linux/drivers/md/raid1.c
Jesper Juhl 990a8baf56 [PATCH] md: remove unneeded NULL checks before kfree
This patch removes some unneeded checks of pointers being NULL before
calling kfree() on them.  kfree() handles NULL pointers just fine, checking
first is pointless.

Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-21 19:07:48 -07:00

1595 lines
39 KiB
C

/*
* 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 (!conf->fullsync) {
if (mddev->curr_resync < max_sector)
bitmap_end_sync(mddev->bitmap,
mddev->curr_resync,
&sync_blocks, 1);
bitmap_close_sync(mddev->bitmap);
}
if (mddev->curr_resync >= max_sector)
conf->fullsync = 0;
close_sync(conf);
return 0;
}
if (!conf->fullsync &&
!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks)) {
/* 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 (!conf->fullsync) {
if (sync_blocks == 0) {
if (!bitmap_start_sync(mddev->bitmap,
sector_nr, &sync_blocks))
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;
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 */