap.h>
#define DEBUG 0
#if DEBUG
#define PRINTK(x...) printk(x)
#else
#define PRINTK(x...)
#endif
/*
* Number of guaranteed r1bios in case of extreme VM load:
*/
#define NR_RAID1_BIOS 256
static mdk_personality_t raid1_personality;
static void unplug_slaves(mddev_t *mddev);
static void * r1bio_pool_alloc(unsigned int __nocast gfp_flags, void *data)
{
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 */
r1_bio = kmalloc(size, gfp_flags);
if (r1_bio)
memset(r1_bio, 0, size);
else
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)
static void * r1buf_pool_alloc(unsigned int __nocast gfp_flags, void *data)
{
struct pool_info *pi = data;
struct page *page;
r1bio_t *r1_bio;
struct bio *bio;
int i, j;
r1_bio = r1bio_pool_alloc(gfp_flags, pi);
if (!r1_bio) {
unplug_slaves(pi->mddev);
return NULL;
}
/*
* Allocate bios : 1 for reading, n-1 for writing
*/
for (j = pi->raid_disks ; j-- ; ) {
bio = bio_alloc(gfp_flags, RESYNC_PAGES);
if (!bio)
goto out_free_bio;
r1_bio->bios[j] = bio;
}
/*
* Allocate RESYNC_PAGES data pages and attach them to
* the first bio;
*/
bio = r1_bio->bios[0];
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;
}
r1_bio->master_bio = NULL;
return r1_bio;
out_free_pages:
for ( ; i > 0 ; i--)
__free_page(bio->bi_io_vec[i-1].bv_page);
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;
int i;
r1bio_t *r1bio = __r1_bio;
struct bio *bio = r1bio->bios[0];
for (i = 0; i < RESYNC_PAGES; i++) {
__free_page(bio->bi_io_vec[i].bv_page);
bio->bi_io_vec[i].bv_page = NULL;
}
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;
if (*bio)
bio_put(*bio);
*bio = NULL;
}
}
static inline void free_r1bio(r1bio_t *r1_bio)
{
unsigned long flags;
conf_t *conf = mddev_to_conf(r1_bio->mddev);
/*
* Wake up any possible resync thread that waits for the device
* to go idle.
*/
spin_lock_irqsave(&conf->resync_lock, flags);
if (!--conf->nr_pending) {
wake_up(&conf->wait_idle);
wake_up(&conf->wait_resume);
}
spin_unlock_irqrestore(&conf->resync_lock, flags);
put_all_bios(conf, r1_bio);
mempool_free(r1_bio, conf->r1bio_pool);
}
static inline void put_buf(r1bio_t *r1_bio)
{
conf_t *conf = mddev_to_conf(r1_bio->mddev);
unsigned long flags;
mempool_free(r1_bio, conf->r1buf_pool);
spin_lock_irqsave(&conf->resync_lock, flags);
if (!conf->barrier)
BUG();
--conf->barrier;
wake_up(&conf->wait_resume);
wake_up(&conf->wait_idle);
if (!--conf->nr_pending) {
wake_up(&conf->wait_idle);
wake_up(&conf->wait_resume);
}
spin_unlock_irqrestore(&conf->resync_lock, flags);
}
static void reschedule_retry(r1bio_t *r1_bio)
{
unsigned long flags;
mddev_t *mddev = r1_bio->mddev;
conf_t *conf = mddev_to_conf(mddev);
spin_lock_irqsave(&conf->device_lock, flags);
list_add(&r1_bio->retry_list, &conf->retry_list);
spin_unlock_irqrestore(&conf->device_lock, flags);
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;
bio_endio(bio, bio->bi_size,
test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
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)
{
conf_t *conf = mddev_to_conf(r1_bio->mddev);
conf->mirrors[disk].head_position =
r1_bio->sector + (r1_bio->sectors);
}
static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
int mirror;
conf_t *conf = mddev_to_conf(r1_bio->mddev);
if (bio->bi_size)
return 1;
mirror = r1_bio->read_disk;
/*
* this branch is our 'one mirror IO has finished' event handler:
*/
if (!uptodate)
md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
else
/*
* Set R1BIO_Uptodate in our master bio, so that
* we will return a good error code for to the higher
* levels even if IO on some other mirrored buffer fails.
*
* The 'master' represents the composite IO operation to
* user-side. So if something waits for IO, then it will
* wait for the 'master' bio.
