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-rw-r--r--drivers/md/raid0.c539
1 files changed, 539 insertions, 0 deletions
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
new file mode 100644
index 00000000000..e7d934eca06
--- /dev/null
+++ b/drivers/md/raid0.c
@@ -0,0 +1,539 @@
+/*
+ raid0.c : Multiple Devices driver for Linux
+ Copyright (C) 1994-96 Marc ZYNGIER
+ <zyngier@ufr-info-p7.ibp.fr> or
+ <maz@gloups.fdn.fr>
+ Copyright (C) 1999, 2000 Ingo Molnar, Red Hat
+
+
+ RAID-0 management functions.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ You should have received a copy of the GNU General Public License
+ (for example /usr/src/linux/COPYING); if not, write to the Free
+ Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include <linux/module.h>
+#include <linux/raid/raid0.h>
+
+#define MAJOR_NR MD_MAJOR
+#define MD_DRIVER
+#define MD_PERSONALITY
+
+static void raid0_unplug(request_queue_t *q)
+{
+ mddev_t *mddev = q->queuedata;
+ raid0_conf_t *conf = mddev_to_conf(mddev);
+ mdk_rdev_t **devlist = conf->strip_zone[0].dev;
+ int i;
+
+ for (i=0; i<mddev->raid_disks; i++) {
+ request_queue_t *r_queue = bdev_get_queue(devlist[i]->bdev);
+
+ if (r_queue->unplug_fn)
+ r_queue->unplug_fn(r_queue);
+ }
+}
+
+static int raid0_issue_flush(request_queue_t *q, struct gendisk *disk,
+ sector_t *error_sector)
+{
+ mddev_t *mddev = q->queuedata;
+ raid0_conf_t *conf = mddev_to_conf(mddev);
+ mdk_rdev_t **devlist = conf->strip_zone[0].dev;
+ int i, ret = 0;
+
+ for (i=0; i<mddev->raid_disks && ret == 0; i++) {
+ struct block_device *bdev = devlist[i]->bdev;
+ request_queue_t *r_queue = bdev_get_queue(bdev);
+
+ if (!r_queue->issue_flush_fn)
+ ret = -EOPNOTSUPP;
+ else
+ ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector);
+ }
+ return ret;
+}
+
+
+static int create_strip_zones (mddev_t *mddev)
+{
+ int i, c, j;
+ sector_t current_offset, curr_zone_offset;
+ sector_t min_spacing;
+ raid0_conf_t *conf = mddev_to_conf(mddev);
+ mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev;
+ struct list_head *tmp1, *tmp2;
+ struct strip_zone *zone;
+ int cnt;
+ char b[BDEVNAME_SIZE];
+
+ /*
+ * The number of 'same size groups'
+ */
+ conf->nr_strip_zones = 0;
+
+ ITERATE_RDEV(mddev,rdev1,tmp1) {
+ printk("raid0: looking at %s\n",
+ bdevname(rdev1->bdev,b));
+ c = 0;
+ ITERATE_RDEV(mddev,rdev2,tmp2) {
+ printk("raid0: comparing %s(%llu)",
+ bdevname(rdev1->bdev,b),
+ (unsigned long long)rdev1->size);
+ printk(" with %s(%llu)\n",
+ bdevname(rdev2->bdev,b),
+ (unsigned long long)rdev2->size);
+ if (rdev2 == rdev1) {
+ printk("raid0: END\n");
+ break;
+ }
+ if (rdev2->size == rdev1->size)
+ {
+ /*
+ * Not unique, don't count it as a new
+ * group
+ */
+ printk("raid0: EQUAL\n");
+ c = 1;
+ break;
+ }
+ printk("raid0: NOT EQUAL\n");
+ }
+ if (!c) {
+ printk("raid0: ==> UNIQUE\n");
+ conf->nr_strip_zones++;
+ printk("raid0: %d zones\n", conf->nr_strip_zones);
+ }
+ }
+ printk("raid0: FINAL %d zones\n", conf->nr_strip_zones);
+
+ conf->strip_zone = kmalloc(sizeof(struct strip_zone)*
+ conf->nr_strip_zones, GFP_KERNEL);
+ if (!conf->strip_zone)
