md/raid5: allow layout/chunksize to be changed on an active 2-drive raid5.
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>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 05b613b..0689d89 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2771,12 +2771,18 @@
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 @@
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 =
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 611ea7b..8a5e14e 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4913,6 +4913,47 @@
}
+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 @@
#endif
.quiesce = raid5_quiesce,
.takeover = raid5_takeover,
+ .reconfig = raid5_reconfig,
};
static struct mdk_personality raid4_personality =