418 lines
10 KiB
C
418 lines
10 KiB
C
/*
|
|
linear.c : Multiple Devices driver for Linux
|
|
Copyright (C) 1994-96 Marc ZYNGIER
|
|
<zyngier@ufr-info-p7.ibp.fr> or
|
|
<maz@gloups.fdn.fr>
|
|
|
|
Linear mode management functions.
|
|
|
|
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 <linux/blkdev.h>
|
|
#include <linux/raid/md_u.h>
|
|
#include <linux/seq_file.h>
|
|
#include "md.h"
|
|
#include "linear.h"
|
|
|
|
/*
|
|
* find which device holds a particular offset
|
|
*/
|
|
static inline dev_info_t *which_dev(mddev_t *mddev, sector_t sector)
|
|
{
|
|
dev_info_t *hash;
|
|
linear_conf_t *conf = mddev_to_conf(mddev);
|
|
sector_t idx = sector >> conf->sector_shift;
|
|
|
|
/*
|
|
* sector_div(a,b) returns the remainer and sets a to a/b
|
|
*/
|
|
(void)sector_div(idx, conf->spacing);
|
|
hash = conf->hash_table[idx];
|
|
|
|
while (sector >= hash->num_sectors + hash->start_sector)
|
|
hash++;
|
|
return hash;
|
|
}
|
|
|
|
/**
|
|
* linear_mergeable_bvec -- tell bio layer if two requests can be merged
|
|
* @q: request queue
|
|
* @bvm: properties of new bio
|
|
* @biovec: the request that could be merged to it.
|
|
*
|
|
* Return amount of bytes we can take at this offset
|
|
*/
|
|
static int linear_mergeable_bvec(struct request_queue *q,
|
|
struct bvec_merge_data *bvm,
|
|
struct bio_vec *biovec)
|
|
{
|
|
mddev_t *mddev = q->queuedata;
|
|
dev_info_t *dev0;
|
|
unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9;
|
|
sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
|
|
|
|
dev0 = which_dev(mddev, sector);
|
|
maxsectors = dev0->num_sectors - (sector - dev0->start_sector);
|
|
|
|
if (maxsectors < bio_sectors)
|
|
maxsectors = 0;
|
|
else
|
|
maxsectors -= bio_sectors;
|
|
|
|
if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0)
|
|
return biovec->bv_len;
|
|
/* The bytes available at this offset could be really big,
|
|
* so we cap at 2^31 to avoid overflow */
|
|
if (maxsectors > (1 << (31-9)))
|
|
return 1<<31;
|
|
return maxsectors << 9;
|
|
}
|
|
|
|
static void linear_unplug(struct request_queue *q)
|
|
{
|
|
mddev_t *mddev = q->queuedata;
|
|
linear_conf_t *conf = mddev_to_conf(mddev);
|
|
int i;
|
|
|
|
for (i=0; i < mddev->raid_disks; i++) {
|
|
struct request_queue *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev);
|
|
blk_unplug(r_queue);
|
|
}
|
|
}
|
|
|
|
static int linear_congested(void *data, int bits)
|
|
{
|
|
mddev_t *mddev = data;
|
|
linear_conf_t *conf = mddev_to_conf(mddev);
|
|
int i, ret = 0;
|
|
|
|
for (i = 0; i < mddev->raid_disks && !ret ; i++) {
|
|
struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);
|
|
ret |= bdi_congested(&q->backing_dev_info, bits);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static sector_t linear_size(mddev_t *mddev, sector_t sectors, int raid_disks)
|
|
{
|
|
linear_conf_t *conf = mddev_to_conf(mddev);
|
|
|
|
WARN_ONCE(sectors || raid_disks,
|
|
"%s does not support generic reshape\n", __func__);
|
|
|
|
return conf->array_sectors;
|
|
}
|
|
|
|
static linear_conf_t *linear_conf(mddev_t *mddev, int raid_disks)
|
|
{
|
|
linear_conf_t *conf;
|
|
dev_info_t **table;
|
|
mdk_rdev_t *rdev;
|
|
int i, nb_zone, cnt;
|
|
sector_t min_sectors;
|
|
sector_t curr_sector;
|
|
|
|
conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(dev_info_t),
|
|
GFP_KERNEL);
|
|
if (!conf)
|
|
return NULL;
|
|
|
|
cnt = 0;
|
|
conf->array_sectors = 0;
|
|
|
|
list_for_each_entry(rdev, &mddev->disks, same_set) {
|
|
int j = rdev->raid_disk;
|
|
dev_info_t *disk = conf->disks + j;
|
|
|
|
if (j < 0 || j >= raid_disks || disk->rdev) {
|
|
printk("linear: disk numbering problem. Aborting!\n");
|
|
goto out;
|
|
}
|
|
|
|
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 &&
|
|
queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
|
|
blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
|
|
|
|
disk->num_sectors = rdev->sectors;
|
|
conf->array_sectors += rdev->sectors;
|
|
|
|
cnt++;
|
|
}
|
|
if (cnt != raid_disks) {
|
|
printk("linear: not enough drives present. Aborting!\n");
|
|
goto out;
|
|
}
|
|
|
|
min_sectors = conf->array_sectors;
|
|
sector_div(min_sectors, PAGE_SIZE/sizeof(struct dev_info *));
|
|
if (min_sectors == 0)
|
|
min_sectors = 1;
|
|
|
|
/* min_sectors is the minimum spacing that will fit the hash
|
|
* table in one PAGE. This may be much smaller than needed.