+ return 1;
+ conf->devlist = kmalloc(sizeof(mdk_rdev_t*)*
+ conf->nr_strip_zones*mddev->raid_disks,
+ GFP_KERNEL);
+ if (!conf->devlist)
+ return 1;
+
+ memset(conf->strip_zone, 0,sizeof(struct strip_zone)*
+ conf->nr_strip_zones);
+ memset(conf->devlist, 0,
+ sizeof(mdk_rdev_t*) * conf->nr_strip_zones * mddev->raid_disks);
+
+ /* The first zone must contain all devices, so here we check that
+ * there is a proper alignment of slots to devices and find them all
+ */
+ zone = &conf->strip_zone[0];
+ cnt = 0;
+ smallest = NULL;
+ zone->dev = conf->devlist;
+ ITERATE_RDEV(mddev, rdev1, tmp1) {
+ int j = rdev1->raid_disk;
+
+ if (j < 0 || j >= mddev->raid_disks) {
+ printk("raid0: bad disk number %d - aborting!\n", j);
+ goto abort;
+ }
+ if (zone->dev[j]) {
+ printk("raid0: multiple devices for %d - aborting!\n",
+ j);
+ goto abort;
+ }
+ zone->dev[j] = rdev1;
+
+ blk_queue_stack_limits(mddev->queue,
+ rdev1->bdev->bd_disk->queue);
+ /* as we don't honour merge_bvec_fn, we must never risk
+ * violating it, so limit ->max_sector to one PAGE, as
+ * a one page request is never in violation.
+ */
+
+ if (rdev1->bdev->bd_disk->queue->merge_bvec_fn &&
+ mddev->queue->max_sectors > (PAGE_SIZE>>9))
+ blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
+
+ if (!smallest || (rdev1->size <smallest->size))
+ smallest = rdev1;
+ cnt++;
+ }
+ if (cnt != mddev->raid_disks) {
+ printk("raid0: too few disks (%d of %d) - aborting!\n",
+ cnt, mddev->raid_disks);
+ goto abort;
+ }
+ zone->nb_dev = cnt;
+ zone->size = smallest->size * cnt;
+ zone->zone_offset = 0;
+
+ current_offset = smallest->size;
+ curr_zone_offset = zone->size;
+
+ /* now do the other zones */
+ for (i = 1; i < conf->nr_strip_zones; i++)
+ {
+ zone = conf->strip_zone + i;
+ zone->dev = conf->strip_zone[i-1].dev + mddev->raid_disks;
+
+ printk("raid0: zone %d\n", i);
+ zone->dev_offset = current_offset;
+ smallest = NULL;
+ c = 0;
+
+ for (j=0; j<cnt; j++) {
+ char b[BDEVNAME_SIZE];
+ rdev = conf->strip_zone[0].dev[j];
+ printk("raid0: checking %s ...", bdevname(rdev->bdev,b));
+ if (rdev->size > current_offset)
+ {
+ printk(" contained as device %d\n", c);
+ zone->dev[c] = rdev;
+ c++;
+ if (!smallest || (rdev->size <smallest->size)) {
+ smallest = rdev;
+ printk(" (%llu) is smallest!.\n",
+ (unsigned long long)rdev->size);
+ }
+ } else
+ printk(" nope.\n");
+ }
+
+ zone->nb_dev = c;
+ zone->size = (smallest->size - current_offset) * c;
+ printk("raid0: zone->nb_dev: %d, size: %llu\n",
+ zone->nb_dev, (unsigned long long)zone->size);
+
+ zone->zone_offset = curr_zone_offset;
+ curr_zone_offset += zone->size;
+
+ current_offset = smallest->size;
+ printk("raid0: current zone offset: %llu\n",
+ (unsigned long long)current_offset);
+ }
+
+ /* Now find appropriate hash spacing.
+ * We want a number which causes most hash entries to cover
+ * at most two strips, but the hash table must be at most
+ * 1 PAGE. We choose the smallest strip, or contiguous collection
+ * of strips, that has big enough size. We never consider the last
+ * strip though as it's size has no bearing on the efficacy of the hash
+ * table.