*/
set_bit(R1BIO_Uptodate, &r1_bio->state);
update_head_pos(mirror, r1_bio);
/*
* we have only one bio on the read side
*/
if (uptodate)
raid_end_bio_io(r1_bio);
else {
/*
* oops, read error:
*/
char b[BDEVNAME_SIZE];
if (printk_ratelimit())
printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
reschedule_retry(r1_bio);
}
rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
return 0;
}
static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
int mirror;
conf_t *conf = mddev_to_conf(r1_bio->mddev);
if (bio->bi_size)
return 1;
for (mirror = 0; mirror < conf->raid_disks; mirror++)
if (r1_bio->bios[mirror] == bio)
break;
/*
* this branch is our 'one mirror IO has finished' event handler:
*/
if (!uptodate) {
md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
/* an I/O failed, we can't clear the bitmap */
set_bit(R1BIO_Degraded, &r1_bio->state);
} else
/*
* Set R1BIO_Uptodate in our master bio, so that
* we will return a good error code for to the higher
* levels even if IO on some other mirrored buffer fails.
*
* The 'master' represents the composite IO operation to
* user-side. So if something waits for IO, then it will
* wait for the 'master' bio.
*/
set_bit(R1BIO_Uptodate, &r1_bio->state);
update_head_pos(mirror, r1_bio);
/*
*
* Let's see if all mirrored write operations have finished
* already.
*/
if (atomic_dec_and_test(&r1_bio->remaining)) {
/* 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));
md_write_end(r1_bio->mddev);
raid_end_bio_io(r1_bio);
}
rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
return 0;
}
/*
* This routine returns the disk from which the requested read should
* be done. There is a per-array 'next expected sequential IO' sector
* number - if this matches on the next IO then we use the last disk.
* There is also a per-disk 'last know head position' sector that is
* maintained from IRQ contexts, both the normal and the resync IO
* completion handlers update this position correctly. If there is no
* perfect sequential match then we pick the disk whose head is closest.
*
* If there are 2 mirrors in the same 2 devices, performance degrades
* because position is mirror, not device based.
*
* The rdev for the device selected will have nr_pending incremented.
*/
static int read_balance(conf_t *conf, r1bio_t *r1_bio)
{
const unsigned long this_sector = r1_bio->sector;
int new_disk = conf->last_used, disk = new_disk;
const int sectors = r1_bio->sectors;
sector_t new_distance, current_distance;
mdk_rdev_t *new_rdev, *rdev;
rcu_read_lock();
/*
* Check if it if we can balance. We can balance on the whole
* device if no resync is going on, or below the resync window.
* We take the first readable disk when above the resync window.
*/
retry:
if (conf->mddev->recovery_cp < MaxSector &&
(this_sector + sectors >= conf->next_resync)) {
/* Choose the first operation device, for consistancy */
new_disk = 0;
while ((new_rdev=conf->mirrors[new_disk].rdev) == NULL ||
!new_rdev->in_sync) {
new_disk++;
if (new_disk == conf->raid_disks) {
new_disk = -1;
break;
}
}
goto rb_out;
}
/* make sure the disk is operational */
while ((new_rdev=conf->mirrors[new_disk].rdev) == NULL ||
!new_rdev->in_sync) {
if (new_disk <= 0)
new_disk = conf->raid_disks;
new_disk--;
if (new_disk == disk) {
new_disk = -1;
goto rb_out;
}
}
disk = new_disk;
/* now disk == new_disk == starting point for search */
/*
* Don't change to another disk for sequential reads:
*/
if (conf->next_seq_sect == this_sector)
goto rb_out;
if (this_sector == conf->mirrors[new_disk].head_position)
goto rb_out;
current_distance = abs(this_sector - conf->mirrors[disk].head_position);
/* Find the disk whose head is closest */
do {
if (disk <= 0)
disk = conf->raid_disks;
disk--;
if ((rdev=conf->mirrors[disk].rdev) == NULL ||
!rdev->in_sync)
continue;
if (!atomic_read(&rdev->nr_pending)) {
new_disk = disk;
new_rdev = rdev;
break;
}
new_distance = abs(this_sector - conf->mirrors[disk].head_position);
if (new_distance < current_distance) {
