dd8ac336c1
This patch renames the "size" field of struct mdk_rdev_s to "sectors" and changes this field to store sectors instead of blocks. All users of this field, linear.c, raid0.c and md.c, are fixed up accordingly which gets rid of many multiplications and divisions. Signed-off-by: Andre Noll <maan@systemlinux.org> Signed-off-by: NeilBrown <neilb@suse.de>
532 lines
14 KiB
C
532 lines
14 KiB
C
/*
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raid0.c : Multiple Devices driver for Linux
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Copyright (C) 1994-96 Marc ZYNGIER
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<zyngier@ufr-info-p7.ibp.fr> or
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<maz@gloups.fdn.fr>
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Copyright (C) 1999, 2000 Ingo Molnar, Red Hat
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RAID-0 management functions.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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You should have received a copy of the GNU General Public License
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(for example /usr/src/linux/COPYING); if not, write to the Free
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Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/blkdev.h>
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#include <linux/seq_file.h>
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#include "md.h"
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#include "raid0.h"
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static void raid0_unplug(struct request_queue *q)
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{
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mddev_t *mddev = q->queuedata;
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raid0_conf_t *conf = mddev_to_conf(mddev);
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mdk_rdev_t **devlist = conf->strip_zone[0].dev;
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int i;
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for (i=0; i<mddev->raid_disks; i++) {
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struct request_queue *r_queue = bdev_get_queue(devlist[i]->bdev);
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blk_unplug(r_queue);
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}
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}
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static int raid0_congested(void *data, int bits)
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{
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mddev_t *mddev = data;
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raid0_conf_t *conf = mddev_to_conf(mddev);
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mdk_rdev_t **devlist = conf->strip_zone[0].dev;
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int i, ret = 0;
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for (i = 0; i < mddev->raid_disks && !ret ; i++) {
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struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
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ret |= bdi_congested(&q->backing_dev_info, bits);
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}
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return ret;
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}
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static int create_strip_zones (mddev_t *mddev)
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{
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int i, c, j;
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sector_t current_start, curr_zone_start;
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sector_t min_spacing;
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raid0_conf_t *conf = mddev_to_conf(mddev);
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mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev;
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struct strip_zone *zone;
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int cnt;
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char b[BDEVNAME_SIZE];
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/*
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* The number of 'same size groups'
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*/
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conf->nr_strip_zones = 0;
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list_for_each_entry(rdev1, &mddev->disks, same_set) {
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printk(KERN_INFO "raid0: looking at %s\n",
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bdevname(rdev1->bdev,b));
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c = 0;
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list_for_each_entry(rdev2, &mddev->disks, same_set) {
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printk(KERN_INFO "raid0: comparing %s(%llu)",
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bdevname(rdev1->bdev,b),
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(unsigned long long)rdev1->sectors);
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printk(KERN_INFO " with %s(%llu)\n",
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bdevname(rdev2->bdev,b),
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(unsigned long long)rdev2->sectors);
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if (rdev2 == rdev1) {
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printk(KERN_INFO "raid0: END\n");
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break;
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}
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if (rdev2->sectors == rdev1->sectors) {
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/*
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* Not unique, don't count it as a new
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* group
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*/
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printk(KERN_INFO "raid0: EQUAL\n");
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c = 1;
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break;
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}
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printk(KERN_INFO "raid0: NOT EQUAL\n");
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}
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if (!c) {
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printk(KERN_INFO "raid0: ==> UNIQUE\n");
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conf->nr_strip_zones++;
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printk(KERN_INFO "raid0: %d zones\n",
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conf->nr_strip_zones);
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}
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}
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printk(KERN_INFO "raid0: FINAL %d zones\n", conf->nr_strip_zones);
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conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
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conf->nr_strip_zones, GFP_KERNEL);
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if (!conf->strip_zone)
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return 1;
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conf->devlist = kzalloc(sizeof(mdk_rdev_t*)*
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conf->nr_strip_zones*mddev->raid_disks,
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GFP_KERNEL);
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if (!conf->devlist)
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return 1;
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/* The first zone must contain all devices, so here we check that
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* there is a proper alignment of slots to devices and find them all
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*/
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zone = &conf->strip_zone[0];
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cnt = 0;
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smallest = NULL;
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zone->dev = conf->devlist;
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list_for_each_entry(rdev1, &mddev->disks, same_set) {
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int j = rdev1->raid_disk;
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if (j < 0 || j >= mddev->raid_disks) {
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printk(KERN_ERR "raid0: bad disk number %d - "
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"aborting!\n", j);
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goto abort;
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}
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if (zone->dev[j]) {
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printk(KERN_ERR "raid0: multiple devices for %d - "
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"aborting!\n", j);
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goto abort;
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}
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zone->dev[j] = rdev1;
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blk_queue_stack_limits(mddev->queue,
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rdev1->bdev->bd_disk->queue);
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/* as we don't honour merge_bvec_fn, we must never risk
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* violating it, so limit ->max_sector to one PAGE, as
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* a one page request is never in violation.