+ */
+ conf->hash_spacing = curr_zone_offset;
+ min_spacing = curr_zone_offset;
+ sector_div(min_spacing, PAGE_SIZE/sizeof(struct strip_zone*));
+ for (i=0; i < conf->nr_strip_zones-1; i++) {
+ sector_t sz = 0;
+ for (j=i; j<conf->nr_strip_zones-1 &&
+ sz < min_spacing ; j++)
+ sz += conf->strip_zone[j].size;
+ if (sz >= min_spacing && sz < conf->hash_spacing)
+ conf->hash_spacing = sz;
+ }
+
+ mddev->queue->unplug_fn = raid0_unplug;
+
+ mddev->queue->issue_flush_fn = raid0_issue_flush;
+
+ printk("raid0: done.\n");
+ return 0;
+ abort:
+ return 1;
+}
+
+/**
+ * raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
+ * @q: request queue
+ * @bio: the buffer head that's been built up so far
+ * @biovec: the request that could be merged to it.
+ *
+ * Return amount of bytes we can accept at this offset
+ */
+static int raid0_mergeable_bvec(request_queue_t *q, struct bio *bio, struct bio_vec *biovec)
+{
+ mddev_t *mddev = q->queuedata;
+ sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
+ int max;
+ unsigned int chunk_sectors = mddev->chunk_size >> 9;
+ unsigned int bio_sectors = bio->bi_size >> 9;
+
+ max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
+ if (max < 0) max = 0; /* bio_add cannot handle a negative return */
+ if (max <= biovec->bv_len && bio_sectors == 0)
+ return biovec->bv_len;
+ else
+ return max;
+}
+
+static int raid0_run (mddev_t *mddev)
+{
+ unsigned cur=0, i=0, nb_zone;
+ s64 size;
+ raid0_conf_t *conf;
+ mdk_rdev_t *rdev;
+ struct list_head *tmp;
+
+ printk("%s: setting max_sectors to %d, segment boundary to %d\n",
+ mdname(mddev),
+ mddev->chunk_size >> 9,
+ (mddev->chunk_size>>1)-1);
+ blk_queue_max_sectors(mddev->queue, mddev->chunk_size >> 9);
+ blk_queue_segment_boundary(mddev->queue, (mddev->chunk_size>>1) - 1);
+
+ conf = kmalloc(sizeof (raid0_conf_t), GFP_KERNEL);
+ if (!conf)
+ goto out;
+ mddev->private = (void *)conf;
+
+ conf->strip_zone = NULL;
+ conf->devlist = NULL;
+ if (create_strip_zones (mddev))
+ goto out_free_conf;
+
+ /* calculate array device size */
+ mddev->array_size = 0;
+ ITERATE_RDEV(mddev,rdev,tmp)
+ mddev->array_size += rdev->size;
+
+ printk("raid0 : md_size is %llu blocks.\n",
+ (unsigned long long)mddev->array_size);
+ printk("raid0 : conf->hash_spacing is %llu blocks.\n",
+ (unsigned long long)conf->hash_spacing);
+ {
+#if __GNUC__ < 3
+ volatile
+#endif
+ sector_t s = mddev->array_size;
+ sector_t space = conf->hash_spacing;
+ int round;
+ conf->preshift = 0;
+ if (sizeof(sector_t) > sizeof(unsigned long)) {
+ /*shift down space and s so that sector_div will work */
+ while (space > (sector_t) (~(unsigned long)0)) {
+ s >>= 1;
+ space >>= 1;
+ s += 1; /* force round-up */
+ conf->preshift++;
+ }
+ }
+ round = sector_div(s, (unsigned long)space) ? 1 : 0;
+ nb_zone = s + round;
+ }
+ printk("raid0 : nb_zone is %d.\n", nb_zone);
+
+ printk("raid0 : Allocating %Zd bytes for hash.\n",
+ nb_zone*sizeof(struct strip_zone*));
+ conf->hash_table = kmalloc (sizeof (struct strip_zone *)*nb_zone, GFP_KERNEL);
+ if (!conf->hash_table)
+ goto out_free_conf;
+ size = conf->strip_zone[cur].size;
+
+ for (i=0; i< nb_zone; i++) {
+ conf->hash_table[i] = conf->strip_zone + cur;
+ while (size <= conf->hash_spacing) {
+ cur++;
+ size += conf->strip_zone[cur].size;
+ }
+ size -= conf->hash_spacing;
+ }
+ if (conf->preshift) {
+ conf->hash_spacing >>= conf->preshift;
+ /* round hash_spacing up so when we divide by it, we
+ * err on the side of too-low, which is safest
+ */
+ conf->hash_spacing++;
+ }
+
+ /* calculate the max read-ahead size.