current_distance = new_distance;
new_disk = disk;
new_rdev = rdev;
}
} while (disk != conf->last_used);
rb_out:
if (new_disk >= 0) {
conf->next_seq_sect = this_sector + sectors;
conf->last_used = new_disk;
atomic_inc(&new_rdev->nr_pending);
if (!new_rdev->in_sync) {
/* cannot risk returning a device that failed
* before we inc'ed nr_pending
*/
atomic_dec(&new_rdev->nr_pending);
goto retry;
}
}
rcu_read_unlock();
return new_disk;
}
static void unplug_slaves(mddev_t *mddev)
{
conf_t *conf = mddev_to_conf(mddev);
int i;
rcu_read_lock();
for (i=0; i<mddev->raid_disks; i++) {
mdk_rdev_t *rdev = conf->mirrors[i].rdev;
if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) {
request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
if (r_queue->unplug_fn)
r_queue->unplug_fn(r_queue);
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
}
}
rcu_read_unlock();
}
static void raid1_unplug(request_queue_t *q)
{
mddev_t *mddev = q->queuedata;
unplug_slaves(mddev);
md_wakeup_thread(mddev->thread);
}
static int raid1_issue_flush(request_queue_t *q, struct gendisk *disk,
sector_t *error_sector)
{
mddev_t *mddev = q->queuedata;
conf_t *conf = mddev_to_conf(mddev);
int i, ret = 0;
rcu_read_lock();
for (i=0; i<mddev->raid_disks && ret == 0; i++) {
mdk_rdev_t *rdev = conf->mirrors[i].rdev;
if (rdev && !rdev->faulty) {
struct block_device *bdev = rdev->bdev;
request_queue_t *r_queue = bdev_get_queue(bdev);
if (!r_queue->issue_flush_fn)
ret = -EOPNOTSUPP;
else {
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
error_sector);
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
}
}
}
rcu_read_unlock();
return ret;
}
/*
* Throttle resync depth, so that we can both get proper overlapping of
* requests, but are still able to handle normal requests quickly.
*/
#define RESYNC_DEPTH 32
static void device_barrier(conf_t *conf, sector_t sect)
{
spin_lock_irq(&conf->resync_lock);
wait_event_lock_irq(conf->wait_idle, !waitqueue_active(&conf->wait_resume),
conf->resync_lock, raid1_unplug(conf->mddev->queue));
if (!conf->barrier++) {
wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
conf->resync_lock, raid1_unplug(conf->mddev->queue));
if (conf->nr_pending)
BUG();
}
wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH,
conf->resync_lock, raid1_unplug(conf->mddev->queue));
conf->next_resync = sect;
spin_unlock_irq(&conf->resync_lock);
}
static int make_request(request_queue_t *q, struct bio * bio)
{
mddev_t *mddev = q->queuedata;
conf_t *conf = mddev_to_conf(mddev);
mirror_info_t *mirror;
r1bio_t *r1_bio;
struct bio *read_bio;
int i, targets = 0, disks;
mdk_rdev_t *rdev;
struct bitmap *bitmap = mddev->bitmap;
unsigned long flags;
struct bio_list bl;
/*
* 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.
*/
md_write_start(mddev, bio); /* wait on superblock update early */
spin_lock_irq(&conf->resync_lock);
wait_event_lock_irq(conf->wait_resume, !conf->barrier, conf->resync_lock, );
conf->nr_pending++;
spin_unlock_irq(&conf->resync_lock);
if (bio_data_dir(bio)==WRITE) {
disk_stat_inc(mddev->gendisk, writes);
disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
} else {
disk_stat_inc(mddev->gendisk, reads);
disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
}
/*
* 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;
r1_bio->state = 0;
r1_bio->mddev = mddev;
r1_bio->sector = bio->bi_sector;
r1_bio->state = 0;
if (bio_data_dir(bio) == READ) {
/*
* read balancing logic:
*/
int rdisk = read_balance(conf, r1_bio);
if (rdisk < 0) {
/* couldn't find anywhere to read from */
raid_end_bio_io(r1_bio);
return 0;
}
mirror = conf->mirrors + rdisk;
r1_bio->read_disk = rdisk;
read_bio = bio_clone(bio, GFP_NOIO);
r1_bio->bios[rdisk] = read_bio;
read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
read_bio->bi_bdev = mirror->rdev->bdev;
read_bio->bi_end_io = raid1_end_read_request;
read_bio->bi_rw = READ;
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;
#if 0
{ static int first=1;
if (first) printk("First Write sector %llu disks %d\n",