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*/
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if (rdev1->bdev->bd_disk->queue->merge_bvec_fn &&
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mddev->queue->max_sectors > (PAGE_SIZE>>9))
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blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
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if (!smallest || (rdev1->sectors < smallest->sectors))
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smallest = rdev1;
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cnt++;
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}
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if (cnt != mddev->raid_disks) {
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printk(KERN_ERR "raid0: too few disks (%d of %d) - "
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"aborting!\n", cnt, mddev->raid_disks);
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goto abort;
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}
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zone->nb_dev = cnt;
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zone->sectors = smallest->sectors * cnt;
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zone->zone_start = 0;
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current_start = smallest->sectors;
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curr_zone_start = zone->sectors;
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/* now do the other zones */
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for (i = 1; i < conf->nr_strip_zones; i++)
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{
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zone = conf->strip_zone + i;
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zone->dev = conf->strip_zone[i-1].dev + mddev->raid_disks;
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printk(KERN_INFO "raid0: zone %d\n", i);
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zone->dev_start = current_start;
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smallest = NULL;
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c = 0;
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for (j=0; j<cnt; j++) {
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char b[BDEVNAME_SIZE];
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rdev = conf->strip_zone[0].dev[j];
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printk(KERN_INFO "raid0: checking %s ...",
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bdevname(rdev->bdev, b));
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if (rdev->sectors <= current_start) {
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printk(KERN_INFO " nope.\n");
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continue;
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}
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printk(KERN_INFO " contained as device %d\n", c);
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zone->dev[c] = rdev;
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c++;
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if (!smallest || rdev->sectors < smallest->sectors) {
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smallest = rdev;
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printk(KERN_INFO " (%llu) is smallest!.\n",
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(unsigned long long)rdev->sectors);
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}
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}
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zone->nb_dev = c;
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zone->sectors = (smallest->sectors - current_start) * c;
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printk(KERN_INFO "raid0: zone->nb_dev: %d, sectors: %llu\n",
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zone->nb_dev, (unsigned long long)zone->sectors);
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zone->zone_start = curr_zone_start;
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curr_zone_start += zone->sectors;
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current_start = smallest->sectors;
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printk(KERN_INFO "raid0: current zone start: %llu\n",
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(unsigned long long)current_start);
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}
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/* Now find appropriate hash spacing.
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* We want a number which causes most hash entries to cover
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* at most two strips, but the hash table must be at most
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* 1 PAGE. We choose the smallest strip, or contiguous collection
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* of strips, that has big enough size. We never consider the last
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* strip though as it's size has no bearing on the efficacy of the hash
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* table.
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*/
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conf->spacing = curr_zone_start;
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min_spacing = curr_zone_start;
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sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*));
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for (i=0; i < conf->nr_strip_zones-1; i++) {
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sector_t s = 0;
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for (j = i; j < conf->nr_strip_zones - 1 &&
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s < min_spacing; j++)
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s += conf->strip_zone[j].sectors;
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if (s >= min_spacing && s < conf->spacing)
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conf->spacing = s;
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}
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mddev->queue->unplug_fn = raid0_unplug;
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mddev->queue->backing_dev_info.congested_fn = raid0_congested;
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mddev->queue->backing_dev_info.congested_data = mddev;
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printk(KERN_INFO "raid0: done.\n");
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return 0;
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abort:
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return 1;
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}
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/**
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* raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
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* @q: request queue
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* @bvm: properties of new bio
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* @biovec: the request that could be merged to it.