+ * For read-ahead of large files to be effective, we need to
+ * readahead at least twice a whole stripe. i.e. number of devices
+ * multiplied by chunk size times 2.
+ * If an individual device has an ra_pages greater than the
+ * chunk size, then we will not drive that device as hard as it
+ * wants. We consider this a configuration error: a larger
+ * chunksize should be used in that case.
+ */
+ {
+ int stripe = mddev->raid_disks * mddev->chunk_size / PAGE_CACHE_SIZE;
+ if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
+ mddev->queue->backing_dev_info.ra_pages = 2* stripe;
+ }
+
+
+ blk_queue_merge_bvec(mddev->queue, raid0_mergeable_bvec);
+ return 0;
+
+out_free_conf:
+ if (conf->strip_zone)
+ kfree(conf->strip_zone);
+ if (conf->devlist)
+ kfree (conf->devlist);
+ kfree(conf);
+ mddev->private = NULL;
+out:
+ return 1;
+}
+
+static int raid0_stop (mddev_t *mddev)
+{
+ raid0_conf_t *conf = mddev_to_conf(mddev);
+
+ blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
+ kfree (conf->hash_table);
+ conf->hash_table = NULL;
+ kfree (conf->strip_zone);
+ conf->strip_zone = NULL;
+ kfree (conf);
+ mddev->private = NULL;
+
+ return 0;
+}
+
+static int raid0_make_request (request_queue_t *q, struct bio *bio)
+{
+ mddev_t *mddev = q->queuedata;
+ unsigned int sect_in_chunk, chunksize_bits, chunk_size, chunk_sects;
+ raid0_conf_t *conf = mddev_to_conf(mddev);
+ struct strip_zone *zone;
+ mdk_rdev_t *tmp_dev;
+ unsigned long chunk;
+ sector_t block, rsect;
+
+ if (bio_data_dir(bio)==WRITE) {
+ disk_stat_inc(mddev->gendisk, writes);
+ disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
+ } else {
+ disk_stat_inc(mddev->gendisk, reads);
+ disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
+ }
+
+ chunk_size = mddev->chunk_size >> 10;
+ chunk_sects = mddev->chunk_size >> 9;
+ chunksize_bits = ffz(~chunk_size);
+ block = bio->bi_sector >> 1;
+
+
+ if (unlikely(chunk_sects < (bio->bi_sector & (chunk_sects - 1)) + (bio->bi_size >> 9))) {
+ 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.
+ */
+ bp = bio_split(bio, bio_split_pool, chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
+ if (raid0_make_request(q, &bp->bio1))
+ generic_make_request(&bp->bio1);
+ if (raid0_make_request(q, &bp->bio2))
+ generic_make_request(&bp->bio2);
+
+ bio_pair_release(bp);
+ return 0;
+ }
+
+
+ {
+#if __GNUC__ < 3
+ volatile
+#endif
+ sector_t x = block >> conf->preshift;
+ sector_div(x, (unsigned long)conf->hash_spacing);
+ zone = conf->hash_table[x];
+ }
+
+ while (block >= (zone->zone_offset + zone->size))
+ zone++;
+
+ sect_in_chunk = bio->bi_sector & ((chunk_size<<1) -1);
+
+
+ {
+ sector_t x = (block - zone->zone_offset) >> chunksize_bits;
+
+ sector_div(x, zone->nb_dev);
+ chunk = x;
+ BUG_ON(x != (sector_t)chunk);
+
+ x = block >> chunksize_bits;
+ tmp_dev = zone->dev[sector_div(x, zone->nb_dev)];
+ }
+ rsect = (((chunk << chunksize_bits) + zone->dev_offset)<<1)
+ + sect_in_chunk;
+
+ bio->bi_bdev = tmp_dev->bdev;
+ bio->bi_sector = rsect + tmp_dev->data_offset;
+
+ /*
+ * Let the main block layer submit the IO and resolve recursion:
+ */
+ 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 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 */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-19 14:32:28 +0000