md/raid10: If there is a spare and a want_replacement device, start replacement.

When attempting to add a spare to a RAID10 array, also consider
adding it as a replacement for a want_replacement device.

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

1 files changed, 36 insertions, 4 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 011827d0df25..6e8aa213f0d5 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -419,6 +419,9 @@ static void raid10_end_write_request(struct bio *bio, int error)
                         md_error(rdev->mddev, rdev);
                 else {
                         set_bit(WriteErrorSeen, &rdev->flags);
+                        if (!test_and_set_bit(WantReplacement, &rdev->flags))
+                                set_bit(MD_RECOVERY_NEEDED,
+                                        &rdev->mddev->recovery);
                         set_bit(R10BIO_WriteError, &r10_bio->state);
                         dec_rdev = 0;
                 }
@@ -1481,8 +1484,25 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
                 struct mirror_info *p = &conf->mirrors[mirror];
                 if (p->recovery_disabled == mddev->recovery_disabled)
                         continue;
-                if (p->rdev)
-                        continue;
+                if (p->rdev) {
+                        if (!test_bit(WantReplacement, &p->rdev->flags) ||
+                            p->replacement != NULL)
+                                continue;
+                        clear_bit(In_sync, &rdev->flags);
+                        set_bit(Replacement, &rdev->flags);
+                        rdev->raid_disk = mirror;
+                        err = 0;
+                        disk_stack_limits(mddev->gendisk, rdev->bdev,
+                                          rdev->data_offset << 9);
+                        if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
+                                blk_queue_max_segments(mddev->queue, 1);
+                                blk_queue_segment_boundary(mddev->queue,
+                                                           PAGE_CACHE_SIZE - 1);
+                        }
+                        conf->fullsync = 1;
+                        rcu_assign_pointer(p->replacement, rdev);
+                        break;
+                }
 
                 disk_stack_limits(mddev->gendisk, rdev->bdev,
                                   rdev->data_offset << 9);
@@ -1658,6 +1678,9 @@ static void end_sync_write(struct bio *bio, int error)
                         md_error(mddev, rdev);
                 else {
                         set_bit(WriteErrorSeen, &rdev->flags);
+                        if (!test_and_set_bit(WantReplacement, &rdev->flags))
+                                set_bit(MD_RECOVERY_NEEDED,
+                                        &rdev->mddev->recovery);
                         set_bit(R10BIO_WriteError, &r10_bio->state);
                 }
         } else if (is_badblock(rdev,
@@ -1852,8 +1875,13 @@ static void fix_recovery_read_error(struct r10bio *r10_bio)
                                           s << 9,
                                           bio->bi_io_vec[idx].bv_page,
                                           WRITE, false);
-                        if (!ok)
+                        if (!ok) {
                                 set_bit(WriteErrorSeen, &rdev->flags);
+                                if (!test_and_set_bit(WantReplacement,
+                                                      &rdev->flags))
+                                        set_bit(MD_RECOVERY_NEEDED,
+                                                &rdev->mddev->recovery);
+                        }
                 }
                 if (!ok) {
                         /* We don't worry if we cannot set a bad block -
@@ -1971,8 +1999,12 @@ static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
         if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
                 /* success */
                 return 1;
-        if (rw == WRITE)
+        if (rw == WRITE) {
                 set_bit(WriteErrorSeen, &rdev->flags);
+                if (!test_and_set_bit(WantReplacement, &rdev->flags))
+                        set_bit(MD_RECOVERY_NEEDED,
+                                &rdev->mddev->recovery);
+        }
         /* need to record an error - either for the block or the device */
         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
                 md_error(rdev->mddev, rdev);