(unsigned long long)r1_bio->sector, disks);
first = 0;
}
#endif
rcu_read_lock();
for (i = 0; i < disks; i++) {
if ((rdev=conf->mirrors[i].rdev) != NULL &&
!rdev->faulty) {
atomic_inc(&rdev->nr_pending);
if (rdev->faulty) {
atomic_dec(&rdev->nr_pending);
r1_bio->bios[i] = NULL;
} else
r1_bio->bios[i] = bio;
targets++;
} else
r1_bio->bios[i] = NULL;
}
rcu_read_unlock();
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);
}
atomic_set(&r1_bio->remaining, 0);
bio_list_init(&bl);
for (i = 0; i < disks; i++) {
struct bio *mbio;
if (!r1_bio->bios[i])
continue;
mbio = bio_clone(bio, GFP_NOIO);
r1_bio->bios[i] = mbio;
mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
mbio->bi_end_io = raid1_end_write_request;
mbio->bi_rw = WRITE;
mbio->bi_private = r1_bio;
atomic_inc(&r1_bio->remaining);
bio_list_add(&bl, mbio);
}
bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors);
spin_lock_irqsave(&conf->device_lock, flags);
bio_list_merge(&conf->pending_bio_list, &bl);
bio_list_init(&bl);
blk_plug_device(mddev->queue);
spin_unlock_irqrestore(&conf->device_lock, flags);
#if 0
while ((bio = bio_list_pop(&bl)) != NULL)
generic_make_request(bio);
#endif
return 0;
}
static void status(struct seq_file *seq, mddev_t *mddev)
{
conf_t *conf = mddev_to_conf(mddev);
int i;
seq_printf(seq, " [%d/%d] [", conf->raid_disks,
conf->working_disks);
for (i = 0; i < conf->raid_disks; i++)
seq_printf(seq, "%s",
conf->mirrors[i].rdev &&
conf->mirrors[i].rdev->in_sync ? "U" : "_");
seq_printf(seq, "]");
}
static void error(mddev_t *mddev, mdk_rdev_t *rdev)
{
char b[BDEVNAME_SIZE];
conf_t *conf = mddev_to_conf(mddev);
/*
* 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
*/
if (rdev->in_sync
&& conf->working_disks == 1)
/*
* Don't fail the drive, act as though we were just a
* normal single drive
*/
return;
if (rdev->in_sync) {
mddev->degraded++;
conf->working_disks--;
/*
* if recovery is running, make sure it aborts.
*/
set_bit(MD_RECOVERY_ERR, &mddev->recovery);
}
rdev->in_sync = 0;
rdev->faulty = 1;
mddev->sb_dirty = 1;
printk(KERN_ALERT "raid1: Disk failure on %s, disabling device. \n"
" Operation continuing on %d devices\n",
bdevname(rdev->bdev,b), conf->working_disks);
}
static void print_conf(conf_t *conf)
{
int i;
mirror_info_t *tmp;
printk("RAID1 conf printout:\n");
if (!conf) {
printk("(!conf)\n");
return;
}
printk(" --- wd:%d rd:%d\n", conf->working_disks,
conf->raid_disks);
for (i = 0; i < conf->raid_disks; i++) {
char b[BDEVNAME_SIZE];
tmp = conf->mirrors + i;
if (tmp->rdev)
printk(" disk %d, wo:%d, o:%d, dev:%s\n",
i, !tmp->rdev->in_sync, !tmp->rdev->faulty,
bdevname(tmp->rdev->bdev,b));
}
}
static void close_sync(conf_t *conf)
{
spin_lock_irq(&conf->resync_lock);
wait_event_lock_irq(conf->wait_resume, !conf->barrier,
conf->resync_lock, raid1_unplug(conf->mddev->queue));
spin_unlock_irq(&conf->resync_lock);
if (conf->barrier) BUG();
if (waitqueue_active(&conf->wait_idle)) BUG();
mempool_destroy(conf->r1buf_pool);
conf->r1buf_pool = NULL;
}
static int raid1_spare_active(mddev_t *mddev)
{
int i;
conf_t *conf = mddev->private;
mirror_info_t *tmp;
/*
* Find all failed disks within the RAID1 configuration
* and mark them readable
*/
for (i = 0; i < conf->raid_disks; i++) {
tmp = conf->mirrors + i;
if (tmp->rdev
&& !tmp->rdev->faulty
&& !tmp->rdev->in_sync) {
conf->working_disks++;
mddev->degraded--;
tmp->rdev->in_sync = 1;
}
}
print_conf(conf);
return 0;
}
static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
{
conf_t *conf = mddev->private;
int found = 0;
int mirror = 0;
mirror_info_t *p;
if (rdev->saved_raid_disk >= 0 &&
conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
mirror = rdev->saved_raid_disk;
for (mirror=0; mirror < mddev->raid_disks; mirror++)
if ( !(p=conf->mirrors+mirror)->rdev) {
blk_queue_stack_limits(mddev->queue,
rdev->bdev->bd_disk->queue);
/* as we don't honour merge_bvec_fn, we must never risk
* violating it, so limit ->max_sector to one PAGE, as
* a one page request is never in violation.
