2604b703b6
md supports multiple different RAID level, each being implemented by a 'personality' (which is often in a separate module). These personalities have fairly artificial 'numbers'. The numbers are use to: 1- provide an index into an array where the various personalities are recorded 2- identify the module (via an alias) which implements are particular personality. Neither of these uses really justify the existence of personality numbers. The array can be replaced by a linked list which is searched (array lookup only happens very rarely). Module identification can be done using an alias based on level rather than 'personality' number. The current 'raid5' modules support two level (4 and 5) but only one personality. This slight awkwardness (which was handled in the mapping from level to personality) can be better handled by allowing raid5 to register 2 personalities. With this change in place, the core md module does not need to have an exhaustive list of all possible personalities, so other personalities can be added independently. This patch also moves the check for chunksize being non-zero into the ->run routines for the personalities that need it, rather than having it in core-md. This has a side effect of allowing 'faulty' and 'linear' not to have a chunk-size set. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
539 lines
14 KiB
C
539 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/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 = 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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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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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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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_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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const int rw = bio_data_dir(bio);
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if (unlikely(bio_barrier(bio))) {
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bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
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return 0;
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}
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disk_stat_inc(mddev->gendisk, ios[rw]);
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disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
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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;
|
|
|
|
bad_map:
|
|
printk("raid0_make_request bug: can't convert block across chunks"
|
|
" or bigger than %dk %llu %d\n", chunk_size,
|
|
(unsigned long long)bio->bi_sector, bio->bi_size >> 10);
|
|
|
|
bio_io_error(bio, bio->bi_size);
|
|
return 0;
|
|
}
|
|
|
|
static void raid0_status (struct seq_file *seq, mddev_t *mddev)
|
|
{
|
|
#undef MD_DEBUG
|
|
#ifdef MD_DEBUG
|
|
int j, k, h;
|
|
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("(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 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-level-0");
|