|
|
* We find the smallest non-terminal set of consecutive devices
|
|
* that is larger than min_sectors and use the size of that as
|
|
* the actual spacing
|
|
*/
|
|
conf->spacing = conf->array_sectors;
|
|
for (i=0; i < cnt-1 ; i++) {
|
|
sector_t tmp = 0;
|
|
int j;
|
|
for (j = i; j < cnt - 1 && tmp < min_sectors; j++)
|
|
tmp += conf->disks[j].num_sectors;
|
|
if (tmp >= min_sectors && tmp < conf->spacing)
|
|
conf->spacing = tmp;
|
|
}
|
|
|
|
/* spacing may be too large for sector_div to work with,
|
|
* so we might need to pre-shift
|
|
*/
|
|
conf->sector_shift = 0;
|
|
if (sizeof(sector_t) > sizeof(u32)) {
|
|
sector_t space = conf->spacing;
|
|
while (space > (sector_t)(~(u32)0)) {
|
|
space >>= 1;
|
|
conf->sector_shift++;
|
|
}
|
|
}
|
|
/*
|
|
* This code was restructured to work around a gcc-2.95.3 internal
|
|
* compiler error. Alter it with care.
|
|
*/
|
|
{
|
|
sector_t sz;
|
|
unsigned round;
|
|
unsigned long base;
|
|
|
|
sz = conf->array_sectors >> conf->sector_shift;
|
|
sz += 1; /* force round-up */
|
|
base = conf->spacing >> conf->sector_shift;
|
|
round = sector_div(sz, base);
|
|
nb_zone = sz + (round ? 1 : 0);
|
|
}
|
|
BUG_ON(nb_zone > PAGE_SIZE / sizeof(struct dev_info *));
|
|
|
|
conf->hash_table = kmalloc (sizeof (struct dev_info *) * nb_zone,
|
|
GFP_KERNEL);
|
|
if (!conf->hash_table)
|
|
goto out;
|
|
|
|
/*
|
|
* Here we generate the linear hash table
|
|
* First calculate the device offsets.
|
|
*/
|
|
conf->disks[0].start_sector = 0;
|
|
for (i = 1; i < raid_disks; i++)
|
|
conf->disks[i].start_sector =
|
|
conf->disks[i-1].start_sector +
|
|
conf->disks[i-1].num_sectors;
|
|
|
|
table = conf->hash_table;
|
|
i = 0;
|
|
for (curr_sector = 0;
|
|
curr_sector < conf->array_sectors;
|
|
curr_sector += conf->spacing) {
|
|
|
|
while (i < raid_disks-1 &&
|
|
curr_sector >= conf->disks[i+1].start_sector)
|
|
i++;
|
|
|
|
*table ++ = conf->disks + i;
|
|
}
|
|
|
|
if (conf->sector_shift) {
|
|
conf->spacing >>= conf->sector_shift;
|
|
/* round spacing up so that when we divide by it,
|
|
* we err on the side of "too-low", which is safest.
|
|
*/
|
|
conf->spacing++;
|
|
}
|
|
|
|
BUG_ON(table - conf->hash_table > nb_zone);
|
|
|
|
return conf;
|
|
|
|
out:
|
|
kfree(conf);
|
|
return NULL;
|
|
}
|
|
|
|
static int linear_run (mddev_t *mddev)
|
|
{
|
|
linear_conf_t *conf;
|
|
|
|
mddev->queue->queue_lock = &mddev->queue->__queue_lock;
|
|
conf = linear_conf(mddev, mddev->raid_disks);
|
|
|
|
if (!conf)
|
|
return 1;
|
|
mddev->private = conf;
|
|
md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
|
|
|
|
blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
|
|
mddev->queue->unplug_fn = linear_unplug;
|
|
mddev->queue->backing_dev_info.congested_fn = linear_congested;
|
|
mddev->queue->backing_dev_info.congested_data = mddev;
|
|
return 0;
|
|
}
|
|
|
|
static int linear_add(mddev_t *mddev, mdk_rdev_t *rdev)
|
|
{
|
|
/* Adding a drive to a linear array allows the array to grow.