*/
if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
mddev->queue->max_sectors > (PAGE_SIZE>>9))
blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
p->head_position = 0;
rdev->raid_disk = mirror;
found = 1;
if (rdev->saved_raid_disk != mirror)
conf->fullsync = 1;
p->rdev = rdev;
break;
}
print_conf(conf);
return found;
}
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) {
if (rdev->in_sync ||
atomic_read(&rdev->nr_pending)) {
err = -EBUSY;
goto abort;
}
p->rdev = NULL;
synchronize_rcu();
if (atomic_read(&rdev->nr_pending)) {
/* lost the race, try later */
err = -EBUSY;
p->rdev = rdev;
}
}
abort:
print_conf(conf);
return err;
}
static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
conf_t *conf = mddev_to_conf(r1_bio->mddev);
if (bio->bi_size)
return 1;
if (r1_bio->bios[r1_bio->read_disk] != bio)
BUG();
update_head_pos(r1_bio->read_disk, r1_bio);
/*
* 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
*/
if (!uptodate) {
md_error(r1_bio->mddev,
conf->mirrors[r1_bio->read_disk].rdev);
set_bit(R1BIO_Degraded, &r1_bio->state);
} else
set_bit(R1BIO_Uptodate, &r1_bio->state);
rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
reschedule_retry(r1_bio);
return 0;
}
static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
mddev_t *mddev = r1_bio->mddev;
conf_t *conf = mddev_to_conf(mddev);
int i;
int mirror=0;
if (bio->bi_size)
return 1;
for (i = 0; i < conf->raid_disks; i++)
if (r1_bio->bios[i] == bio) {
mirror = i;
break;
}
if (!uptodate) {
md_error(mddev, conf->mirrors[mirror].rdev);
set_bit(R1BIO_Degraded, &r1_bio->state);
}
update_head_pos(mirror, r1_bio);
if (atomic_dec_and_test(&r1_bio->remaining)) {
md_done_sync(mddev, r1_bio->sectors, uptodate);
put_buf(r1_bio);
}
rdev_dec_pending(conf->mirrors[mirror].rdev, mddev);
return 0;
}
static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
{
conf_t *conf = mddev_to_conf(mddev);
int i;
int disks = conf->raid_disks;
struct bio *bio, *wbio;
bio = r1_bio->bios[r1_bio->read_disk];
/*
if (r1_bio->sector == 0) printk("First sync write startss\n");
*/
/*
* schedule writes
*/
if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
/*
* There is no point trying a read-for-reconstruct as
* reconstruct is about to be aborted
*/
char b[BDEVNAME_SIZE];
printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
" for block %llu\n",
bdevname(bio->bi_bdev,b),
(unsigned long long)r1_bio->sector);
md_done_sync(mddev, r1_bio->sectors, 0);
put_buf(r1_bio);
return;
}
atomic_set(&r1_bio->remaining, 1);
for (i = 0; i < disks ; i++) {
wbio = r1_bio->bios[i];
if (wbio->bi_end_io != end_sync_write)
continue;
atomic_inc(&conf->mirrors[i].rdev->nr_pending);
atomic_inc(&r1_bio->remaining);
md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
generic_make_request(wbio);
}
if (atomic_dec_and_test(&r1_bio->remaining)) {
/* if we're here, all write(s) have completed, so clean up */
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.
