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fd01b88c75
Having mddev_t and 'struct mddev_s' is ugly and not preferred Signed-off-by: NeilBrown <neilb@suse.de>
704 lines
19 KiB
C
704 lines
19 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 <linux/slab.h>
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#include "md.h"
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#include "raid0.h"
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#include "raid5.h"
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static int raid0_congested(void *data, int bits)
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{
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struct mddev *mddev = data;
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raid0_conf_t *conf = mddev->private;
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struct md_rdev **devlist = conf->devlist;
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int raid_disks = conf->strip_zone[0].nb_dev;
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int i, ret = 0;
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if (mddev_congested(mddev, bits))
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return 1;
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for (i = 0; i < 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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/*
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* inform the user of the raid configuration
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*/
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static void dump_zones(struct mddev *mddev)
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{
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int j, k;
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sector_t zone_size = 0;
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sector_t zone_start = 0;
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char b[BDEVNAME_SIZE];
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raid0_conf_t *conf = mddev->private;
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int raid_disks = conf->strip_zone[0].nb_dev;
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printk(KERN_INFO "md: RAID0 configuration for %s - %d zone%s\n",
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mdname(mddev),
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conf->nr_strip_zones, conf->nr_strip_zones==1?"":"s");
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for (j = 0; j < conf->nr_strip_zones; j++) {
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printk(KERN_INFO "md: zone%d=[", j);
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for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
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printk(KERN_CONT "%s%s", k?"/":"",
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bdevname(conf->devlist[j*raid_disks
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+ k]->bdev, b));
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printk(KERN_CONT "]\n");
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zone_size = conf->strip_zone[j].zone_end - zone_start;
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printk(KERN_INFO " zone-offset=%10lluKB, "
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"device-offset=%10lluKB, size=%10lluKB\n",
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(unsigned long long)zone_start>>1,
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(unsigned long long)conf->strip_zone[j].dev_start>>1,
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(unsigned long long)zone_size>>1);
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zone_start = conf->strip_zone[j].zone_end;
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}
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printk(KERN_INFO "\n");
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}
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static int create_strip_zones(struct mddev *mddev, raid0_conf_t **private_conf)
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{
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int i, c, err;
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sector_t curr_zone_end, sectors;
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struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
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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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char b2[BDEVNAME_SIZE];
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raid0_conf_t *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
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if (!conf)
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return -ENOMEM;
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list_for_each_entry(rdev1, &mddev->disks, same_set) {
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pr_debug("md/raid0:%s: looking at %s\n",
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mdname(mddev),
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bdevname(rdev1->bdev, b));
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c = 0;
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/* round size to chunk_size */
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sectors = rdev1->sectors;
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sector_div(sectors, mddev->chunk_sectors);
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rdev1->sectors = sectors * mddev->chunk_sectors;
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list_for_each_entry(rdev2, &mddev->disks, same_set) {
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pr_debug("md/raid0:%s: comparing %s(%llu)"
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" with %s(%llu)\n",
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mdname(mddev),
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bdevname(rdev1->bdev,b),
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(unsigned long long)rdev1->sectors,
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bdevname(rdev2->bdev,b2),
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(unsigned long long)rdev2->sectors);
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if (rdev2 == rdev1) {
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pr_debug("md/raid0:%s: END\n",
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mdname(mddev));
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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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pr_debug("md/raid0:%s: EQUAL\n",
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mdname(mddev));
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c = 1;
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break;
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}
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pr_debug("md/raid0:%s: NOT EQUAL\n",
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mdname(mddev));
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}
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if (!c) {
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pr_debug("md/raid0:%s: ==> UNIQUE\n",
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mdname(mddev));
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conf->nr_strip_zones++;
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pr_debug("md/raid0:%s: %d zones\n",
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mdname(mddev), conf->nr_strip_zones);
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}
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}
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pr_debug("md/raid0:%s: FINAL %d zones\n",
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mdname(mddev), conf->nr_strip_zones);
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err = -ENOMEM;
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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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goto abort;
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conf->devlist = kzalloc(sizeof(struct md_rdev*)*
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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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goto abort;
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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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dev = conf->devlist;
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err = -EINVAL;
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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 (mddev->level == 10) {
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/* taking over a raid10-n2 array */
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j /= 2;
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rdev1->new_raid_disk = j;
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}
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if (mddev->level == 1) {
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/* taiking over a raid1 array-
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* we have only one active disk
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*/
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j = 0;
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rdev1->new_raid_disk = j;
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}
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if (j < 0 || j >= mddev->raid_disks) {
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printk(KERN_ERR "md/raid0:%s: bad disk number %d - "
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"aborting!\n", mdname(mddev), j);
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goto abort;
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}
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if (dev[j]) {
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printk(KERN_ERR "md/raid0:%s: multiple devices for %d - "
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"aborting!\n", mdname(mddev), j);
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goto abort;
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}
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dev[j] = rdev1;
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disk_stack_limits(mddev->gendisk, rdev1->bdev,
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rdev1->data_offset << 9);
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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_segments to 1, lying within
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* a single page.
