linux/drivers/md/raid0.c

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/*
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/blkdev.h>
#include <linux/seq_file.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include "md.h"
#include "raid0.h"
#include "raid5.h"
static void raid0_unplug(struct request_queue *q)
{
mddev_t *mddev = q->queuedata;
raid0_conf_t *conf = mddev->private;
mdk_rdev_t **devlist = conf->devlist;
int raid_disks = conf->strip_zone[0].nb_dev;
int i;
for (i=0; i < raid_disks; i++) {
struct request_queue *r_queue = bdev_get_queue(devlist[i]->bdev);
blk_unplug(r_queue);
}
}
static int raid0_congested(void *data, int bits)
{
mddev_t *mddev = data;
raid0_conf_t *conf = mddev->private;
mdk_rdev_t **devlist = conf->devlist;
int raid_disks = conf->strip_zone[0].nb_dev;
int i, ret = 0;
if (mddev_congested(mddev, bits))
return 1;
for (i = 0; i < raid_disks && !ret ; i++) {
struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
ret |= bdi_congested(&q->backing_dev_info, bits);
}
return ret;
}
/*
* inform the user of the raid configuration
*/
static void dump_zones(mddev_t *mddev)
{
int j, k, h;
sector_t zone_size = 0;
sector_t zone_start = 0;
char b[BDEVNAME_SIZE];
raid0_conf_t *conf = mddev->private;
int raid_disks = conf->strip_zone[0].nb_dev;
printk(KERN_INFO "******* %s configuration *********\n",
mdname(mddev));
h = 0;
for (j = 0; j < conf->nr_strip_zones; j++) {
printk(KERN_INFO "zone%d=[", j);
for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
printk(KERN_CONT "%s/",
bdevname(conf->devlist[j*raid_disks
+ k]->bdev, b));
printk(KERN_CONT "]\n");
zone_size = conf->strip_zone[j].zone_end - zone_start;
printk(KERN_INFO " zone offset=%llukb "
"device offset=%llukb size=%llukb\n",
(unsigned long long)zone_start>>1,
(unsigned long long)conf->strip_zone[j].dev_start>>1,
(unsigned long long)zone_size>>1);
zone_start = conf->strip_zone[j].zone_end;
}
printk(KERN_INFO "**********************************\n\n");
}
static int create_strip_zones(mddev_t *mddev, raid0_conf_t **private_conf)
{
int i, c, err;
sector_t curr_zone_end, sectors;
mdk_rdev_t *smallest, *rdev1, *rdev2, *rdev, **dev;
struct strip_zone *zone;
int cnt;
char b[BDEVNAME_SIZE];
raid0_conf_t *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
if (!conf)
return -ENOMEM;
list_for_each_entry(rdev1, &mddev->disks, same_set) {
printk(KERN_INFO "md/raid0:%s: looking at %s\n",
mdname(mddev),
bdevname(rdev1->bdev, b));
c = 0;
/* round size to chunk_size */
sectors = rdev1->sectors;
sector_div(sectors, mddev->chunk_sectors);
rdev1->sectors = sectors * mddev->chunk_sectors;
list_for_each_entry(rdev2, &mddev->disks, same_set) {
printk(KERN_INFO "md/raid0:%s: comparing %s(%llu)",
mdname(mddev),
bdevname(rdev1->bdev,b),
(unsigned long long)rdev1->sectors);
printk(KERN_CONT " with %s(%llu)\n",
bdevname(rdev2->bdev,b),
(unsigned long long)rdev2->sectors);
if (rdev2 == rdev1) {
printk(KERN_INFO "md/raid0:%s: END\n",
mdname(mddev));
break;
}
if (rdev2->sectors == rdev1->sectors) {
/*
* Not unique, don't count it as a new
* group
*/
printk(KERN_INFO "md/raid0:%s: EQUAL\n",
mdname(mddev));
c = 1;
break;
}
printk(KERN_INFO "md/raid0:%s: NOT EQUAL\n",
mdname(mddev));
}
if (!c) {
printk(KERN_INFO "md/raid0:%s: ==> UNIQUE\n",
mdname(mddev));
conf->nr_strip_zones++;
printk(KERN_INFO "md/raid0:%s: %d zones\n",
mdname(mddev), conf->nr_strip_zones);
}
}
printk(KERN_INFO "md/raid0:%s: FINAL %d zones\n",
mdname(mddev), conf->nr_strip_zones);
err = -ENOMEM;
conf->strip_zone = kzalloc(sizeof(struct strip_zone)*