*/
static void raid1d(mddev_t *mddev)
{
r1bio_t *r1_bio;
struct bio *bio;
unsigned long flags;
conf_t *conf = mddev_to_conf(mddev);
struct list_head *head = &conf->retry_list;
int unplug=0;
mdk_rdev_t *rdev;
md_check_recovery(mddev);
for (;;) {
char b[BDEVNAME_SIZE];
spin_lock_irqsave(&conf->device_lock, flags);
if (conf->pending_bio_list.head) {
bio = bio_list_get(&conf->pending_bio_list);
blk_remove_plug(mddev->queue);
spin_unlock_irqrestore(&conf->device_lock, flags);
/* flush any pending bitmap writes to disk before proceeding w/ I/O */
if (bitmap_unplug(mddev->bitmap) != 0)
printk("%s: bitmap file write failed!\n", mdname(mddev));
while (bio) { /* submit pending writes */
struct bio *next = bio->bi_next;
bio->bi_next = NULL;
generic_make_request(bio);
bio = next;
}
unplug = 1;
continue;
}
if (list_empty(head))
break;
r1_bio = list_entry(head->prev, r1bio_t, retry_list);
list_del(head->prev);
spin_unlock_irqrestore(&conf->device_lock, flags);
mddev = r1_bio->mddev;
conf = mddev_to_conf(mddev);
if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
sync_request_write(mddev, r1_bio);
unplug = 1;
} else {
int disk;
bio = r1_bio->bios[r1_bio->read_disk];
if ((disk=read_balance(conf, r1_bio)) == -1) {
printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
" read error for block %llu\n",
bdevname(bio->bi_bdev,b),
(unsigned long long)r1_bio->sector);
raid_end_bio_io(r1_bio);
} else {
r1_bio->bios[r1_bio->read_disk] = NULL;
r1_bio->read_disk = disk;
bio_put(bio);
bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
r1_bio->bios[r1_bio->read_disk] = bio;
rdev = conf->mirrors[disk].rdev;
if (printk_ratelimit())
printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
" another mirror\n",
bdevname(rdev->bdev,b),
(unsigned long long)r1_bio->sector);
bio->bi_sector = r1_bio->sector + rdev->data_offset;
bio->bi_bdev = rdev->bdev;
bio->bi_end_io = raid1_end_read_request;
bio->bi_rw = READ;
bio->bi_private = r1_bio;
unplug = 1;
generic_make_request(bio);
}
}
}
spin_unlock_irqrestore(&conf->device_lock, flags);
if (unplug)
unplug_slaves(mddev);
}
static int init_resync(conf_t *conf)
{
int buffs;
buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
if (conf->r1buf_pool)
BUG();
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.
*/
static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
{
conf_t *conf = mddev_to_conf(mddev);
mirror_info_t *mirror;
r1bio_t *r1_bio;
struct bio *bio;
sector_t max_sector, nr_sectors;
int disk;
int i;
int write_targets = 0;
int sync_blocks;
if (!conf->r1buf_pool)
{
/*
printk("sync start - bitmap %p\n", mddev->bitmap);
*/
if (init_resync(conf))
return 0;
}
max_sector = mddev->size << 1;
if (sector_nr >= max_sector) {
/* 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
*/
if (mddev->curr_resync < max_sector) /* aborted */
bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
&sync_blocks, 1);
else /* completed sync */
conf->fullsync = 0;
bitmap_close_sync(mddev->bitmap);
close_sync(conf);
return 0;
}
if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, mddev->degraded) &&
!conf->fullsync) {
/* We can skip this block, and probably several more */
*skipped = 1;
return sync_blocks;
}
/*
* If there is non-resync activity waiting for us then
* put in a delay to throttle resync.
*/
if (!go_faster && waitqueue_active(&conf->wait_resume))
msleep_interruptible(1000);
device_barrier(conf, sector_nr + RESYNC_SECTORS);
/*
* If reconstructing, and >1 working disc,
* could dedicate one to rebuild and others to
* service read requests ..