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*/
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if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) {
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blk_queue_max_segments(mddev->queue, 1);
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blk_queue_segment_boundary(mddev->queue,
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PAGE_CACHE_SIZE - 1);
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}
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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 "md/raid0:%s: too few disks (%d of %d) - "
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"aborting!\n", mdname(mddev), 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->zone_end = smallest->sectors * cnt;
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curr_zone_end = zone->zone_end;
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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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int j;
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zone = conf->strip_zone + i;
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dev = conf->devlist + i * mddev->raid_disks;
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pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
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zone->dev_start = smallest->sectors;
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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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rdev = conf->devlist[j];
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if (rdev->sectors <= zone->dev_start) {
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pr_debug("md/raid0:%s: checking %s ... nope\n",
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mdname(mddev),
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bdevname(rdev->bdev, b));
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continue;
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}
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pr_debug("md/raid0:%s: checking %s ..."
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" contained as device %d\n",
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mdname(mddev),
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bdevname(rdev->bdev, b), c);
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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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pr_debug("md/raid0:%s: (%llu) is smallest!.\n",
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mdname(mddev),
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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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sectors = (smallest->sectors - zone->dev_start) * c;
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pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
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mdname(mddev),
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zone->nb_dev, (unsigned long long)sectors);
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curr_zone_end += sectors;
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zone->zone_end = curr_zone_end;
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pr_debug("md/raid0:%s: current zone start: %llu\n",
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mdname(mddev),
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(unsigned long long)smallest->sectors);
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}
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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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/*
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* now since we have the hard sector sizes, we can make sure
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* chunk size is a multiple of that sector size
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*/
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if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) {
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printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n",
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mdname(mddev),
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mddev->chunk_sectors << 9);
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goto abort;
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}
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blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
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blk_queue_io_opt(mddev->queue,
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(mddev->chunk_sectors << 9) * mddev->raid_disks);
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pr_debug("md/raid0:%s: done.\n", mdname(mddev));
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*private_conf = conf;
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return 0;
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abort:
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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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*private_conf = NULL;
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return err;
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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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struct mddev *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_sectors;
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unsigned int bio_sectors = bvm->bi_size >> 9;
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if (is_power_of_2(chunk_sectors))
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max = (chunk_sectors - ((sector & (chunk_sectors-1))
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+ bio_sectors)) << 9;
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else
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max = (chunk_sectors - (sector_div(sector, chunk_sectors)
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+ 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 sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
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{
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sector_t array_sectors = 0;
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struct md_rdev *rdev;
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WARN_ONCE(sectors || raid_disks,
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"%s does not support generic reshape\n", __func__);
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list_for_each_entry(rdev, &mddev->disks, same_set)
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array_sectors += rdev->sectors;
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return array_sectors;
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}
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static int raid0_run(struct mddev *mddev)
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{
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raid0_conf_t *conf;
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int ret;
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if (mddev->chunk_sectors == 0) {
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printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n",
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mdname(mddev));
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return -EINVAL;
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}
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if (md_check_no_bitmap(mddev))
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return -EINVAL;
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blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
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/* if private is not null, we are here after takeover */
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if (mddev->private == NULL) {
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ret = create_strip_zones(mddev, &conf);
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if (ret < 0)
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return ret;