conf->nr_strip_zones, GFP_KERNEL);
if (!conf->strip_zone)
goto abort;
conf->devlist = kzalloc(sizeof(mdk_rdev_t*)*
conf->nr_strip_zones*mddev->raid_disks,
GFP_KERNEL);
if (!conf->devlist)
goto abort;
/* 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;
dev = conf->devlist;
err = -EINVAL;
list_for_each_entry(rdev1, &mddev->disks, same_set) {
int j = rdev1->raid_disk;
if (mddev->level == 10)
/* taking over a raid10-n2 array */
j /= 2;
if (j < 0 || j >= mddev->raid_disks) {
printk(KERN_ERR "md/raid0:%s: bad disk number %d - "
"aborting!\n", mdname(mddev), j);
goto abort;
}
if (dev[j]) {
printk(KERN_ERR "md/raid0:%s: multiple devices for %d - "
"aborting!\n", mdname(mddev), j);
goto abort;
}
dev[j] = rdev1;
disk_stack_limits(mddev->gendisk, rdev1->bdev,
rdev1->data_offset << 9);
/* as we don't honour merge_bvec_fn, we must never risk
* violating it, so limit ->max_segments to 1, lying within
* a single page.
*/
if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) {
blk_queue_max_segments(mddev->queue, 1);
blk_queue_segment_boundary(mddev->queue,
PAGE_CACHE_SIZE - 1);
}
if (!smallest || (rdev1->sectors < smallest->sectors))
smallest = rdev1;
cnt++;
}
if (cnt != mddev->raid_disks) {
printk(KERN_ERR "md/raid0:%s: too few disks (%d of %d) - "
"aborting!\n", mdname(mddev), cnt, mddev->raid_disks);
goto abort;
}
zone->nb_dev = cnt;
zone->zone_end = smallest->sectors * cnt;
curr_zone_end = zone->zone_end;
/* now do the other zones */
for (i = 1; i < conf->nr_strip_zones; i++)
{
int j;
zone = conf->strip_zone + i;
dev = conf->devlist + i * mddev->raid_disks;
printk(KERN_INFO "md/raid0:%s: zone %d\n",
mdname(mddev), i);
zone->dev_start = smallest->sectors;
smallest = NULL;
c = 0;
for (j=0; j<cnt; j++) {
rdev = conf->devlist[j];
printk(KERN_INFO "md/raid0:%s: checking %s ...",
mdname(mddev),
bdevname(rdev->bdev, b));
if (rdev->sectors <= zone->dev_start) {
printk(KERN_CONT " nope.\n");
continue;
}
printk(KERN_CONT " contained as device %d\n", c);
dev[c] = rdev;
c++;
if (!smallest || rdev->sectors < smallest->sectors) {
smallest = rdev;
printk(KERN_INFO "md/raid0:%s: (%llu) is smallest!.\n",
mdname(mddev),
(unsigned long long)rdev->sectors);
}
}
zone->nb_dev = c;
sectors = (smallest->sectors - zone->dev_start) * c;
printk(KERN_INFO "md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
mdname(mddev),
zone->nb_dev, (unsigned long long)sectors);
curr_zone_end += sectors;
zone->zone_end = curr_zone_end;
printk(KERN_INFO "md/raid0:%s: current zone start: %llu\n",
mdname(mddev),
(unsigned long long)smallest->sectors);
}
mddev->queue->unplug_fn = raid0_unplug;
mddev->queue->backing_dev_info.congested_fn = raid0_congested;
mddev->queue->backing_dev_info.congested_data = mddev;
/*
* now since we have the hard sector sizes, we can make sure
* chunk size is a multiple of that sector size
*/
if ((mddev->chunk_sectors << 9) % queue_logical_block_size(mddev->queue)) {
printk(KERN_ERR "md/raid0:%s: chunk_size of %d not valid\n",
mdname(mddev),
mddev->chunk_sectors << 9);
goto abort;
}
blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
blk_queue_io_opt(mddev->queue,
(mddev->chunk_sectors << 9) * mddev->raid_disks);
printk(KERN_INFO "md/raid0:%s: done.\n", mdname(mddev));
*private_conf = conf;
return 0;
abort:
kfree(conf->strip_zone);
kfree(conf->devlist);
kfree(conf);
*private_conf = NULL;
return err;
}
/**
* raid0_mergeable_bvec -- tell bio layer if a two requests can be merged
* @q: request queue
* @bvm: properties of new bio
* @biovec: the request that could be merged to it.