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*
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* Return amount of bytes we can accept at this offset
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*/
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static int raid0_mergeable_bvec(struct request_queue *q,
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struct bvec_merge_data *bvm,
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struct bio_vec *biovec)
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{
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mddev_t *mddev = q->queuedata;
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sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
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int max;
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unsigned int chunk_sectors = mddev->chunk_size >> 9;
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unsigned int bio_sectors = bvm->bi_size >> 9;
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max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
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if (max < 0) max = 0; /* bio_add cannot handle a negative return */
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if (max <= biovec->bv_len && bio_sectors == 0)
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return biovec->bv_len;
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else
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return max;
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}
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static int raid0_run (mddev_t *mddev)
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{
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unsigned cur=0, i=0, nb_zone;
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s64 sectors;
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raid0_conf_t *conf;
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mdk_rdev_t *rdev;
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if (mddev->chunk_size == 0) {
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printk(KERN_ERR "md/raid0: non-zero chunk size required.\n");
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return -EINVAL;
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}
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printk(KERN_INFO "%s: setting max_sectors to %d, segment boundary to %d\n",
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mdname(mddev),
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mddev->chunk_size >> 9,
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(mddev->chunk_size>>1)-1);
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blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9);
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blk_queue_segment_boundary(mddev->queue, (mddev->chunk_size>>1) - 1);
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mddev->queue->queue_lock = &mddev->queue->__queue_lock;
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conf = kmalloc(sizeof (raid0_conf_t), GFP_KERNEL);
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if (!conf)
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goto out;
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mddev->private = (void *)conf;
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conf->strip_zone = NULL;
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conf->devlist = NULL;
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if (create_strip_zones (mddev))
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goto out_free_conf;
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/* calculate array device size */
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mddev->array_sectors = 0;
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list_for_each_entry(rdev, &mddev->disks, same_set)
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mddev->array_sectors += rdev->sectors;
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printk(KERN_INFO "raid0 : md_size is %llu sectors.\n",
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(unsigned long long)mddev->array_sectors);
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printk(KERN_INFO "raid0 : conf->spacing is %llu sectors.\n",
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(unsigned long long)conf->spacing);
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{
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sector_t s = mddev->array_sectors;
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sector_t space = conf->spacing;
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int round;
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conf->sector_shift = 0;
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if (sizeof(sector_t) > sizeof(u32)) {
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/*shift down space and s so that sector_div will work */
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while (space > (sector_t) (~(u32)0)) {
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s >>= 1;
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space >>= 1;
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s += 1; /* force round-up */
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conf->sector_shift++;
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}
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}
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round = sector_div(s, (u32)space) ? 1 : 0;
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nb_zone = s + round;
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}
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printk(KERN_INFO "raid0 : nb_zone is %d.\n", nb_zone);
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printk(KERN_INFO "raid0 : Allocating %zu bytes for hash.\n",
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nb_zone*sizeof(struct strip_zone*));
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conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL);
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if (!conf->hash_table)
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goto out_free_conf;
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sectors = conf->strip_zone[cur].sectors;
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conf->hash_table[0] = conf->strip_zone + cur;
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for (i=1; i< nb_zone; i++) {
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while (sectors <= conf->spacing) {
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cur++;
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sectors += conf->strip_zone[cur].sectors;
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}
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sectors -= conf->spacing;
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conf->hash_table[i] = conf->strip_zone + cur;
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}
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if (conf->sector_shift) {
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conf->spacing >>= conf->sector_shift;
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/* round spacing up so when we divide by it, we
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* err on the side of too-low, which is safest
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*/
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conf->spacing++;
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}
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/* calculate the max read-ahead size.
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* For read-ahead of large files to be effective, we need to
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* readahead at least twice a whole stripe. i.e. number of devices
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* multiplied by chunk size times 2.
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* If an individual device has an ra_pages greater than the
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* chunk size, then we will not drive that device as hard as it
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* wants. We consider this a configuration error: a larger
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* chunksize should be used in that case.
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*/
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{
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int stripe = mddev->raid_disks * mddev->chunk_size / PAGE_SIZE;
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if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
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mddev->queue->backing_dev_info.ra_pages = 2* stripe;
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}
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blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
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return 0;
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out_free_conf:
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kfree(conf->strip_zone);
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kfree(conf->devlist);
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kfree(conf);
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mddev->private = NULL;
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out:
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return -ENOMEM;
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}
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static int raid0_stop (mddev_t *mddev)
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{
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raid0_conf_t *conf = mddev_to_conf(mddev);
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blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
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kfree(conf->hash_table);
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conf->hash_table = NULL;
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kfree(conf->strip_zone);
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conf->strip_zone = NULL;
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kfree(conf);
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mddev->private = NULL;
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return 0;
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}
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static int raid0_make_request (struct request_queue *q, struct bio *bio)
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{
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mddev_t *mddev = q->queuedata;
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unsigned int sect_in_chunk, chunksect_bits, chunk_sects;
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raid0_conf_t *conf = mddev_to_conf(mddev);
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struct strip_zone *zone;
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mdk_rdev_t *tmp_dev;
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sector_t chunk;
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sector_t sector, rsect;
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const int rw = bio_data_dir(bio);
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int cpu;
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if (unlikely(bio_barrier(bio))) {
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bio_endio(bio, -EOPNOTSUPP);
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return 0;
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}
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cpu = part_stat_lock();
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part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
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part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
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bio_sectors(bio));
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part_stat_unlock();
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chunk_sects = mddev->chunk_size >> 9;
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chunksect_bits = ffz(~chunk_sects);
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sector = bio->bi_sector;
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if (unlikely(chunk_sects < (bio->bi_sector & (chunk_sects - 1)) + (bio->bi_size >> 9))) {
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struct bio_pair *bp;
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/* Sanity check -- queue functions should prevent this happening */
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if (bio->bi_vcnt != 1 ||
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bio->bi_idx != 0)
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goto bad_map;
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/* This is a one page bio that upper layers
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* refuse to split for us, so we need to split it.