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mddev->private = conf;
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}
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conf = mddev->private;
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/* calculate array device size */
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md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
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printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n",
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mdname(mddev),
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(unsigned long long)mddev->array_sectors);
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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 *
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(mddev->chunk_sectors << 9) / 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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dump_zones(mddev);
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return md_integrity_register(mddev);
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}
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static int raid0_stop(struct mddev *mddev)
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{
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raid0_conf_t *conf = mddev->private;
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blk_sync_queue(mddev->queue); /* the unplug fn references '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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return 0;
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}
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/* Find the zone which holds a particular offset
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* Update *sectorp to be an offset in that zone
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*/
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static struct strip_zone *find_zone(struct raid0_private_data *conf,
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sector_t *sectorp)
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{
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int i;
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struct strip_zone *z = conf->strip_zone;
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sector_t sector = *sectorp;
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for (i = 0; i < conf->nr_strip_zones; i++)
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if (sector < z[i].zone_end) {
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if (i)
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*sectorp = sector - z[i-1].zone_end;
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return z + i;
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}
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BUG();
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}
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/*
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* remaps the bio to the target device. we separate two flows.
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* power 2 flow and a general flow for the sake of perfromance
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*/
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static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
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sector_t sector, sector_t *sector_offset)
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{
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unsigned int sect_in_chunk;
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sector_t chunk;
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raid0_conf_t *conf = mddev->private;
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int raid_disks = conf->strip_zone[0].nb_dev;
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unsigned int chunk_sects = mddev->chunk_sectors;
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if (is_power_of_2(chunk_sects)) {
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int chunksect_bits = ffz(~chunk_sects);
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/* find the sector offset inside the chunk */
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sect_in_chunk = sector & (chunk_sects - 1);
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sector >>= chunksect_bits;
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/* chunk in zone */
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chunk = *sector_offset;
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/* quotient is the chunk in real device*/
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sector_div(chunk, zone->nb_dev << chunksect_bits);
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} else{
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sect_in_chunk = sector_div(sector, chunk_sects);
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chunk = *sector_offset;
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sector_div(chunk, chunk_sects * zone->nb_dev);
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}
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/*
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* position the bio over the real device
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* real sector = chunk in device + starting of zone
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* + the position in the chunk
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*/
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*sector_offset = (chunk * chunk_sects) + sect_in_chunk;
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return conf->devlist[(zone - conf->strip_zone)*raid_disks
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+ sector_div(sector, zone->nb_dev)];
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}
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/*
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* Is io distribute over 1 or more chunks ?
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*/
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static inline int is_io_in_chunk_boundary(struct mddev *mddev,
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unsigned int chunk_sects, struct bio *bio)
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{
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if (likely(is_power_of_2(chunk_sects))) {
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return chunk_sects >= ((bio->bi_sector & (chunk_sects-1))
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+ (bio->bi_size >> 9));
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} else{
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sector_t sector = bio->bi_sector;
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return chunk_sects >= (sector_div(sector, chunk_sects)
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+ (bio->bi_size >> 9));
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}
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}
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static int raid0_make_request(struct mddev *mddev, struct bio *bio)
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{
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unsigned int chunk_sects;
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sector_t sector_offset;
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struct strip_zone *zone;
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struct md_rdev *tmp_dev;
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if (unlikely(bio->bi_rw & REQ_FLUSH)) {
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md_flush_request(mddev, bio);
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return 0;
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|
}
|
|
|
|
chunk_sects = mddev->chunk_sectors;
|
|
if (unlikely(!is_io_in_chunk_boundary(mddev, chunk_sects, bio))) {
|
|
sector_t sector = bio->bi_sector;
|
|
struct bio_pair *bp;
|
|
/* Sanity check -- queue functions should prevent this happening */
|
|
if (bio->bi_vcnt != 1 ||
|
|
bio->bi_idx != 0)
|
|
goto bad_map;
|
|
/* This is a one page bio that upper layers
|
|
* refuse to split for us, so we need to split it.