*
* Return amount of bytes we can accept at this offset
*/
static int raid0_mergeable_bvec(struct request_queue *q,
struct bvec_merge_data *bvm,
struct bio_vec *biovec)
{
mddev_t *mddev = q->queuedata;
sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
int max;
unsigned int chunk_sectors = mddev->chunk_sectors;
unsigned int bio_sectors = bvm->bi_size >> 9;
if (is_power_of_2(chunk_sectors))
max = (chunk_sectors - ((sector & (chunk_sectors-1))
+ bio_sectors)) << 9;
else
max = (chunk_sectors - (sector_div(sector, chunk_sectors)
+ 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 sector_t raid0_size(mddev_t *mddev, sector_t sectors, int raid_disks)
{
sector_t array_sectors = 0;
mdk_rdev_t *rdev;
WARN_ONCE(sectors || raid_disks,
"%s does not support generic reshape\n", __func__);
list_for_each_entry(rdev, &mddev->disks, same_set)
array_sectors += rdev->sectors;
return array_sectors;
}
static int raid0_run(mddev_t *mddev)
{
raid0_conf_t *conf;
int ret;
if (mddev->chunk_sectors == 0) {
printk(KERN_ERR "md/raid0:%s: chunk size must be set.\n",
mdname(mddev));
return -EINVAL;
}
if (md_check_no_bitmap(mddev))
return -EINVAL;
blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
mddev->queue->queue_lock = &mddev->queue->__queue_lock;
/* if private is not null, we are here after takeover */
if (mddev->private == NULL) {
ret = create_strip_zones(mddev, &conf);
if (ret < 0)
return ret;
mddev->private = conf;
}
conf = mddev->private;
if (conf->scale_raid_disks) {
int i;
for (i=0; i < conf->strip_zone[0].nb_dev; i++)
conf->devlist[i]->raid_disk /= conf->scale_raid_disks;
/* FIXME update sysfs rd links */
}
/* calculate array device size */
md_set_array_sectors(mddev, raid0_size(mddev, 0, 0));
printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n",
mdname(mddev),
(unsigned long long)mddev->array_sectors);
/* 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_sectors << 9) / PAGE_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);
dump_zones(mddev);
md_integrity_register(mddev);
return 0;
}
static int raid0_stop(mddev_t *mddev)
{
raid0_conf_t *conf = mddev->private;
blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
kfree(conf->strip_zone);
kfree(conf->devlist);
kfree(conf);
mddev->private = NULL;
return 0;
}
/* Find the zone which holds a particular offset
* Update *sectorp to be an offset in that zone
*/
static struct strip_zone *find_zone(struct raid0_private_data *conf,
sector_t *sectorp)
{
int i;
struct strip_zone *z = conf->strip_zone;
sector_t sector = *sectorp;
for (i = 0; i < conf->nr_strip_zones; i++)
if (sector < z[i].zone_end) {
if (i)
*sectorp = sector - z[i-1].zone_end;
return z + i;
}
BUG();
}
/*
* remaps the bio to the target device. we separate two flows.
* power 2 flow and a general flow for the sake of perfromance
*/
static mdk_rdev_t *map_sector(mddev_t *mddev, struct strip_zone *zone,
sector_t sector, sector_t *sector_offset)
{
unsigned int sect_in_chunk;
sector_t chunk;
raid0_conf_t *conf = mddev->private;
int raid_disks = conf->strip_zone[0].nb_dev;
unsigned int chunk_sects = mddev->chunk_sectors;
if (is_power_of_2(chunk_sects)) {
int chunksect_bits = ffz(~chunk_sects);
/* find the sector offset inside the chunk */
sect_in_chunk = sector & (chunk_sects - 1);
sector >>= chunksect_bits;
/* chunk in zone */
chunk = *sector_offset;
/* quotient is the chunk in real device*/
sector_div(chunk, zone->nb_dev << chunksect_bits);
} else{
sect_in_chunk = sector_div(sector, chunk_sects);
chunk = *sector_offset;
sector_div(chunk, chunk_sects * zone->nb_dev);
}
/*
* position the bio over the real device
* real sector = chunk in device + starting of zone
* + the position in the chunk
*/
*sector_offset = (chunk * chunk_sects) + sect_in_chunk;
return conf->devlist[(zone - conf->strip_zone)*raid_disks
+ sector_div(sector, zone->nb_dev)];
}
/*
* Is io distribute over 1 or more chunks ?
