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md/raid5: allow layout/chunksize to be changed on an active 2-drive raid5.

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2-drive raid5's aren't very interesting.  But if you are converting
a raid1 into a raid5, you will at least temporarily have one.  And
that it a good time to set the layout/chunksize for the new RAID5
if you aren't happy with the defaults.

layout and chunksize don't actually affect the placement of data
on a 2-drive raid5, so we just do some internal book-keeping.

Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2009-03-31 14:56:41 +11:00
parent d562b0c431
commit b354603527
2 changed files with 66 additions and 13 deletions
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37
drivers/md/md.c
View File

@ -2771,12 +2771,18 @@ layout_store(mddev_t *mddev, const char *buf, size_t len)
if (!*buf || (*e && *e != '\n'))
return -EINVAL;
if (mddev->pers)
return -EBUSY;
mddev->new_layout = n;
if (mddev->reshape_position == MaxSector)
mddev->layout = n;
if (mddev->pers) {
int err;
if (mddev->pers->reconfig == NULL)
return -EBUSY;
err = mddev->pers->reconfig(mddev, n, -1);
if (err)
return err;
} else {
mddev->new_layout = n;
if (mddev->reshape_position == MaxSector)
mddev->layout = n;
}
return len;
}
static struct md_sysfs_entry md_layout =
@ -2833,19 +2839,24 @@ chunk_size_show(mddev_t *mddev, char *page)
static ssize_t
chunk_size_store(mddev_t *mddev, const char *buf, size_t len)
{
/* can only set chunk_size if array is not yet active */
char *e;
unsigned long n = simple_strtoul(buf, &e, 10);
if (!*buf || (*e && *e != '\n'))
return -EINVAL;
if (mddev->pers)
return -EBUSY;
mddev->new_chunk = n;
if (mddev->reshape_position == MaxSector)
mddev->chunk_size = n;
if (mddev->pers) {
int err;
if (mddev->pers->reconfig == NULL)
return -EBUSY;
err = mddev->pers->reconfig(mddev, -1, n);
if (err)
return err;
} else {
mddev->new_chunk = n;
if (mddev->reshape_position == MaxSector)
mddev->chunk_size = n;
}
return len;
}
static struct md_sysfs_entry md_chunk_size =

42
drivers/md/raid5.c
View File

@ -4913,6 +4913,47 @@ static void *raid5_takeover_raid1(mddev_t *mddev)
}
static int raid5_reconfig(mddev_t *mddev, int new_layout, int new_chunk)
{
/* Currently the layout and chunk size can only be changed
* for a 2-drive raid array, as in that case no data shuffling
* is required.
* Later we might validate these and set new_* so a reshape
* can complete the change.
*/
raid5_conf_t *conf = mddev_to_conf(mddev);
if (new_layout >= 0 && !algorithm_valid_raid5(new_layout))
return -EINVAL;
if (new_chunk > 0) {
if (new_chunk & (new_chunk-1))
/* not a power of 2 */
return -EINVAL;
if (new_chunk < PAGE_SIZE)
return -EINVAL;
if (mddev->array_sectors & ((new_chunk>>9)-1))
/* not factor of array size */
return -EINVAL;
}
/* They look valid */
if (mddev->raid_disks != 2)
return -EINVAL;
if (new_layout >= 0) {
conf->algorithm = new_layout;
mddev->layout = mddev->new_layout = new_layout;
}
if (new_chunk > 0) {
conf->chunk_size = new_chunk;
mddev->chunk_size = mddev->new_chunk = new_chunk;
}
set_bit(MD_CHANGE_DEVS, &mddev->flags);
md_wakeup_thread(mddev->thread);
return 0;
}
static void *raid5_takeover(mddev_t *mddev)
{
/* raid5 can take over:
@ -5023,6 +5064,7 @@ static struct mdk_personality raid5_personality =
#endif
.quiesce = raid5_quiesce,
.takeover = raid5_takeover,
.reconfig = raid5_reconfig,
};
static struct mdk_personality raid4_personality =