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, 4 insertions, 4 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 3f91c2e1dfe7..832fb4d56657 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2480,7 +2480,7 @@ static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
                                 rdev_clear_badblocks(
                                         rdev,
                                         r10_bio->devs[m].addr,
-                                        r10_bio->sectors);
+                                        r10_bio->sectors, 0);
                         } else {
                                 if (!rdev_set_badblocks(
                                             rdev,
@@ -2496,7 +2496,7 @@ static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
                                 rdev_clear_badblocks(
                                         rdev,
                                         r10_bio->devs[m].addr,
-                                        r10_bio->sectors);
+                                        r10_bio->sectors, 0);
                         } else {
                                 if (!rdev_set_badblocks(
                                             rdev,
@@ -2515,7 +2515,7 @@ static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
                                 rdev_clear_badblocks(
                                         rdev,
                                         r10_bio->devs[m].addr,
-                                        r10_bio->sectors);
+                                        r10_bio->sectors, 0);
                                 rdev_dec_pending(rdev, conf->mddev);
                         } else if (bio != NULL &&
                                    !test_bit(BIO_UPTODATE, &bio->bi_flags)) {
@@ -2532,7 +2532,7 @@ static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
                                 rdev_clear_badblocks(
                                         rdev,
                                         r10_bio->devs[m].addr,
-                                        r10_bio->sectors);
+                                        r10_bio->sectors, 0);
                                 rdev_dec_pending(rdev, conf->mddev);
                         }
                 }