Revision 475049809977bf3975d78f2d2fd992e19ce2d59e authored by Roel Kluin on 10 March 2009, 19:55:45 UTC, committed by Linus Torvalds on 10 March 2009, 22:55:10 UTC
get_nid_for_pfn() returns int Presumably the (nid < 0) case has never happened. We do know that it is happening on one system while creating a symlink for a memory section so it should also happen on the same system if unregister_mem_sect_under_nodes() were called to remove the same symlink. The test was actually added in response to a problem with an earlier version reported by Yasunori Goto where one or more of the leading pages of a memory section on the 2nd node of one of his systems was uninitialized because I believe they coincided with a memory hole. That earlier version did not ignore uninitialized pages and determined the nid by considering only the 1st page of each memory section. This caused the symlink to the 1st memory section on the 2nd node to be incorrectly created in /sys/devices/system/node/node0 instead of /sys/devices/system/node/node1. The problem was fixed by adding the test to skip over uninitialized pages. I suspect we have not seen any reports of the non-removal of a symlink due to the incorrect declaration of the nid variable in unregister_mem_sect_under_nodes() because - systems where a memory section could have an uninitialized range of leading pages are probably rare. - memory remove is probably not done very frequently on the systems that are capable of demonstrating the problem. - lingering symlink(s) that should have been removed may have simply gone unnoticed. [garyhade@us.ibm.com: wrote changelog] Signed-off-by: Roel Kluin <roel.kluin@gmail.com> Cc: Gary Hade <garyhade@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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linear.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/raid/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 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 &&
mddev->queue->max_sectors > (PAGE_SIZE>>9))
blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
disk->num_sectors = rdev->size * 2;
conf->array_sectors += rdev->size * 2;
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;
mddev->array_sectors = conf->array_sectors;
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++;
mddev->array_sectors = newconf->array_sectors;
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,
};
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");
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