Hello Neil, I'm sending patches with new takeover transitions proposal:
0->5(4), 5(4)->0, 10->0, 0->10.
Regards,
Maciek
Signed-off-by: Maciej Trela <maciej.trela@xxxxxxxxx>
---
drivers/md/raid5.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 50 insertions(+), 0 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e84204e..0fe78ea 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5614,6 +5614,39 @@ static void raid5_quiesce(mddev_t *mddev, int state)
}
+static void *raid5_takeover_raid0(mddev_t *mddev)
+{
+ int chunksect;
+
+ if (mddev->degraded > 0) {
+ printk(KERN_ERR "ERROR: Raid0 with degraded disks!: %d\n", mddev->degraded);
+ return ERR_PTR(-EINVAL);
+ }
+
+ chunksect = 64*2; /* 64K by default */
+
+ /* The array must be an exact multiple of chunksize */
+ while (chunksect && (mddev->array_sectors & (chunksect-1)))
+ chunksect >>= 1;
+
+ if ((chunksect<<9) < STRIPE_SIZE) {
+ /* array size does not allow a suitable chunk size */
+ return ERR_PTR(-EINVAL);
+ }
+
+ mddev->new_level = 5;
+ mddev->new_layout = ALGORITHM_PARITY_N;
+ mddev->new_chunk_sectors = chunksect;
+ mddev->degraded++;
+ mddev->raid_disks++;
+ mddev->delta_disks++;
+ /* make sure it will be not marked as dirty */
+ mddev->recovery_cp = MaxSector;
+
+ return setup_conf(mddev);
+}
+
+
static void *raid5_takeover_raid1(mddev_t *mddev)
{
int chunksect;
@@ -5737,12 +5770,29 @@ static int raid6_check_reshape(mddev_t *mddev)
static void *raid5_takeover(mddev_t *mddev)
{
+ mdk_rdev_t *rdev;
+ sector_t sectors, dev_sectors;
+
/* raid5 can take over:
* raid0 - if all devices are the same - make it a raid4 layout
* raid1 - if there are two drives. We need to know the chunk size
* raid4 - trivial - just use a raid4 layout.
* raid6 - Providing it is a *_6 layout
*/
+ if (mddev->level == 0) {
+ /* make sure all devices are the same (only one zone is supported) */
+ sectors = mddev->dev_sectors;
+ sector_div(sectors, mddev->chunk_sectors);
+ list_for_each_entry(rdev, &mddev->disks, same_set) {
+ dev_sectors = rdev->sectors;
+ sector_div(dev_sectors, mddev->chunk_sectors);
+ if (dev_sectors != sectors) {
+ printk("error: cannot takeover raid 0 with different dev sizes.\n");
+ return ERR_PTR(-EINVAL);
+ }
+ }
+ return raid5_takeover_raid0(mddev);
+ }
if (mddev->level == 1)
return raid5_takeover_raid1(mddev);
--
1.6.3.3
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