538 строки
14 KiB
C
538 строки
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/module.h>
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#include <linux/raid/raid0.h>
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#define MAJOR_NR MD_MAJOR
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#define MD_DRIVER
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#define MD_PERSONALITY
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static void raid0_unplug(request_queue_t *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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request_queue_t *r_queue = bdev_get_queue(devlist[i]->bdev);
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if (r_queue->unplug_fn)
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r_queue->unplug_fn(r_queue);
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}
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}
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static int raid0_issue_flush(request_queue_t *q, struct gendisk *disk,
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sector_t *error_sector)
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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, ret = 0;
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for (i=0; i<mddev->raid_disks && ret == 0; i++) {
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struct block_device *bdev = devlist[i]->bdev;
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request_queue_t *r_queue = bdev_get_queue(bdev);
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if (!r_queue->issue_flush_fn)
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ret = -EOPNOTSUPP;
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else
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ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
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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_offset, curr_zone_offset;
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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 list_head *tmp1, *tmp2;
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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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ITERATE_RDEV(mddev,rdev1,tmp1) {
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printk("raid0: looking at %s\n",
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bdevname(rdev1->bdev,b));
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c = 0;
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ITERATE_RDEV(mddev,rdev2,tmp2) {
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printk("raid0: comparing %s(%llu)",
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bdevname(rdev1->bdev,b),
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(unsigned long long)rdev1->size);
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printk(" with %s(%llu)\n",
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bdevname(rdev2->bdev,b),
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(unsigned long long)rdev2->size);
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if (rdev2 == rdev1) {
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printk("raid0: END\n");
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break;
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}
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if (rdev2->size == rdev1->size)
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{
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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("raid0: EQUAL\n");
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c = 1;
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break;
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}
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printk("raid0: NOT EQUAL\n");
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}
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if (!c) {
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printk("raid0: ==> UNIQUE\n");
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conf->nr_strip_zones++;
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printk("raid0: %d zones\n", conf->nr_strip_zones);
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}
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}
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printk("raid0: FINAL %d zones\n", conf->nr_strip_zones);
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conf->strip_zone = kmalloc(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 = kmalloc(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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memset(conf->strip_zone, 0,sizeof(struct strip_zone)*
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conf->nr_strip_zones);
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memset(conf->devlist, 0,
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sizeof(mdk_rdev_t*) * conf->nr_strip_zones * mddev->raid_disks);
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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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ITERATE_RDEV(mddev, rdev1, tmp1) {
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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("raid0: bad disk number %d - 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("raid0: multiple devices for %d - aborting!\n",
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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->size <smallest->size))
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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("raid0: too few disks (%d of %d) - aborting!\n",
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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->size = smallest->size * cnt;
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zone->zone_offset = 0;
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current_offset = smallest->size;
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curr_zone_offset = zone->size;
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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("raid0: zone %d\n", i);
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zone->dev_offset = current_offset;
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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("raid0: checking %s ...", bdevname(rdev->bdev,b));
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if (rdev->size > current_offset)
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{
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printk(" 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->size <smallest->size)) {
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smallest = rdev;
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printk(" (%llu) is smallest!.\n",
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(unsigned long long)rdev->size);
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}
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} else
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printk(" nope.\n");
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}
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zone->nb_dev = c;
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zone->size = (smallest->size - current_offset) * c;
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printk("raid0: zone->nb_dev: %d, size: %llu\n",
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zone->nb_dev, (unsigned long long)zone->size);
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zone->zone_offset = curr_zone_offset;
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curr_zone_offset += zone->size;
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current_offset = smallest->size;
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printk("raid0: current zone offset: %llu\n",
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(unsigned long long)current_offset);
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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->hash_spacing = curr_zone_offset;
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min_spacing = curr_zone_offset;
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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 sz = 0;
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for (j=i; j<conf->nr_strip_zones-1 &&