*/
disk = conf->last_used;
/* make sure disk is operational */
while (conf->mirrors[disk].rdev == NULL ||
!conf->mirrors[disk].rdev->in_sync) {
if (disk <= 0)
disk = conf->raid_disks;
disk--;
if (disk == conf->last_used)
break;
}
conf->last_used = disk;
atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
mirror = conf->mirrors + disk;
r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
spin_lock_irq(&conf->resync_lock);
conf->nr_pending++;
spin_unlock_irq(&conf->resync_lock);
r1_bio->mddev = mddev;
r1_bio->sector = sector_nr;
r1_bio->state = 0;
set_bit(R1BIO_IsSync, &r1_bio->state);
r1_bio->read_disk = disk;
for (i=0; i < conf->raid_disks; i++) {
bio = r1_bio->bios[i];
/* take from bio_init */
bio->bi_next = NULL;
bio->bi_flags |= 1 << BIO_UPTODATE;
bio->bi_rw = 0;
bio->bi_vcnt = 0;
bio->bi_idx = 0;
bio->bi_phys_segments = 0;
bio->bi_hw_segments = 0;
bio->bi_size = 0;
bio->bi_end_io = NULL;
bio->bi_private = NULL;
if (i == disk) {
bio->bi_rw = READ;
bio->bi_end_io = end_sync_read;
} else if (conf->mirrors[i].rdev &&
!conf->mirrors[i].rdev->faulty &&
(!conf->mirrors[i].rdev->in_sync ||
sector_nr + RESYNC_SECTORS > mddev->recovery_cp)) {
bio->bi_rw = WRITE;
bio->bi_end_io = end_sync_write;
write_targets ++;
} else
continue;
bio->bi_sector = sector_nr + conf->mirrors[i].rdev->data_offset;
bio->bi_bdev = conf->mirrors[i].rdev->bdev;
bio->bi_private = r1_bio;
}
if (write_targets + 1 < conf->raid_disks)
/* array degraded, can't clear bitmap */
set_bit(R1BIO_Degraded, &r1_bio->state);
if (write_targets == 0) {
/* There is nowhere to write, so all non-sync
* drives must be failed - so we are finished
*/
sector_t rv = max_sector - sector_nr;
*skipped = 1;
put_buf(r1_bio);
rdev_dec_pending(conf->mirrors[disk].rdev, mddev);
return rv;
}
nr_sectors = 0;
sync_blocks = 0;
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;
if (sync_blocks == 0) {
if (!bitmap_start_sync(mddev->bitmap, sector_nr,
&sync_blocks, mddev->degraded) &&
!conf->fullsync)
break;
if (sync_blocks < (PAGE_SIZE>>9))
BUG();
if (len > (sync_blocks<<9))
len = sync_blocks<<9;
}
for (i=0 ; i < conf->raid_disks; i++) {
bio = r1_bio->bios[i];
if (bio->bi_end_io) {
page = r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page;
if (bio_add_page(bio, page, len, 0) == 0) {
/* stop here */
r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page = page;
while (i > 0) {
i--;
bio = r1_bio->bios[i];
if (bio->bi_end_io==NULL)
continue;
/* 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;
sync_blocks -= (len>>9);
} while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
bio_full:
bio = r1_bio->bios[disk];
r1_bio->sectors = nr_sectors;
md_sync_acct(mirror->rdev->bdev, nr_sectors);
generic_make_request(bio);
return nr_sectors;
}
static int run(mddev_t *mddev)
{
conf_t *conf;
int i, j, disk_idx;
mirror_info_t *disk;
mdk_rdev_t *rdev;
struct list_head *tmp;
if (mddev->level != 1) {
printk("raid1: %s: raid level not set to mirroring (%d)\n",
mdname(mddev), mddev->level);
goto out;
}
/*
* copy the already verified devices into our private RAID1
* bookkeeping area. [whatever we allocate in run(),
* should be freed in stop()]
*/
conf = kmalloc(sizeof(conf_t), GFP_KERNEL);
mddev->private = conf;
if (!conf)
goto out_no_mem;
memset(conf, 0, sizeof(*conf));
conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks,
GFP_KERNEL);
if (!conf->mirrors)
goto out_no_mem;
memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks);
conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
if (!conf->poolinfo)
goto out_no_mem;
conf->poolinfo->mddev = mddev;
conf->poolinfo->raid_disks = mddev->raid_disks;
conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
r1bio_pool_free,
conf->poolinfo);
if (!conf->r1bio_pool)
goto out_no_mem;
ITERATE_RDEV(mddev, rdev, tmp) {
disk_idx = rdev->raid_disk;
if (disk_idx >= mddev->raid_disks
|| disk_idx < 0)
continue;
disk = conf->mirrors + disk_idx;
disk->rdev = rdev;
blk_queue_stack_limits(mddev->queue,
rdev->bdev->bd_disk->queue);
/* as we don't honour merge_bvec_fn, we must never risk
* violating it, so limit ->max_sector to one PAGE, as
* a one page request is never in violation.
*/
if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
mddev->queue->max_sectors > (PAGE_SIZE>>9))
blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
disk->head_position = 0;
if (!rdev->faulty && rdev->in_sync)
conf->working_disks++;
}
conf->raid_disks = mddev->raid_disks;
conf->mddev = mddev;
spin_lock_init(&conf->device_lock);
INIT_LIST_HEAD(&conf->retry_list);
if (conf->working_disks == 1)
mddev->recovery_cp = MaxSector;
spin_lock_init(&conf->resync_lock);
init_waitqueue_head(&conf->wait_idle);
init_waitqueue_head(&conf->wait_resume);
bio_list_init(&conf->pending_bio_list);
bio_list_init(&conf->flushing_bio_list);
if (!conf->working_disks) {
printk(KERN_ERR "raid1: no operational mirrors for %s\n",
mdname(mddev));
goto out_free_conf;
}
mddev->degraded = 0;
for (i = 0; i < conf->raid_disks; i++) {
disk = conf->mirrors + i;
if (!disk->rdev) {
disk->head_position = 0;
mddev->degraded++;
}
}
/*
* find the first working one and use it as a starting point
* to read balancing.
