md: add possibility to change data-offset for devices.

When reshaping we can avoid costly intermediate backup by
changing the 'start' address of the array on the device
(if there is enough room).

So as a first step, allow such a change to be requested
through sysfs, and recorded in v1.x metadata.

(As we didn't previous check that all 'pad' fields were zero,
 we need a new FEATURE flag for this.
 A (belatedly) check that all remaining 'pad' fields are
 zero to avoid a repeat of this)

The new data offset must be requested separately for each device.
This allows each to have a different change in the data offset.
This is not likely to be used often but as data_offset can be
set per-device, new_data_offset should be too.

This patch also removes the 'acknowledged' arg to rdev_set_badblocks as
it is never used and never will be.  At the same time we add a new
arg ('in_new') which is currently always zero but will be used more
soon.

When a reshape finishes we will need to update the data_offset
and rdev->sectors.  So provide an exported function to do that.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 15dd59b84e94..71a7dc038a82 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -2024,7 +2024,7 @@ static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio
                         continue;
                 if (test_bit(BIO_UPTODATE, &bio->bi_flags) &&
                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
-                        rdev_clear_badblocks(rdev, r1_bio->sector, s);
+                        rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
                 }
                 if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
@@ -2044,7 +2044,7 @@ static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
                         struct md_rdev *rdev = conf->mirrors[m].rdev;
                         rdev_clear_badblocks(rdev,
                                              r1_bio->sector,
-                                             r1_bio->sectors);
+                                             r1_bio->sectors, 0);
                         rdev_dec_pending(rdev, conf->mddev);
                 } else if (r1_bio->bios[m] != NULL) {
                         /* This drive got a write error.  We need to