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@xxxxxxx>
---
drivers/md/md.c | 31 +++++++++++++++++++++----------
drivers/md/raid5.c | 40 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 61 insertions(+), 10 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index bd003d7..6fc07fe 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2727,12 +2727,19 @@ layout_store(mddev_t *mddev, const char *buf, size_t len)
if (!*buf || (*e && *e != '\n'))
return -EINVAL;
- if (mddev->pers)
- return -EBUSY;
- if (mddev->reshape_position != MaxSector)
- mddev->new_layout = n;
- else
- 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 {
+ if (mddev->reshape_position != MaxSector)
+ mddev->new_layout = n;
+ else
+ mddev->layout = n;
+ }
return len;
}
static struct md_sysfs_entry md_layout =
@@ -2789,16 +2796,20 @@ 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;
- else if (mddev->reshape_position != MaxSector)
+ if (mddev->pers) {
+ int err;
+ if (mddev->pers->reconfig == NULL)
+ return -EBUSY;
+ err = mddev->pers->reconfig(mddev, -1, n);
+ if (err)
+ return err;
+ } else if (mddev->reshape_position != MaxSector)
mddev->new_chunk = n;
else
mddev->chunk_size = n;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 8847c14..1546e9b 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4912,6 +4912,45 @@ 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;
+ }
+ return 0;
+}
+
static void *raid5_takeover(mddev_t *mddev)
{
/* raid5 can take over:
@@ -5032,6 +5071,7 @@ static struct mdk_personality raid5_personality =
#endif
.quiesce = raid5_quiesce,
.takeover = raid5_takeover,
+ .reconfig = raid5_reconfig,
};
static struct mdk_personality raid4_personality =
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