*/
static inline int is_io_in_chunk_boundary(mddev_t *mddev,
unsigned int chunk_sects, struct bio *bio)
{
if (likely(is_power_of_2(chunk_sects))) {
return chunk_sects >= ((bio->bi_sector & (chunk_sects-1))
+ (bio->bi_size >> 9));
} else{
sector_t sector = bio->bi_sector;
return chunk_sects >= (sector_div(sector, chunk_sects)
+ (bio->bi_size >> 9));
}
}
static int raid0_make_request(mddev_t *mddev, struct bio *bio)
{
unsigned int chunk_sects;
sector_t sector_offset;
struct strip_zone *zone;
mdk_rdev_t *tmp_dev;
if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
md: support barrier requests on all personalities. Previously barriers were only supported on RAID1. This is because other levels requires synchronisation across all devices and so needed a different approach. Here is that approach. When a barrier arrives, we send a zero-length barrier to every active device. When that completes - and if the original request was not empty - we submit the barrier request itself (with the barrier flag cleared) and then submit a fresh load of zero length barriers. The barrier request itself is asynchronous, but any subsequent request will block until the barrier completes. The reason for clearing the barrier flag is that a barrier request is allowed to fail. If we pass a non-empty barrier through a striping raid level it is conceivable that part of it could succeed and part could fail. That would be way too hard to deal with. So if the first run of zero length barriers succeed, we assume all is sufficiently well that we send the request and ignore errors in the second run of barriers. RAID5 needs extra care as write requests may not have been submitted to the underlying devices yet. So we flush the stripe cache before proceeding with the barrier. Note that the second set of zero-length barriers are submitted immediately after the original request is submitted. Thus when a personality finds mddev->barrier to be set during make_request, it should not return from make_request until the corresponding per-device request(s) have been queued. That will be done in later patches. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Andre Noll <maan@systemlinux.org>
2009-12-14 01:49:49 +00:00
md_barrier_request(mddev, bio);
return 0;
}
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, &sector_offset);
tmp_dev = map_sector(mddev, zone, bio->bi_sector,
&sector_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, mddev_t *mddev)
{
#undef MD_DEBUG
#ifdef MD_DEBUG
int j, k, h;
char b[BDEVNAME_SIZE];
raid0_conf_t *conf = mddev->private;
int raid_disks = conf->strip_zone[0].nb_dev;
sector_t zone_size;
sector_t zone_start = 0;
h = 0;
for (j = 0; j < conf->nr_strip_zones; j++) {
seq_printf(seq, " z%d", j);
seq_printf(seq, "=[");
for (k = 0; k < conf->strip_zone[j].nb_dev; k++)
seq_printf(seq, "%s/", bdevname(
conf->devlist[j*raid_disks + k]
->bdev, b));
zone_size = conf->strip_zone[j].zone_end - zone_start;
seq_printf(seq, "] ze=%lld ds=%lld s=%lld\n",
(unsigned long long)zone_start>>1,
(unsigned long long)conf->strip_zone[j].dev_start>>1,
(unsigned long long)zone_size>>1);
zone_start = conf->strip_zone[j].zone_end;
}
#endif
seq_printf(seq, " %dk chunks", mddev->chunk_sectors / 2);
return;
}
static void *raid0_takeover_raid5(mddev_t *mddev)
{
mdk_rdev_t *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_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(mddev_t *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_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);
priv_conf->scale_raid_disks = 2;
return priv_conf;
}
static void *raid0_takeover(mddev_t *mddev)
{
/* raid0 can take over:
* raid5 - providing it is Raid4 layout and one disk is faulty
* raid10 - assuming we have all necessary active disks
*/
if (mddev->level == 5) {
if (mddev->layout == ALGORITHM_PARITY_N)
return raid0_takeover_raid5(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);
return ERR_PTR(-EINVAL);
}
static void raid0_quiesce(mddev_t *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");