|
|
*/
|
|
if (likely(is_power_of_2(chunk_sects)))
|
|
bp = bio_split(bio, chunk_sects - (sector &
|
|
(chunk_sects-1)));
|
|
else
|
|
bp = bio_split(bio, chunk_sects -
|
|
sector_div(sector, chunk_sects));
|
|
if (raid0_make_request(mddev, &bp->bio1))
|
|
generic_make_request(&bp->bio1);
|
|
if (raid0_make_request(mddev, &bp->bio2))
|
|
generic_make_request(&bp->bio2);
|
|
|
|
bio_pair_release(bp);
|
|
return 0;
|
|
}
|
|
|
|
sector_offset = bio->bi_sector;
|
|
zone = find_zone(mddev->private, §or_offset);
|
|
tmp_dev = map_sector(mddev, zone, bio->bi_sector,
|
|
§or_offset);
|
|
bio->bi_bdev = tmp_dev->bdev;
|
|
bio->bi_sector = sector_offset + zone->dev_start +
|
|
tmp_dev->data_offset;
|
|
/*
|
|
* Let the main block layer submit the IO and resolve recursion:
|
|
*/
|
|
return 1;
|
|
|
|
bad_map:
|
|
printk("md/raid0:%s: make_request bug: can't convert block across chunks"
|
|
" or bigger than %dk %llu %d\n",
|
|
mdname(mddev), chunk_sects / 2,
|
|
(unsigned long long)bio->bi_sector, bio->bi_size >> 10);
|
|
|
|
bio_io_error(bio);
|
|
return 0;
|
|
}
|
|
|
|
static void raid0_status(struct seq_file *seq, struct mddev *mddev)
|
|
{
|
|
seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
|
|
return;
|
|
}
|
|
|
|
static void *raid0_takeover_raid45(struct mddev *mddev)
|
|
{
|
|
struct md_rdev *rdev;
|
|
raid0_conf_t *priv_conf;
|
|
|
|
if (mddev->degraded != 1) {
|
|
printk(KERN_ERR "md/raid0:%s: raid5 must be degraded! Degraded disks: %d\n",
|
|
mdname(mddev),
|
|
mddev->degraded);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
list_for_each_entry(rdev, &mddev->disks, same_set) {
|
|
/* check slot number for a disk */
|
|
if (rdev->raid_disk == mddev->raid_disks-1) {
|
|
printk(KERN_ERR "md/raid0:%s: raid5 must have missing parity disk!\n",
|
|
mdname(mddev));
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
}
|
|
|
|
/* Set new parameters */
|
|
mddev->new_level = 0;
|
|
mddev->new_layout = 0;
|
|
mddev->new_chunk_sectors = mddev->chunk_sectors;
|
|
mddev->raid_disks--;
|
|
mddev->delta_disks = -1;
|
|
/* make sure it will be not marked as dirty */
|
|
mddev->recovery_cp = MaxSector;
|
|
|
|
create_strip_zones(mddev, &priv_conf);
|
|
return priv_conf;
|
|
}
|
|
|
|
static void *raid0_takeover_raid10(struct mddev *mddev)
|
|
{
|
|
raid0_conf_t *priv_conf;
|
|
|
|
/* Check layout:
|
|
* - far_copies must be 1
|
|
* - near_copies must be 2
|
|
* - disks number must be even
|
|
* - all mirrors must be already degraded
|
|
*/
|
|
if (mddev->layout != ((1 << 8) + 2)) {
|
|
printk(KERN_ERR "md/raid0:%s:: Raid0 cannot takover layout: 0x%x\n",
|
|
mdname(mddev),
|
|
mddev->layout);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
if (mddev->raid_disks & 1) {
|
|
printk(KERN_ERR "md/raid0:%s: Raid0 cannot takover Raid10 with odd disk number.\n",
|
|
mdname(mddev));