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*/
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bp = bio_split(bio, chunk_sects - (bio->bi_sector & (chunk_sects - 1)));
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if (raid0_make_request(q, &bp->bio1))
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generic_make_request(&bp->bio1);
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if (raid0_make_request(q, &bp->bio2))
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generic_make_request(&bp->bio2);
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bio_pair_release(bp);
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return 0;
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}
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{
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sector_t x = sector >> conf->sector_shift;
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sector_div(x, (u32)conf->spacing);
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zone = conf->hash_table[x];
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}
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while (sector >= zone->zone_start + zone->sectors)
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zone++;
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sect_in_chunk = bio->bi_sector & (chunk_sects - 1);
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{
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sector_t x = (sector - zone->zone_start) >> chunksect_bits;
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sector_div(x, zone->nb_dev);
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chunk = x;
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x = sector >> chunksect_bits;
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tmp_dev = zone->dev[sector_div(x, zone->nb_dev)];
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}
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rsect = (chunk << chunksect_bits) + zone->dev_start + sect_in_chunk;
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bio->bi_bdev = tmp_dev->bdev;
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bio->bi_sector = rsect + tmp_dev->data_offset;
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/*
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* Let the main block layer submit the IO and resolve recursion:
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*/
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return 1;
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bad_map:
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printk("raid0_make_request bug: can't convert block across chunks"
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" or bigger than %dk %llu %d\n", chunk_sects / 2,
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(unsigned long long)bio->bi_sector, bio->bi_size >> 10);
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bio_io_error(bio);
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return 0;
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}
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static void raid0_status (struct seq_file *seq, mddev_t *mddev)
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{
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#undef MD_DEBUG
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#ifdef MD_DEBUG
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int j, k, h;
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char b[BDEVNAME_SIZE];
|
|
raid0_conf_t *conf = mddev_to_conf(mddev);
|
|
|
|
h = 0;
|
|
for (j = 0; j < conf->nr_strip_zones; j++) {
|
|
seq_printf(seq, " z%d", j);
|
|
if (conf->hash_table[h] == conf->strip_zone+j)
|
|
seq_printf(seq, "(h%d)", h++);
|
|
seq_printf(seq, "=[");
|
|
for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
|
|
seq_printf(seq, "%s/", bdevname(
|
|
conf->strip_zone[j].dev[k]->bdev,b));
|
|
|
|
seq_printf(seq, "] zs=%d ds=%d s=%d\n",
|
|
conf->strip_zone[j].zone_start,
|
|
conf->strip_zone[j].dev_start,
|
|
conf->strip_zone[j].sectors);
|
|
}
|
|
#endif
|
|
seq_printf(seq, " %dk chunks", mddev->chunk_size/1024);
|
|
return;
|
|
}
|
|
|
|
static struct mdk_personality raid0_personality=
|
|
{
|
|
.name = "raid0",
|
|
.level = 0,
|
|
.owner = THIS_MODULE,
|
|
.make_request = raid0_make_request,
|
|
.run = raid0_run,
|
|
.stop = raid0_stop,
|
|
.status = raid0_status,
|
|
};
|
|
|
|
static int __init raid0_init (void)
|
|
{
|
|
return register_md_personality (&raid0_personality);
|
|
}
|
|
|
|
static void raid0_exit (void)
|
|
{
|
|
unregister_md_personality (&raid0_personality);
|
|
}
|
|
|
|
module_init(raid0_init);
|
|
module_exit(raid0_exit);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("md-personality-2"); /* RAID0 */
|
|
MODULE_ALIAS("md-raid0");
|
|
MODULE_ALIAS("md-level-0");
|