|
|
* It is permitted if the new drive has a matching superblock
|
|
* already on it, with raid_disk equal to raid_disks.
|
|
* It is achieved by creating a new linear_private_data structure
|
|
* and swapping it in in-place of the current one.
|
|
* The current one is never freed until the array is stopped.
|
|
* This avoids races.
|
|
*/
|
|
linear_conf_t *newconf;
|
|
|
|
if (rdev->saved_raid_disk != mddev->raid_disks)
|
|
return -EINVAL;
|
|
|
|
rdev->raid_disk = rdev->saved_raid_disk;
|
|
|
|
newconf = linear_conf(mddev,mddev->raid_disks+1);
|
|
|
|
if (!newconf)
|
|
return -ENOMEM;
|
|
|
|
newconf->prev = mddev_to_conf(mddev);
|
|
mddev->private = newconf;
|
|
mddev->raid_disks++;
|
|
md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
|
|
set_capacity(mddev->gendisk, mddev->array_sectors);
|
|
return 0;
|
|
}
|
|
|
|
static int linear_stop (mddev_t *mddev)
|
|
{
|
|
linear_conf_t *conf = mddev_to_conf(mddev);
|
|
|
|
blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
|
|
do {
|
|
linear_conf_t *t = conf->prev;
|
|
kfree(conf->hash_table);
|
|
kfree(conf);
|
|
conf = t;
|
|
} while (conf);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int linear_make_request (struct request_queue *q, struct bio *bio)
|
|
{
|
|
const int rw = bio_data_dir(bio);
|
|
mddev_t *mddev = q->queuedata;
|
|
dev_info_t *tmp_dev;
|
|
int cpu;
|
|
|
|
if (unlikely(bio_barrier(bio))) {
|
|
bio_endio(bio, -EOPNOTSUPP);
|
|
return 0;
|
|
}
|
|
|
|
cpu = part_stat_lock();
|
|
part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
|
|
part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
|
|
bio_sectors(bio));
|
|
part_stat_unlock();
|
|
|
|
tmp_dev = which_dev(mddev, bio->bi_sector);
|
|
|
|
if (unlikely(bio->bi_sector >= (tmp_dev->num_sectors +
|
|
tmp_dev->start_sector)
|
|
|| (bio->bi_sector <
|
|
tmp_dev->start_sector))) {
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
printk("linear_make_request: Sector %llu out of bounds on "
|
|
"dev %s: %llu sectors, offset %llu\n",
|
|
(unsigned long long)bio->bi_sector,
|
|
bdevname(tmp_dev->rdev->bdev, b),
|
|
(unsigned long long)tmp_dev->num_sectors,
|
|
(unsigned long long)tmp_dev->start_sector);
|
|
bio_io_error(bio);
|
|
return 0;
|
|
}
|
|
if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
|
|
tmp_dev->start_sector + tmp_dev->num_sectors)) {
|
|
/* This bio crosses a device boundary, so we have to
|
|
* split it.
|
|
*/
|
|
struct bio_pair *bp;
|
|
|
|
bp = bio_split(bio,
|
|
tmp_dev->start_sector + tmp_dev->num_sectors
|
|
- bio->bi_sector);
|
|
|
|
if (linear_make_request(q, &bp->bio1))
|
|
generic_make_request(&bp->bio1);
|
|
if (linear_make_request(q, &bp->bio2))
|
|
generic_make_request(&bp->bio2);
|
|
bio_pair_release(bp);
|
|
return 0;
|
|
}
|
|
|
|
bio->bi_bdev = tmp_dev->rdev->bdev;
|
|
bio->bi_sector = bio->bi_sector - tmp_dev->start_sector
|
|
+ tmp_dev->rdev->data_offset;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void linear_status (struct seq_file *seq, mddev_t *mddev)
|
|
{
|
|
|
|
seq_printf(seq, " %dk rounding", mddev->chunk_size/1024);
|
|
}
|
|
|
|
|
|
static struct mdk_personality linear_personality =
|
|
{
|
|
.name = "linear",
|
|
.level = LEVEL_LINEAR,
|
|
.owner = THIS_MODULE,
|
|
.make_request = linear_make_request,
|
|
.run = linear_run,
|
|
.stop = linear_stop,
|
|
.status = linear_status,
|
|
.hot_add_disk = linear_add,
|
|
.size = linear_size,
|
|
};
|
|
|
|
static int __init linear_init (void)
|
|
{
|
|
return register_md_personality (&linear_personality);
|
|
}
|
|
|
|
static void linear_exit (void)
|
|
{
|
|
unregister_md_personality (&linear_personality);
|
|
}
|
|
|
|
|
|
module_init(linear_init);
|
|
module_exit(linear_exit);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
|
|
MODULE_ALIAS("md-linear");
|
|
MODULE_ALIAS("md-level--1");
|