md: separate meta and data devs
Allow the metadata to be on a separate device from the
data.
This doesn't mean the data and metadata will by on separate
physical devices - it simply gives device-mapper and userspace
tools more flexibility.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 0bc10cc..b98a85f 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -765,7 +765,7 @@
*/
struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, mddev);
- bio->bi_bdev = rdev->bdev;
+ bio->bi_bdev = rdev->meta_bdev ? rdev->meta_bdev : rdev->bdev;
bio->bi_sector = sector;
bio_add_page(bio, page, size, 0);
bio->bi_private = rdev;
@@ -803,7 +803,8 @@
rw |= REQ_SYNC | REQ_UNPLUG;
- bio->bi_bdev = rdev->bdev;
+ bio->bi_bdev = (metadata_op && rdev->meta_bdev) ?
+ rdev->meta_bdev : rdev->bdev;
if (metadata_op)
bio->bi_sector = sector + rdev->sb_start;
else
@@ -4435,7 +4436,9 @@
* We don't want the data to overlap the metadata,
* Internal Bitmap issues have been handled elsewhere.
*/
- if (rdev->data_offset < rdev->sb_start) {
+ if (rdev->meta_bdev) {
+ /* Nothing to check */;
+ } else if (rdev->data_offset < rdev->sb_start) {
if (mddev->dev_sectors &&
rdev->data_offset + mddev->dev_sectors
> rdev->sb_start) {
@@ -5532,7 +5535,6 @@
* sb_start or, if that is <data_offset, it must fit before the size
* of each device. If num_sectors is zero, we find the largest size
* that fits.
-
*/
if (mddev->sync_thread)
return -EBUSY;