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sz < min_spacing ; j++)
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sz += conf->strip_zone[j].size;
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if (sz >= min_spacing && sz < conf->hash_spacing)
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conf->hash_spacing = sz;
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}
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mddev->queue->unplug_fn = raid0_unplug;
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mddev->queue->issue_flush_fn = raid0_issue_flush;
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printk("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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* @bio: the buffer head that's been built up so far
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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(request_queue_t *q, struct bio *bio, struct bio_vec *biovec)
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{
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mddev_t *mddev = q->queuedata;
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sector_t sector = bio->bi_sector + get_start_sect(bio->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 = bio->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 size;
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raid0_conf_t *conf;
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mdk_rdev_t *rdev;
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struct list_head *tmp;
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printk("%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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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_size = 0;
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ITERATE_RDEV(mddev,rdev,tmp)
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mddev->array_size += rdev->size;
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printk("raid0 : md_size is %llu blocks.\n",
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(unsigned long long)mddev->array_size);
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printk("raid0 : conf->hash_spacing is %llu blocks.\n",
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(unsigned long long)conf->hash_spacing);
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{
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#if __GNUC__ < 3
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volatile
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#endif
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sector_t s = mddev->array_size;
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sector_t space = conf->hash_spacing;
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int round;
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conf->preshift = 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->preshift++;
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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("raid0 : nb_zone is %d.\n", nb_zone);
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printk("raid0 : Allocating %Zd 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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size = conf->strip_zone[cur].size;
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for (i=0; i< nb_zone; i++) {
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conf->hash_table[i] = conf->strip_zone + cur;
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while (size <= conf->hash_spacing) {
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cur++;
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size += conf->strip_zone[cur].size;
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}
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size -= conf->hash_spacing;
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}
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if (conf->preshift) {
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conf->hash_spacing >>= conf->preshift;
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/* round hash_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->hash_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_CACHE_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 1;
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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 (request_queue_t *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, chunksize_bits, chunk_size, 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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unsigned long chunk;
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sector_t block, rsect;
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if (bio_data_dir(bio)==WRITE) {
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disk_stat_inc(mddev->gendisk, writes);
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disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
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} else {
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disk_stat_inc(mddev->gendisk, reads);
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disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
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}
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chunk_size = mddev->chunk_size >> 10;
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chunk_sects = mddev->chunk_size >> 9;
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chunksize_bits = ffz(~chunk_size);
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block = bio->bi_sector >> 1;
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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, bio_split_pool, 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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#if __GNUC__ < 3
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volatile
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#endif
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sector_t x = block >> conf->preshift;
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sector_div(x, (u32)conf->hash_spacing);
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zone = conf->hash_table[x];
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}
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while (block >= (zone->zone_offset + zone->size))
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zone++;
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sect_in_chunk = bio->bi_sector & ((chunk_size<<1) -1);
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{
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sector_t x = (block - zone->zone_offset) >> chunksize_bits;
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sector_div(x, zone->nb_dev);
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chunk = x;
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BUG_ON(x != (sector_t)chunk);
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x = block >> chunksize_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 << chunksize_bits) + zone->dev_offset)<<1)
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+ 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_size,
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(unsigned long long)bio->bi_sector, bio->bi_size >> 10);
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bio_io_error(bio, bio->bi_size);
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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];
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raid0_conf_t *conf = mddev_to_conf(mddev);
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|
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("(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, "] zo=%d do=%d s=%d\n",
|
|
conf->strip_zone[j].zone_offset,
|
|
conf->strip_zone[j].dev_offset,
|
|
conf->strip_zone[j].size);
|
|
}
|
|
#endif
|
|
seq_printf(seq, " %dk chunks", mddev->chunk_size/1024);
|
|
return;
|
|
}
|
|
|
|
static mdk_personality_t raid0_personality=
|
|
{
|
|
.name = "raid0",
|
|
.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, &raid0_personality);
|
|
}
|
|
|
|
static void raid0_exit (void)
|
|
{
|
|
unregister_md_personality (RAID0);
|
|
}
|
|
|
|
module_init(raid0_init);
|
|
module_exit(raid0_exit);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("md-personality-2"); /* RAID0 */
|