*/
for (j = 0; j < conf->raid_disks &&
(!conf->mirrors[j].rdev ||
!conf->mirrors[j].rdev->in_sync) ; j++)
/* nothing */;
conf->last_used = j;
mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
if (!mddev->thread) {
printk(KERN_ERR
"raid1: couldn't allocate thread for %s\n",
mdname(mddev));
goto out_free_conf;
}
if (mddev->bitmap) mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
printk(KERN_INFO
"raid1: raid set %s active with %d out of %d mirrors\n",
mdname(mddev), mddev->raid_disks - mddev->degraded,
mddev->raid_disks);
/*
* Ok, everything is just fine now
*/
mddev->array_size = mddev->size;
mddev->queue->unplug_fn = raid1_unplug;
mddev->queue->issue_flush_fn = raid1_issue_flush;
return 0;
out_no_mem:
printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
mdname(mddev));
out_free_conf:
if (conf) {
if (conf->r1bio_pool)
mempool_destroy(conf->r1bio_pool);
kfree(conf->mirrors);
kfree(conf->poolinfo);
kfree(conf);
mddev->private = NULL;
}
out:
return -EIO;
}
static int stop(mddev_t *mddev)
{
conf_t *conf = mddev_to_conf(mddev);
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);
kfree(conf->mirrors);
kfree(conf->poolinfo);
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.
*/
mddev->array_size = sectors>>1;
set_capacity(mddev->gendisk, mddev->array_size << 1);
mddev->changed = 1;
if (mddev->array_size > mddev->size && mddev->recovery_cp == MaxSector) {
mddev->recovery_cp = mddev->size << 1;
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
}
mddev->size = mddev->array_size;
mddev->resync_max_sectors = sectors;
return 0;
}
static int raid1_reshape(mddev_t *mddev, int raid_disks)
{
/* 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.
*
* At the same time, we "pack" the devices so that all the missing
* devices have the higher raid_disk numbers.
*/
mempool_t *newpool, *oldpool;
struct pool_info *newpoolinfo;
mirror_info_t *newmirrors;
conf_t *conf = mddev_to_conf(mddev);
int cnt;
int d, d2;
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)
return -EBUSY;
}
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;
}
newmirrors = kmalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
if (!newmirrors) {
kfree(newpoolinfo);
mempool_destroy(newpool);
return -ENOMEM;
}
memset(newmirrors, 0, sizeof(struct mirror_info)*raid_disks);
spin_lock_irq(&conf->resync_lock);
conf->barrier++;
wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
conf->resync_lock, raid1_unplug(mddev->queue));
spin_unlock_irq(&conf->resync_lock);
/* ok, everything is stopped */
oldpool = conf->r1bio_pool;
conf->r1bio_pool = newpool;
for (d=d2=0; d < conf->raid_disks; d++)
if (conf->mirrors[d].rdev) {
conf->mirrors[d].rdev->raid_disk = d2;
newmirrors[d2++].rdev = conf->mirrors[d].rdev;
}
kfree(conf->mirrors);
conf->mirrors = newmirrors;
kfree(conf->poolinfo);
conf->poolinfo = newpoolinfo;
mddev->degraded += (raid_disks - conf->raid_disks);
conf->raid_disks = mddev->raid_disks = raid_disks;
conf->last_used = 0; /* just make sure it is in-range */
spin_lock_irq(&conf->resync_lock);
conf->barrier--;
spin_unlock_irq(&conf->resync_lock);
wake_up(&conf->wait_resume);
wake_up(&conf->wait_idle);
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
md_wakeup_thread(mddev->thread);
mempool_destroy(oldpool);
return 0;
}
static mdk_personality_t raid1_personality =
{
.name = "raid1",
.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,
.reshape = raid1_reshape,
};
static int __init raid_init(void)
{
return register_md_personality(RAID1, &raid1_personality);
}
static void raid_exit(void)
{
unregister_md_personality(RAID1);
}
module_init(raid_init);
module_exit(raid_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS("md-personality-3"); /* RAID1 */