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
if (mddev->degraded != (mddev->raid_disks>>1)) {
|
|
printk(KERN_ERR "md/raid0:%s: All mirrors must be already degraded!\n",
|
|
mdname(mddev));
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
/* Set new parameters */
|
|
mddev->new_level = 0;
|
|
mddev->new_layout = 0;
|
|
mddev->new_chunk_sectors = mddev->chunk_sectors;
|
|
mddev->delta_disks = - mddev->raid_disks / 2;
|
|
mddev->raid_disks += mddev->delta_disks;
|
|
mddev->degraded = 0;
|
|
/* make sure it will be not marked as dirty */
|
|
mddev->recovery_cp = MaxSector;
|
|
|
|
create_strip_zones(mddev, &priv_conf);
|
|
return priv_conf;
|
|
}
|
|
|
|
static void *raid0_takeover_raid1(struct mddev *mddev)
|
|
{
|
|
raid0_conf_t *priv_conf;
|
|
|
|
/* Check layout:
|
|
* - (N - 1) mirror drives must be already faulty
|
|
*/
|
|
if ((mddev->raid_disks - 1) != mddev->degraded) {
|
|
printk(KERN_ERR "md/raid0:%s: (N - 1) mirrors drives must be already faulty!\n",
|
|
mdname(mddev));
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
/* Set new parameters */
|
|
mddev->new_level = 0;
|
|
mddev->new_layout = 0;
|
|
mddev->new_chunk_sectors = 128; /* by default set chunk size to 64k */
|
|
mddev->delta_disks = 1 - mddev->raid_disks;
|
|
mddev->raid_disks = 1;
|
|
/* make sure it will be not marked as dirty */
|
|
mddev->recovery_cp = MaxSector;
|
|
|
|
create_strip_zones(mddev, &priv_conf);
|
|
return priv_conf;
|
|
}
|
|
|
|
static void *raid0_takeover(struct mddev *mddev)
|
|
{
|
|
/* raid0 can take over:
|
|
* raid4 - if all data disks are active.
|
|
* raid5 - providing it is Raid4 layout and one disk is faulty
|
|
* raid10 - assuming we have all necessary active disks
|
|
* raid1 - with (N -1) mirror drives faulty
|
|
*/
|
|
if (mddev->level == 4)
|
|
return raid0_takeover_raid45(mddev);
|
|
|
|
if (mddev->level == 5) {
|
|
if (mddev->layout == ALGORITHM_PARITY_N)
|
|
return raid0_takeover_raid45(mddev);
|
|
|
|
printk(KERN_ERR "md/raid0:%s: Raid can only takeover Raid5 with layout: %d\n",
|
|
mdname(mddev), ALGORITHM_PARITY_N);
|
|
}
|
|
|
|
if (mddev->level == 10)
|
|
return raid0_takeover_raid10(mddev);
|
|
|
|
if (mddev->level == 1)
|
|
return raid0_takeover_raid1(mddev);
|
|
|
|
printk(KERN_ERR "Takeover from raid%i to raid0 not supported\n",
|
|
mddev->level);
|
|
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
static void raid0_quiesce(struct mddev *mddev, int state)
|
|
{
|
|
}
|
|
|
|
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,
|
|
.size = raid0_size,
|
|
.takeover = raid0_takeover,
|
|
.quiesce = raid0_quiesce,
|
|
};
|
|
|
|
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_DESCRIPTION("RAID0 (striping) personality for MD");
|
|
MODULE_ALIAS("md-personality-2"); /* RAID0 */
|
|
MODULE_ALIAS("md-raid0");
|
|
MODULE_ALIAS("md-level-0");
|